// SPDX-License-Identifier: GPL-2.0-or-later
/* A network driver using virtio.
 *
 * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
 */
//#define DEBUG
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/module.h>
#include <linux/virtio.h>
#include <linux/virtio_net.h>
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/scatterlist.h>
#include <linux/if_vlan.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/average.h>
#include <linux/filter.h>
#include <linux/kernel.h>
#include <linux/dim.h>
#include <net/route.h>
#include <net/xdp.h>
#include <net/net_failover.h>
#include <net/netdev_rx_queue.h>
#include <net/netdev_queues.h>
#include <net/xdp_sock_drv.h>

static int napi_weight = NAPI_POLL_WEIGHT;
module_param(napi_weight, int, 0444);

static bool csum = true, gso = true, napi_tx = true;
module_param(csum, bool, 0444);
module_param(gso, bool, 0444);
module_param(napi_tx, bool, 0644);

#define VIRTIO_OFFLOAD_MAP_MIN  46
#define VIRTIO_OFFLOAD_MAP_MAX  47
#define VIRTIO_FEATURES_MAP_MIN 65
#define VIRTIO_O2F_DELTA        (VIRTIO_FEATURES_MAP_MIN - \
                                 VIRTIO_OFFLOAD_MAP_MIN)

static bool virtio_is_mapped_offload(unsigned int obit)
{
        return obit >= VIRTIO_OFFLOAD_MAP_MIN &&
               obit <= VIRTIO_OFFLOAD_MAP_MAX;
}

static unsigned int virtio_offload_to_feature(unsigned int obit)
{
        return virtio_is_mapped_offload(obit) ? obit + VIRTIO_O2F_DELTA : obit;
}

/* FIXME: MTU in config. */
#define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
#define GOOD_COPY_LEN   128

#define VIRTNET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)

/* Separating two types of XDP xmit */
#define VIRTIO_XDP_TX           BIT(0)
#define VIRTIO_XDP_REDIR        BIT(1)

/* RX packet size EWMA. The average packet size is used to determine the packet
 * buffer size when refilling RX rings. As the entire RX ring may be refilled
 * at once, the weight is chosen so that the EWMA will be insensitive to short-
 * term, transient changes in packet size.
 */
DECLARE_EWMA(pkt_len, 0, 64)

#define VIRTNET_DRIVER_VERSION "1.0.0"

static const unsigned long guest_offloads[] = {
        VIRTIO_NET_F_GUEST_TSO4,
        VIRTIO_NET_F_GUEST_TSO6,
        VIRTIO_NET_F_GUEST_ECN,
        VIRTIO_NET_F_GUEST_UFO,
        VIRTIO_NET_F_GUEST_CSUM,
        VIRTIO_NET_F_GUEST_USO4,
        VIRTIO_NET_F_GUEST_USO6,
        VIRTIO_NET_F_GUEST_HDRLEN,
        VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_MAPPED,
        VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM_MAPPED,
};

#define GUEST_OFFLOAD_GRO_HW_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
                        (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
                        (1ULL << VIRTIO_NET_F_GUEST_ECN)  | \
                        (1ULL << VIRTIO_NET_F_GUEST_UFO)  | \
                        (1ULL << VIRTIO_NET_F_GUEST_USO4) | \
                        (1ULL << VIRTIO_NET_F_GUEST_USO6) | \
                        (1ULL << VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_MAPPED) | \
                        (1ULL << VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM_MAPPED))

struct virtnet_stat_desc {
        char desc[ETH_GSTRING_LEN];
        size_t offset;
        size_t qstat_offset;
};

struct virtnet_sq_free_stats {
        u64 packets;
        u64 bytes;
        u64 napi_packets;
        u64 napi_bytes;
        u64 xsk;
};

struct virtnet_sq_stats {
        struct u64_stats_sync syncp;
        u64_stats_t packets;
        u64_stats_t bytes;
        u64_stats_t xdp_tx;
        u64_stats_t xdp_tx_drops;
        u64_stats_t kicks;
        u64_stats_t tx_timeouts;
        u64_stats_t stop;
        u64_stats_t wake;
};

struct virtnet_rq_stats {
        struct u64_stats_sync syncp;
        u64_stats_t packets;
        u64_stats_t bytes;
        u64_stats_t drops;
        u64_stats_t xdp_packets;
        u64_stats_t xdp_tx;
        u64_stats_t xdp_redirects;
        u64_stats_t xdp_drops;
        u64_stats_t kicks;
};

#define VIRTNET_SQ_STAT(name, m) {name, offsetof(struct virtnet_sq_stats, m), -1}
#define VIRTNET_RQ_STAT(name, m) {name, offsetof(struct virtnet_rq_stats, m), -1}

#define VIRTNET_SQ_STAT_QSTAT(name, m)                          \
        {                                                       \
                name,                                           \
                offsetof(struct virtnet_sq_stats, m),           \
                offsetof(struct netdev_queue_stats_tx, m),      \
        }

#define VIRTNET_RQ_STAT_QSTAT(name, m)                          \
        {                                                       \
                name,                                           \
                offsetof(struct virtnet_rq_stats, m),           \
                offsetof(struct netdev_queue_stats_rx, m),      \
        }

static const struct virtnet_stat_desc virtnet_sq_stats_desc[] = {
        VIRTNET_SQ_STAT("xdp_tx",       xdp_tx),
        VIRTNET_SQ_STAT("xdp_tx_drops", xdp_tx_drops),
        VIRTNET_SQ_STAT("kicks",        kicks),
        VIRTNET_SQ_STAT("tx_timeouts",  tx_timeouts),
};

static const struct virtnet_stat_desc virtnet_rq_stats_desc[] = {
        VIRTNET_RQ_STAT("drops",         drops),
        VIRTNET_RQ_STAT("xdp_packets",   xdp_packets),
        VIRTNET_RQ_STAT("xdp_tx",        xdp_tx),
        VIRTNET_RQ_STAT("xdp_redirects", xdp_redirects),
        VIRTNET_RQ_STAT("xdp_drops",     xdp_drops),
        VIRTNET_RQ_STAT("kicks",         kicks),
};

static const struct virtnet_stat_desc virtnet_sq_stats_desc_qstat[] = {
        VIRTNET_SQ_STAT_QSTAT("packets", packets),
        VIRTNET_SQ_STAT_QSTAT("bytes",   bytes),
        VIRTNET_SQ_STAT_QSTAT("stop",    stop),
        VIRTNET_SQ_STAT_QSTAT("wake",    wake),
};

static const struct virtnet_stat_desc virtnet_rq_stats_desc_qstat[] = {
        VIRTNET_RQ_STAT_QSTAT("packets", packets),
        VIRTNET_RQ_STAT_QSTAT("bytes",   bytes),
};

#define VIRTNET_STATS_DESC_CQ(name) \
        {#name, offsetof(struct virtio_net_stats_cvq, name), -1}

#define VIRTNET_STATS_DESC_RX(class, name) \
        {#name, offsetof(struct virtio_net_stats_rx_ ## class, rx_ ## name), -1}

#define VIRTNET_STATS_DESC_TX(class, name) \
        {#name, offsetof(struct virtio_net_stats_tx_ ## class, tx_ ## name), -1}


static const struct virtnet_stat_desc virtnet_stats_cvq_desc[] = {
        VIRTNET_STATS_DESC_CQ(command_num),
        VIRTNET_STATS_DESC_CQ(ok_num),
};

static const struct virtnet_stat_desc virtnet_stats_rx_basic_desc[] = {
        VIRTNET_STATS_DESC_RX(basic, packets),
        VIRTNET_STATS_DESC_RX(basic, bytes),

        VIRTNET_STATS_DESC_RX(basic, notifications),
        VIRTNET_STATS_DESC_RX(basic, interrupts),
};

static const struct virtnet_stat_desc virtnet_stats_tx_basic_desc[] = {
        VIRTNET_STATS_DESC_TX(basic, packets),
        VIRTNET_STATS_DESC_TX(basic, bytes),

        VIRTNET_STATS_DESC_TX(basic, notifications),
        VIRTNET_STATS_DESC_TX(basic, interrupts),
};

static const struct virtnet_stat_desc virtnet_stats_rx_csum_desc[] = {
        VIRTNET_STATS_DESC_RX(csum, needs_csum),
};

static const struct virtnet_stat_desc virtnet_stats_tx_gso_desc[] = {
        VIRTNET_STATS_DESC_TX(gso, gso_packets_noseg),
        VIRTNET_STATS_DESC_TX(gso, gso_bytes_noseg),
};

static const struct virtnet_stat_desc virtnet_stats_rx_speed_desc[] = {
        VIRTNET_STATS_DESC_RX(speed, ratelimit_bytes),
};

static const struct virtnet_stat_desc virtnet_stats_tx_speed_desc[] = {
        VIRTNET_STATS_DESC_TX(speed, ratelimit_bytes),
};

#define VIRTNET_STATS_DESC_RX_QSTAT(class, name, qstat_field)                   \
        {                                                                       \
                #name,                                                          \
                offsetof(struct virtio_net_stats_rx_ ## class, rx_ ## name),    \
                offsetof(struct netdev_queue_stats_rx, qstat_field),            \
        }

#define VIRTNET_STATS_DESC_TX_QSTAT(class, name, qstat_field)                   \
        {                                                                       \
                #name,                                                          \
                offsetof(struct virtio_net_stats_tx_ ## class, tx_ ## name),    \
                offsetof(struct netdev_queue_stats_tx, qstat_field),            \
        }

static const struct virtnet_stat_desc virtnet_stats_rx_basic_desc_qstat[] = {
        VIRTNET_STATS_DESC_RX_QSTAT(basic, drops,         hw_drops),
        VIRTNET_STATS_DESC_RX_QSTAT(basic, drop_overruns, hw_drop_overruns),
};

static const struct virtnet_stat_desc virtnet_stats_tx_basic_desc_qstat[] = {
        VIRTNET_STATS_DESC_TX_QSTAT(basic, drops,          hw_drops),
        VIRTNET_STATS_DESC_TX_QSTAT(basic, drop_malformed, hw_drop_errors),
};

static const struct virtnet_stat_desc virtnet_stats_rx_csum_desc_qstat[] = {
        VIRTNET_STATS_DESC_RX_QSTAT(csum, csum_valid, csum_unnecessary),
        VIRTNET_STATS_DESC_RX_QSTAT(csum, csum_none,  csum_none),
        VIRTNET_STATS_DESC_RX_QSTAT(csum, csum_bad,   csum_bad),
};

static const struct virtnet_stat_desc virtnet_stats_tx_csum_desc_qstat[] = {
        VIRTNET_STATS_DESC_TX_QSTAT(csum, csum_none,  csum_none),
        VIRTNET_STATS_DESC_TX_QSTAT(csum, needs_csum, needs_csum),
};

static const struct virtnet_stat_desc virtnet_stats_rx_gso_desc_qstat[] = {
        VIRTNET_STATS_DESC_RX_QSTAT(gso, gso_packets,           hw_gro_packets),
        VIRTNET_STATS_DESC_RX_QSTAT(gso, gso_bytes,             hw_gro_bytes),
        VIRTNET_STATS_DESC_RX_QSTAT(gso, gso_packets_coalesced, hw_gro_wire_packets),
        VIRTNET_STATS_DESC_RX_QSTAT(gso, gso_bytes_coalesced,   hw_gro_wire_bytes),
};

static const struct virtnet_stat_desc virtnet_stats_tx_gso_desc_qstat[] = {
        VIRTNET_STATS_DESC_TX_QSTAT(gso, gso_packets,        hw_gso_packets),
        VIRTNET_STATS_DESC_TX_QSTAT(gso, gso_bytes,          hw_gso_bytes),
        VIRTNET_STATS_DESC_TX_QSTAT(gso, gso_segments,       hw_gso_wire_packets),
        VIRTNET_STATS_DESC_TX_QSTAT(gso, gso_segments_bytes, hw_gso_wire_bytes),
};

static const struct virtnet_stat_desc virtnet_stats_rx_speed_desc_qstat[] = {
        VIRTNET_STATS_DESC_RX_QSTAT(speed, ratelimit_packets, hw_drop_ratelimits),
};

static const struct virtnet_stat_desc virtnet_stats_tx_speed_desc_qstat[] = {
        VIRTNET_STATS_DESC_TX_QSTAT(speed, ratelimit_packets, hw_drop_ratelimits),
};

#define VIRTNET_Q_TYPE_RX 0
#define VIRTNET_Q_TYPE_TX 1
#define VIRTNET_Q_TYPE_CQ 2

struct virtnet_interrupt_coalesce {
        u32 max_packets;
        u32 max_usecs;
};

/* The dma information of pages allocated at a time. */
struct virtnet_rq_dma {
        dma_addr_t addr;
        u32 ref;
        u16 len;
        u16 need_sync;
};

/* Internal representation of a send virtqueue */
struct send_queue {
        /* Virtqueue associated with this send _queue */
        struct virtqueue *vq;

        /* TX: fragments + linear part + virtio header */
        struct scatterlist sg[MAX_SKB_FRAGS + 2];

        /* Name of the send queue: output.$index */
        char name[16];

        struct virtnet_sq_stats stats;

        struct virtnet_interrupt_coalesce intr_coal;

        struct napi_struct napi;

        /* Record whether sq is in reset state. */
        bool reset;

        struct xsk_buff_pool *xsk_pool;

        dma_addr_t xsk_hdr_dma_addr;
};

/* Internal representation of a receive virtqueue */
struct receive_queue {
        /* Virtqueue associated with this receive_queue */
        struct virtqueue *vq;

        struct napi_struct napi;

        struct bpf_prog __rcu *xdp_prog;

        struct virtnet_rq_stats stats;

        /* The number of rx notifications */
        u16 calls;

        /* Is dynamic interrupt moderation enabled? */
        bool dim_enabled;

        /* Used to protect dim_enabled and inter_coal */
        struct mutex dim_lock;

        /* Dynamic Interrupt Moderation */
        struct dim dim;

        u32 packets_in_napi;

        struct virtnet_interrupt_coalesce intr_coal;

        /* Chain pages by the private ptr. */
        struct page *pages;

        /* Average packet length for mergeable receive buffers. */
        struct ewma_pkt_len mrg_avg_pkt_len;

        /* Page frag for packet buffer allocation. */
        struct page_frag alloc_frag;

        /* RX: fragments + linear part + virtio header */
        struct scatterlist sg[MAX_SKB_FRAGS + 2];

        /* Min single buffer size for mergeable buffers case. */
        unsigned int min_buf_len;

        /* Name of this receive queue: input.$index */
        char name[16];

        struct xdp_rxq_info xdp_rxq;

        /* Record the last dma info to free after new pages is allocated. */
        struct virtnet_rq_dma *last_dma;

        struct xsk_buff_pool *xsk_pool;

        /* xdp rxq used by xsk */
        struct xdp_rxq_info xsk_rxq_info;

        struct xdp_buff **xsk_buffs;
};

/* Control VQ buffers: protected by the rtnl lock */
struct control_buf {
        struct virtio_net_ctrl_hdr hdr;
        virtio_net_ctrl_ack status;
};

struct virtnet_info {
        struct virtio_device *vdev;
        struct virtqueue *cvq;
        struct net_device *dev;
        struct send_queue *sq;
        struct receive_queue *rq;
        unsigned int status;

        /* Max # of queue pairs supported by the device */
        u16 max_queue_pairs;

        /* # of queue pairs currently used by the driver */
        u16 curr_queue_pairs;

        /* # of XDP queue pairs currently used by the driver */
        u16 xdp_queue_pairs;

        /* xdp_queue_pairs may be 0, when xdp is already loaded. So add this. */
        bool xdp_enabled;

        /* I like... big packets and I cannot lie! */
        bool big_packets;

        /* number of sg entries allocated for big packets */
        unsigned int big_packets_num_skbfrags;

        /* Host will merge rx buffers for big packets (shake it! shake it!) */
        bool mergeable_rx_bufs;

        /* Host supports rss and/or hash report */
        bool has_rss;
        bool has_rss_hash_report;
        u8 rss_key_size;
        u16 rss_indir_table_size;
        u32 rss_hash_types_supported;
        u32 rss_hash_types_saved;

        /* Has control virtqueue */
        bool has_cvq;

        /* Lock to protect the control VQ */
        struct mutex cvq_lock;

        /* Host can handle any s/g split between our header and packet data */
        bool any_header_sg;

        /* Packet virtio header size */
        u8 hdr_len;

        /* UDP tunnel support */
        bool tx_tnl;

        bool rx_tnl;

        bool rx_tnl_csum;

        /* Work struct for config space updates */
        struct work_struct config_work;

        /* Work struct for setting rx mode */
        struct work_struct rx_mode_work;

        /* OK to queue work setting RX mode? */
        bool rx_mode_work_enabled;

        /* Does the affinity hint is set for virtqueues? */
        bool affinity_hint_set;

        /* CPU hotplug instances for online & dead */
        struct hlist_node node;
        struct hlist_node node_dead;

        struct control_buf *ctrl;

        /* Ethtool settings */
        u8 duplex;
        u32 speed;

        /* Is rx dynamic interrupt moderation enabled? */
        bool rx_dim_enabled;

        /* Interrupt coalescing settings */
        struct virtnet_interrupt_coalesce intr_coal_tx;
        struct virtnet_interrupt_coalesce intr_coal_rx;

        unsigned long guest_offloads;
        unsigned long guest_offloads_capable;

        /* failover when STANDBY feature enabled */
        struct failover *failover;

        u64 device_stats_cap;

        struct virtio_net_rss_config_hdr *rss_hdr;

        /* Must be last as it ends in a flexible-array member. */
        TRAILING_OVERLAP(struct virtio_net_rss_config_trailer, rss_trailer, hash_key_data,
                u8 rss_hash_key_data[NETDEV_RSS_KEY_LEN];
        );
};
static_assert(offsetof(struct virtnet_info, rss_trailer.hash_key_data) ==
              offsetof(struct virtnet_info, rss_hash_key_data));

struct padded_vnet_hdr {
        struct virtio_net_hdr_v1_hash hdr;
        /*
         * hdr is in a separate sg buffer, and data sg buffer shares same page
         * with this header sg. This padding makes next sg 16 byte aligned
         * after the header.
         */
        char padding[12];
};

struct virtio_net_common_hdr {
        union {
                struct virtio_net_hdr hdr;
                struct virtio_net_hdr_mrg_rxbuf mrg_hdr;
                struct virtio_net_hdr_v1_hash hash_v1_hdr;
                struct virtio_net_hdr_v1_hash_tunnel tnl_hdr;
        };
};

static struct virtio_net_common_hdr xsk_hdr;

static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
static void virtnet_sq_free_unused_buf_done(struct virtqueue *vq);
static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
                               struct net_device *dev,
                               unsigned int *xdp_xmit,
                               struct virtnet_rq_stats *stats);
static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,
                                 struct sk_buff *skb, u8 flags);
static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
                                               struct sk_buff *curr_skb,
                                               struct page *page, void *buf,
                                               int len, int truesize);
static void virtnet_xsk_completed(struct send_queue *sq, int num);

enum virtnet_xmit_type {
        VIRTNET_XMIT_TYPE_SKB,
        VIRTNET_XMIT_TYPE_SKB_ORPHAN,
        VIRTNET_XMIT_TYPE_XDP,
        VIRTNET_XMIT_TYPE_XSK,
};

static size_t virtnet_rss_hdr_size(const struct virtnet_info *vi)
{
        u16 indir_table_size = vi->has_rss ? vi->rss_indir_table_size : 1;

        return struct_size(vi->rss_hdr, indirection_table, indir_table_size);
}

static size_t virtnet_rss_trailer_size(const struct virtnet_info *vi)
{
        return struct_size(&vi->rss_trailer, hash_key_data, vi->rss_key_size);
}

/* We use the last two bits of the pointer to distinguish the xmit type. */
#define VIRTNET_XMIT_TYPE_MASK (BIT(0) | BIT(1))

#define VIRTIO_XSK_FLAG_OFFSET 2

static enum virtnet_xmit_type virtnet_xmit_ptr_unpack(void **ptr)
{
        unsigned long p = (unsigned long)*ptr;

        *ptr = (void *)(p & ~VIRTNET_XMIT_TYPE_MASK);

        return p & VIRTNET_XMIT_TYPE_MASK;
}

static void *virtnet_xmit_ptr_pack(void *ptr, enum virtnet_xmit_type type)
{
        return (void *)((unsigned long)ptr | type);
}

static int virtnet_add_outbuf(struct send_queue *sq, int num, void *data,
                              enum virtnet_xmit_type type)
{
        return virtqueue_add_outbuf(sq->vq, sq->sg, num,
                                    virtnet_xmit_ptr_pack(data, type),
                                    GFP_ATOMIC);
}

static u32 virtnet_ptr_to_xsk_buff_len(void *ptr)
{
        return ((unsigned long)ptr) >> VIRTIO_XSK_FLAG_OFFSET;
}

static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
{
        sg_dma_address(sg) = addr;
        sg_dma_len(sg) = len;
}

static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
                            bool in_napi, struct virtnet_sq_free_stats *stats)
{
        struct xdp_frame *frame;
        struct sk_buff *skb;
        unsigned int len;
        void *ptr;

        while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
                switch (virtnet_xmit_ptr_unpack(&ptr)) {
                case VIRTNET_XMIT_TYPE_SKB:
                        skb = ptr;

                        pr_debug("Sent skb %p\n", skb);
                        stats->napi_packets++;
                        stats->napi_bytes += skb->len;
                        napi_consume_skb(skb, in_napi);
                        break;

                case VIRTNET_XMIT_TYPE_SKB_ORPHAN:
                        skb = ptr;

                        stats->packets++;
                        stats->bytes += skb->len;
                        napi_consume_skb(skb, in_napi);
                        break;

                case VIRTNET_XMIT_TYPE_XDP:
                        frame = ptr;

                        stats->packets++;
                        stats->bytes += xdp_get_frame_len(frame);
                        xdp_return_frame(frame);
                        break;

                case VIRTNET_XMIT_TYPE_XSK:
                        stats->bytes += virtnet_ptr_to_xsk_buff_len(ptr);
                        stats->xsk++;
                        break;
                }
        }
        netdev_tx_completed_queue(txq, stats->napi_packets, stats->napi_bytes);
}

static void virtnet_free_old_xmit(struct send_queue *sq,
                                  struct netdev_queue *txq,
                                  bool in_napi,
                                  struct virtnet_sq_free_stats *stats)
{
        __free_old_xmit(sq, txq, in_napi, stats);

        if (stats->xsk)
                virtnet_xsk_completed(sq, stats->xsk);
}

/* Converting between virtqueue no. and kernel tx/rx queue no.
 * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
 */
static int vq2txq(struct virtqueue *vq)
{
        return (vq->index - 1) / 2;
}

static int txq2vq(int txq)
{
        return txq * 2 + 1;
}

static int vq2rxq(struct virtqueue *vq)
{
        return vq->index / 2;
}

static int rxq2vq(int rxq)
{
        return rxq * 2;
}

static int vq_type(struct virtnet_info *vi, int qid)
{
        if (qid == vi->max_queue_pairs * 2)
                return VIRTNET_Q_TYPE_CQ;

        if (qid % 2)
                return VIRTNET_Q_TYPE_TX;

        return VIRTNET_Q_TYPE_RX;
}

static inline struct virtio_net_common_hdr *
skb_vnet_common_hdr(struct sk_buff *skb)
{
        return (struct virtio_net_common_hdr *)skb->cb;
}

/*
 * private is used to chain pages for big packets, put the whole
 * most recent used list in the beginning for reuse
 */
static void give_pages(struct receive_queue *rq, struct page *page)
{
        struct page *end;

        /* Find end of list, sew whole thing into vi->rq.pages. */
        for (end = page; end->private; end = (struct page *)end->private);
        end->private = (unsigned long)rq->pages;
        rq->pages = page;
}

static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
{
        struct page *p = rq->pages;

        if (p) {
                rq->pages = (struct page *)p->private;
                /* clear private here, it is used to chain pages */
                p->private = 0;
        } else
                p = alloc_page(gfp_mask);
        return p;
}

static void virtnet_rq_free_buf(struct virtnet_info *vi,
                                struct receive_queue *rq, void *buf)
{
        if (vi->mergeable_rx_bufs)
                put_page(virt_to_head_page(buf));
        else if (vi->big_packets)
                give_pages(rq, buf);
        else
                put_page(virt_to_head_page(buf));
}

static void enable_rx_mode_work(struct virtnet_info *vi)
{
        rtnl_lock();
        vi->rx_mode_work_enabled = true;
        rtnl_unlock();
}

static void disable_rx_mode_work(struct virtnet_info *vi)
{
        rtnl_lock();
        vi->rx_mode_work_enabled = false;
        rtnl_unlock();
}

static void virtqueue_napi_schedule(struct napi_struct *napi,
                                    struct virtqueue *vq)
{
        if (napi_schedule_prep(napi)) {
                virtqueue_disable_cb(vq);
                __napi_schedule(napi);
        }
}

static bool virtqueue_napi_complete(struct napi_struct *napi,
                                    struct virtqueue *vq, int processed)
{
        int opaque;

        opaque = virtqueue_enable_cb_prepare(vq);
        if (napi_complete_done(napi, processed)) {
                if (unlikely(virtqueue_poll(vq, opaque)))
                        virtqueue_napi_schedule(napi, vq);
                else
                        return true;
        } else {
                virtqueue_disable_cb(vq);
        }

        return false;
}

static void virtnet_tx_wake_queue(struct virtnet_info *vi,
                                struct send_queue *sq)
{
        unsigned int index = vq2txq(sq->vq);
        struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index);

        if (netif_tx_queue_stopped(txq)) {
                u64_stats_update_begin(&sq->stats.syncp);
                u64_stats_inc(&sq->stats.wake);
                u64_stats_update_end(&sq->stats.syncp);
                netif_tx_wake_queue(txq);
        }
}

static void skb_xmit_done(struct virtqueue *vq)
{
        struct virtnet_info *vi = vq->vdev->priv;
        unsigned int index = vq2txq(vq);
        struct send_queue *sq = &vi->sq[index];
        struct napi_struct *napi = &sq->napi;

        /* Suppress further interrupts. */
        virtqueue_disable_cb(vq);

        if (napi->weight)
                virtqueue_napi_schedule(napi, vq);
        else
                virtnet_tx_wake_queue(vi, sq);
}

#define MRG_CTX_HEADER_SHIFT 22
static void *mergeable_len_to_ctx(unsigned int truesize,
                                  unsigned int headroom)
{
        return (void *)(unsigned long)((headroom << MRG_CTX_HEADER_SHIFT) | truesize);
}

static unsigned int mergeable_ctx_to_headroom(void *mrg_ctx)
{
        return (unsigned long)mrg_ctx >> MRG_CTX_HEADER_SHIFT;
}

static unsigned int mergeable_ctx_to_truesize(void *mrg_ctx)
{
        return (unsigned long)mrg_ctx & ((1 << MRG_CTX_HEADER_SHIFT) - 1);
}

static int check_mergeable_len(struct net_device *dev, void *mrg_ctx,
                               unsigned int len)
{
        unsigned int headroom, tailroom, room, truesize;

        truesize = mergeable_ctx_to_truesize(mrg_ctx);
        headroom = mergeable_ctx_to_headroom(mrg_ctx);
        tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
        room = SKB_DATA_ALIGN(headroom + tailroom);

        if (len > truesize - room) {
                pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
                         dev->name, len, (unsigned long)(truesize - room));
                DEV_STATS_INC(dev, rx_length_errors);
                return -1;
        }

        return 0;
}

static struct sk_buff *virtnet_build_skb(void *buf, unsigned int buflen,
                                         unsigned int headroom,
                                         unsigned int len)
{
        struct sk_buff *skb;

        skb = build_skb(buf, buflen);
        if (unlikely(!skb))
                return NULL;

        skb_reserve(skb, headroom);
        skb_put(skb, len);

        return skb;
}

/* Called from bottom half context */
static struct sk_buff *page_to_skb(struct virtnet_info *vi,
                                   struct receive_queue *rq,
                                   struct page *page, unsigned int offset,
                                   unsigned int len, unsigned int truesize,
                                   unsigned int headroom)
{
        struct sk_buff *skb;
        struct virtio_net_common_hdr *hdr;
        unsigned int copy, hdr_len, hdr_padded_len;
        struct page *page_to_free = NULL;
        int tailroom, shinfo_size;
        char *p, *hdr_p, *buf;

        p = page_address(page) + offset;
        hdr_p = p;

        hdr_len = vi->hdr_len;
        if (vi->mergeable_rx_bufs)
                hdr_padded_len = hdr_len;
        else
                hdr_padded_len = sizeof(struct padded_vnet_hdr);

        buf = p - headroom;
        len -= hdr_len;
        offset += hdr_padded_len;
        p += hdr_padded_len;
        tailroom = truesize - headroom  - hdr_padded_len - len;

        shinfo_size = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

        if (!NET_IP_ALIGN && len > GOOD_COPY_LEN && tailroom >= shinfo_size) {
                skb = virtnet_build_skb(buf, truesize, p - buf, len);
                if (unlikely(!skb))
                        return NULL;

                page = (struct page *)page->private;
                if (page)
                        give_pages(rq, page);
                goto ok;
        }

        /* copy small packet so we can reuse these pages for small data */
        skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN);
        if (unlikely(!skb))
                return NULL;

        /* Copy all frame if it fits skb->head, otherwise
         * we let virtio_net_hdr_to_skb() and GRO pull headers as needed.
         */
        if (len <= skb_tailroom(skb))
                copy = len;
        else
                copy = ETH_HLEN;
        skb_put_data(skb, p, copy);

        len -= copy;
        offset += copy;

        if (vi->mergeable_rx_bufs) {
                if (len)
                        skb_add_rx_frag(skb, 0, page, offset, len, truesize);
                else
                        page_to_free = page;
                goto ok;
        }

        BUG_ON(offset >= PAGE_SIZE);
        while (len) {
                unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
                skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
                                frag_size, truesize);
                len -= frag_size;
                page = (struct page *)page->private;
                offset = 0;
        }

        if (page)
                give_pages(rq, page);

ok:
        hdr = skb_vnet_common_hdr(skb);
        memcpy(hdr, hdr_p, hdr_len);
        if (page_to_free)
                put_page(page_to_free);

        return skb;
}

static void virtnet_rq_unmap(struct receive_queue *rq, void *buf, u32 len)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct page *page = virt_to_head_page(buf);
        struct virtnet_rq_dma *dma;
        void *head;
        int offset;

        BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);

        head = page_address(page);

        dma = head;

        --dma->ref;

        if (dma->need_sync && len) {
                offset = buf - (head + sizeof(*dma));

                virtqueue_map_sync_single_range_for_cpu(rq->vq, dma->addr,
                                                        offset, len,
                                                        DMA_FROM_DEVICE);
        }

        if (dma->ref)
                return;

        virtqueue_unmap_single_attrs(rq->vq, dma->addr, dma->len,
                                     DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
        put_page(page);
}

static void *virtnet_rq_get_buf(struct receive_queue *rq, u32 *len, void **ctx)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        void *buf;

        BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);

        buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
        if (buf)
                virtnet_rq_unmap(rq, buf, *len);

        return buf;
}

static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct virtnet_rq_dma *dma;
        dma_addr_t addr;
        u32 offset;
        void *head;

        BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);

        head = page_address(rq->alloc_frag.page);

        offset = buf - head;

        dma = head;

        addr = dma->addr - sizeof(*dma) + offset;

        sg_init_table(rq->sg, 1);
        sg_fill_dma(rq->sg, addr, len);
}

static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
{
        struct page_frag *alloc_frag = &rq->alloc_frag;
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct virtnet_rq_dma *dma;
        void *buf, *head;
        dma_addr_t addr;

        BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);

        head = page_address(alloc_frag->page);

        dma = head;

        /* new pages */
        if (!alloc_frag->offset) {
                if (rq->last_dma) {
                        /* Now, the new page is allocated, the last dma
                         * will not be used. So the dma can be unmapped
                         * if the ref is 0.
                         */
                        virtnet_rq_unmap(rq, rq->last_dma, 0);
                        rq->last_dma = NULL;
                }

                dma->len = alloc_frag->size - sizeof(*dma);

                addr = virtqueue_map_single_attrs(rq->vq, dma + 1,
                                                  dma->len, DMA_FROM_DEVICE, 0);
                if (virtqueue_map_mapping_error(rq->vq, addr))
                        return NULL;

                dma->addr = addr;
                dma->need_sync = virtqueue_map_need_sync(rq->vq, addr);

                /* Add a reference to dma to prevent the entire dma from
                 * being released during error handling. This reference
                 * will be freed after the pages are no longer used.
                 */
                get_page(alloc_frag->page);
                dma->ref = 1;
                alloc_frag->offset = sizeof(*dma);

                rq->last_dma = dma;
        }

        ++dma->ref;

        buf = head + alloc_frag->offset;

        get_page(alloc_frag->page);
        alloc_frag->offset += size;

        return buf;
}

static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
{
        struct virtnet_info *vi = vq->vdev->priv;
        struct receive_queue *rq;
        int i = vq2rxq(vq);

        rq = &vi->rq[i];

        if (rq->xsk_pool) {
                xsk_buff_free((struct xdp_buff *)buf);
                return;
        }

        if (!vi->big_packets || vi->mergeable_rx_bufs)
                virtnet_rq_unmap(rq, buf, 0);

        virtnet_rq_free_buf(vi, rq, buf);
}

static void free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
                          bool in_napi)
{
        struct virtnet_sq_free_stats stats = {0};

        virtnet_free_old_xmit(sq, txq, in_napi, &stats);

        /* Avoid overhead when no packets have been processed
         * happens when called speculatively from start_xmit.
         */
        if (!stats.packets && !stats.napi_packets)
                return;

        u64_stats_update_begin(&sq->stats.syncp);
        u64_stats_add(&sq->stats.bytes, stats.bytes + stats.napi_bytes);
        u64_stats_add(&sq->stats.packets, stats.packets + stats.napi_packets);
        u64_stats_update_end(&sq->stats.syncp);
}

static bool is_xdp_raw_buffer_queue(struct virtnet_info *vi, int q)
{
        if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs))
                return false;
        else if (q < vi->curr_queue_pairs)
                return true;
        else
                return false;
}

static bool tx_may_stop(struct virtnet_info *vi,
                        struct net_device *dev,
                        struct send_queue *sq)
{
        int qnum;

        qnum = sq - vi->sq;

        /* If running out of space, stop queue to avoid getting packets that we
         * are then unable to transmit.
         * An alternative would be to force queuing layer to requeue the skb by
         * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
         * returned in a normal path of operation: it means that driver is not
         * maintaining the TX queue stop/start state properly, and causes
         * the stack to do a non-trivial amount of useless work.
         * Since most packets only take 1 or 2 ring slots, stopping the queue
         * early means 16 slots are typically wasted.
         */
        if (sq->vq->num_free < MAX_SKB_FRAGS + 2) {
                struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);

                netif_tx_stop_queue(txq);
                u64_stats_update_begin(&sq->stats.syncp);
                u64_stats_inc(&sq->stats.stop);
                u64_stats_update_end(&sq->stats.syncp);

                return true;
        }

        return false;
}

static void check_sq_full_and_disable(struct virtnet_info *vi,
                                      struct net_device *dev,
                                      struct send_queue *sq)
{
        bool use_napi = sq->napi.weight;
        int qnum;

        qnum = sq - vi->sq;

        if (tx_may_stop(vi, dev, sq)) {
                struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);

                if (use_napi) {
                        if (unlikely(!virtqueue_enable_cb_delayed(sq->vq)))
                                virtqueue_napi_schedule(&sq->napi, sq->vq);
                } else if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
                        /* More just got used, free them then recheck. */
                        free_old_xmit(sq, txq, false);
                        if (sq->vq->num_free >= MAX_SKB_FRAGS + 2) {
                                netif_start_subqueue(dev, qnum);
                                u64_stats_update_begin(&sq->stats.syncp);
                                u64_stats_inc(&sq->stats.wake);
                                u64_stats_update_end(&sq->stats.syncp);
                                virtqueue_disable_cb(sq->vq);
                        }
                }
        }
}

/* Note that @len is the length of received data without virtio header */
static struct xdp_buff *buf_to_xdp(struct virtnet_info *vi,
                                   struct receive_queue *rq, void *buf,
                                   u32 len, bool first_buf)
{
        struct xdp_buff *xdp;
        u32 bufsize;

        xdp = (struct xdp_buff *)buf;

        /* In virtnet_add_recvbuf_xsk, we use part of XDP_PACKET_HEADROOM for
         * virtio header and ask the vhost to fill data from
         *         hard_start + XDP_PACKET_HEADROOM - vi->hdr_len
         * The first buffer has virtio header so the remaining region for frame
         * data is
         *         xsk_pool_get_rx_frame_size()
         * While other buffers than the first one do not have virtio header, so
         * the maximum frame data's length can be
         *         xsk_pool_get_rx_frame_size() + vi->hdr_len
         */
        bufsize = xsk_pool_get_rx_frame_size(rq->xsk_pool);
        if (!first_buf)
                bufsize += vi->hdr_len;

        if (unlikely(len > bufsize)) {
                pr_debug("%s: rx error: len %u exceeds truesize %u\n",
                         vi->dev->name, len, bufsize);
                DEV_STATS_INC(vi->dev, rx_length_errors);
                xsk_buff_free(xdp);
                return NULL;
        }

        if (first_buf) {
                xsk_buff_set_size(xdp, len);
        } else {
                xdp_prepare_buff(xdp, xdp->data_hard_start,
                                 XDP_PACKET_HEADROOM - vi->hdr_len, len, 1);
                xdp->flags = 0;
        }

        xsk_buff_dma_sync_for_cpu(xdp);

        return xdp;
}

static struct sk_buff *xsk_construct_skb(struct receive_queue *rq,
                                         struct xdp_buff *xdp)
{
        unsigned int metasize = xdp->data - xdp->data_meta;
        struct sk_buff *skb;
        unsigned int size;

        size = xdp->data_end - xdp->data_hard_start;
        skb = napi_alloc_skb(&rq->napi, size);
        if (unlikely(!skb)) {
                xsk_buff_free(xdp);
                return NULL;
        }

        skb_reserve(skb, xdp->data_meta - xdp->data_hard_start);

        size = xdp->data_end - xdp->data_meta;
        memcpy(__skb_put(skb, size), xdp->data_meta, size);

        if (metasize) {
                __skb_pull(skb, metasize);
                skb_metadata_set(skb, metasize);
        }

        xsk_buff_free(xdp);

        return skb;
}

static struct sk_buff *virtnet_receive_xsk_small(struct net_device *dev, struct virtnet_info *vi,
                                                 struct receive_queue *rq, struct xdp_buff *xdp,
                                                 unsigned int *xdp_xmit,
                                                 struct virtnet_rq_stats *stats)
{
        struct bpf_prog *prog;
        u32 ret;

        ret = XDP_PASS;
        rcu_read_lock();
        prog = rcu_dereference(rq->xdp_prog);
        if (prog)
                ret = virtnet_xdp_handler(prog, xdp, dev, xdp_xmit, stats);
        rcu_read_unlock();

        switch (ret) {
        case XDP_PASS:
                return xsk_construct_skb(rq, xdp);

        case XDP_TX:
        case XDP_REDIRECT:
                return NULL;

        default:
                /* drop packet */
                xsk_buff_free(xdp);
                u64_stats_inc(&stats->drops);
                return NULL;
        }
}

static void xsk_drop_follow_bufs(struct net_device *dev,
                                 struct receive_queue *rq,
                                 u32 num_buf,
                                 struct virtnet_rq_stats *stats)
{
        struct xdp_buff *xdp;
        u32 len;

        while (num_buf-- > 1) {
                xdp = virtqueue_get_buf(rq->vq, &len);
                if (unlikely(!xdp)) {
                        pr_debug("%s: rx error: %d buffers missing\n",
                                 dev->name, num_buf);
                        DEV_STATS_INC(dev, rx_length_errors);
                        break;
                }
                u64_stats_add(&stats->bytes, len);
                xsk_buff_free(xdp);
        }
}

static int xsk_append_merge_buffer(struct virtnet_info *vi,
                                   struct receive_queue *rq,
                                   struct sk_buff *head_skb,
                                   u32 num_buf,
                                   struct virtio_net_hdr_mrg_rxbuf *hdr,
                                   struct virtnet_rq_stats *stats)
{
        struct sk_buff *curr_skb;
        struct xdp_buff *xdp;
        u32 len, truesize;
        struct page *page;
        void *buf;

        curr_skb = head_skb;

        while (--num_buf) {
                buf = virtqueue_get_buf(rq->vq, &len);
                if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers out of %d missing\n",
                                 vi->dev->name, num_buf,
                                 virtio16_to_cpu(vi->vdev,
                                                 hdr->num_buffers));
                        DEV_STATS_INC(vi->dev, rx_length_errors);
                        return -EINVAL;
                }

                u64_stats_add(&stats->bytes, len);

                xdp = buf_to_xdp(vi, rq, buf, len, false);
                if (!xdp)
                        goto err;

                buf = napi_alloc_frag(len);
                if (!buf) {
                        xsk_buff_free(xdp);
                        goto err;
                }

                memcpy(buf, xdp->data, len);

                xsk_buff_free(xdp);

                page = virt_to_page(buf);

                truesize = len;

                curr_skb  = virtnet_skb_append_frag(head_skb, curr_skb, page,
                                                    buf, len, truesize);
                if (!curr_skb) {
                        put_page(page);
                        goto err;
                }
        }

        return 0;

err:
        xsk_drop_follow_bufs(vi->dev, rq, num_buf, stats);
        return -EINVAL;
}

static struct sk_buff *virtnet_receive_xsk_merge(struct net_device *dev, struct virtnet_info *vi,
                                                 struct receive_queue *rq, struct xdp_buff *xdp,
                                                 unsigned int *xdp_xmit,
                                                 struct virtnet_rq_stats *stats)
{
        struct virtio_net_hdr_mrg_rxbuf *hdr;
        struct bpf_prog *prog;
        struct sk_buff *skb;
        u32 ret, num_buf;

        hdr = xdp->data - vi->hdr_len;
        num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);

        ret = XDP_PASS;
        rcu_read_lock();
        prog = rcu_dereference(rq->xdp_prog);
        if (prog) {
                /* TODO: support multi buffer. */
                if (num_buf == 1)
                        ret = virtnet_xdp_handler(prog, xdp, dev, xdp_xmit,
                                                  stats);
                else
                        ret = XDP_ABORTED;
        }
        rcu_read_unlock();

        switch (ret) {
        case XDP_PASS:
                skb = xsk_construct_skb(rq, xdp);
                if (!skb)
                        goto drop_bufs;

                if (xsk_append_merge_buffer(vi, rq, skb, num_buf, hdr, stats)) {
                        dev_kfree_skb(skb);
                        goto drop;
                }

                return skb;

        case XDP_TX:
        case XDP_REDIRECT:
                return NULL;

        default:
                /* drop packet */
                xsk_buff_free(xdp);
        }

drop_bufs:
        xsk_drop_follow_bufs(dev, rq, num_buf, stats);

drop:
        u64_stats_inc(&stats->drops);
        return NULL;
}

static void virtnet_receive_xsk_buf(struct virtnet_info *vi, struct receive_queue *rq,
                                    void *buf, u32 len,
                                    unsigned int *xdp_xmit,
                                    struct virtnet_rq_stats *stats)
{
        struct net_device *dev = vi->dev;
        struct sk_buff *skb = NULL;
        struct xdp_buff *xdp;
        u8 flags;

        len -= vi->hdr_len;

        u64_stats_add(&stats->bytes, len);

        xdp = buf_to_xdp(vi, rq, buf, len, true);
        if (!xdp)
                return;

        if (unlikely(len < ETH_HLEN)) {
                pr_debug("%s: short packet %i\n", dev->name, len);
                DEV_STATS_INC(dev, rx_length_errors);
                xsk_buff_free(xdp);
                return;
        }

        flags = ((struct virtio_net_common_hdr *)(xdp->data - vi->hdr_len))->hdr.flags;

        if (!vi->mergeable_rx_bufs)
                skb = virtnet_receive_xsk_small(dev, vi, rq, xdp, xdp_xmit, stats);
        else
                skb = virtnet_receive_xsk_merge(dev, vi, rq, xdp, xdp_xmit, stats);

        if (skb)
                virtnet_receive_done(vi, rq, skb, flags);
}

static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue *rq,
                                   struct xsk_buff_pool *pool, gfp_t gfp)
{
        struct xdp_buff **xsk_buffs;
        dma_addr_t addr;
        int err = 0;
        u32 len, i;
        int num;

        xsk_buffs = rq->xsk_buffs;

        num = xsk_buff_alloc_batch(pool, xsk_buffs, rq->vq->num_free);
        if (!num)
                return -ENOMEM;

        len = xsk_pool_get_rx_frame_size(pool) + vi->hdr_len;

        for (i = 0; i < num; ++i) {
                /* Use the part of XDP_PACKET_HEADROOM as the virtnet hdr space.
                 * We assume XDP_PACKET_HEADROOM is larger than hdr->len.
                 * (see function virtnet_xsk_pool_enable)
                 */
                addr = xsk_buff_xdp_get_dma(xsk_buffs[i]) - vi->hdr_len;

                sg_init_table(rq->sg, 1);
                sg_fill_dma(rq->sg, addr, len);

                err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1,
                                                    xsk_buffs[i], NULL, gfp);
                if (err)
                        goto err;
        }

        return num;

err:
        for (; i < num; ++i)
                xsk_buff_free(xsk_buffs[i]);

        return err;
}

static void *virtnet_xsk_to_ptr(u32 len)
{
        unsigned long p;

        p = len << VIRTIO_XSK_FLAG_OFFSET;

        return virtnet_xmit_ptr_pack((void *)p, VIRTNET_XMIT_TYPE_XSK);
}

static int virtnet_xsk_xmit_one(struct send_queue *sq,
                                struct xsk_buff_pool *pool,
                                struct xdp_desc *desc)
{
        struct virtnet_info *vi;
        dma_addr_t addr;

        vi = sq->vq->vdev->priv;

        addr = xsk_buff_raw_get_dma(pool, desc->addr);
        xsk_buff_raw_dma_sync_for_device(pool, addr, desc->len);

        sg_init_table(sq->sg, 2);
        sg_fill_dma(sq->sg, sq->xsk_hdr_dma_addr, vi->hdr_len);
        sg_fill_dma(sq->sg + 1, addr, desc->len);

        return virtqueue_add_outbuf_premapped(sq->vq, sq->sg, 2,
                                              virtnet_xsk_to_ptr(desc->len),
                                              GFP_ATOMIC);
}

static int virtnet_xsk_xmit_batch(struct send_queue *sq,
                                  struct xsk_buff_pool *pool,
                                  unsigned int budget,
                                  u64 *kicks)
{
        struct xdp_desc *descs = pool->tx_descs;
        bool kick = false;
        u32 nb_pkts, i;
        int err;

        budget = min_t(u32, budget, sq->vq->num_free);

        nb_pkts = xsk_tx_peek_release_desc_batch(pool, budget);
        if (!nb_pkts)
                return 0;

        for (i = 0; i < nb_pkts; i++) {
                err = virtnet_xsk_xmit_one(sq, pool, &descs[i]);
                if (unlikely(err)) {
                        xsk_tx_completed(sq->xsk_pool, nb_pkts - i);
                        break;
                }

                kick = true;
        }

        if (kick && virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
                (*kicks)++;

        return i;
}

static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
                             int budget)
{
        struct virtnet_info *vi = sq->vq->vdev->priv;
        struct virtnet_sq_free_stats stats = {};
        struct net_device *dev = vi->dev;
        u64 kicks = 0;
        int sent;

        /* Avoid to wakeup napi meanless, so call __free_old_xmit instead of
         * free_old_xmit().
         */
        __free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq), true, &stats);

        if (stats.xsk)
                xsk_tx_completed(sq->xsk_pool, stats.xsk);

        sent = virtnet_xsk_xmit_batch(sq, pool, budget, &kicks);

        if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
                check_sq_full_and_disable(vi, vi->dev, sq);

        if (sent) {
                struct netdev_queue *txq;

                txq = netdev_get_tx_queue(vi->dev, sq - vi->sq);
                txq_trans_cond_update(txq);
        }

        u64_stats_update_begin(&sq->stats.syncp);
        u64_stats_add(&sq->stats.packets, stats.packets);
        u64_stats_add(&sq->stats.bytes,   stats.bytes);
        u64_stats_add(&sq->stats.kicks,   kicks);
        u64_stats_add(&sq->stats.xdp_tx,  sent);
        u64_stats_update_end(&sq->stats.syncp);

        if (xsk_uses_need_wakeup(pool))
                xsk_set_tx_need_wakeup(pool);

        return sent;
}

static void xsk_wakeup(struct send_queue *sq)
{
        if (napi_if_scheduled_mark_missed(&sq->napi))
                return;

        local_bh_disable();
        virtqueue_napi_schedule(&sq->napi, sq->vq);
        local_bh_enable();
}

static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct send_queue *sq;

        if (!netif_running(dev))
                return -ENETDOWN;

        if (qid >= vi->curr_queue_pairs)
                return -EINVAL;

        sq = &vi->sq[qid];

        xsk_wakeup(sq);
        return 0;
}

static void virtnet_xsk_completed(struct send_queue *sq, int num)
{
        xsk_tx_completed(sq->xsk_pool, num);

        /* If this is called by rx poll, start_xmit and xdp xmit we should
         * wakeup the tx napi to consume the xsk tx queue, because the tx
         * interrupt may not be triggered.
         */
        xsk_wakeup(sq);
}

static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
                                   struct send_queue *sq,
                                   struct xdp_frame *xdpf)
{
        struct virtio_net_hdr_mrg_rxbuf *hdr;
        struct skb_shared_info *shinfo;
        u8 nr_frags = 0;
        int err, i;

        if (unlikely(xdpf->headroom < vi->hdr_len))
                return -EOVERFLOW;

        if (unlikely(xdp_frame_has_frags(xdpf))) {
                shinfo = xdp_get_shared_info_from_frame(xdpf);
                nr_frags = shinfo->nr_frags;
        }

        /* In wrapping function virtnet_xdp_xmit(), we need to free
         * up the pending old buffers, where we need to calculate the
         * position of skb_shared_info in xdp_get_frame_len() and
         * xdp_return_frame(), which will involve to xdpf->data and
         * xdpf->headroom. Therefore, we need to update the value of
         * headroom synchronously here.
         */
        xdpf->headroom -= vi->hdr_len;
        xdpf->data -= vi->hdr_len;
        /* Zero header and leave csum up to XDP layers */
        hdr = xdpf->data;
        memset(hdr, 0, vi->hdr_len);
        xdpf->len   += vi->hdr_len;

        sg_init_table(sq->sg, nr_frags + 1);
        sg_set_buf(sq->sg, xdpf->data, xdpf->len);
        for (i = 0; i < nr_frags; i++) {
                skb_frag_t *frag = &shinfo->frags[i];

                sg_set_page(&sq->sg[i + 1], skb_frag_page(frag),
                            skb_frag_size(frag), skb_frag_off(frag));
        }

        err = virtnet_add_outbuf(sq, nr_frags + 1, xdpf, VIRTNET_XMIT_TYPE_XDP);
        if (unlikely(err))
                return -ENOSPC; /* Caller handle free/refcnt */

        return 0;
}

/* when vi->curr_queue_pairs > nr_cpu_ids, the txq/sq is only used for xdp tx on
 * the current cpu, so it does not need to be locked.
 *
 * Here we use marco instead of inline functions because we have to deal with
 * three issues at the same time: 1. the choice of sq. 2. judge and execute the
 * lock/unlock of txq 3. make sparse happy. It is difficult for two inline
 * functions to perfectly solve these three problems at the same time.
 */
#define virtnet_xdp_get_sq(vi) ({                                       \
        int cpu = smp_processor_id();                                   \
        struct netdev_queue *txq;                                       \
        typeof(vi) v = (vi);                                            \
        unsigned int qp;                                                \
                                                                        \
        if (v->curr_queue_pairs > nr_cpu_ids) {                         \
                qp = v->curr_queue_pairs - v->xdp_queue_pairs;          \
                qp += cpu;                                              \
                txq = netdev_get_tx_queue(v->dev, qp);                  \
                __netif_tx_acquire(txq);                                \
        } else {                                                        \
                qp = cpu % v->curr_queue_pairs;                         \
                txq = netdev_get_tx_queue(v->dev, qp);                  \
                __netif_tx_lock(txq, cpu);                              \
        }                                                               \
        v->sq + qp;                                                     \
})

#define virtnet_xdp_put_sq(vi, q) {                                     \
        struct netdev_queue *txq;                                       \
        typeof(vi) v = (vi);                                            \
                                                                        \
        txq = netdev_get_tx_queue(v->dev, (q) - v->sq);                 \
        if (v->curr_queue_pairs > nr_cpu_ids)                           \
                __netif_tx_release(txq);                                \
        else                                                            \
                __netif_tx_unlock(txq);                                 \
}

static int virtnet_xdp_xmit(struct net_device *dev,
                            int n, struct xdp_frame **frames, u32 flags)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct virtnet_sq_free_stats stats = {0};
        struct receive_queue *rq = vi->rq;
        struct bpf_prog *xdp_prog;
        struct send_queue *sq;
        int nxmit = 0;
        int kicks = 0;
        int ret;
        int i;

        /* Only allow ndo_xdp_xmit if XDP is loaded on dev, as this
         * indicate XDP resources have been successfully allocated.
         */
        xdp_prog = rcu_access_pointer(rq->xdp_prog);
        if (!xdp_prog)
                return -ENXIO;

        sq = virtnet_xdp_get_sq(vi);

        if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
                ret = -EINVAL;
                goto out;
        }

        /* Free up any pending old buffers before queueing new ones. */
        virtnet_free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq),
                              false, &stats);

        for (i = 0; i < n; i++) {
                struct xdp_frame *xdpf = frames[i];

                if (__virtnet_xdp_xmit_one(vi, sq, xdpf))
                        break;
                nxmit++;
        }
        ret = nxmit;

        if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
                check_sq_full_and_disable(vi, dev, sq);

        if (flags & XDP_XMIT_FLUSH) {
                if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
                        kicks = 1;
        }
out:
        u64_stats_update_begin(&sq->stats.syncp);
        u64_stats_add(&sq->stats.bytes, stats.bytes);
        u64_stats_add(&sq->stats.packets, stats.packets);
        u64_stats_add(&sq->stats.xdp_tx, n);
        u64_stats_add(&sq->stats.xdp_tx_drops, n - nxmit);
        u64_stats_add(&sq->stats.kicks, kicks);
        u64_stats_update_end(&sq->stats.syncp);

        virtnet_xdp_put_sq(vi, sq);
        return ret;
}

static void put_xdp_frags(struct xdp_buff *xdp)
{
        struct skb_shared_info *shinfo;
        struct page *xdp_page;
        int i;

        if (xdp_buff_has_frags(xdp)) {
                shinfo = xdp_get_shared_info_from_buff(xdp);
                for (i = 0; i < shinfo->nr_frags; i++) {
                        xdp_page = skb_frag_page(&shinfo->frags[i]);
                        put_page(xdp_page);
                }
        }
}

static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
                               struct net_device *dev,
                               unsigned int *xdp_xmit,
                               struct virtnet_rq_stats *stats)
{
        struct xdp_frame *xdpf;
        int err;
        u32 act;

        act = bpf_prog_run_xdp(xdp_prog, xdp);
        u64_stats_inc(&stats->xdp_packets);

        switch (act) {
        case XDP_PASS:
                return act;

        case XDP_TX:
                u64_stats_inc(&stats->xdp_tx);
                xdpf = xdp_convert_buff_to_frame(xdp);
                if (unlikely(!xdpf)) {
                        netdev_dbg(dev, "convert buff to frame failed for xdp\n");
                        return XDP_DROP;
                }

                err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
                if (unlikely(!err)) {
                        xdp_return_frame_rx_napi(xdpf);
                } else if (unlikely(err < 0)) {
                        trace_xdp_exception(dev, xdp_prog, act);
                        return XDP_DROP;
                }
                *xdp_xmit |= VIRTIO_XDP_TX;
                return act;

        case XDP_REDIRECT:
                u64_stats_inc(&stats->xdp_redirects);
                err = xdp_do_redirect(dev, xdp, xdp_prog);
                if (err)
                        return XDP_DROP;

                *xdp_xmit |= VIRTIO_XDP_REDIR;
                return act;

        default:
                bpf_warn_invalid_xdp_action(dev, xdp_prog, act);
                fallthrough;
        case XDP_ABORTED:
                trace_xdp_exception(dev, xdp_prog, act);
                fallthrough;
        case XDP_DROP:
                return XDP_DROP;
        }
}

static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
{
        return vi->xdp_enabled ? XDP_PACKET_HEADROOM : 0;
}

/* We copy the packet for XDP in the following cases:
 *
 * 1) Packet is scattered across multiple rx buffers.
 * 2) Headroom space is insufficient.
 *
 * This is inefficient but it's a temporary condition that
 * we hit right after XDP is enabled and until queue is refilled
 * with large buffers with sufficient headroom - so it should affect
 * at most queue size packets.
 * Afterwards, the conditions to enable
 * XDP should preclude the underlying device from sending packets
 * across multiple buffers (num_buf > 1), and we make sure buffers
 * have enough headroom.
 */
static struct page *xdp_linearize_page(struct net_device *dev,
                                       struct receive_queue *rq,
                                       int *num_buf,
                                       struct page *p,
                                       int offset,
                                       int page_off,
                                       unsigned int *len)
{
        int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
        struct page *page;

        if (page_off + *len + tailroom > PAGE_SIZE)
                return NULL;

        page = alloc_page(GFP_ATOMIC);
        if (!page)
                return NULL;

        memcpy(page_address(page) + page_off, page_address(p) + offset, *len);
        page_off += *len;

        /* Only mergeable mode can go inside this while loop. In small mode,
         * *num_buf == 1, so it cannot go inside.
         */
        while (--*num_buf) {
                unsigned int buflen;
                void *buf;
                void *ctx;
                int off;

                buf = virtnet_rq_get_buf(rq, &buflen, &ctx);
                if (unlikely(!buf))
                        goto err_buf;

                p = virt_to_head_page(buf);
                off = buf - page_address(p);

                if (check_mergeable_len(dev, ctx, buflen)) {
                        put_page(p);
                        goto err_buf;
                }

                /* guard against a misconfigured or uncooperative backend that
                 * is sending packet larger than the MTU.
                 */
                if ((page_off + buflen + tailroom) > PAGE_SIZE) {
                        put_page(p);
                        goto err_buf;
                }

                memcpy(page_address(page) + page_off,
                       page_address(p) + off, buflen);
                page_off += buflen;
                put_page(p);
        }

        /* Headroom does not contribute to packet length */
        *len = page_off - XDP_PACKET_HEADROOM;
        return page;
err_buf:
        __free_pages(page, 0);
        return NULL;
}

static struct sk_buff *receive_small_build_skb(struct virtnet_info *vi,
                                               unsigned int xdp_headroom,
                                               void *buf,
                                               unsigned int len)
{
        unsigned int header_offset;
        unsigned int headroom;
        unsigned int buflen;
        struct sk_buff *skb;

        header_offset = VIRTNET_RX_PAD + xdp_headroom;
        headroom = vi->hdr_len + header_offset;
        buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
                SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

        skb = virtnet_build_skb(buf, buflen, headroom, len);
        if (unlikely(!skb))
                return NULL;

        buf += header_offset;
        memcpy(skb_vnet_common_hdr(skb), buf, vi->hdr_len);

        return skb;
}

static struct sk_buff *receive_small_xdp(struct net_device *dev,
                                         struct virtnet_info *vi,
                                         struct receive_queue *rq,
                                         struct bpf_prog *xdp_prog,
                                         void *buf,
                                         unsigned int xdp_headroom,
                                         unsigned int len,
                                         unsigned int *xdp_xmit,
                                         struct virtnet_rq_stats *stats)
{
        unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom;
        unsigned int headroom = vi->hdr_len + header_offset;
        struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset;
        struct page *page = virt_to_head_page(buf);
        struct page *xdp_page;
        unsigned int buflen;
        struct xdp_buff xdp;
        struct sk_buff *skb;
        unsigned int metasize = 0;
        u32 act;

        if (unlikely(hdr->hdr.gso_type))
                goto err_xdp;

        /* Partially checksummed packets must be dropped. */
        if (unlikely(hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
                goto err_xdp;

        buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
                SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

        if (unlikely(xdp_headroom < virtnet_get_headroom(vi))) {
                int offset = buf - page_address(page) + header_offset;
                unsigned int tlen = len + vi->hdr_len;
                int num_buf = 1;

                xdp_headroom = virtnet_get_headroom(vi);
                header_offset = VIRTNET_RX_PAD + xdp_headroom;
                headroom = vi->hdr_len + header_offset;
                buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
                xdp_page = xdp_linearize_page(dev, rq, &num_buf, page,
                                              offset, header_offset,
                                              &tlen);
                if (!xdp_page)
                        goto err_xdp;

                buf = page_address(xdp_page);
                put_page(page);
                page = xdp_page;
        }

        xdp_init_buff(&xdp, buflen, &rq->xdp_rxq);
        xdp_prepare_buff(&xdp, buf + VIRTNET_RX_PAD + vi->hdr_len,
                         xdp_headroom, len, true);

        act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);

        switch (act) {
        case XDP_PASS:
                /* Recalculate length in case bpf program changed it */
                len = xdp.data_end - xdp.data;
                metasize = xdp.data - xdp.data_meta;
                break;

        case XDP_TX:
        case XDP_REDIRECT:
                goto xdp_xmit;

        default:
                goto err_xdp;
        }

        skb = virtnet_build_skb(buf, buflen, xdp.data - buf, len);
        if (unlikely(!skb))
                goto err;

        if (metasize)
                skb_metadata_set(skb, metasize);

        return skb;

err_xdp:
        u64_stats_inc(&stats->xdp_drops);
err:
        u64_stats_inc(&stats->drops);
        put_page(page);
xdp_xmit:
        return NULL;
}

static struct sk_buff *receive_small(struct net_device *dev,
                                     struct virtnet_info *vi,
                                     struct receive_queue *rq,
                                     void *buf, void *ctx,
                                     unsigned int len,
                                     unsigned int *xdp_xmit,
                                     struct virtnet_rq_stats *stats)
{
        unsigned int xdp_headroom = (unsigned long)ctx;
        struct page *page = virt_to_head_page(buf);
        struct sk_buff *skb;

        /* We passed the address of virtnet header to virtio-core,
         * so truncate the padding.
         */
        buf -= VIRTNET_RX_PAD + xdp_headroom;

        len -= vi->hdr_len;
        u64_stats_add(&stats->bytes, len);

        if (unlikely(len > GOOD_PACKET_LEN)) {
                pr_debug("%s: rx error: len %u exceeds max size %d\n",
                         dev->name, len, GOOD_PACKET_LEN);
                DEV_STATS_INC(dev, rx_length_errors);
                goto err;
        }

        if (unlikely(vi->xdp_enabled)) {
                struct bpf_prog *xdp_prog;

                rcu_read_lock();
                xdp_prog = rcu_dereference(rq->xdp_prog);
                if (xdp_prog) {
                        skb = receive_small_xdp(dev, vi, rq, xdp_prog, buf,
                                                xdp_headroom, len, xdp_xmit,
                                                stats);
                        rcu_read_unlock();
                        return skb;
                }
                rcu_read_unlock();
        }

        skb = receive_small_build_skb(vi, xdp_headroom, buf, len);
        if (likely(skb))
                return skb;

err:
        u64_stats_inc(&stats->drops);
        put_page(page);
        return NULL;
}

static struct sk_buff *receive_big(struct net_device *dev,
                                   struct virtnet_info *vi,
                                   struct receive_queue *rq,
                                   void *buf,
                                   unsigned int len,
                                   struct virtnet_rq_stats *stats)
{
        struct page *page = buf;
        struct sk_buff *skb;

        /* Make sure that len does not exceed the size allocated in
         * add_recvbuf_big.
         */
        if (unlikely(len > (vi->big_packets_num_skbfrags + 1) * PAGE_SIZE)) {
                pr_debug("%s: rx error: len %u exceeds allocated size %lu\n",
                         dev->name, len,
                         (vi->big_packets_num_skbfrags + 1) * PAGE_SIZE);
                goto err;
        }

        skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE, 0);
        u64_stats_add(&stats->bytes, len - vi->hdr_len);
        if (unlikely(!skb))
                goto err;

        return skb;

err:
        u64_stats_inc(&stats->drops);
        give_pages(rq, page);
        return NULL;
}

static void mergeable_buf_free(struct receive_queue *rq, int num_buf,
                               struct net_device *dev,
                               struct virtnet_rq_stats *stats)
{
        struct page *page;
        void *buf;
        int len;

        while (num_buf-- > 1) {
                buf = virtnet_rq_get_buf(rq, &len, NULL);
                if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers missing\n",
                                 dev->name, num_buf);
                        DEV_STATS_INC(dev, rx_length_errors);
                        break;
                }
                u64_stats_add(&stats->bytes, len);
                page = virt_to_head_page(buf);
                put_page(page);
        }
}

/* Why not use xdp_build_skb_from_frame() ?
 * XDP core assumes that xdp frags are PAGE_SIZE in length, while in
 * virtio-net there are 2 points that do not match its requirements:
 *  1. The size of the prefilled buffer is not fixed before xdp is set.
 *  2. xdp_build_skb_from_frame() does more checks that we don't need,
 *     like eth_type_trans() (which virtio-net does in receive_buf()).
 */
static struct sk_buff *build_skb_from_xdp_buff(struct net_device *dev,
                                               struct virtnet_info *vi,
                                               struct xdp_buff *xdp,
                                               unsigned int xdp_frags_truesz)
{
        struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
        unsigned int headroom, data_len;
        struct sk_buff *skb;
        int metasize;
        u8 nr_frags;

        if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
                pr_debug("Error building skb as missing reserved tailroom for xdp");
                return NULL;
        }

        if (unlikely(xdp_buff_has_frags(xdp)))
                nr_frags = sinfo->nr_frags;

        skb = build_skb(xdp->data_hard_start, xdp->frame_sz);
        if (unlikely(!skb))
                return NULL;

        headroom = xdp->data - xdp->data_hard_start;
        data_len = xdp->data_end - xdp->data;
        skb_reserve(skb, headroom);
        __skb_put(skb, data_len);

        metasize = xdp->data - xdp->data_meta;
        metasize = metasize > 0 ? metasize : 0;
        if (metasize)
                skb_metadata_set(skb, metasize);

        if (unlikely(xdp_buff_has_frags(xdp)))
                xdp_update_skb_frags_info(skb, nr_frags, sinfo->xdp_frags_size,
                                          xdp_frags_truesz,
                                          xdp_buff_get_skb_flags(xdp));

        return skb;
}

/* TODO: build xdp in big mode */
static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
                                      struct virtnet_info *vi,
                                      struct receive_queue *rq,
                                      struct xdp_buff *xdp,
                                      void *buf,
                                      unsigned int len,
                                      unsigned int frame_sz,
                                      int *num_buf,
                                      unsigned int *xdp_frags_truesize,
                                      struct virtnet_rq_stats *stats)
{
        struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
        struct skb_shared_info *shinfo;
        unsigned int xdp_frags_truesz = 0;
        unsigned int truesize;
        struct page *page;
        skb_frag_t *frag;
        int offset;
        void *ctx;

        xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
        xdp_prepare_buff(xdp, buf - XDP_PACKET_HEADROOM,
                         XDP_PACKET_HEADROOM + vi->hdr_len, len - vi->hdr_len, true);

        if (!*num_buf)
                return 0;

        if (*num_buf > 1) {
                /* If we want to build multi-buffer xdp, we need
                 * to specify that the flags of xdp_buff have the
                 * XDP_FLAGS_HAS_FRAG bit.
                 */
                if (!xdp_buff_has_frags(xdp))
                        xdp_buff_set_frags_flag(xdp);

                shinfo = xdp_get_shared_info_from_buff(xdp);
                shinfo->nr_frags = 0;
                shinfo->xdp_frags_size = 0;
        }

        if (*num_buf > MAX_SKB_FRAGS + 1)
                return -EINVAL;

        while (--*num_buf > 0) {
                buf = virtnet_rq_get_buf(rq, &len, &ctx);
                if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers out of %d missing\n",
                                 dev->name, *num_buf,
                                 virtio16_to_cpu(vi->vdev, hdr->num_buffers));
                        DEV_STATS_INC(dev, rx_length_errors);
                        goto err;
                }

                u64_stats_add(&stats->bytes, len);
                page = virt_to_head_page(buf);
                offset = buf - page_address(page);

                if (check_mergeable_len(dev, ctx, len)) {
                        put_page(page);
                        goto err;
                }

                truesize = mergeable_ctx_to_truesize(ctx);
                xdp_frags_truesz += truesize;

                frag = &shinfo->frags[shinfo->nr_frags++];
                skb_frag_fill_page_desc(frag, page, offset, len);
                if (page_is_pfmemalloc(page))
                        xdp_buff_set_frag_pfmemalloc(xdp);

                shinfo->xdp_frags_size += len;
        }

        *xdp_frags_truesize = xdp_frags_truesz;
        return 0;

err:
        put_xdp_frags(xdp);
        return -EINVAL;
}

static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
                                   struct receive_queue *rq,
                                   struct bpf_prog *xdp_prog,
                                   void *ctx,
                                   unsigned int *frame_sz,
                                   int *num_buf,
                                   struct page **page,
                                   int offset,
                                   unsigned int *len,
                                   struct virtio_net_hdr_mrg_rxbuf *hdr)
{
        unsigned int truesize = mergeable_ctx_to_truesize(ctx);
        unsigned int headroom = mergeable_ctx_to_headroom(ctx);
        struct page *xdp_page;
        unsigned int xdp_room;

        /* Transient failure which in theory could occur if
         * in-flight packets from before XDP was enabled reach
         * the receive path after XDP is loaded.
         */
        if (unlikely(hdr->hdr.gso_type))
                return NULL;

        /* Partially checksummed packets must be dropped. */
        if (unlikely(hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
                return NULL;

        /* Now XDP core assumes frag size is PAGE_SIZE, but buffers
         * with headroom may add hole in truesize, which
         * make their length exceed PAGE_SIZE. So we disabled the
         * hole mechanism for xdp. See add_recvbuf_mergeable().
         */
        *frame_sz = truesize;

        if (likely(headroom >= virtnet_get_headroom(vi) &&
                   (*num_buf == 1 || xdp_prog->aux->xdp_has_frags))) {
                return page_address(*page) + offset;
        }

        /* This happens when headroom is not enough because
         * of the buffer was prefilled before XDP is set.
         * This should only happen for the first several packets.
         * In fact, vq reset can be used here to help us clean up
         * the prefilled buffers, but many existing devices do not
         * support it, and we don't want to bother users who are
         * using xdp normally.
         */
        if (!xdp_prog->aux->xdp_has_frags) {
                /* linearize data for XDP */
                xdp_page = xdp_linearize_page(vi->dev, rq, num_buf,
                                              *page, offset,
                                              XDP_PACKET_HEADROOM,
                                              len);
                if (!xdp_page)
                        return NULL;
        } else {
                xdp_room = SKB_DATA_ALIGN(XDP_PACKET_HEADROOM +
                                          sizeof(struct skb_shared_info));
                if (*len + xdp_room > PAGE_SIZE)
                        return NULL;

                xdp_page = alloc_page(GFP_ATOMIC);
                if (!xdp_page)
                        return NULL;

                memcpy(page_address(xdp_page) + XDP_PACKET_HEADROOM,
                       page_address(*page) + offset, *len);
        }

        *frame_sz = PAGE_SIZE;

        put_page(*page);

        *page = xdp_page;

        return page_address(*page) + XDP_PACKET_HEADROOM;
}

static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
                                             struct virtnet_info *vi,
                                             struct receive_queue *rq,
                                             struct bpf_prog *xdp_prog,
                                             void *buf,
                                             void *ctx,
                                             unsigned int len,
                                             unsigned int *xdp_xmit,
                                             struct virtnet_rq_stats *stats)
{
        struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
        int num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
        struct page *page = virt_to_head_page(buf);
        int offset = buf - page_address(page);
        unsigned int xdp_frags_truesz = 0;
        struct sk_buff *head_skb;
        unsigned int frame_sz;
        struct xdp_buff xdp;
        void *data;
        u32 act;
        int err;

        data = mergeable_xdp_get_buf(vi, rq, xdp_prog, ctx, &frame_sz, &num_buf, &page,
                                     offset, &len, hdr);
        if (unlikely(!data))
                goto err_xdp;

        err = virtnet_build_xdp_buff_mrg(dev, vi, rq, &xdp, data, len, frame_sz,
                                         &num_buf, &xdp_frags_truesz, stats);
        if (unlikely(err))
                goto err_xdp;

        act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);

        switch (act) {
        case XDP_PASS:
                head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
                if (unlikely(!head_skb))
                        break;
                return head_skb;

        case XDP_TX:
        case XDP_REDIRECT:
                return NULL;

        default:
                break;
        }

        put_xdp_frags(&xdp);

err_xdp:
        put_page(page);
        mergeable_buf_free(rq, num_buf, dev, stats);

        u64_stats_inc(&stats->xdp_drops);
        u64_stats_inc(&stats->drops);
        return NULL;
}

static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
                                               struct sk_buff *curr_skb,
                                               struct page *page, void *buf,
                                               int len, int truesize)
{
        int num_skb_frags;
        int offset;

        num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
        if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
                struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);

                if (unlikely(!nskb))
                        return NULL;

                if (curr_skb == head_skb)
                        skb_shinfo(curr_skb)->frag_list = nskb;
                else
                        curr_skb->next = nskb;
                curr_skb = nskb;
                head_skb->truesize += nskb->truesize;
                num_skb_frags = 0;
        }

        if (curr_skb != head_skb) {
                head_skb->data_len += len;
                head_skb->len += len;
                head_skb->truesize += truesize;
        }

        offset = buf - page_address(page);
        if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
                put_page(page);
                skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
                                     len, truesize);
        } else {
                skb_add_rx_frag(curr_skb, num_skb_frags, page,
                                offset, len, truesize);
        }

        return curr_skb;
}

static struct sk_buff *receive_mergeable(struct net_device *dev,
                                         struct virtnet_info *vi,
                                         struct receive_queue *rq,
                                         void *buf,
                                         void *ctx,
                                         unsigned int len,
                                         unsigned int *xdp_xmit,
                                         struct virtnet_rq_stats *stats)
{
        struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
        int num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
        struct page *page = virt_to_head_page(buf);
        int offset = buf - page_address(page);
        struct sk_buff *head_skb, *curr_skb;
        unsigned int truesize = mergeable_ctx_to_truesize(ctx);
        unsigned int headroom = mergeable_ctx_to_headroom(ctx);

        head_skb = NULL;
        u64_stats_add(&stats->bytes, len - vi->hdr_len);

        if (check_mergeable_len(dev, ctx, len))
                goto err_skb;

        if (unlikely(vi->xdp_enabled)) {
                struct bpf_prog *xdp_prog;

                rcu_read_lock();
                xdp_prog = rcu_dereference(rq->xdp_prog);
                if (xdp_prog) {
                        head_skb = receive_mergeable_xdp(dev, vi, rq, xdp_prog, buf, ctx,
                                                         len, xdp_xmit, stats);
                        rcu_read_unlock();
                        return head_skb;
                }
                rcu_read_unlock();
        }

        head_skb = page_to_skb(vi, rq, page, offset, len, truesize, headroom);
        curr_skb = head_skb;

        if (unlikely(!curr_skb))
                goto err_skb;
        while (--num_buf) {
                buf = virtnet_rq_get_buf(rq, &len, &ctx);
                if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers out of %d missing\n",
                                 dev->name, num_buf,
                                 virtio16_to_cpu(vi->vdev,
                                                 hdr->num_buffers));
                        DEV_STATS_INC(dev, rx_length_errors);
                        goto err_buf;
                }

                u64_stats_add(&stats->bytes, len);
                page = virt_to_head_page(buf);

                if (check_mergeable_len(dev, ctx, len))
                        goto err_skb;

                truesize = mergeable_ctx_to_truesize(ctx);
                curr_skb  = virtnet_skb_append_frag(head_skb, curr_skb, page,
                                                    buf, len, truesize);
                if (!curr_skb)
                        goto err_skb;
        }

        ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
        return head_skb;

err_skb:
        put_page(page);
        mergeable_buf_free(rq, num_buf, dev, stats);

err_buf:
        u64_stats_inc(&stats->drops);
        dev_kfree_skb(head_skb);
        return NULL;
}

static inline u32
virtio_net_hash_value(const struct virtio_net_hdr_v1_hash *hdr_hash)
{
        return __le16_to_cpu(hdr_hash->hash_value_lo) |
                (__le16_to_cpu(hdr_hash->hash_value_hi) << 16);
}

static void virtio_skb_set_hash(const struct virtio_net_hdr_v1_hash *hdr_hash,
                                struct sk_buff *skb)
{
        enum pkt_hash_types rss_hash_type;

        if (!hdr_hash || !skb)
                return;

        switch (__le16_to_cpu(hdr_hash->hash_report)) {
        case VIRTIO_NET_HASH_REPORT_TCPv4:
        case VIRTIO_NET_HASH_REPORT_UDPv4:
        case VIRTIO_NET_HASH_REPORT_TCPv6:
        case VIRTIO_NET_HASH_REPORT_UDPv6:
        case VIRTIO_NET_HASH_REPORT_TCPv6_EX:
        case VIRTIO_NET_HASH_REPORT_UDPv6_EX:
                rss_hash_type = PKT_HASH_TYPE_L4;
                break;
        case VIRTIO_NET_HASH_REPORT_IPv4:
        case VIRTIO_NET_HASH_REPORT_IPv6:
        case VIRTIO_NET_HASH_REPORT_IPv6_EX:
                rss_hash_type = PKT_HASH_TYPE_L3;
                break;
        case VIRTIO_NET_HASH_REPORT_NONE:
        default:
                rss_hash_type = PKT_HASH_TYPE_NONE;
        }
        skb_set_hash(skb, virtio_net_hash_value(hdr_hash), rss_hash_type);
}

static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,
                                 struct sk_buff *skb, u8 flags)
{
        struct virtio_net_common_hdr *hdr;
        struct net_device *dev = vi->dev;

        hdr = skb_vnet_common_hdr(skb);
        if (dev->features & NETIF_F_RXHASH && vi->has_rss_hash_report)
                virtio_skb_set_hash(&hdr->hash_v1_hdr, skb);

        hdr->hdr.flags = flags;
        if (virtio_net_handle_csum_offload(skb, &hdr->hdr, vi->rx_tnl_csum)) {
                net_warn_ratelimited("%s: bad csum: flags: %x, gso_type: %x rx_tnl_csum %d\n",
                                     dev->name, hdr->hdr.flags,
                                     hdr->hdr.gso_type, vi->rx_tnl_csum);
                goto frame_err;
        }

        if (virtio_net_hdr_tnl_to_skb(skb, &hdr->tnl_hdr, vi->rx_tnl,
                                      vi->rx_tnl_csum,
                                      virtio_is_little_endian(vi->vdev))) {
                net_warn_ratelimited("%s: bad gso: type: %x, size: %u, flags %x tunnel %d tnl csum %d\n",
                                     dev->name, hdr->hdr.gso_type,
                                     hdr->hdr.gso_size, hdr->hdr.flags,
                                     vi->rx_tnl, vi->rx_tnl_csum);
                goto frame_err;
        }

        skb_record_rx_queue(skb, vq2rxq(rq->vq));
        skb->protocol = eth_type_trans(skb, dev);
        pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
                 ntohs(skb->protocol), skb->len, skb->pkt_type);

        napi_gro_receive(&rq->napi, skb);
        return;

frame_err:
        DEV_STATS_INC(dev, rx_frame_errors);
        dev_kfree_skb(skb);
}

static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
                        void *buf, unsigned int len, void **ctx,
                        unsigned int *xdp_xmit,
                        struct virtnet_rq_stats *stats)
{
        struct net_device *dev = vi->dev;
        struct sk_buff *skb;
        u8 flags;

        if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
                pr_debug("%s: short packet %i\n", dev->name, len);
                DEV_STATS_INC(dev, rx_length_errors);
                virtnet_rq_free_buf(vi, rq, buf);
                return;
        }

        /* About the flags below:
         * 1. Save the flags early, as the XDP program might overwrite them.
         * These flags ensure packets marked as VIRTIO_NET_HDR_F_DATA_VALID
         * stay valid after XDP processing.
         * 2. XDP doesn't work with partially checksummed packets (refer to
         * virtnet_xdp_set()), so packets marked as
         * VIRTIO_NET_HDR_F_NEEDS_CSUM get dropped during XDP processing.
         */

        if (vi->mergeable_rx_bufs) {
                flags = ((struct virtio_net_common_hdr *)buf)->hdr.flags;
                skb = receive_mergeable(dev, vi, rq, buf, ctx, len, xdp_xmit,
                                        stats);
        } else if (vi->big_packets) {
                void *p = page_address((struct page *)buf);

                flags = ((struct virtio_net_common_hdr *)p)->hdr.flags;
                skb = receive_big(dev, vi, rq, buf, len, stats);
        } else {
                flags = ((struct virtio_net_common_hdr *)buf)->hdr.flags;
                skb = receive_small(dev, vi, rq, buf, ctx, len, xdp_xmit, stats);
        }

        if (unlikely(!skb))
                return;

        virtnet_receive_done(vi, rq, skb, flags);
}

/* Unlike mergeable buffers, all buffers are allocated to the
 * same size, except for the headroom. For this reason we do
 * not need to use  mergeable_len_to_ctx here - it is enough
 * to store the headroom as the context ignoring the truesize.
 */
static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
                             gfp_t gfp)
{
        char *buf;
        unsigned int xdp_headroom = virtnet_get_headroom(vi);
        void *ctx = (void *)(unsigned long)xdp_headroom;
        int len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom;
        int err;

        len = SKB_DATA_ALIGN(len) +
              SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

        if (unlikely(!skb_page_frag_refill(len, &rq->alloc_frag, gfp)))
                return -ENOMEM;

        buf = virtnet_rq_alloc(rq, len, gfp);
        if (unlikely(!buf))
                return -ENOMEM;

        buf += VIRTNET_RX_PAD + xdp_headroom;

        virtnet_rq_init_one_sg(rq, buf, vi->hdr_len + GOOD_PACKET_LEN);

        err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
        if (err < 0) {
                virtnet_rq_unmap(rq, buf, 0);
                put_page(virt_to_head_page(buf));
        }

        return err;
}

static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
                           gfp_t gfp)
{
        struct page *first, *list = NULL;
        char *p;
        int i, err, offset;

        sg_init_table(rq->sg, vi->big_packets_num_skbfrags + 2);

        /* page in rq->sg[vi->big_packets_num_skbfrags + 1] is list tail */
        for (i = vi->big_packets_num_skbfrags + 1; i > 1; --i) {
                first = get_a_page(rq, gfp);
                if (!first) {
                        if (list)
                                give_pages(rq, list);
                        return -ENOMEM;
                }
                sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);

                /* chain new page in list head to match sg */
                first->private = (unsigned long)list;
                list = first;
        }

        first = get_a_page(rq, gfp);
        if (!first) {
                give_pages(rq, list);
                return -ENOMEM;
        }
        p = page_address(first);

        /* rq->sg[0], rq->sg[1] share the same page */
        /* a separated rq->sg[0] for header - required in case !any_header_sg */
        sg_set_buf(&rq->sg[0], p, vi->hdr_len);

        /* rq->sg[1] for data packet, from offset */
        offset = sizeof(struct padded_vnet_hdr);
        sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);

        /* chain first in list head */
        first->private = (unsigned long)list;
        err = virtqueue_add_inbuf(rq->vq, rq->sg, vi->big_packets_num_skbfrags + 2,
                                  first, gfp);
        if (err < 0)
                give_pages(rq, first);

        return err;
}

static unsigned int get_mergeable_buf_len(struct receive_queue *rq,
                                          struct ewma_pkt_len *avg_pkt_len,
                                          unsigned int room)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        const size_t hdr_len = vi->hdr_len;
        unsigned int len;

        if (room)
                return PAGE_SIZE - room;

        len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),
                                rq->min_buf_len, PAGE_SIZE - hdr_len);

        return ALIGN(len, L1_CACHE_BYTES);
}

static int add_recvbuf_mergeable(struct virtnet_info *vi,
                                 struct receive_queue *rq, gfp_t gfp)
{
        struct page_frag *alloc_frag = &rq->alloc_frag;
        unsigned int headroom = virtnet_get_headroom(vi);
        unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
        unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
        unsigned int len, hole;
        void *ctx;
        char *buf;
        int err;

        /* Extra tailroom is needed to satisfy XDP's assumption. This
         * means rx frags coalescing won't work, but consider we've
         * disabled GSO for XDP, it won't be a big issue.
         */
        len = get_mergeable_buf_len(rq, &rq->mrg_avg_pkt_len, room);

        if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp)))
                return -ENOMEM;

        if (!alloc_frag->offset && len + room + sizeof(struct virtnet_rq_dma) > alloc_frag->size)
                len -= sizeof(struct virtnet_rq_dma);

        buf = virtnet_rq_alloc(rq, len + room, gfp);
        if (unlikely(!buf))
                return -ENOMEM;

        buf += headroom; /* advance address leaving hole at front of pkt */
        hole = alloc_frag->size - alloc_frag->offset;
        if (hole < len + room) {
                /* To avoid internal fragmentation, if there is very likely not
                 * enough space for another buffer, add the remaining space to
                 * the current buffer.
                 * XDP core assumes that frame_size of xdp_buff and the length
                 * of the frag are PAGE_SIZE, so we disable the hole mechanism.
                 */
                if (!headroom)
                        len += hole;
                alloc_frag->offset += hole;
        }

        virtnet_rq_init_one_sg(rq, buf, len);

        ctx = mergeable_len_to_ctx(len + room, headroom);
        err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
        if (err < 0) {
                virtnet_rq_unmap(rq, buf, 0);
                put_page(virt_to_head_page(buf));
        }

        return err;
}

/*
 * Returns false if we couldn't fill entirely (OOM).
 *
 * Normally run in the receive path, but can also be run from ndo_open
 * before we're receiving packets, or from refill_work which is
 * careful to disable receiving (using napi_disable).
 */
static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
                          gfp_t gfp)
{
        int err;

        if (rq->xsk_pool) {
                err = virtnet_add_recvbuf_xsk(vi, rq, rq->xsk_pool, gfp);
                goto kick;
        }

        do {
                if (vi->mergeable_rx_bufs)
                        err = add_recvbuf_mergeable(vi, rq, gfp);
                else if (vi->big_packets)
                        err = add_recvbuf_big(vi, rq, gfp);
                else
                        err = add_recvbuf_small(vi, rq, gfp);

                if (err)
                        break;
        } while (rq->vq->num_free);

kick:
        if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
                unsigned long flags;

                flags = u64_stats_update_begin_irqsave(&rq->stats.syncp);
                u64_stats_inc(&rq->stats.kicks);
                u64_stats_update_end_irqrestore(&rq->stats.syncp, flags);
        }

        return err != -ENOMEM;
}

static void skb_recv_done(struct virtqueue *rvq)
{
        struct virtnet_info *vi = rvq->vdev->priv;
        struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];

        rq->calls++;
        virtqueue_napi_schedule(&rq->napi, rvq);
}

static void virtnet_napi_do_enable(struct virtqueue *vq,
                                   struct napi_struct *napi)
{
        napi_enable(napi);

        /* If all buffers were filled by other side before we napi_enabled, we
         * won't get another interrupt, so process any outstanding packets now.
         * Call local_bh_enable after to trigger softIRQ processing.
         */
        local_bh_disable();
        virtqueue_napi_schedule(napi, vq);
        local_bh_enable();
}

static void virtnet_napi_enable(struct receive_queue *rq)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        int qidx = vq2rxq(rq->vq);

        virtnet_napi_do_enable(rq->vq, &rq->napi);
        netif_queue_set_napi(vi->dev, qidx, NETDEV_QUEUE_TYPE_RX, &rq->napi);
}

static void virtnet_napi_tx_enable(struct send_queue *sq)
{
        struct virtnet_info *vi = sq->vq->vdev->priv;
        struct napi_struct *napi = &sq->napi;
        int qidx = vq2txq(sq->vq);

        if (!napi->weight)
                return;

        /* Tx napi touches cachelines on the cpu handling tx interrupts. Only
         * enable the feature if this is likely affine with the transmit path.
         */
        if (!vi->affinity_hint_set) {
                napi->weight = 0;
                return;
        }

        virtnet_napi_do_enable(sq->vq, napi);
        netif_queue_set_napi(vi->dev, qidx, NETDEV_QUEUE_TYPE_TX, napi);
}

static void virtnet_napi_tx_disable(struct send_queue *sq)
{
        struct virtnet_info *vi = sq->vq->vdev->priv;
        struct napi_struct *napi = &sq->napi;
        int qidx = vq2txq(sq->vq);

        if (napi->weight) {
                netif_queue_set_napi(vi->dev, qidx, NETDEV_QUEUE_TYPE_TX, NULL);
                napi_disable(napi);
        }
}

static void virtnet_napi_disable(struct receive_queue *rq)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct napi_struct *napi = &rq->napi;
        int qidx = vq2rxq(rq->vq);

        netif_queue_set_napi(vi->dev, qidx, NETDEV_QUEUE_TYPE_RX, NULL);
        napi_disable(napi);
}

static int virtnet_receive_xsk_bufs(struct virtnet_info *vi,
                                    struct receive_queue *rq,
                                    int budget,
                                    unsigned int *xdp_xmit,
                                    struct virtnet_rq_stats *stats)
{
        unsigned int len;
        int packets = 0;
        void *buf;

        while (packets < budget) {
                buf = virtqueue_get_buf(rq->vq, &len);
                if (!buf)
                        break;

                virtnet_receive_xsk_buf(vi, rq, buf, len, xdp_xmit, stats);
                packets++;
        }

        return packets;
}

static int virtnet_receive_packets(struct virtnet_info *vi,
                                   struct receive_queue *rq,
                                   int budget,
                                   unsigned int *xdp_xmit,
                                   struct virtnet_rq_stats *stats)
{
        unsigned int len;
        int packets = 0;
        void *buf;

        if (!vi->big_packets || vi->mergeable_rx_bufs) {
                void *ctx;
                while (packets < budget &&
                       (buf = virtnet_rq_get_buf(rq, &len, &ctx))) {
                        receive_buf(vi, rq, buf, len, ctx, xdp_xmit, stats);
                        packets++;
                }
        } else {
                while (packets < budget &&
                       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
                        receive_buf(vi, rq, buf, len, NULL, xdp_xmit, stats);
                        packets++;
                }
        }

        return packets;
}

static int virtnet_receive(struct receive_queue *rq, int budget,
                           unsigned int *xdp_xmit)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct virtnet_rq_stats stats = {};
        int i, packets;

        if (rq->xsk_pool)
                packets = virtnet_receive_xsk_bufs(vi, rq, budget, xdp_xmit, &stats);
        else
                packets = virtnet_receive_packets(vi, rq, budget, xdp_xmit, &stats);

        u64_stats_set(&stats.packets, packets);
        if (rq->vq->num_free > min((unsigned int)budget, virtqueue_get_vring_size(rq->vq)) / 2) {
                if (!try_fill_recv(vi, rq, GFP_ATOMIC))
                        /* We need to retry refilling in the next NAPI poll so
                         * we must return budget to make sure the NAPI is
                         * repolled.
                         */
                        packets = budget;
        }

        u64_stats_update_begin(&rq->stats.syncp);
        for (i = 0; i < ARRAY_SIZE(virtnet_rq_stats_desc); i++) {
                size_t offset = virtnet_rq_stats_desc[i].offset;
                u64_stats_t *item, *src;

                item = (u64_stats_t *)((u8 *)&rq->stats + offset);
                src = (u64_stats_t *)((u8 *)&stats + offset);
                u64_stats_add(item, u64_stats_read(src));
        }

        u64_stats_add(&rq->stats.packets, u64_stats_read(&stats.packets));
        u64_stats_add(&rq->stats.bytes, u64_stats_read(&stats.bytes));

        u64_stats_update_end(&rq->stats.syncp);

        return packets;
}

static void virtnet_poll_cleantx(struct receive_queue *rq, int budget)
{
        struct virtnet_info *vi = rq->vq->vdev->priv;
        unsigned int index = vq2rxq(rq->vq);
        struct send_queue *sq = &vi->sq[index];
        struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index);

        if (!sq->napi.weight || is_xdp_raw_buffer_queue(vi, index))
                return;

        if (__netif_tx_trylock(txq)) {
                if (sq->reset) {
                        __netif_tx_unlock(txq);
                        return;
                }

                do {
                        virtqueue_disable_cb(sq->vq);
                        free_old_xmit(sq, txq, !!budget);
                } while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));

                if (sq->vq->num_free >= MAX_SKB_FRAGS + 2)
                        virtnet_tx_wake_queue(vi, sq);

                __netif_tx_unlock(txq);
        }
}

static void virtnet_rx_dim_update(struct virtnet_info *vi, struct receive_queue *rq)
{
        struct dim_sample cur_sample = {};

        if (!rq->packets_in_napi)
                return;

        /* Don't need protection when fetching stats, since fetcher and
         * updater of the stats are in same context
         */
        dim_update_sample(rq->calls,
                          u64_stats_read(&rq->stats.packets),
                          u64_stats_read(&rq->stats.bytes),
                          &cur_sample);

        net_dim(&rq->dim, &cur_sample);
        rq->packets_in_napi = 0;
}

static int virtnet_poll(struct napi_struct *napi, int budget)
{
        struct receive_queue *rq =
                container_of(napi, struct receive_queue, napi);
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct send_queue *sq;
        unsigned int received;
        unsigned int xdp_xmit = 0;
        bool napi_complete;

        virtnet_poll_cleantx(rq, budget);

        received = virtnet_receive(rq, budget, &xdp_xmit);
        rq->packets_in_napi += received;

        if (xdp_xmit & VIRTIO_XDP_REDIR)
                xdp_do_flush();

        /* Out of packets? */
        if (received < budget) {
                napi_complete = virtqueue_napi_complete(napi, rq->vq, received);
                /* Intentionally not taking dim_lock here. This may result in a
                 * spurious net_dim call. But if that happens virtnet_rx_dim_work
                 * will not act on the scheduled work.
                 */
                if (napi_complete && rq->dim_enabled)
                        virtnet_rx_dim_update(vi, rq);
        }

        if (xdp_xmit & VIRTIO_XDP_TX) {
                sq = virtnet_xdp_get_sq(vi);
                if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
                        u64_stats_update_begin(&sq->stats.syncp);
                        u64_stats_inc(&sq->stats.kicks);
                        u64_stats_update_end(&sq->stats.syncp);
                }
                virtnet_xdp_put_sq(vi, sq);
        }

        return received;
}

static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index)
{
        virtnet_napi_tx_disable(&vi->sq[qp_index]);
        virtnet_napi_disable(&vi->rq[qp_index]);
        xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq);
}

static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
{
        struct net_device *dev = vi->dev;
        int err;

        err = xdp_rxq_info_reg(&vi->rq[qp_index].xdp_rxq, dev, qp_index,
                               vi->rq[qp_index].napi.napi_id);
        if (err < 0)
                return err;

        err = xdp_rxq_info_reg_mem_model(&vi->rq[qp_index].xdp_rxq,
                                         MEM_TYPE_PAGE_SHARED, NULL);
        if (err < 0)
                goto err_xdp_reg_mem_model;

        virtnet_napi_enable(&vi->rq[qp_index]);
        virtnet_napi_tx_enable(&vi->sq[qp_index]);

        return 0;

err_xdp_reg_mem_model:
        xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq);
        return err;
}

static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
{
        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
                return;
        net_dim_work_cancel(dim);
}

static void virtnet_update_settings(struct virtnet_info *vi)
{
        u32 speed;
        u8 duplex;

        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
                return;

        virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);

        if (ethtool_validate_speed(speed))
                vi->speed = speed;

        virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);

        if (ethtool_validate_duplex(duplex))
                vi->duplex = duplex;
}

static int virtnet_open(struct net_device *dev)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int i, err;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                if (i < vi->curr_queue_pairs)
                        /* Pre-fill rq agressively, to make sure we are ready to
                         * get packets immediately.
                         */
                        try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);

                err = virtnet_enable_queue_pair(vi, i);
                if (err < 0)
                        goto err_enable_qp;
        }

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
                if (vi->status & VIRTIO_NET_S_LINK_UP)
                        netif_carrier_on(vi->dev);
                virtio_config_driver_enable(vi->vdev);
        } else {
                vi->status = VIRTIO_NET_S_LINK_UP;
                netif_carrier_on(dev);
        }

        return 0;

err_enable_qp:
        for (i--; i >= 0; i--) {
                virtnet_disable_queue_pair(vi, i);
                virtnet_cancel_dim(vi, &vi->rq[i].dim);
        }

        return err;
}

static int virtnet_poll_tx(struct napi_struct *napi, int budget)
{
        struct send_queue *sq = container_of(napi, struct send_queue, napi);
        struct virtnet_info *vi = sq->vq->vdev->priv;
        unsigned int index = vq2txq(sq->vq);
        struct netdev_queue *txq;
        int opaque, xsk_done = 0;
        bool done;

        if (unlikely(is_xdp_raw_buffer_queue(vi, index))) {
                /* We don't need to enable cb for XDP */
                napi_complete_done(napi, 0);
                return 0;
        }

        txq = netdev_get_tx_queue(vi->dev, index);
        __netif_tx_lock(txq, raw_smp_processor_id());
        virtqueue_disable_cb(sq->vq);

        if (sq->xsk_pool)
                xsk_done = virtnet_xsk_xmit(sq, sq->xsk_pool, budget);
        else
                free_old_xmit(sq, txq, !!budget);

        if (sq->vq->num_free >= MAX_SKB_FRAGS + 2)
                virtnet_tx_wake_queue(vi, sq);

        if (xsk_done >= budget) {
                __netif_tx_unlock(txq);
                return budget;
        }

        opaque = virtqueue_enable_cb_prepare(sq->vq);

        done = napi_complete_done(napi, 0);

        if (!done)
                virtqueue_disable_cb(sq->vq);

        __netif_tx_unlock(txq);

        if (done) {
                if (unlikely(virtqueue_poll(sq->vq, opaque))) {
                        if (napi_schedule_prep(napi)) {
                                __netif_tx_lock(txq, raw_smp_processor_id());
                                virtqueue_disable_cb(sq->vq);
                                __netif_tx_unlock(txq);
                                __napi_schedule(napi);
                        }
                }
        }

        return 0;
}

static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan)
{
        const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
        struct virtnet_info *vi = sq->vq->vdev->priv;
        struct virtio_net_hdr_v1_hash_tunnel *hdr;
        int num_sg;
        unsigned hdr_len = vi->hdr_len;
        bool feature_hdrlen;
        bool can_push;

        feature_hdrlen = virtio_has_feature(vi->vdev,
                                            VIRTIO_NET_F_GUEST_HDRLEN);

        pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);

        /* Make sure it's safe to cast between formats */
        BUILD_BUG_ON(__alignof__(*hdr) != __alignof__(hdr->hash_hdr));
        BUILD_BUG_ON(__alignof__(*hdr) != __alignof__(hdr->hash_hdr.hdr));

        can_push = vi->any_header_sg &&
                !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
                !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
        /* Even if we can, don't push here yet as this would skew
         * csum_start offset below. */
        if (can_push)
                hdr = (struct virtio_net_hdr_v1_hash_tunnel *)(skb->data -
                                                               hdr_len);
        else
                hdr = &skb_vnet_common_hdr(skb)->tnl_hdr;

        if (virtio_net_hdr_tnl_from_skb(skb, hdr, vi->tx_tnl,
                                        virtio_is_little_endian(vi->vdev), 0,
                                        false, feature_hdrlen))
                return -EPROTO;

        if (vi->mergeable_rx_bufs)
                hdr->hash_hdr.hdr.num_buffers = 0;

        sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2));
        if (can_push) {
                __skb_push(skb, hdr_len);
                num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
                if (unlikely(num_sg < 0))
                        return num_sg;
                /* Pull header back to avoid skew in tx bytes calculations. */
                __skb_pull(skb, hdr_len);
        } else {
                sg_set_buf(sq->sg, hdr, hdr_len);
                num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len);
                if (unlikely(num_sg < 0))
                        return num_sg;
                num_sg++;
        }

        return virtnet_add_outbuf(sq, num_sg, skb,
                                  orphan ? VIRTNET_XMIT_TYPE_SKB_ORPHAN : VIRTNET_XMIT_TYPE_SKB);
}

static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int qnum = skb_get_queue_mapping(skb);
        struct send_queue *sq = &vi->sq[qnum];
        int err;
        struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
        bool xmit_more = netdev_xmit_more();
        bool use_napi = sq->napi.weight;
        bool kick;

        if (!use_napi)
                free_old_xmit(sq, txq, false);
        else
                virtqueue_disable_cb(sq->vq);

        /* timestamp packet in software */
        skb_tx_timestamp(skb);

        /* Try to transmit */
        err = xmit_skb(sq, skb, !use_napi);

        /* This should not happen! */
        if (unlikely(err)) {
                DEV_STATS_INC(dev, tx_fifo_errors);
                if (net_ratelimit())
                        dev_warn(&dev->dev,
                                 "Unexpected TXQ (%d) queue failure: %d\n",
                                 qnum, err);
                DEV_STATS_INC(dev, tx_dropped);
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }

        /* Don't wait up for transmitted skbs to be freed. */
        if (!use_napi) {
                skb_orphan(skb);
                skb_dst_drop(skb);
                nf_reset_ct(skb);
        }

        if (use_napi)
                tx_may_stop(vi, dev, sq);
        else
                check_sq_full_and_disable(vi, dev,sq);

        kick = use_napi ? __netdev_tx_sent_queue(txq, skb->len, xmit_more) :
                          !xmit_more || netif_xmit_stopped(txq);
        if (kick) {
                if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
                        u64_stats_update_begin(&sq->stats.syncp);
                        u64_stats_inc(&sq->stats.kicks);
                        u64_stats_update_end(&sq->stats.syncp);
                }
        }

        if (use_napi && kick && unlikely(!virtqueue_enable_cb_delayed(sq->vq)))
                virtqueue_napi_schedule(&sq->napi, sq->vq);

        return NETDEV_TX_OK;
}

static void virtnet_rx_pause(struct virtnet_info *vi,
                             struct receive_queue *rq)
{
        bool running = netif_running(vi->dev);

        if (running) {
                virtnet_napi_disable(rq);
                virtnet_cancel_dim(vi, &rq->dim);
        }
}

static void virtnet_rx_pause_all(struct virtnet_info *vi)
{
        int i;

        for (i = 0; i < vi->max_queue_pairs; i++)
                virtnet_rx_pause(vi, &vi->rq[i]);
}

static void virtnet_rx_resume(struct virtnet_info *vi,
                              struct receive_queue *rq,
                              bool refill)
{
        if (netif_running(vi->dev)) {
                /* Pre-fill rq agressively, to make sure we are ready to get
                 * packets immediately.
                 */
                if (refill)
                        try_fill_recv(vi, rq, GFP_KERNEL);

                virtnet_napi_enable(rq);
        }
}

static void virtnet_rx_resume_all(struct virtnet_info *vi)
{
        int i;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                if (i < vi->curr_queue_pairs)
                        virtnet_rx_resume(vi, &vi->rq[i], true);
                else
                        virtnet_rx_resume(vi, &vi->rq[i], false);
        }
}

static int virtnet_rx_resize(struct virtnet_info *vi,
                             struct receive_queue *rq, u32 ring_num)
{
        int err, qindex;

        qindex = rq - vi->rq;

        virtnet_rx_pause(vi, rq);

        err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_unmap_free_buf, NULL);
        if (err)
                netdev_err(vi->dev, "resize rx fail: rx queue index: %d err: %d\n", qindex, err);

        virtnet_rx_resume(vi, rq, true);
        return err;
}

static void virtnet_tx_pause(struct virtnet_info *vi, struct send_queue *sq)
{
        bool running = netif_running(vi->dev);
        struct netdev_queue *txq;
        int qindex;

        qindex = sq - vi->sq;

        if (running)
                virtnet_napi_tx_disable(sq);

        txq = netdev_get_tx_queue(vi->dev, qindex);

        /* 1. wait all ximt complete
         * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue()
         */
        __netif_tx_lock_bh(txq);

        /* Prevent rx poll from accessing sq. */
        sq->reset = true;

        /* Prevent the upper layer from trying to send packets. */
        netif_stop_subqueue(vi->dev, qindex);
        u64_stats_update_begin(&sq->stats.syncp);
        u64_stats_inc(&sq->stats.stop);
        u64_stats_update_end(&sq->stats.syncp);

        __netif_tx_unlock_bh(txq);
}

static void virtnet_tx_resume(struct virtnet_info *vi, struct send_queue *sq)
{
        bool running = netif_running(vi->dev);
        struct netdev_queue *txq;
        int qindex;

        qindex = sq - vi->sq;

        txq = netdev_get_tx_queue(vi->dev, qindex);

        __netif_tx_lock_bh(txq);
        sq->reset = false;
        virtnet_tx_wake_queue(vi, sq);
        __netif_tx_unlock_bh(txq);

        if (running)
                virtnet_napi_tx_enable(sq);
}

static int virtnet_tx_resize(struct virtnet_info *vi, struct send_queue *sq,
                             u32 ring_num)
{
        int qindex, err;

        if (ring_num <= MAX_SKB_FRAGS + 2) {
                netdev_err(vi->dev, "tx size (%d) cannot be smaller than %d\n",
                           ring_num, MAX_SKB_FRAGS + 2);
                return -EINVAL;
        }

        qindex = sq - vi->sq;

        virtnet_tx_pause(vi, sq);

        err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf,
                               virtnet_sq_free_unused_buf_done);
        if (err)
                netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err);

        virtnet_tx_resume(vi, sq);

        return err;
}

/*
 * Send command via the control virtqueue and check status.  Commands
 * supported by the hypervisor, as indicated by feature bits, should
 * never fail unless improperly formatted.
 */
static bool virtnet_send_command_reply(struct virtnet_info *vi, u8 class, u8 cmd,
                                       struct scatterlist *out,
                                       struct scatterlist *in)
{
        struct scatterlist *sgs[5], hdr, stat;
        u32 out_num = 0, tmp, in_num = 0;
        bool ok;
        int ret;

        /* Caller should know better */
        BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));

        mutex_lock(&vi->cvq_lock);
        vi->ctrl->status = ~0;
        vi->ctrl->hdr.class = class;
        vi->ctrl->hdr.cmd = cmd;
        /* Add header */
        sg_init_one(&hdr, &vi->ctrl->hdr, sizeof(vi->ctrl->hdr));
        sgs[out_num++] = &hdr;

        if (out)
                sgs[out_num++] = out;

        /* Add return status. */
        sg_init_one(&stat, &vi->ctrl->status, sizeof(vi->ctrl->status));
        sgs[out_num + in_num++] = &stat;

        if (in)
                sgs[out_num + in_num++] = in;

        BUG_ON(out_num + in_num > ARRAY_SIZE(sgs));
        ret = virtqueue_add_sgs(vi->cvq, sgs, out_num, in_num, vi, GFP_ATOMIC);
        if (ret < 0) {
                dev_warn(&vi->vdev->dev,
                         "Failed to add sgs for command vq: %d\n.", ret);
                mutex_unlock(&vi->cvq_lock);
                return false;
        }

        if (unlikely(!virtqueue_kick(vi->cvq)))
                goto unlock;

        /* Spin for a response, the kick causes an ioport write, trapping
         * into the hypervisor, so the request should be handled immediately.
         */
        while (!virtqueue_get_buf(vi->cvq, &tmp) &&
               !virtqueue_is_broken(vi->cvq)) {
                cond_resched();
                cpu_relax();
        }

unlock:
        ok = vi->ctrl->status == VIRTIO_NET_OK;
        mutex_unlock(&vi->cvq_lock);
        return ok;
}

static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
                                 struct scatterlist *out)
{
        return virtnet_send_command_reply(vi, class, cmd, out, NULL);
}

static int virtnet_set_mac_address(struct net_device *dev, void *p)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct virtio_device *vdev = vi->vdev;
        int ret;
        struct sockaddr *addr;
        struct scatterlist sg;

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STANDBY))
                return -EOPNOTSUPP;

        addr = kmemdup(p, sizeof(*addr), GFP_KERNEL);
        if (!addr)
                return -ENOMEM;

        ret = eth_prepare_mac_addr_change(dev, addr);
        if (ret)
                goto out;

        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
                sg_init_one(&sg, addr->sa_data, dev->addr_len);
                if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
                                          VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
                        dev_warn(&vdev->dev,
                                 "Failed to set mac address by vq command.\n");
                        ret = -EINVAL;
                        goto out;
                }
        } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
                   !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
                unsigned int i;

                /* Naturally, this has an atomicity problem. */
                for (i = 0; i < dev->addr_len; i++)
                        virtio_cwrite8(vdev,
                                       offsetof(struct virtio_net_config, mac) +
                                       i, addr->sa_data[i]);
        }

        eth_commit_mac_addr_change(dev, p);
        ret = 0;

out:
        kfree(addr);
        return ret;
}

static void virtnet_stats(struct net_device *dev,
                          struct rtnl_link_stats64 *tot)
{
        struct virtnet_info *vi = netdev_priv(dev);
        unsigned int start;
        int i;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                u64 tpackets, tbytes, terrors, rpackets, rbytes, rdrops;
                struct receive_queue *rq = &vi->rq[i];
                struct send_queue *sq = &vi->sq[i];

                do {
                        start = u64_stats_fetch_begin(&sq->stats.syncp);
                        tpackets = u64_stats_read(&sq->stats.packets);
                        tbytes   = u64_stats_read(&sq->stats.bytes);
                        terrors  = u64_stats_read(&sq->stats.tx_timeouts);
                } while (u64_stats_fetch_retry(&sq->stats.syncp, start));

                do {
                        start = u64_stats_fetch_begin(&rq->stats.syncp);
                        rpackets = u64_stats_read(&rq->stats.packets);
                        rbytes   = u64_stats_read(&rq->stats.bytes);
                        rdrops   = u64_stats_read(&rq->stats.drops);
                } while (u64_stats_fetch_retry(&rq->stats.syncp, start));

                tot->rx_packets += rpackets;
                tot->tx_packets += tpackets;
                tot->rx_bytes   += rbytes;
                tot->tx_bytes   += tbytes;
                tot->rx_dropped += rdrops;
                tot->tx_errors  += terrors;
        }

        tot->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
        tot->tx_fifo_errors = DEV_STATS_READ(dev, tx_fifo_errors);
        tot->rx_length_errors = DEV_STATS_READ(dev, rx_length_errors);
        tot->rx_frame_errors = DEV_STATS_READ(dev, rx_frame_errors);
}

static void virtnet_ack_link_announce(struct virtnet_info *vi)
{
        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
                                  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
                dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
}

static bool virtnet_commit_rss_command(struct virtnet_info *vi);

static void virtnet_rss_update_by_qpairs(struct virtnet_info *vi, u16 queue_pairs)
{
        u32 indir_val = 0;
        int i = 0;

        for (; i < vi->rss_indir_table_size; ++i) {
                indir_val = ethtool_rxfh_indir_default(i, queue_pairs);
                vi->rss_hdr->indirection_table[i] = cpu_to_le16(indir_val);
        }
        vi->rss_trailer.max_tx_vq = cpu_to_le16(queue_pairs);
}

static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
{
        struct virtio_net_ctrl_mq *mq __free(kfree) = NULL;
        struct virtio_net_rss_config_hdr *old_rss_hdr;
        struct virtio_net_rss_config_trailer old_rss_trailer;
        struct net_device *dev = vi->dev;
        struct scatterlist sg;

        if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
                return 0;

        /* Firstly check if we need update rss. Do updating if both (1) rss enabled and
         * (2) no user configuration.
         *
         * During rss command processing, device updates queue_pairs using rss.max_tx_vq. That is,
         * the device updates queue_pairs together with rss, so we can skip the separate queue_pairs
         * update (VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET below) and return directly.
         */
        if (vi->has_rss && !netif_is_rxfh_configured(dev)) {
                old_rss_hdr = vi->rss_hdr;
                old_rss_trailer = vi->rss_trailer;
                vi->rss_hdr = devm_kzalloc(&vi->vdev->dev, virtnet_rss_hdr_size(vi), GFP_KERNEL);
                if (!vi->rss_hdr) {
                        vi->rss_hdr = old_rss_hdr;
                        return -ENOMEM;
                }

                *vi->rss_hdr = *old_rss_hdr;
                virtnet_rss_update_by_qpairs(vi, queue_pairs);

                if (!virtnet_commit_rss_command(vi)) {
                        /* restore ctrl_rss if commit_rss_command failed */
                        devm_kfree(&vi->vdev->dev, vi->rss_hdr);
                        vi->rss_hdr = old_rss_hdr;
                        vi->rss_trailer = old_rss_trailer;

                        dev_warn(&dev->dev, "Fail to set num of queue pairs to %d, because committing RSS failed\n",
                                 queue_pairs);
                        return -EINVAL;
                }
                devm_kfree(&vi->vdev->dev, old_rss_hdr);
                goto succ;
        }

        mq = kzalloc_obj(*mq);
        if (!mq)
                return -ENOMEM;

        mq->virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
        sg_init_one(&sg, mq, sizeof(*mq));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
                                  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
                dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
                         queue_pairs);
                return -EINVAL;
        }
succ:
        vi->curr_queue_pairs = queue_pairs;
        if (dev->flags & IFF_UP) {
                local_bh_disable();
                for (int i = 0; i < vi->curr_queue_pairs; ++i)
                        virtqueue_napi_schedule(&vi->rq[i].napi, vi->rq[i].vq);
                local_bh_enable();
        }

        return 0;
}

static int virtnet_close(struct net_device *dev)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int i;

        /* Prevent the config change callback from changing carrier
         * after close
         */
        virtio_config_driver_disable(vi->vdev);
        /* Stop getting status/speed updates: we don't care until next
         * open
         */
        cancel_work_sync(&vi->config_work);

        for (i = 0; i < vi->max_queue_pairs; i++) {
                virtnet_disable_queue_pair(vi, i);
                virtnet_cancel_dim(vi, &vi->rq[i].dim);
        }

        netif_carrier_off(dev);

        return 0;
}

static void virtnet_rx_mode_work(struct work_struct *work)
{
        struct virtnet_info *vi =
                container_of(work, struct virtnet_info, rx_mode_work);
        u8 *promisc_allmulti  __free(kfree) = NULL;
        struct net_device *dev = vi->dev;
        struct scatterlist sg[2];
        struct virtio_net_ctrl_mac *mac_data;
        struct netdev_hw_addr *ha;
        int uc_count;
        int mc_count;
        void *buf;
        int i;

        /* We can't dynamically set ndo_set_rx_mode, so return gracefully */
        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
                return;

        promisc_allmulti = kzalloc_obj(*promisc_allmulti);
        if (!promisc_allmulti) {
                dev_warn(&dev->dev, "Failed to set RX mode, no memory.\n");
                return;
        }

        rtnl_lock();

        *promisc_allmulti = !!(dev->flags & IFF_PROMISC);
        sg_init_one(sg, promisc_allmulti, sizeof(*promisc_allmulti));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
                                  VIRTIO_NET_CTRL_RX_PROMISC, sg))
                dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
                         *promisc_allmulti ? "en" : "dis");

        *promisc_allmulti = !!(dev->flags & IFF_ALLMULTI);
        sg_init_one(sg, promisc_allmulti, sizeof(*promisc_allmulti));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
                                  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
                dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
                         *promisc_allmulti ? "en" : "dis");

        netif_addr_lock_bh(dev);

        uc_count = netdev_uc_count(dev);
        mc_count = netdev_mc_count(dev);
        /* MAC filter - use one buffer for both lists */
        buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
                      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
        mac_data = buf;
        if (!buf) {
                netif_addr_unlock_bh(dev);
                rtnl_unlock();
                return;
        }

        sg_init_table(sg, 2);

        /* Store the unicast list and count in the front of the buffer */
        mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
        i = 0;
        netdev_for_each_uc_addr(ha, dev)
                memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);

        sg_set_buf(&sg[0], mac_data,
                   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));

        /* multicast list and count fill the end */
        mac_data = (void *)&mac_data->macs[uc_count][0];

        mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
        i = 0;
        netdev_for_each_mc_addr(ha, dev)
                memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);

        netif_addr_unlock_bh(dev);

        sg_set_buf(&sg[1], mac_data,
                   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
                                  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
                dev_warn(&dev->dev, "Failed to set MAC filter table.\n");

        rtnl_unlock();

        kfree(buf);
}

static void virtnet_set_rx_mode(struct net_device *dev)
{
        struct virtnet_info *vi = netdev_priv(dev);

        if (vi->rx_mode_work_enabled)
                schedule_work(&vi->rx_mode_work);
}

static int virtnet_vlan_rx_add_vid(struct net_device *dev,
                                   __be16 proto, u16 vid)
{
        struct virtnet_info *vi = netdev_priv(dev);
        __virtio16 *_vid __free(kfree) = NULL;
        struct scatterlist sg;

        _vid = kzalloc_obj(*_vid);
        if (!_vid)
                return -ENOMEM;

        *_vid = cpu_to_virtio16(vi->vdev, vid);
        sg_init_one(&sg, _vid, sizeof(*_vid));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
                                  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
                dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
        return 0;
}

static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
                                    __be16 proto, u16 vid)
{
        struct virtnet_info *vi = netdev_priv(dev);
        __virtio16 *_vid __free(kfree) = NULL;
        struct scatterlist sg;

        _vid = kzalloc_obj(*_vid);
        if (!_vid)
                return -ENOMEM;

        *_vid = cpu_to_virtio16(vi->vdev, vid);
        sg_init_one(&sg, _vid, sizeof(*_vid));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
                                  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
                dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
        return 0;
}

static void virtnet_clean_affinity(struct virtnet_info *vi)
{
        int i;

        if (vi->affinity_hint_set) {
                for (i = 0; i < vi->max_queue_pairs; i++) {
                        virtqueue_set_affinity(vi->rq[i].vq, NULL);
                        virtqueue_set_affinity(vi->sq[i].vq, NULL);
                }

                vi->affinity_hint_set = false;
        }
}

static void virtnet_set_affinity(struct virtnet_info *vi)
{
        cpumask_var_t mask;
        int stragglers;
        int group_size;
        int i, start = 0, cpu;
        int num_cpu;
        int stride;

        if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
                virtnet_clean_affinity(vi);
                return;
        }

        num_cpu = num_online_cpus();
        stride = max_t(int, num_cpu / vi->curr_queue_pairs, 1);
        stragglers = num_cpu >= vi->curr_queue_pairs ?
                        num_cpu % vi->curr_queue_pairs :
                        0;

        for (i = 0; i < vi->curr_queue_pairs; i++) {
                group_size = stride + (i < stragglers ? 1 : 0);

                for_each_online_cpu_wrap(cpu, start) {
                        if (!group_size--) {
                                start = cpu;
                                break;
                        }
                        cpumask_set_cpu(cpu, mask);
                }

                virtqueue_set_affinity(vi->rq[i].vq, mask);
                virtqueue_set_affinity(vi->sq[i].vq, mask);
                __netif_set_xps_queue(vi->dev, cpumask_bits(mask), i, XPS_CPUS);
                cpumask_clear(mask);
        }

        vi->affinity_hint_set = true;
        free_cpumask_var(mask);
}

static int virtnet_cpu_online(unsigned int cpu, struct hlist_node *node)
{
        struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
                                                   node);
        virtnet_set_affinity(vi);
        return 0;
}

static int virtnet_cpu_dead(unsigned int cpu, struct hlist_node *node)
{
        struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
                                                   node_dead);
        virtnet_set_affinity(vi);
        return 0;
}

static int virtnet_cpu_down_prep(unsigned int cpu, struct hlist_node *node)
{
        struct virtnet_info *vi = hlist_entry_safe(node, struct virtnet_info,
                                                   node);

        virtnet_clean_affinity(vi);
        return 0;
}

static enum cpuhp_state virtionet_online;

static int virtnet_cpu_notif_add(struct virtnet_info *vi)
{
        int ret;

        ret = cpuhp_state_add_instance_nocalls(virtionet_online, &vi->node);
        if (ret)
                return ret;
        ret = cpuhp_state_add_instance_nocalls(CPUHP_VIRT_NET_DEAD,
                                               &vi->node_dead);
        if (!ret)
                return ret;
        cpuhp_state_remove_instance_nocalls(virtionet_online, &vi->node);
        return ret;
}

static void virtnet_cpu_notif_remove(struct virtnet_info *vi)
{
        cpuhp_state_remove_instance_nocalls(virtionet_online, &vi->node);
        cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_NET_DEAD,
                                            &vi->node_dead);
}

static int virtnet_send_ctrl_coal_vq_cmd(struct virtnet_info *vi,
                                         u16 vqn, u32 max_usecs, u32 max_packets)
{
        struct virtio_net_ctrl_coal_vq *coal_vq __free(kfree) = NULL;
        struct scatterlist sgs;

        coal_vq = kzalloc_obj(*coal_vq);
        if (!coal_vq)
                return -ENOMEM;

        coal_vq->vqn = cpu_to_le16(vqn);
        coal_vq->coal.max_usecs = cpu_to_le32(max_usecs);
        coal_vq->coal.max_packets = cpu_to_le32(max_packets);
        sg_init_one(&sgs, coal_vq, sizeof(*coal_vq));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
                                  VIRTIO_NET_CTRL_NOTF_COAL_VQ_SET,
                                  &sgs))
                return -EINVAL;

        return 0;
}

static int virtnet_send_rx_ctrl_coal_vq_cmd(struct virtnet_info *vi,
                                            u16 queue, u32 max_usecs,
                                            u32 max_packets)
{
        int err;

        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
                return -EOPNOTSUPP;

        err = virtnet_send_ctrl_coal_vq_cmd(vi, rxq2vq(queue),
                                            max_usecs, max_packets);
        if (err)
                return err;

        vi->rq[queue].intr_coal.max_usecs = max_usecs;
        vi->rq[queue].intr_coal.max_packets = max_packets;

        return 0;
}

static int virtnet_send_tx_ctrl_coal_vq_cmd(struct virtnet_info *vi,
                                            u16 queue, u32 max_usecs,
                                            u32 max_packets)
{
        int err;

        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
                return -EOPNOTSUPP;

        err = virtnet_send_ctrl_coal_vq_cmd(vi, txq2vq(queue),
                                            max_usecs, max_packets);
        if (err)
                return err;

        vi->sq[queue].intr_coal.max_usecs = max_usecs;
        vi->sq[queue].intr_coal.max_packets = max_packets;

        return 0;
}

static void virtnet_get_ringparam(struct net_device *dev,
                                  struct ethtool_ringparam *ring,
                                  struct kernel_ethtool_ringparam *kernel_ring,
                                  struct netlink_ext_ack *extack)
{
        struct virtnet_info *vi = netdev_priv(dev);

        ring->rx_max_pending = vi->rq[0].vq->num_max;
        ring->tx_max_pending = vi->sq[0].vq->num_max;
        ring->rx_pending = virtqueue_get_vring_size(vi->rq[0].vq);
        ring->tx_pending = virtqueue_get_vring_size(vi->sq[0].vq);
}

static int virtnet_set_ringparam(struct net_device *dev,
                                 struct ethtool_ringparam *ring,
                                 struct kernel_ethtool_ringparam *kernel_ring,
                                 struct netlink_ext_ack *extack)
{
        struct virtnet_info *vi = netdev_priv(dev);
        u32 rx_pending, tx_pending;
        struct receive_queue *rq;
        struct send_queue *sq;
        int i, err;

        if (ring->rx_mini_pending || ring->rx_jumbo_pending)
                return -EINVAL;

        rx_pending = virtqueue_get_vring_size(vi->rq[0].vq);
        tx_pending = virtqueue_get_vring_size(vi->sq[0].vq);

        if (ring->rx_pending == rx_pending &&
            ring->tx_pending == tx_pending)
                return 0;

        if (ring->rx_pending > vi->rq[0].vq->num_max)
                return -EINVAL;

        if (ring->tx_pending > vi->sq[0].vq->num_max)
                return -EINVAL;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                rq = vi->rq + i;
                sq = vi->sq + i;

                if (ring->tx_pending != tx_pending) {
                        err = virtnet_tx_resize(vi, sq, ring->tx_pending);
                        if (err)
                                return err;

                        /* Upon disabling and re-enabling a transmit virtqueue, the device must
                         * set the coalescing parameters of the virtqueue to those configured
                         * through the VIRTIO_NET_CTRL_NOTF_COAL_TX_SET command, or, if the driver
                         * did not set any TX coalescing parameters, to 0.
                         */
                        err = virtnet_send_tx_ctrl_coal_vq_cmd(vi, i,
                                                               vi->intr_coal_tx.max_usecs,
                                                               vi->intr_coal_tx.max_packets);

                        /* Don't break the tx resize action if the vq coalescing is not
                         * supported. The same is true for rx resize below.
                         */
                        if (err && err != -EOPNOTSUPP)
                                return err;
                }

                if (ring->rx_pending != rx_pending) {
                        err = virtnet_rx_resize(vi, rq, ring->rx_pending);
                        if (err)
                                return err;

                        /* The reason is same as the transmit virtqueue reset */
                        mutex_lock(&vi->rq[i].dim_lock);
                        err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, i,
                                                               vi->intr_coal_rx.max_usecs,
                                                               vi->intr_coal_rx.max_packets);
                        mutex_unlock(&vi->rq[i].dim_lock);
                        if (err && err != -EOPNOTSUPP)
                                return err;
                }
        }

        return 0;
}

static bool virtnet_commit_rss_command(struct virtnet_info *vi)
{
        struct net_device *dev = vi->dev;
        struct scatterlist sgs[2];

        /* prepare sgs */
        sg_init_table(sgs, 2);
        sg_set_buf(&sgs[0], vi->rss_hdr, virtnet_rss_hdr_size(vi));
        sg_set_buf(&sgs[1], &vi->rss_trailer, virtnet_rss_trailer_size(vi));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
                                  vi->has_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG
                                  : VIRTIO_NET_CTRL_MQ_HASH_CONFIG, sgs))
                goto err;

        return true;

err:
        dev_warn(&dev->dev, "VIRTIONET issue with committing RSS sgs\n");
        return false;

}

static void virtnet_init_default_rss(struct virtnet_info *vi)
{
        vi->rss_hdr->hash_types = cpu_to_le32(vi->rss_hash_types_supported);
        vi->rss_hash_types_saved = vi->rss_hash_types_supported;
        vi->rss_hdr->indirection_table_mask = vi->rss_indir_table_size
                                                ? cpu_to_le16(vi->rss_indir_table_size - 1) : 0;
        vi->rss_hdr->unclassified_queue = 0;

        virtnet_rss_update_by_qpairs(vi, vi->curr_queue_pairs);

        vi->rss_trailer.hash_key_length = vi->rss_key_size;

        netdev_rss_key_fill(vi->rss_hash_key_data, vi->rss_key_size);
}

static int virtnet_get_hashflow(struct net_device *dev,
                                struct ethtool_rxfh_fields *info)
{
        struct virtnet_info *vi = netdev_priv(dev);

        info->data = 0;
        switch (info->flow_type) {
        case TCP_V4_FLOW:
                if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_TCPv4) {
                        info->data = RXH_IP_SRC | RXH_IP_DST |
                                                 RXH_L4_B_0_1 | RXH_L4_B_2_3;
                } else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
                        info->data = RXH_IP_SRC | RXH_IP_DST;
                }
                break;
        case TCP_V6_FLOW:
                if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_TCPv6) {
                        info->data = RXH_IP_SRC | RXH_IP_DST |
                                                 RXH_L4_B_0_1 | RXH_L4_B_2_3;
                } else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
                        info->data = RXH_IP_SRC | RXH_IP_DST;
                }
                break;
        case UDP_V4_FLOW:
                if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_UDPv4) {
                        info->data = RXH_IP_SRC | RXH_IP_DST |
                                                 RXH_L4_B_0_1 | RXH_L4_B_2_3;
                } else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
                        info->data = RXH_IP_SRC | RXH_IP_DST;
                }
                break;
        case UDP_V6_FLOW:
                if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_UDPv6) {
                        info->data = RXH_IP_SRC | RXH_IP_DST |
                                                 RXH_L4_B_0_1 | RXH_L4_B_2_3;
                } else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
                        info->data = RXH_IP_SRC | RXH_IP_DST;
                }
                break;
        case IPV4_FLOW:
                if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4)
                        info->data = RXH_IP_SRC | RXH_IP_DST;

                break;
        case IPV6_FLOW:
                if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv6)
                        info->data = RXH_IP_SRC | RXH_IP_DST;

                break;
        default:
                info->data = 0;
                break;
        }

        return 0;
}

static int virtnet_set_hashflow(struct net_device *dev,
                                const struct ethtool_rxfh_fields *info,
                                struct netlink_ext_ack *extack)
{
        struct virtnet_info *vi = netdev_priv(dev);
        u32 new_hashtypes = vi->rss_hash_types_saved;
        bool is_disable = info->data & RXH_DISCARD;
        bool is_l4 = info->data == (RXH_IP_SRC | RXH_IP_DST | RXH_L4_B_0_1 | RXH_L4_B_2_3);

        /* supports only 'sd', 'sdfn' and 'r' */
        if (!((info->data == (RXH_IP_SRC | RXH_IP_DST)) | is_l4 | is_disable))
                return -EINVAL;

        switch (info->flow_type) {
        case TCP_V4_FLOW:
                new_hashtypes &= ~(VIRTIO_NET_RSS_HASH_TYPE_IPv4 | VIRTIO_NET_RSS_HASH_TYPE_TCPv4);
                if (!is_disable)
                        new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv4
                                | (is_l4 ? VIRTIO_NET_RSS_HASH_TYPE_TCPv4 : 0);
                break;
        case UDP_V4_FLOW:
                new_hashtypes &= ~(VIRTIO_NET_RSS_HASH_TYPE_IPv4 | VIRTIO_NET_RSS_HASH_TYPE_UDPv4);
                if (!is_disable)
                        new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv4
                                | (is_l4 ? VIRTIO_NET_RSS_HASH_TYPE_UDPv4 : 0);
                break;
        case IPV4_FLOW:
                new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_IPv4;
                if (!is_disable)
                        new_hashtypes = VIRTIO_NET_RSS_HASH_TYPE_IPv4;
                break;
        case TCP_V6_FLOW:
                new_hashtypes &= ~(VIRTIO_NET_RSS_HASH_TYPE_IPv6 | VIRTIO_NET_RSS_HASH_TYPE_TCPv6);
                if (!is_disable)
                        new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv6
                                | (is_l4 ? VIRTIO_NET_RSS_HASH_TYPE_TCPv6 : 0);
                break;
        case UDP_V6_FLOW:
                new_hashtypes &= ~(VIRTIO_NET_RSS_HASH_TYPE_IPv6 | VIRTIO_NET_RSS_HASH_TYPE_UDPv6);
                if (!is_disable)
                        new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv6
                                | (is_l4 ? VIRTIO_NET_RSS_HASH_TYPE_UDPv6 : 0);
                break;
        case IPV6_FLOW:
                new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_IPv6;
                if (!is_disable)
                        new_hashtypes = VIRTIO_NET_RSS_HASH_TYPE_IPv6;
                break;
        default:
                /* unsupported flow */
                return -EINVAL;
        }

        /* if unsupported hashtype was set */
        if (new_hashtypes != (new_hashtypes & vi->rss_hash_types_supported))
                return -EINVAL;

        if (new_hashtypes != vi->rss_hash_types_saved) {
                vi->rss_hash_types_saved = new_hashtypes;
                vi->rss_hdr->hash_types = cpu_to_le32(vi->rss_hash_types_saved);
                if (vi->dev->features & NETIF_F_RXHASH)
                        if (!virtnet_commit_rss_command(vi))
                                return -EINVAL;
        }

        return 0;
}

static void virtnet_get_drvinfo(struct net_device *dev,
                                struct ethtool_drvinfo *info)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct virtio_device *vdev = vi->vdev;

        strscpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
        strscpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
        strscpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));

}

/* TODO: Eliminate OOO packets during switching */
static int virtnet_set_channels(struct net_device *dev,
                                struct ethtool_channels *channels)
{
        struct virtnet_info *vi = netdev_priv(dev);
        u16 queue_pairs = channels->combined_count;
        int err;

        /* We don't support separate rx/tx channels.
         * We don't allow setting 'other' channels.
         */
        if (channels->rx_count || channels->tx_count || channels->other_count)
                return -EINVAL;

        if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
                return -EINVAL;

        /* For now we don't support modifying channels while XDP is loaded
         * also when XDP is loaded all RX queues have XDP programs so we only
         * need to check a single RX queue.
         */
        if (vi->rq[0].xdp_prog)
                return -EINVAL;

        cpus_read_lock();
        err = virtnet_set_queues(vi, queue_pairs);
        if (err) {
                cpus_read_unlock();
                goto err;
        }
        virtnet_set_affinity(vi);
        cpus_read_unlock();

        netif_set_real_num_tx_queues(dev, queue_pairs);
        netif_set_real_num_rx_queues(dev, queue_pairs);
 err:
        return err;
}

static void virtnet_stats_sprintf(u8 **p, const char *fmt, const char *noq_fmt,
                                  int num, int qid, const struct virtnet_stat_desc *desc)
{
        int i;

        if (qid < 0) {
                for (i = 0; i < num; ++i)
                        ethtool_sprintf(p, noq_fmt, desc[i].desc);
        } else {
                for (i = 0; i < num; ++i)
                        ethtool_sprintf(p, fmt, qid, desc[i].desc);
        }
}

/* qid == -1: for rx/tx queue total field */
static void virtnet_get_stats_string(struct virtnet_info *vi, int type, int qid, u8 **data)
{
        const struct virtnet_stat_desc *desc;
        const char *fmt, *noq_fmt;
        u8 *p = *data;
        u32 num;

        if (type == VIRTNET_Q_TYPE_CQ && qid >= 0) {
                noq_fmt = "cq_hw_%s";

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_CVQ) {
                        desc = &virtnet_stats_cvq_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_cvq_desc);

                        virtnet_stats_sprintf(&p, NULL, noq_fmt, num, -1, desc);
                }
        }

        if (type == VIRTNET_Q_TYPE_RX) {
                fmt = "rx%u_%s";
                noq_fmt = "rx_%s";

                desc = &virtnet_rq_stats_desc[0];
                num = ARRAY_SIZE(virtnet_rq_stats_desc);

                virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);

                fmt = "rx%u_hw_%s";
                noq_fmt = "rx_hw_%s";

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_BASIC) {
                        desc = &virtnet_stats_rx_basic_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_rx_basic_desc);

                        virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_CSUM) {
                        desc = &virtnet_stats_rx_csum_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_rx_csum_desc);

                        virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_SPEED) {
                        desc = &virtnet_stats_rx_speed_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_rx_speed_desc);

                        virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);
                }
        }

        if (type == VIRTNET_Q_TYPE_TX) {
                fmt = "tx%u_%s";
                noq_fmt = "tx_%s";

                desc = &virtnet_sq_stats_desc[0];
                num = ARRAY_SIZE(virtnet_sq_stats_desc);

                virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);

                fmt = "tx%u_hw_%s";
                noq_fmt = "tx_hw_%s";

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_BASIC) {
                        desc = &virtnet_stats_tx_basic_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_tx_basic_desc);

                        virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_GSO) {
                        desc = &virtnet_stats_tx_gso_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_tx_gso_desc);

                        virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_SPEED) {
                        desc = &virtnet_stats_tx_speed_desc[0];
                        num = ARRAY_SIZE(virtnet_stats_tx_speed_desc);

                        virtnet_stats_sprintf(&p, fmt, noq_fmt, num, qid, desc);
                }
        }

        *data = p;
}

struct virtnet_stats_ctx {
        /* The stats are write to qstats or ethtool -S */
        bool to_qstat;

        /* Used to calculate the offset inside the output buffer. */
        u32 desc_num[3];

        /* The actual supported stat types. */
        u64 bitmap[3];

        /* Used to calculate the reply buffer size. */
        u32 size[3];

        /* Record the output buffer. */
        u64 *data;
};

static void virtnet_stats_ctx_init(struct virtnet_info *vi,
                                   struct virtnet_stats_ctx *ctx,
                                   u64 *data, bool to_qstat)
{
        u32 queue_type;

        ctx->data = data;
        ctx->to_qstat = to_qstat;

        if (to_qstat) {
                ctx->desc_num[VIRTNET_Q_TYPE_RX] = ARRAY_SIZE(virtnet_rq_stats_desc_qstat);
                ctx->desc_num[VIRTNET_Q_TYPE_TX] = ARRAY_SIZE(virtnet_sq_stats_desc_qstat);

                queue_type = VIRTNET_Q_TYPE_RX;

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_BASIC) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_BASIC;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_basic_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_basic);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_CSUM) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_CSUM;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_csum_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_csum);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_GSO) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_GSO;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_gso_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_gso);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_SPEED) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_SPEED;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_speed_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_speed);
                }

                queue_type = VIRTNET_Q_TYPE_TX;

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_BASIC) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_BASIC;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_basic_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_basic);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_CSUM) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_CSUM;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_csum_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_csum);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_GSO) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_GSO;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_gso_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_gso);
                }

                if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_SPEED) {
                        ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_SPEED;
                        ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_speed_desc_qstat);
                        ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_speed);
                }

                return;
        }

        ctx->desc_num[VIRTNET_Q_TYPE_RX] = ARRAY_SIZE(virtnet_rq_stats_desc);
        ctx->desc_num[VIRTNET_Q_TYPE_TX] = ARRAY_SIZE(virtnet_sq_stats_desc);

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_CVQ) {
                queue_type = VIRTNET_Q_TYPE_CQ;

                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_CVQ;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_cvq_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_cvq);
        }

        queue_type = VIRTNET_Q_TYPE_RX;

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_BASIC) {
                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_BASIC;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_basic_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_basic);
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_CSUM) {
                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_CSUM;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_csum_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_csum);
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_SPEED) {
                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_RX_SPEED;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_rx_speed_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_rx_speed);
        }

        queue_type = VIRTNET_Q_TYPE_TX;

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_BASIC) {
                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_BASIC;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_basic_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_basic);
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_GSO) {
                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_GSO;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_gso_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_gso);
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_SPEED) {
                ctx->bitmap[queue_type]   |= VIRTIO_NET_STATS_TYPE_TX_SPEED;
                ctx->desc_num[queue_type] += ARRAY_SIZE(virtnet_stats_tx_speed_desc);
                ctx->size[queue_type]     += sizeof(struct virtio_net_stats_tx_speed);
        }
}

/* stats_sum_queue - Calculate the sum of the same fields in sq or rq.
 * @sum: the position to store the sum values
 * @num: field num
 * @q_value: the first queue fields
 * @q_num: number of the queues
 */
static void stats_sum_queue(u64 *sum, u32 num, u64 *q_value, u32 q_num)
{
        u32 step = num;
        int i, j;
        u64 *p;

        for (i = 0; i < num; ++i) {
                p = sum + i;
                *p = 0;

                for (j = 0; j < q_num; ++j)
                        *p += *(q_value + i + j * step);
        }
}

static void virtnet_fill_total_fields(struct virtnet_info *vi,
                                      struct virtnet_stats_ctx *ctx)
{
        u64 *data, *first_rx_q, *first_tx_q;
        u32 num_cq, num_rx, num_tx;

        num_cq = ctx->desc_num[VIRTNET_Q_TYPE_CQ];
        num_rx = ctx->desc_num[VIRTNET_Q_TYPE_RX];
        num_tx = ctx->desc_num[VIRTNET_Q_TYPE_TX];

        first_rx_q = ctx->data + num_rx + num_tx + num_cq;
        first_tx_q = first_rx_q + vi->curr_queue_pairs * num_rx;

        data = ctx->data;

        stats_sum_queue(data, num_rx, first_rx_q, vi->curr_queue_pairs);

        data = ctx->data + num_rx;

        stats_sum_queue(data, num_tx, first_tx_q, vi->curr_queue_pairs);
}

static void virtnet_fill_stats_qstat(struct virtnet_info *vi, u32 qid,
                                     struct virtnet_stats_ctx *ctx,
                                     const u8 *base, bool drv_stats, u8 reply_type)
{
        const struct virtnet_stat_desc *desc;
        const u64_stats_t *v_stat;
        u64 offset, bitmap;
        const __le64 *v;
        u32 queue_type;
        int i, num;

        queue_type = vq_type(vi, qid);
        bitmap = ctx->bitmap[queue_type];

        if (drv_stats) {
                if (queue_type == VIRTNET_Q_TYPE_RX) {
                        desc = &virtnet_rq_stats_desc_qstat[0];
                        num = ARRAY_SIZE(virtnet_rq_stats_desc_qstat);
                } else {
                        desc = &virtnet_sq_stats_desc_qstat[0];
                        num = ARRAY_SIZE(virtnet_sq_stats_desc_qstat);
                }

                for (i = 0; i < num; ++i) {
                        offset = desc[i].qstat_offset / sizeof(*ctx->data);
                        v_stat = (const u64_stats_t *)(base + desc[i].offset);
                        ctx->data[offset] = u64_stats_read(v_stat);
                }
                return;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_BASIC) {
                desc = &virtnet_stats_rx_basic_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_rx_basic_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_BASIC)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_CSUM) {
                desc = &virtnet_stats_rx_csum_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_rx_csum_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_CSUM)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_GSO) {
                desc = &virtnet_stats_rx_gso_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_rx_gso_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_GSO)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_SPEED) {
                desc = &virtnet_stats_rx_speed_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_rx_speed_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_SPEED)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_BASIC) {
                desc = &virtnet_stats_tx_basic_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_tx_basic_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_BASIC)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_CSUM) {
                desc = &virtnet_stats_tx_csum_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_tx_csum_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_CSUM)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_GSO) {
                desc = &virtnet_stats_tx_gso_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_tx_gso_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_GSO)
                        goto found;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_SPEED) {
                desc = &virtnet_stats_tx_speed_desc_qstat[0];
                num = ARRAY_SIZE(virtnet_stats_tx_speed_desc_qstat);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_SPEED)
                        goto found;
        }

        return;

found:
        for (i = 0; i < num; ++i) {
                offset = desc[i].qstat_offset / sizeof(*ctx->data);
                v = (const __le64 *)(base + desc[i].offset);
                ctx->data[offset] = le64_to_cpu(*v);
        }
}

/* virtnet_fill_stats - copy the stats to qstats or ethtool -S
 * The stats source is the device or the driver.
 *
 * @vi: virtio net info
 * @qid: the vq id
 * @ctx: stats ctx (initiated by virtnet_stats_ctx_init())
 * @base: pointer to the device reply or the driver stats structure.
 * @drv_stats: designate the base type (device reply, driver stats)
 * @type: the type of the device reply (if drv_stats is true, this must be zero)
 */
static void virtnet_fill_stats(struct virtnet_info *vi, u32 qid,
                               struct virtnet_stats_ctx *ctx,
                               const u8 *base, bool drv_stats, u8 reply_type)
{
        u32 queue_type, num_rx, num_tx, num_cq;
        const struct virtnet_stat_desc *desc;
        const u64_stats_t *v_stat;
        u64 offset, bitmap;
        const __le64 *v;
        int i, num;

        if (ctx->to_qstat)
                return virtnet_fill_stats_qstat(vi, qid, ctx, base, drv_stats, reply_type);

        num_cq = ctx->desc_num[VIRTNET_Q_TYPE_CQ];
        num_rx = ctx->desc_num[VIRTNET_Q_TYPE_RX];
        num_tx = ctx->desc_num[VIRTNET_Q_TYPE_TX];

        queue_type = vq_type(vi, qid);
        bitmap = ctx->bitmap[queue_type];

        /* skip the total fields of pairs */
        offset = num_rx + num_tx;

        if (queue_type == VIRTNET_Q_TYPE_TX) {
                offset += num_cq + num_rx * vi->curr_queue_pairs + num_tx * (qid / 2);

                num = ARRAY_SIZE(virtnet_sq_stats_desc);
                if (drv_stats) {
                        desc = &virtnet_sq_stats_desc[0];
                        goto drv_stats;
                }

                offset += num;

        } else if (queue_type == VIRTNET_Q_TYPE_RX) {
                offset += num_cq + num_rx * (qid / 2);

                num = ARRAY_SIZE(virtnet_rq_stats_desc);
                if (drv_stats) {
                        desc = &virtnet_rq_stats_desc[0];
                        goto drv_stats;
                }

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_CVQ) {
                desc = &virtnet_stats_cvq_desc[0];
                num = ARRAY_SIZE(virtnet_stats_cvq_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_CVQ)
                        goto found;

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_BASIC) {
                desc = &virtnet_stats_rx_basic_desc[0];
                num = ARRAY_SIZE(virtnet_stats_rx_basic_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_BASIC)
                        goto found;

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_CSUM) {
                desc = &virtnet_stats_rx_csum_desc[0];
                num = ARRAY_SIZE(virtnet_stats_rx_csum_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_CSUM)
                        goto found;

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_RX_SPEED) {
                desc = &virtnet_stats_rx_speed_desc[0];
                num = ARRAY_SIZE(virtnet_stats_rx_speed_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_RX_SPEED)
                        goto found;

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_BASIC) {
                desc = &virtnet_stats_tx_basic_desc[0];
                num = ARRAY_SIZE(virtnet_stats_tx_basic_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_BASIC)
                        goto found;

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_GSO) {
                desc = &virtnet_stats_tx_gso_desc[0];
                num = ARRAY_SIZE(virtnet_stats_tx_gso_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_GSO)
                        goto found;

                offset += num;
        }

        if (bitmap & VIRTIO_NET_STATS_TYPE_TX_SPEED) {
                desc = &virtnet_stats_tx_speed_desc[0];
                num = ARRAY_SIZE(virtnet_stats_tx_speed_desc);
                if (reply_type == VIRTIO_NET_STATS_TYPE_REPLY_TX_SPEED)
                        goto found;

                offset += num;
        }

        return;

found:
        for (i = 0; i < num; ++i) {
                v = (const __le64 *)(base + desc[i].offset);
                ctx->data[offset + i] = le64_to_cpu(*v);
        }

        return;

drv_stats:
        for (i = 0; i < num; ++i) {
                v_stat = (const u64_stats_t *)(base + desc[i].offset);
                ctx->data[offset + i] = u64_stats_read(v_stat);
        }
}

static int __virtnet_get_hw_stats(struct virtnet_info *vi,
                                  struct virtnet_stats_ctx *ctx,
                                  struct virtio_net_ctrl_queue_stats *req,
                                  int req_size, void *reply, int res_size)
{
        struct virtio_net_stats_reply_hdr *hdr;
        struct scatterlist sgs_in, sgs_out;
        void *p;
        u32 qid;
        int ok;

        sg_init_one(&sgs_out, req, req_size);
        sg_init_one(&sgs_in, reply, res_size);

        ok = virtnet_send_command_reply(vi, VIRTIO_NET_CTRL_STATS,
                                        VIRTIO_NET_CTRL_STATS_GET,
                                        &sgs_out, &sgs_in);

        if (!ok)
                return ok;

        for (p = reply; p - reply < res_size; p += le16_to_cpu(hdr->size)) {
                hdr = p;
                qid = le16_to_cpu(hdr->vq_index);
                virtnet_fill_stats(vi, qid, ctx, p, false, hdr->type);
        }

        return 0;
}

static void virtnet_make_stat_req(struct virtnet_info *vi,
                                  struct virtnet_stats_ctx *ctx,
                                  struct virtio_net_ctrl_queue_stats *req,
                                  int qid, int *idx)
{
        int qtype = vq_type(vi, qid);
        u64 bitmap = ctx->bitmap[qtype];

        if (!bitmap)
                return;

        req->stats[*idx].vq_index = cpu_to_le16(qid);
        req->stats[*idx].types_bitmap[0] = cpu_to_le64(bitmap);
        *idx += 1;
}

/* qid: -1: get stats of all vq.
 *     > 0: get the stats for the special vq. This must not be cvq.
 */
static int virtnet_get_hw_stats(struct virtnet_info *vi,
                                struct virtnet_stats_ctx *ctx, int qid)
{
        int qnum, i, j, res_size, qtype, last_vq, first_vq;
        struct virtio_net_ctrl_queue_stats *req;
        bool enable_cvq;
        void *reply;
        int ok;

        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_DEVICE_STATS))
                return 0;

        if (qid == -1) {
                last_vq = vi->curr_queue_pairs * 2 - 1;
                first_vq = 0;
                enable_cvq = true;
        } else {
                last_vq = qid;
                first_vq = qid;
                enable_cvq = false;
        }

        qnum = 0;
        res_size = 0;
        for (i = first_vq; i <= last_vq ; ++i) {
                qtype = vq_type(vi, i);
                if (ctx->bitmap[qtype]) {
                        ++qnum;
                        res_size += ctx->size[qtype];
                }
        }

        if (enable_cvq && ctx->bitmap[VIRTNET_Q_TYPE_CQ]) {
                res_size += ctx->size[VIRTNET_Q_TYPE_CQ];
                qnum += 1;
        }

        req = kzalloc_objs(*req, qnum);
        if (!req)
                return -ENOMEM;

        reply = kmalloc(res_size, GFP_KERNEL);
        if (!reply) {
                kfree(req);
                return -ENOMEM;
        }

        j = 0;
        for (i = first_vq; i <= last_vq ; ++i)
                virtnet_make_stat_req(vi, ctx, req, i, &j);

        if (enable_cvq)
                virtnet_make_stat_req(vi, ctx, req, vi->max_queue_pairs * 2, &j);

        ok = __virtnet_get_hw_stats(vi, ctx, req, sizeof(*req) * j, reply, res_size);

        kfree(req);
        kfree(reply);

        return ok;
}

static void virtnet_get_strings(struct net_device *dev, u32 stringset, u8 *data)
{
        struct virtnet_info *vi = netdev_priv(dev);
        unsigned int i;
        u8 *p = data;

        switch (stringset) {
        case ETH_SS_STATS:
                /* Generate the total field names. */
                virtnet_get_stats_string(vi, VIRTNET_Q_TYPE_RX, -1, &p);
                virtnet_get_stats_string(vi, VIRTNET_Q_TYPE_TX, -1, &p);

                virtnet_get_stats_string(vi, VIRTNET_Q_TYPE_CQ, 0, &p);

                for (i = 0; i < vi->curr_queue_pairs; ++i)
                        virtnet_get_stats_string(vi, VIRTNET_Q_TYPE_RX, i, &p);

                for (i = 0; i < vi->curr_queue_pairs; ++i)
                        virtnet_get_stats_string(vi, VIRTNET_Q_TYPE_TX, i, &p);
                break;
        }
}

static int virtnet_get_sset_count(struct net_device *dev, int sset)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct virtnet_stats_ctx ctx = {0};
        u32 pair_count;

        switch (sset) {
        case ETH_SS_STATS:
                virtnet_stats_ctx_init(vi, &ctx, NULL, false);

                pair_count = ctx.desc_num[VIRTNET_Q_TYPE_RX] + ctx.desc_num[VIRTNET_Q_TYPE_TX];

                return pair_count + ctx.desc_num[VIRTNET_Q_TYPE_CQ] +
                        vi->curr_queue_pairs * pair_count;
        default:
                return -EOPNOTSUPP;
        }
}

static void virtnet_get_ethtool_stats(struct net_device *dev,
                                      struct ethtool_stats *stats, u64 *data)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct virtnet_stats_ctx ctx = {0};
        unsigned int start, i;
        const u8 *stats_base;

        virtnet_stats_ctx_init(vi, &ctx, data, false);
        if (virtnet_get_hw_stats(vi, &ctx, -1))
                dev_warn(&vi->dev->dev, "Failed to get hw stats.\n");

        for (i = 0; i < vi->curr_queue_pairs; i++) {
                struct receive_queue *rq = &vi->rq[i];
                struct send_queue *sq = &vi->sq[i];

                stats_base = (const u8 *)&rq->stats;
                do {
                        start = u64_stats_fetch_begin(&rq->stats.syncp);
                        virtnet_fill_stats(vi, i * 2, &ctx, stats_base, true, 0);
                } while (u64_stats_fetch_retry(&rq->stats.syncp, start));

                stats_base = (const u8 *)&sq->stats;
                do {
                        start = u64_stats_fetch_begin(&sq->stats.syncp);
                        virtnet_fill_stats(vi, i * 2 + 1, &ctx, stats_base, true, 0);
                } while (u64_stats_fetch_retry(&sq->stats.syncp, start));
        }

        virtnet_fill_total_fields(vi, &ctx);
}

static void virtnet_get_channels(struct net_device *dev,
                                 struct ethtool_channels *channels)
{
        struct virtnet_info *vi = netdev_priv(dev);

        channels->combined_count = vi->curr_queue_pairs;
        channels->max_combined = vi->max_queue_pairs;
        channels->max_other = 0;
        channels->rx_count = 0;
        channels->tx_count = 0;
        channels->other_count = 0;
}

static int virtnet_set_link_ksettings(struct net_device *dev,
                                      const struct ethtool_link_ksettings *cmd)
{
        struct virtnet_info *vi = netdev_priv(dev);

        return ethtool_virtdev_set_link_ksettings(dev, cmd,
                                                  &vi->speed, &vi->duplex);
}

static int virtnet_get_link_ksettings(struct net_device *dev,
                                      struct ethtool_link_ksettings *cmd)
{
        struct virtnet_info *vi = netdev_priv(dev);

        cmd->base.speed = vi->speed;
        cmd->base.duplex = vi->duplex;
        cmd->base.port = PORT_OTHER;

        return 0;
}

static int virtnet_send_tx_notf_coal_cmds(struct virtnet_info *vi,
                                          struct ethtool_coalesce *ec)
{
        struct virtio_net_ctrl_coal_tx *coal_tx __free(kfree) = NULL;
        struct scatterlist sgs_tx;
        int i;

        coal_tx = kzalloc_obj(*coal_tx);
        if (!coal_tx)
                return -ENOMEM;

        coal_tx->tx_usecs = cpu_to_le32(ec->tx_coalesce_usecs);
        coal_tx->tx_max_packets = cpu_to_le32(ec->tx_max_coalesced_frames);
        sg_init_one(&sgs_tx, coal_tx, sizeof(*coal_tx));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
                                  VIRTIO_NET_CTRL_NOTF_COAL_TX_SET,
                                  &sgs_tx))
                return -EINVAL;

        vi->intr_coal_tx.max_usecs = ec->tx_coalesce_usecs;
        vi->intr_coal_tx.max_packets = ec->tx_max_coalesced_frames;
        for (i = 0; i < vi->max_queue_pairs; i++) {
                vi->sq[i].intr_coal.max_usecs = ec->tx_coalesce_usecs;
                vi->sq[i].intr_coal.max_packets = ec->tx_max_coalesced_frames;
        }

        return 0;
}

static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi,
                                          struct ethtool_coalesce *ec)
{
        struct virtio_net_ctrl_coal_rx *coal_rx __free(kfree) = NULL;
        bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce;
        struct scatterlist sgs_rx;
        int i;

        if (rx_ctrl_dim_on && !virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
                return -EOPNOTSUPP;

        if (rx_ctrl_dim_on && (ec->rx_coalesce_usecs != vi->intr_coal_rx.max_usecs ||
                               ec->rx_max_coalesced_frames != vi->intr_coal_rx.max_packets))
                return -EINVAL;

        if (rx_ctrl_dim_on && !vi->rx_dim_enabled) {
                vi->rx_dim_enabled = true;
                for (i = 0; i < vi->max_queue_pairs; i++) {
                        mutex_lock(&vi->rq[i].dim_lock);
                        vi->rq[i].dim_enabled = true;
                        mutex_unlock(&vi->rq[i].dim_lock);
                }
                return 0;
        }

        coal_rx = kzalloc_obj(*coal_rx);
        if (!coal_rx)
                return -ENOMEM;

        if (!rx_ctrl_dim_on && vi->rx_dim_enabled) {
                vi->rx_dim_enabled = false;
                for (i = 0; i < vi->max_queue_pairs; i++) {
                        mutex_lock(&vi->rq[i].dim_lock);
                        vi->rq[i].dim_enabled = false;
                        mutex_unlock(&vi->rq[i].dim_lock);
                }
        }

        /* Since the per-queue coalescing params can be set,
         * we need apply the global new params even if they
         * are not updated.
         */
        coal_rx->rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
        coal_rx->rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);
        sg_init_one(&sgs_rx, coal_rx, sizeof(*coal_rx));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
                                  VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,
                                  &sgs_rx))
                return -EINVAL;

        vi->intr_coal_rx.max_usecs = ec->rx_coalesce_usecs;
        vi->intr_coal_rx.max_packets = ec->rx_max_coalesced_frames;
        for (i = 0; i < vi->max_queue_pairs; i++) {
                mutex_lock(&vi->rq[i].dim_lock);
                vi->rq[i].intr_coal.max_usecs = ec->rx_coalesce_usecs;
                vi->rq[i].intr_coal.max_packets = ec->rx_max_coalesced_frames;
                mutex_unlock(&vi->rq[i].dim_lock);
        }

        return 0;
}

static int virtnet_send_notf_coal_cmds(struct virtnet_info *vi,
                                       struct ethtool_coalesce *ec)
{
        int err;

        err = virtnet_send_tx_notf_coal_cmds(vi, ec);
        if (err)
                return err;

        err = virtnet_send_rx_notf_coal_cmds(vi, ec);
        if (err)
                return err;

        return 0;
}

static int virtnet_send_rx_notf_coal_vq_cmds(struct virtnet_info *vi,
                                             struct ethtool_coalesce *ec,
                                             u16 queue)
{
        bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce;
        u32 max_usecs, max_packets;
        bool cur_rx_dim;
        int err;

        mutex_lock(&vi->rq[queue].dim_lock);
        cur_rx_dim = vi->rq[queue].dim_enabled;
        max_usecs = vi->rq[queue].intr_coal.max_usecs;
        max_packets = vi->rq[queue].intr_coal.max_packets;

        if (rx_ctrl_dim_on && (ec->rx_coalesce_usecs != max_usecs ||
                               ec->rx_max_coalesced_frames != max_packets)) {
                mutex_unlock(&vi->rq[queue].dim_lock);
                return -EINVAL;
        }

        if (rx_ctrl_dim_on && !cur_rx_dim) {
                vi->rq[queue].dim_enabled = true;
                mutex_unlock(&vi->rq[queue].dim_lock);
                return 0;
        }

        if (!rx_ctrl_dim_on && cur_rx_dim)
                vi->rq[queue].dim_enabled = false;

        /* If no params are updated, userspace ethtool will
         * reject the modification.
         */
        err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, queue,
                                               ec->rx_coalesce_usecs,
                                               ec->rx_max_coalesced_frames);
        mutex_unlock(&vi->rq[queue].dim_lock);
        return err;
}

static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
                                          struct ethtool_coalesce *ec,
                                          u16 queue)
{
        int err;

        err = virtnet_send_rx_notf_coal_vq_cmds(vi, ec, queue);
        if (err)
                return err;

        err = virtnet_send_tx_ctrl_coal_vq_cmd(vi, queue,
                                               ec->tx_coalesce_usecs,
                                               ec->tx_max_coalesced_frames);
        if (err)
                return err;

        return 0;
}

static void virtnet_rx_dim_work(struct work_struct *work)
{
        struct dim *dim = container_of(work, struct dim, work);
        struct receive_queue *rq = container_of(dim,
                        struct receive_queue, dim);
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct net_device *dev = vi->dev;
        struct dim_cq_moder update_moder;
        int qnum, err;

        qnum = rq - vi->rq;

        mutex_lock(&rq->dim_lock);
        if (!rq->dim_enabled)
                goto out;

        update_moder = net_dim_get_rx_irq_moder(dev, dim);
        if (update_moder.usec != rq->intr_coal.max_usecs ||
            update_moder.pkts != rq->intr_coal.max_packets) {
                err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
                                                       update_moder.usec,
                                                       update_moder.pkts);
                if (err)
                        pr_debug("%s: Failed to send dim parameters on rxq%d\n",
                                 dev->name, qnum);
        }
out:
        dim->state = DIM_START_MEASURE;
        mutex_unlock(&rq->dim_lock);
}

static int virtnet_coal_params_supported(struct ethtool_coalesce *ec)
{
        /* usecs coalescing is supported only if VIRTIO_NET_F_NOTF_COAL
         * or VIRTIO_NET_F_VQ_NOTF_COAL feature is negotiated.
         */
        if (ec->rx_coalesce_usecs || ec->tx_coalesce_usecs)
                return -EOPNOTSUPP;

        if (ec->tx_max_coalesced_frames > 1 ||
            ec->rx_max_coalesced_frames != 1)
                return -EINVAL;

        return 0;
}

static int virtnet_should_update_vq_weight(int dev_flags, int weight,
                                           int vq_weight, bool *should_update)
{
        if (weight ^ vq_weight) {
                if (dev_flags & IFF_UP)
                        return -EBUSY;
                *should_update = true;
        }

        return 0;
}

static int virtnet_set_coalesce(struct net_device *dev,
                                struct ethtool_coalesce *ec,
                                struct kernel_ethtool_coalesce *kernel_coal,
                                struct netlink_ext_ack *extack)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int ret, queue_number, napi_weight, i;
        bool update_napi = false;

        /* Can't change NAPI weight if the link is up */
        napi_weight = ec->tx_max_coalesced_frames ? NAPI_POLL_WEIGHT : 0;
        for (queue_number = 0; queue_number < vi->max_queue_pairs; queue_number++) {
                ret = virtnet_should_update_vq_weight(dev->flags, napi_weight,
                                                      vi->sq[queue_number].napi.weight,
                                                      &update_napi);
                if (ret)
                        return ret;

                if (update_napi) {
                        /* All queues that belong to [queue_number, vi->max_queue_pairs] will be
                         * updated for the sake of simplicity, which might not be necessary
                         */
                        break;
                }
        }

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL))
                ret = virtnet_send_notf_coal_cmds(vi, ec);
        else
                ret = virtnet_coal_params_supported(ec);

        if (ret)
                return ret;

        if (update_napi) {
                /* xsk xmit depends on the tx napi. So if xsk is active,
                 * prevent modifications to tx napi.
                 */
                for (i = queue_number; i < vi->max_queue_pairs; i++) {
                        if (vi->sq[i].xsk_pool)
                                return -EBUSY;
                }

                for (; queue_number < vi->max_queue_pairs; queue_number++)
                        vi->sq[queue_number].napi.weight = napi_weight;
        }

        return ret;
}

static int virtnet_get_coalesce(struct net_device *dev,
                                struct ethtool_coalesce *ec,
                                struct kernel_ethtool_coalesce *kernel_coal,
                                struct netlink_ext_ack *extack)
{
        struct virtnet_info *vi = netdev_priv(dev);

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {
                ec->rx_coalesce_usecs = vi->intr_coal_rx.max_usecs;
                ec->tx_coalesce_usecs = vi->intr_coal_tx.max_usecs;
                ec->tx_max_coalesced_frames = vi->intr_coal_tx.max_packets;
                ec->rx_max_coalesced_frames = vi->intr_coal_rx.max_packets;
                ec->use_adaptive_rx_coalesce = vi->rx_dim_enabled;
        } else {
                ec->rx_max_coalesced_frames = 1;

                if (vi->sq[0].napi.weight)
                        ec->tx_max_coalesced_frames = 1;
        }

        return 0;
}

static int virtnet_set_per_queue_coalesce(struct net_device *dev,
                                          u32 queue,
                                          struct ethtool_coalesce *ec)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int ret, napi_weight;
        bool update_napi = false;

        if (queue >= vi->max_queue_pairs)
                return -EINVAL;

        /* Can't change NAPI weight if the link is up */
        napi_weight = ec->tx_max_coalesced_frames ? NAPI_POLL_WEIGHT : 0;
        ret = virtnet_should_update_vq_weight(dev->flags, napi_weight,
                                              vi->sq[queue].napi.weight,
                                              &update_napi);
        if (ret)
                return ret;

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
                ret = virtnet_send_notf_coal_vq_cmds(vi, ec, queue);
        else
                ret = virtnet_coal_params_supported(ec);

        if (ret)
                return ret;

        if (update_napi)
                vi->sq[queue].napi.weight = napi_weight;

        return 0;
}

static int virtnet_get_per_queue_coalesce(struct net_device *dev,
                                          u32 queue,
                                          struct ethtool_coalesce *ec)
{
        struct virtnet_info *vi = netdev_priv(dev);

        if (queue >= vi->max_queue_pairs)
                return -EINVAL;

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
                mutex_lock(&vi->rq[queue].dim_lock);
                ec->rx_coalesce_usecs = vi->rq[queue].intr_coal.max_usecs;
                ec->tx_coalesce_usecs = vi->sq[queue].intr_coal.max_usecs;
                ec->tx_max_coalesced_frames = vi->sq[queue].intr_coal.max_packets;
                ec->rx_max_coalesced_frames = vi->rq[queue].intr_coal.max_packets;
                ec->use_adaptive_rx_coalesce = vi->rq[queue].dim_enabled;
                mutex_unlock(&vi->rq[queue].dim_lock);
        } else {
                ec->rx_max_coalesced_frames = 1;

                if (vi->sq[queue].napi.weight)
                        ec->tx_max_coalesced_frames = 1;
        }

        return 0;
}

static void virtnet_init_settings(struct net_device *dev)
{
        struct virtnet_info *vi = netdev_priv(dev);

        vi->speed = SPEED_UNKNOWN;
        vi->duplex = DUPLEX_UNKNOWN;
}

static u32 virtnet_get_rxfh_key_size(struct net_device *dev)
{
        return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size;
}

static u32 virtnet_get_rxfh_indir_size(struct net_device *dev)
{
        return ((struct virtnet_info *)netdev_priv(dev))->rss_indir_table_size;
}

static int virtnet_get_rxfh(struct net_device *dev,
                            struct ethtool_rxfh_param *rxfh)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int i;

        if (rxfh->indir) {
                for (i = 0; i < vi->rss_indir_table_size; ++i)
                        rxfh->indir[i] = le16_to_cpu(vi->rss_hdr->indirection_table[i]);
        }

        if (rxfh->key)
                memcpy(rxfh->key, vi->rss_hash_key_data, vi->rss_key_size);

        rxfh->hfunc = ETH_RSS_HASH_TOP;

        return 0;
}

static int virtnet_set_rxfh(struct net_device *dev,
                            struct ethtool_rxfh_param *rxfh,
                            struct netlink_ext_ack *extack)
{
        struct virtnet_info *vi = netdev_priv(dev);
        bool update = false;
        int i;

        if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
            rxfh->hfunc != ETH_RSS_HASH_TOP)
                return -EOPNOTSUPP;

        if (rxfh->indir) {
                if (!vi->has_rss)
                        return -EOPNOTSUPP;

                for (i = 0; i < vi->rss_indir_table_size; ++i)
                        vi->rss_hdr->indirection_table[i] = cpu_to_le16(rxfh->indir[i]);
                update = true;
        }

        if (rxfh->key) {
                /* If either _F_HASH_REPORT or _F_RSS are negotiated, the
                 * device provides hash calculation capabilities, that is,
                 * hash_key is configured.
                 */
                if (!vi->has_rss && !vi->has_rss_hash_report)
                        return -EOPNOTSUPP;

                memcpy(vi->rss_hash_key_data, rxfh->key, vi->rss_key_size);
                update = true;
        }

        if (update)
                virtnet_commit_rss_command(vi);

        return 0;
}

static u32 virtnet_get_rx_ring_count(struct net_device *dev)
{
        struct virtnet_info *vi = netdev_priv(dev);

        return vi->curr_queue_pairs;
}

static const struct ethtool_ops virtnet_ethtool_ops = {
        .supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |
                ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
        .get_drvinfo = virtnet_get_drvinfo,
        .get_link = ethtool_op_get_link,
        .get_ringparam = virtnet_get_ringparam,
        .set_ringparam = virtnet_set_ringparam,
        .get_strings = virtnet_get_strings,
        .get_sset_count = virtnet_get_sset_count,
        .get_ethtool_stats = virtnet_get_ethtool_stats,
        .set_channels = virtnet_set_channels,
        .get_channels = virtnet_get_channels,
        .get_ts_info = ethtool_op_get_ts_info,
        .get_link_ksettings = virtnet_get_link_ksettings,
        .set_link_ksettings = virtnet_set_link_ksettings,
        .set_coalesce = virtnet_set_coalesce,
        .get_coalesce = virtnet_get_coalesce,
        .set_per_queue_coalesce = virtnet_set_per_queue_coalesce,
        .get_per_queue_coalesce = virtnet_get_per_queue_coalesce,
        .get_rxfh_key_size = virtnet_get_rxfh_key_size,
        .get_rxfh_indir_size = virtnet_get_rxfh_indir_size,
        .get_rxfh = virtnet_get_rxfh,
        .set_rxfh = virtnet_set_rxfh,
        .get_rxfh_fields = virtnet_get_hashflow,
        .set_rxfh_fields = virtnet_set_hashflow,
        .get_rx_ring_count = virtnet_get_rx_ring_count,
};

static void virtnet_get_queue_stats_rx(struct net_device *dev, int i,
                                       struct netdev_queue_stats_rx *stats)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct receive_queue *rq = &vi->rq[i];
        struct virtnet_stats_ctx ctx = {0};

        virtnet_stats_ctx_init(vi, &ctx, (void *)stats, true);

        virtnet_get_hw_stats(vi, &ctx, i * 2);
        virtnet_fill_stats(vi, i * 2, &ctx, (void *)&rq->stats, true, 0);
}

static void virtnet_get_queue_stats_tx(struct net_device *dev, int i,
                                       struct netdev_queue_stats_tx *stats)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct send_queue *sq = &vi->sq[i];
        struct virtnet_stats_ctx ctx = {0};

        virtnet_stats_ctx_init(vi, &ctx, (void *)stats, true);

        virtnet_get_hw_stats(vi, &ctx, i * 2 + 1);
        virtnet_fill_stats(vi, i * 2 + 1, &ctx, (void *)&sq->stats, true, 0);
}

static void virtnet_get_base_stats(struct net_device *dev,
                                   struct netdev_queue_stats_rx *rx,
                                   struct netdev_queue_stats_tx *tx)
{
        struct virtnet_info *vi = netdev_priv(dev);

        /* The queue stats of the virtio-net will not be reset. So here we
         * return 0.
         */
        rx->bytes = 0;
        rx->packets = 0;

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_BASIC) {
                rx->hw_drops = 0;
                rx->hw_drop_overruns = 0;
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_CSUM) {
                rx->csum_unnecessary = 0;
                rx->csum_none = 0;
                rx->csum_bad = 0;
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_GSO) {
                rx->hw_gro_packets = 0;
                rx->hw_gro_bytes = 0;
                rx->hw_gro_wire_packets = 0;
                rx->hw_gro_wire_bytes = 0;
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_RX_SPEED)
                rx->hw_drop_ratelimits = 0;

        tx->bytes = 0;
        tx->packets = 0;
        tx->stop = 0;
        tx->wake = 0;

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_BASIC) {
                tx->hw_drops = 0;
                tx->hw_drop_errors = 0;
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_CSUM) {
                tx->csum_none = 0;
                tx->needs_csum = 0;
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_GSO) {
                tx->hw_gso_packets = 0;
                tx->hw_gso_bytes = 0;
                tx->hw_gso_wire_packets = 0;
                tx->hw_gso_wire_bytes = 0;
        }

        if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_SPEED)
                tx->hw_drop_ratelimits = 0;

        netdev_stat_queue_sum(dev,
                              dev->real_num_rx_queues, vi->max_queue_pairs, rx,
                              dev->real_num_tx_queues, vi->max_queue_pairs, tx);
}

static const struct netdev_stat_ops virtnet_stat_ops = {
        .get_queue_stats_rx     = virtnet_get_queue_stats_rx,
        .get_queue_stats_tx     = virtnet_get_queue_stats_tx,
        .get_base_stats         = virtnet_get_base_stats,
};

static void virtnet_freeze_down(struct virtio_device *vdev)
{
        struct virtnet_info *vi = vdev->priv;

        /* Make sure no work handler is accessing the device */
        flush_work(&vi->config_work);
        disable_rx_mode_work(vi);
        flush_work(&vi->rx_mode_work);

        if (netif_running(vi->dev)) {
                rtnl_lock();
                virtnet_close(vi->dev);
                rtnl_unlock();
        }

        netif_tx_lock_bh(vi->dev);
        netif_device_detach(vi->dev);
        netif_tx_unlock_bh(vi->dev);
}

static int init_vqs(struct virtnet_info *vi);

static int virtnet_restore_up(struct virtio_device *vdev)
{
        struct virtnet_info *vi = vdev->priv;
        int err;

        err = init_vqs(vi);
        if (err)
                return err;

        virtio_device_ready(vdev);

        enable_rx_mode_work(vi);

        if (netif_running(vi->dev)) {
                rtnl_lock();
                err = virtnet_open(vi->dev);
                rtnl_unlock();
                if (err)
                        return err;
        }

        netif_tx_lock_bh(vi->dev);
        netif_device_attach(vi->dev);
        netif_tx_unlock_bh(vi->dev);
        return err;
}

static int virtnet_set_guest_offloads(struct virtnet_info *vi, u64 offloads)
{
        __virtio64 *_offloads __free(kfree) = NULL;
        struct scatterlist sg;

        _offloads = kzalloc_obj(*_offloads);
        if (!_offloads)
                return -ENOMEM;

        *_offloads = cpu_to_virtio64(vi->vdev, offloads);

        sg_init_one(&sg, _offloads, sizeof(*_offloads));

        if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_GUEST_OFFLOADS,
                                  VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET, &sg)) {
                dev_warn(&vi->dev->dev, "Fail to set guest offload.\n");
                return -EINVAL;
        }

        return 0;
}

static int virtnet_clear_guest_offloads(struct virtnet_info *vi)
{
        u64 offloads = 0;

        if (!vi->guest_offloads)
                return 0;

        return virtnet_set_guest_offloads(vi, offloads);
}

static int virtnet_restore_guest_offloads(struct virtnet_info *vi)
{
        u64 offloads = vi->guest_offloads;

        if (!vi->guest_offloads)
                return 0;

        return virtnet_set_guest_offloads(vi, offloads);
}

static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queue *rq,
                                    struct xsk_buff_pool *pool)
{
        int err, qindex;

        qindex = rq - vi->rq;

        if (pool) {
                err = xdp_rxq_info_reg(&rq->xsk_rxq_info, vi->dev, qindex, rq->napi.napi_id);
                if (err < 0)
                        return err;

                err = xdp_rxq_info_reg_mem_model(&rq->xsk_rxq_info,
                                                 MEM_TYPE_XSK_BUFF_POOL, NULL);
                if (err < 0)
                        goto unreg;

                xsk_pool_set_rxq_info(pool, &rq->xsk_rxq_info);
        }

        virtnet_rx_pause(vi, rq);

        err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf, NULL);
        if (err) {
                netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);

                pool = NULL;
        }

        rq->xsk_pool = pool;

        virtnet_rx_resume(vi, rq, true);

        if (pool)
                return 0;

unreg:
        xdp_rxq_info_unreg(&rq->xsk_rxq_info);
        return err;
}

static int virtnet_sq_bind_xsk_pool(struct virtnet_info *vi,
                                    struct send_queue *sq,
                                    struct xsk_buff_pool *pool)
{
        int err, qindex;

        qindex = sq - vi->sq;

        virtnet_tx_pause(vi, sq);

        err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf,
                              virtnet_sq_free_unused_buf_done);
        if (err) {
                netdev_err(vi->dev, "reset tx fail: tx queue index: %d err: %d\n", qindex, err);
                pool = NULL;
        }

        sq->xsk_pool = pool;

        virtnet_tx_resume(vi, sq);

        return err;
}

static int virtnet_xsk_pool_enable(struct net_device *dev,
                                   struct xsk_buff_pool *pool,
                                   u16 qid)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct receive_queue *rq;
        struct device *dma_dev;
        struct send_queue *sq;
        dma_addr_t hdr_dma;
        int err, size;

        if (vi->hdr_len > xsk_pool_get_headroom(pool))
                return -EINVAL;

        /* In big_packets mode, xdp cannot work, so there is no need to
         * initialize xsk of rq.
         */
        if (vi->big_packets && !vi->mergeable_rx_bufs)
                return -ENOENT;

        if (qid >= vi->curr_queue_pairs)
                return -EINVAL;

        sq = &vi->sq[qid];
        rq = &vi->rq[qid];

        /* xsk assumes that tx and rx must have the same dma device. The af-xdp
         * may use one buffer to receive from the rx and reuse this buffer to
         * send by the tx. So the dma dev of sq and rq must be the same one.
         *
         * But vq->dma_dev allows every vq has the respective dma dev. So I
         * check the dma dev of vq and sq is the same dev.
         */
        if (virtqueue_dma_dev(rq->vq) != virtqueue_dma_dev(sq->vq))
                return -EINVAL;

        dma_dev = virtqueue_dma_dev(rq->vq);
        if (!dma_dev)
                return -EINVAL;

        size = virtqueue_get_vring_size(rq->vq);

        rq->xsk_buffs = kvzalloc_objs(*rq->xsk_buffs, size);
        if (!rq->xsk_buffs)
                return -ENOMEM;

        hdr_dma = virtqueue_map_single_attrs(sq->vq, &xsk_hdr, vi->hdr_len,
                                             DMA_TO_DEVICE, 0);
        if (virtqueue_map_mapping_error(sq->vq, hdr_dma)) {
                err = -ENOMEM;
                goto err_free_buffs;
        }

        err = xsk_pool_dma_map(pool, dma_dev, 0);
        if (err)
                goto err_xsk_map;

        err = virtnet_rq_bind_xsk_pool(vi, rq, pool);
        if (err)
                goto err_rq;

        err = virtnet_sq_bind_xsk_pool(vi, sq, pool);
        if (err)
                goto err_sq;

        /* Now, we do not support tx offload(such as tx csum), so all the tx
         * virtnet hdr is zero. So all the tx packets can share a single hdr.
         */
        sq->xsk_hdr_dma_addr = hdr_dma;

        return 0;

err_sq:
        virtnet_rq_bind_xsk_pool(vi, rq, NULL);
err_rq:
        xsk_pool_dma_unmap(pool, 0);
err_xsk_map:
        virtqueue_unmap_single_attrs(rq->vq, hdr_dma, vi->hdr_len,
                                     DMA_TO_DEVICE, 0);
err_free_buffs:
        kvfree(rq->xsk_buffs);
        return err;
}

static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
{
        struct virtnet_info *vi = netdev_priv(dev);
        struct xsk_buff_pool *pool;
        struct receive_queue *rq;
        struct send_queue *sq;
        int err;

        if (qid >= vi->curr_queue_pairs)
                return -EINVAL;

        sq = &vi->sq[qid];
        rq = &vi->rq[qid];

        pool = rq->xsk_pool;

        err = virtnet_rq_bind_xsk_pool(vi, rq, NULL);
        err |= virtnet_sq_bind_xsk_pool(vi, sq, NULL);

        xsk_pool_dma_unmap(pool, 0);

        virtqueue_unmap_single_attrs(sq->vq, sq->xsk_hdr_dma_addr,
                                     vi->hdr_len, DMA_TO_DEVICE, 0);
        kvfree(rq->xsk_buffs);

        return err;
}

static int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp)
{
        if (xdp->xsk.pool)
                return virtnet_xsk_pool_enable(dev, xdp->xsk.pool,
                                               xdp->xsk.queue_id);
        else
                return virtnet_xsk_pool_disable(dev, xdp->xsk.queue_id);
}

static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
                           struct netlink_ext_ack *extack)
{
        unsigned int room = SKB_DATA_ALIGN(XDP_PACKET_HEADROOM +
                                           sizeof(struct skb_shared_info));
        unsigned int max_sz = PAGE_SIZE - room - ETH_HLEN;
        struct virtnet_info *vi = netdev_priv(dev);
        struct bpf_prog *old_prog;
        u16 xdp_qp = 0, curr_qp;
        int i, err;

        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)
            && (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO4) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO6))) {
                NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing GRO_HW/CSUM, disable GRO_HW/CSUM first");
                return -EOPNOTSUPP;
        }

        if (vi->mergeable_rx_bufs && !vi->any_header_sg) {
                NL_SET_ERR_MSG_MOD(extack, "XDP expects header/data in single page, any_header_sg required");
                return -EINVAL;
        }

        if (prog && !prog->aux->xdp_has_frags && dev->mtu > max_sz) {
                NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP without frags");
                netdev_warn(dev, "single-buffer XDP requires MTU less than %u\n", max_sz);
                return -EINVAL;
        }

        curr_qp = vi->curr_queue_pairs - vi->xdp_queue_pairs;
        if (prog)
                xdp_qp = nr_cpu_ids;

        /* XDP requires extra queues for XDP_TX */
        if (curr_qp + xdp_qp > vi->max_queue_pairs) {
                netdev_warn_once(dev, "XDP request %i queues but max is %i. XDP_TX and XDP_REDIRECT will operate in a slower locked tx mode.\n",
                                 curr_qp + xdp_qp, vi->max_queue_pairs);
                xdp_qp = 0;
        }

        old_prog = rtnl_dereference(vi->rq[0].xdp_prog);
        if (!prog && !old_prog)
                return 0;

        if (prog)
                bpf_prog_add(prog, vi->max_queue_pairs - 1);

        virtnet_rx_pause_all(vi);

        /* Make sure NAPI is not using any XDP TX queues for RX. */
        if (netif_running(dev)) {
                for (i = 0; i < vi->max_queue_pairs; i++)
                        virtnet_napi_tx_disable(&vi->sq[i]);
        }

        if (!prog) {
                for (i = 0; i < vi->max_queue_pairs; i++) {
                        rcu_assign_pointer(vi->rq[i].xdp_prog, prog);
                        if (i == 0)
                                virtnet_restore_guest_offloads(vi);
                }
                synchronize_net();
        }

        err = virtnet_set_queues(vi, curr_qp + xdp_qp);
        if (err)
                goto err;
        netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp);
        vi->xdp_queue_pairs = xdp_qp;

        if (prog) {
                vi->xdp_enabled = true;
                for (i = 0; i < vi->max_queue_pairs; i++) {
                        rcu_assign_pointer(vi->rq[i].xdp_prog, prog);
                        if (i == 0 && !old_prog)
                                virtnet_clear_guest_offloads(vi);
                }
                if (!old_prog)
                        xdp_features_set_redirect_target(dev, true);
        } else {
                xdp_features_clear_redirect_target(dev);
                vi->xdp_enabled = false;
        }

        virtnet_rx_resume_all(vi);
        for (i = 0; i < vi->max_queue_pairs; i++) {
                if (old_prog)
                        bpf_prog_put(old_prog);
                if (netif_running(dev))
                        virtnet_napi_tx_enable(&vi->sq[i]);
        }

        return 0;

err:
        if (!prog) {
                virtnet_clear_guest_offloads(vi);
                for (i = 0; i < vi->max_queue_pairs; i++)
                        rcu_assign_pointer(vi->rq[i].xdp_prog, old_prog);
        }

        virtnet_rx_resume_all(vi);
        if (netif_running(dev)) {
                for (i = 0; i < vi->max_queue_pairs; i++)
                        virtnet_napi_tx_enable(&vi->sq[i]);
        }
        if (prog)
                bpf_prog_sub(prog, vi->max_queue_pairs - 1);
        return err;
}

static int virtnet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
{
        switch (xdp->command) {
        case XDP_SETUP_PROG:
                return virtnet_xdp_set(dev, xdp->prog, xdp->extack);
        case XDP_SETUP_XSK_POOL:
                return virtnet_xsk_pool_setup(dev, xdp);
        default:
                return -EINVAL;
        }
}

static int virtnet_get_phys_port_name(struct net_device *dev, char *buf,
                                      size_t len)
{
        struct virtnet_info *vi = netdev_priv(dev);
        int ret;

        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STANDBY))
                return -EOPNOTSUPP;

        ret = snprintf(buf, len, "sby");
        if (ret >= len)
                return -EOPNOTSUPP;

        return 0;
}

static int virtnet_set_features(struct net_device *dev,
                                netdev_features_t features)
{
        struct virtnet_info *vi = netdev_priv(dev);
        u64 offloads;
        int err;

        if ((dev->features ^ features) & NETIF_F_GRO_HW) {
                if (vi->xdp_enabled)
                        return -EBUSY;

                if (features & NETIF_F_GRO_HW)
                        offloads = vi->guest_offloads_capable;
                else
                        offloads = vi->guest_offloads_capable &
                                   ~GUEST_OFFLOAD_GRO_HW_MASK;

                err = virtnet_set_guest_offloads(vi, offloads);
                if (err)
                        return err;
                vi->guest_offloads = offloads;
        }

        if ((dev->features ^ features) & NETIF_F_RXHASH) {
                if (features & NETIF_F_RXHASH)
                        vi->rss_hdr->hash_types = cpu_to_le32(vi->rss_hash_types_saved);
                else
                        vi->rss_hdr->hash_types = cpu_to_le32(VIRTIO_NET_HASH_REPORT_NONE);

                if (!virtnet_commit_rss_command(vi))
                        return -EINVAL;
        }

        return 0;
}

static void virtnet_tx_timeout(struct net_device *dev, unsigned int txqueue)
{
        struct virtnet_info *priv = netdev_priv(dev);
        struct send_queue *sq = &priv->sq[txqueue];
        struct netdev_queue *txq = netdev_get_tx_queue(dev, txqueue);

        u64_stats_update_begin(&sq->stats.syncp);
        u64_stats_inc(&sq->stats.tx_timeouts);
        u64_stats_update_end(&sq->stats.syncp);

        netdev_err(dev, "TX timeout on queue: %u, sq: %s, vq: 0x%x, name: %s, %u usecs ago\n",
                   txqueue, sq->name, sq->vq->index, sq->vq->name,
                   jiffies_to_usecs(jiffies - READ_ONCE(txq->trans_start)));
}

static int virtnet_init_irq_moder(struct virtnet_info *vi)
{
        u8 profile_flags = 0, coal_flags = 0;
        int ret, i;

        profile_flags |= DIM_PROFILE_RX;
        coal_flags |= DIM_COALESCE_USEC | DIM_COALESCE_PKTS;
        ret = net_dim_init_irq_moder(vi->dev, profile_flags, coal_flags,
                                     DIM_CQ_PERIOD_MODE_START_FROM_EQE,
                                     0, virtnet_rx_dim_work, NULL);

        if (ret)
                return ret;

        for (i = 0; i < vi->max_queue_pairs; i++)
                net_dim_setting(vi->dev, &vi->rq[i].dim, false);

        return 0;
}

static void virtnet_free_irq_moder(struct virtnet_info *vi)
{
        if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
                return;

        rtnl_lock();
        net_dim_free_irq_moder(vi->dev);
        rtnl_unlock();
}

static const struct net_device_ops virtnet_netdev = {
        .ndo_open            = virtnet_open,
        .ndo_stop            = virtnet_close,
        .ndo_start_xmit      = start_xmit,
        .ndo_validate_addr   = eth_validate_addr,
        .ndo_set_mac_address = virtnet_set_mac_address,
        .ndo_set_rx_mode     = virtnet_set_rx_mode,
        .ndo_get_stats64     = virtnet_stats,
        .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
        .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
        .ndo_bpf                = virtnet_xdp,
        .ndo_xdp_xmit           = virtnet_xdp_xmit,
        .ndo_xsk_wakeup         = virtnet_xsk_wakeup,
        .ndo_features_check     = passthru_features_check,
        .ndo_get_phys_port_name = virtnet_get_phys_port_name,
        .ndo_set_features       = virtnet_set_features,
        .ndo_tx_timeout         = virtnet_tx_timeout,
};

static void virtnet_config_changed_work(struct work_struct *work)
{
        struct virtnet_info *vi =
                container_of(work, struct virtnet_info, config_work);
        u16 v;

        if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
                                 struct virtio_net_config, status, &v) < 0)
                return;

        if (v & VIRTIO_NET_S_ANNOUNCE) {
                netdev_notify_peers(vi->dev);
                virtnet_ack_link_announce(vi);
        }

        /* Ignore unknown (future) status bits */
        v &= VIRTIO_NET_S_LINK_UP;

        if (vi->status == v)
                return;

        vi->status = v;

        if (vi->status & VIRTIO_NET_S_LINK_UP) {
                virtnet_update_settings(vi);
                netif_carrier_on(vi->dev);
                netif_tx_wake_all_queues(vi->dev);
        } else {
                netif_carrier_off(vi->dev);
                netif_tx_stop_all_queues(vi->dev);
        }
}

static void virtnet_config_changed(struct virtio_device *vdev)
{
        struct virtnet_info *vi = vdev->priv;

        schedule_work(&vi->config_work);
}

static void virtnet_free_queues(struct virtnet_info *vi)
{
        int i;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                __netif_napi_del(&vi->rq[i].napi);
                __netif_napi_del(&vi->sq[i].napi);
        }

        /* We called __netif_napi_del(),
         * we need to respect an RCU grace period before freeing vi->rq
         */
        synchronize_net();

        kfree(vi->rq);
        kfree(vi->sq);
        kfree(vi->ctrl);
}

static void _free_receive_bufs(struct virtnet_info *vi)
{
        struct bpf_prog *old_prog;
        int i;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                while (vi->rq[i].pages)
                        __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);

                old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
                RCU_INIT_POINTER(vi->rq[i].xdp_prog, NULL);
                if (old_prog)
                        bpf_prog_put(old_prog);
        }
}

static void free_receive_bufs(struct virtnet_info *vi)
{
        rtnl_lock();
        _free_receive_bufs(vi);
        rtnl_unlock();
}

static void free_receive_page_frags(struct virtnet_info *vi)
{
        int i;
        for (i = 0; i < vi->max_queue_pairs; i++)
                if (vi->rq[i].alloc_frag.page) {
                        if (vi->rq[i].last_dma)
                                virtnet_rq_unmap(&vi->rq[i], vi->rq[i].last_dma, 0);
                        put_page(vi->rq[i].alloc_frag.page);
                }
}

static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
{
        struct virtnet_info *vi = vq->vdev->priv;
        struct send_queue *sq;
        int i = vq2txq(vq);

        sq = &vi->sq[i];

        switch (virtnet_xmit_ptr_unpack(&buf)) {
        case VIRTNET_XMIT_TYPE_SKB:
        case VIRTNET_XMIT_TYPE_SKB_ORPHAN:
                dev_kfree_skb(buf);
                break;

        case VIRTNET_XMIT_TYPE_XDP:
                xdp_return_frame(buf);
                break;

        case VIRTNET_XMIT_TYPE_XSK:
                xsk_tx_completed(sq->xsk_pool, 1);
                break;
        }
}

static void virtnet_sq_free_unused_buf_done(struct virtqueue *vq)
{
        struct virtnet_info *vi = vq->vdev->priv;
        int i = vq2txq(vq);

        netdev_tx_reset_queue(netdev_get_tx_queue(vi->dev, i));
}

static void free_unused_bufs(struct virtnet_info *vi)
{
        void *buf;
        int i;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                struct virtqueue *vq = vi->sq[i].vq;
                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
                        virtnet_sq_free_unused_buf(vq, buf);
                cond_resched();
        }

        for (i = 0; i < vi->max_queue_pairs; i++) {
                struct virtqueue *vq = vi->rq[i].vq;

                while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
                        virtnet_rq_unmap_free_buf(vq, buf);
                cond_resched();
        }
}

static void virtnet_del_vqs(struct virtnet_info *vi)
{
        struct virtio_device *vdev = vi->vdev;

        virtnet_clean_affinity(vi);

        vdev->config->del_vqs(vdev);

        virtnet_free_queues(vi);
}

/* How large should a single buffer be so a queue full of these can fit at
 * least one full packet?
 * Logic below assumes the mergeable buffer header is used.
 */
static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqueue *vq)
{
        const unsigned int hdr_len = vi->hdr_len;
        unsigned int rq_size = virtqueue_get_vring_size(vq);
        unsigned int packet_len = vi->big_packets ? IP_MAX_MTU : vi->dev->max_mtu;
        unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len;
        unsigned int min_buf_len = DIV_ROUND_UP(buf_len, rq_size);

        return max(max(min_buf_len, hdr_len) - hdr_len,
                   (unsigned int)GOOD_PACKET_LEN);
}

static int virtnet_find_vqs(struct virtnet_info *vi)
{
        struct virtqueue_info *vqs_info;
        struct virtqueue **vqs;
        int ret = -ENOMEM;
        int total_vqs;
        bool *ctx;
        u16 i;

        /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
         * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
         * possible control vq.
         */
        total_vqs = vi->max_queue_pairs * 2 +
                    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);

        /* Allocate space for find_vqs parameters */
        vqs = kzalloc_objs(*vqs, total_vqs);
        if (!vqs)
                goto err_vq;
        vqs_info = kzalloc_objs(*vqs_info, total_vqs);
        if (!vqs_info)
                goto err_vqs_info;
        if (!vi->big_packets || vi->mergeable_rx_bufs) {
                ctx = kzalloc_objs(*ctx, total_vqs);
                if (!ctx)
                        goto err_ctx;
        } else {
                ctx = NULL;
        }

        /* Parameters for control virtqueue, if any */
        if (vi->has_cvq) {
                vqs_info[total_vqs - 1].name = "control";
        }

        /* Allocate/initialize parameters for send/receive virtqueues */
        for (i = 0; i < vi->max_queue_pairs; i++) {
                vqs_info[rxq2vq(i)].callback = skb_recv_done;
                vqs_info[txq2vq(i)].callback = skb_xmit_done;
                sprintf(vi->rq[i].name, "input.%u", i);
                sprintf(vi->sq[i].name, "output.%u", i);
                vqs_info[rxq2vq(i)].name = vi->rq[i].name;
                vqs_info[txq2vq(i)].name = vi->sq[i].name;
                if (ctx)
                        vqs_info[rxq2vq(i)].ctx = true;
        }

        ret = virtio_find_vqs(vi->vdev, total_vqs, vqs, vqs_info, NULL);
        if (ret)
                goto err_find;

        if (vi->has_cvq) {
                vi->cvq = vqs[total_vqs - 1];
                if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
                        vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
        }

        for (i = 0; i < vi->max_queue_pairs; i++) {
                vi->rq[i].vq = vqs[rxq2vq(i)];
                vi->rq[i].min_buf_len = mergeable_min_buf_len(vi, vi->rq[i].vq);
                vi->sq[i].vq = vqs[txq2vq(i)];
        }

        /* run here: ret == 0. */


err_find:
        kfree(ctx);
err_ctx:
        kfree(vqs_info);
err_vqs_info:
        kfree(vqs);
err_vq:
        return ret;
}

static int virtnet_alloc_queues(struct virtnet_info *vi)
{
        int i;

        if (vi->has_cvq) {
                vi->ctrl = kzalloc_obj(*vi->ctrl);
                if (!vi->ctrl)
                        goto err_ctrl;
        } else {
                vi->ctrl = NULL;
        }
        vi->sq = kzalloc_objs(*vi->sq, vi->max_queue_pairs);
        if (!vi->sq)
                goto err_sq;
        vi->rq = kzalloc_objs(*vi->rq, vi->max_queue_pairs);
        if (!vi->rq)
                goto err_rq;

        for (i = 0; i < vi->max_queue_pairs; i++) {
                vi->rq[i].pages = NULL;
                netif_napi_add_config(vi->dev, &vi->rq[i].napi, virtnet_poll,
                                      i);
                vi->rq[i].napi.weight = napi_weight;
                netif_napi_add_tx_weight(vi->dev, &vi->sq[i].napi,
                                         virtnet_poll_tx,
                                         napi_tx ? napi_weight : 0);

                sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
                ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
                sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));

                u64_stats_init(&vi->rq[i].stats.syncp);
                u64_stats_init(&vi->sq[i].stats.syncp);
                mutex_init(&vi->rq[i].dim_lock);
        }

        return 0;

err_rq:
        kfree(vi->sq);
err_sq:
        kfree(vi->ctrl);
err_ctrl:
        return -ENOMEM;
}

static int init_vqs(struct virtnet_info *vi)
{
        int ret;

        /* Allocate send & receive queues */
        ret = virtnet_alloc_queues(vi);
        if (ret)
                goto err;

        ret = virtnet_find_vqs(vi);
        if (ret)
                goto err_free;

        cpus_read_lock();
        virtnet_set_affinity(vi);
        cpus_read_unlock();

        return 0;

err_free:
        virtnet_free_queues(vi);
err:
        return ret;
}

#ifdef CONFIG_SYSFS
static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
                char *buf)
{
        struct virtnet_info *vi = netdev_priv(queue->dev);
        unsigned int queue_index = get_netdev_rx_queue_index(queue);
        unsigned int headroom = virtnet_get_headroom(vi);
        unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
        struct ewma_pkt_len *avg;

        BUG_ON(queue_index >= vi->max_queue_pairs);
        avg = &vi->rq[queue_index].mrg_avg_pkt_len;
        return sprintf(buf, "%u\n",
                       get_mergeable_buf_len(&vi->rq[queue_index], avg,
                                       SKB_DATA_ALIGN(headroom + tailroom)));
}

static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
        __ATTR_RO(mergeable_rx_buffer_size);

static struct attribute *virtio_net_mrg_rx_attrs[] = {
        &mergeable_rx_buffer_size_attribute.attr,
        NULL
};

static const struct attribute_group virtio_net_mrg_rx_group = {
        .name = "virtio_net",
        .attrs = virtio_net_mrg_rx_attrs
};
#endif

static bool virtnet_fail_on_feature(struct virtio_device *vdev,
                                    unsigned int fbit,
                                    const char *fname, const char *dname)
{
        if (!virtio_has_feature(vdev, fbit))
                return false;

        dev_err(&vdev->dev, "device advertises feature %s but not %s",
                fname, dname);

        return true;
}

#define VIRTNET_FAIL_ON(vdev, fbit, dbit)                       \
        virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)

static bool virtnet_validate_features(struct virtio_device *vdev)
{
        if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
            (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_RSS,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_HASH_REPORT,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_NOTF_COAL,
                             "VIRTIO_NET_F_CTRL_VQ") ||
             VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_VQ_NOTF_COAL,
                             "VIRTIO_NET_F_CTRL_VQ"))) {
                return false;
        }

        return true;
}

#define MIN_MTU ETH_MIN_MTU
#define MAX_MTU ETH_MAX_MTU

static int virtnet_validate(struct virtio_device *vdev)
{
        if (!vdev->config->get) {
                dev_err(&vdev->dev, "%s failure: config access disabled\n",
                        __func__);
                return -EINVAL;
        }

        if (!virtnet_validate_features(vdev))
                return -EINVAL;

        if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
                int mtu = virtio_cread16(vdev,
                                         offsetof(struct virtio_net_config,
                                                  mtu));
                if (mtu < MIN_MTU)
                        __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
        }

        if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY) &&
            !virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
                dev_warn(&vdev->dev, "device advertises feature VIRTIO_NET_F_STANDBY but not VIRTIO_NET_F_MAC, disabling standby");
                __virtio_clear_bit(vdev, VIRTIO_NET_F_STANDBY);
        }

        return 0;
}

static bool virtnet_check_guest_gso(const struct virtnet_info *vi)
{
        return virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO) ||
                (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO4) &&
                virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO6));
}

static void virtnet_set_big_packets(struct virtnet_info *vi, const int mtu)
{
        bool guest_gso = virtnet_check_guest_gso(vi);

        /* If device can receive ANY guest GSO packets, regardless of mtu,
         * allocate packets of maximum size, otherwise limit it to only
         * mtu size worth only.
         */
        if (mtu > ETH_DATA_LEN || guest_gso) {
                vi->big_packets = true;
                vi->big_packets_num_skbfrags = guest_gso ? MAX_SKB_FRAGS : DIV_ROUND_UP(mtu, PAGE_SIZE);
        }
}

#define VIRTIO_NET_HASH_REPORT_MAX_TABLE      10
static enum xdp_rss_hash_type
virtnet_xdp_rss_type[VIRTIO_NET_HASH_REPORT_MAX_TABLE] = {
        [VIRTIO_NET_HASH_REPORT_NONE] = XDP_RSS_TYPE_NONE,
        [VIRTIO_NET_HASH_REPORT_IPv4] = XDP_RSS_TYPE_L3_IPV4,
        [VIRTIO_NET_HASH_REPORT_TCPv4] = XDP_RSS_TYPE_L4_IPV4_TCP,
        [VIRTIO_NET_HASH_REPORT_UDPv4] = XDP_RSS_TYPE_L4_IPV4_UDP,
        [VIRTIO_NET_HASH_REPORT_IPv6] = XDP_RSS_TYPE_L3_IPV6,
        [VIRTIO_NET_HASH_REPORT_TCPv6] = XDP_RSS_TYPE_L4_IPV6_TCP,
        [VIRTIO_NET_HASH_REPORT_UDPv6] = XDP_RSS_TYPE_L4_IPV6_UDP,
        [VIRTIO_NET_HASH_REPORT_IPv6_EX] = XDP_RSS_TYPE_L3_IPV6_EX,
        [VIRTIO_NET_HASH_REPORT_TCPv6_EX] = XDP_RSS_TYPE_L4_IPV6_TCP_EX,
        [VIRTIO_NET_HASH_REPORT_UDPv6_EX] = XDP_RSS_TYPE_L4_IPV6_UDP_EX
};

static int virtnet_xdp_rx_hash(const struct xdp_md *_ctx, u32 *hash,
                               enum xdp_rss_hash_type *rss_type)
{
        const struct xdp_buff *xdp = (void *)_ctx;
        struct virtio_net_hdr_v1_hash *hdr_hash;
        struct virtnet_info *vi;
        u16 hash_report;

        if (!(xdp->rxq->dev->features & NETIF_F_RXHASH))
                return -ENODATA;

        vi = netdev_priv(xdp->rxq->dev);
        hdr_hash = (struct virtio_net_hdr_v1_hash *)(xdp->data - vi->hdr_len);
        hash_report = __le16_to_cpu(hdr_hash->hash_report);

        if (hash_report >= VIRTIO_NET_HASH_REPORT_MAX_TABLE)
                hash_report = VIRTIO_NET_HASH_REPORT_NONE;

        *rss_type = virtnet_xdp_rss_type[hash_report];
        *hash = virtio_net_hash_value(hdr_hash);
        return 0;
}

static const struct xdp_metadata_ops virtnet_xdp_metadata_ops = {
        .xmo_rx_hash                    = virtnet_xdp_rx_hash,
};

static int virtnet_probe(struct virtio_device *vdev)
{
        int i, err = -ENOMEM;
        struct net_device *dev;
        struct virtnet_info *vi;
        u16 max_queue_pairs;
        int mtu = 0;
        u16 key_sz;

        /* Find if host supports multiqueue/rss virtio_net device */
        max_queue_pairs = 1;
        if (virtio_has_feature(vdev, VIRTIO_NET_F_MQ) || virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
                max_queue_pairs =
                     virtio_cread16(vdev, offsetof(struct virtio_net_config, max_virtqueue_pairs));

        /* We need at least 2 queue's */
        if (max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
            max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
            !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
                max_queue_pairs = 1;

        /* Allocate ourselves a network device with room for our info */
        dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
        if (!dev)
                return -ENOMEM;

        /* Set up network device as normal. */
        dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE |
                           IFF_TX_SKB_NO_LINEAR;
        dev->netdev_ops = &virtnet_netdev;
        dev->stat_ops = &virtnet_stat_ops;
        dev->features = NETIF_F_HIGHDMA;

        dev->ethtool_ops = &virtnet_ethtool_ops;
        SET_NETDEV_DEV(dev, &vdev->dev);

        /* Do we support "hardware" checksums? */
        if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
                /* This opens up the world of extra features. */
                dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG;
                if (csum)
                        dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;

                if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
                        dev->hw_features |= NETIF_F_TSO
                                | NETIF_F_TSO_ECN | NETIF_F_TSO6;
                }
                /* Individual feature bits: what can host handle? */
                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
                        dev->hw_features |= NETIF_F_TSO;
                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
                        dev->hw_features |= NETIF_F_TSO6;
                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
                        dev->hw_features |= NETIF_F_TSO_ECN;
                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_USO))
                        dev->hw_features |= NETIF_F_GSO_UDP_L4;

                if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO)) {
                        dev->hw_features |= NETIF_F_GSO_UDP_TUNNEL;
                        dev->hw_enc_features = dev->hw_features;
                }
                if (dev->hw_features & NETIF_F_GSO_UDP_TUNNEL &&
                    virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO_CSUM)) {
                        dev->hw_features |= NETIF_F_GSO_UDP_TUNNEL_CSUM;
                        dev->hw_enc_features |= NETIF_F_GSO_UDP_TUNNEL_CSUM;
                }

                dev->features |= NETIF_F_GSO_ROBUST;

                if (gso)
                        dev->features |= dev->hw_features;
                /* (!csum && gso) case will be fixed by register_netdev() */
        }

        /* 1. With VIRTIO_NET_F_GUEST_CSUM negotiation, the driver doesn't
         * need to calculate checksums for partially checksummed packets,
         * as they're considered valid by the upper layer.
         * 2. Without VIRTIO_NET_F_GUEST_CSUM negotiation, the driver only
         * receives fully checksummed packets. The device may assist in
         * validating these packets' checksums, so the driver won't have to.
         */
        dev->features |= NETIF_F_RXCSUM;

        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
            virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6))
                dev->features |= NETIF_F_GRO_HW;
        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS))
                dev->hw_features |= NETIF_F_GRO_HW;

        dev->vlan_features = dev->features;
        dev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
                NETDEV_XDP_ACT_XSK_ZEROCOPY;

        /* MTU range: 68 - 65535 */
        dev->min_mtu = MIN_MTU;
        dev->max_mtu = MAX_MTU;

        /* Configuration may specify what MAC to use.  Otherwise random. */
        if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
                u8 addr[ETH_ALEN];

                virtio_cread_bytes(vdev,
                                   offsetof(struct virtio_net_config, mac),
                                   addr, ETH_ALEN);
                eth_hw_addr_set(dev, addr);
        } else {
                eth_hw_addr_random(dev);
                dev_info(&vdev->dev, "Assigned random MAC address %pM\n",
                         dev->dev_addr);
        }

        /* Set up our device-specific information */
        vi = netdev_priv(dev);
        vi->dev = dev;
        vi->vdev = vdev;
        vdev->priv = vi;

        INIT_WORK(&vi->config_work, virtnet_config_changed_work);
        INIT_WORK(&vi->rx_mode_work, virtnet_rx_mode_work);

        if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) {
                vi->mergeable_rx_bufs = true;
                dev->xdp_features |= NETDEV_XDP_ACT_RX_SG;
        }

        if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
                vi->has_rss_hash_report = true;

        if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) {
                vi->has_rss = true;

                vi->rss_indir_table_size =
                        virtio_cread16(vdev, offsetof(struct virtio_net_config,
                                rss_max_indirection_table_length));
        }
        vi->rss_hdr = devm_kzalloc(&vdev->dev, virtnet_rss_hdr_size(vi), GFP_KERNEL);
        if (!vi->rss_hdr) {
                err = -ENOMEM;
                goto free;
        }

        if (vi->has_rss || vi->has_rss_hash_report) {
                key_sz = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));

                vi->rss_key_size = min_t(u16, key_sz, NETDEV_RSS_KEY_LEN);
                if (key_sz > vi->rss_key_size)
                        dev_warn(&vdev->dev,
                                 "rss_max_key_size=%u exceeds driver limit %u, clamping\n",
                                 key_sz, vi->rss_key_size);

                vi->rss_hash_types_supported =
                    virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types));
                vi->rss_hash_types_supported &=
                                ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX |
                                  VIRTIO_NET_RSS_HASH_TYPE_TCP_EX |
                                  VIRTIO_NET_RSS_HASH_TYPE_UDP_EX);

                dev->hw_features |= NETIF_F_RXHASH;
                dev->xdp_metadata_ops = &virtnet_xdp_metadata_ops;
        }

        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO) ||
            virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO))
                vi->hdr_len = sizeof(struct virtio_net_hdr_v1_hash_tunnel);
        else if (vi->has_rss_hash_report)
                vi->hdr_len = sizeof(struct virtio_net_hdr_v1_hash);
        else if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
                 virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
                vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
        else
                vi->hdr_len = sizeof(struct virtio_net_hdr);

        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM))
                vi->rx_tnl_csum = true;
        if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO))
                vi->rx_tnl = true;
        if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO))
                vi->tx_tnl = true;

        if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
            virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
                vi->any_header_sg = true;

        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
                vi->has_cvq = true;

        mutex_init(&vi->cvq_lock);

        if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
                mtu = virtio_cread16(vdev,
                                     offsetof(struct virtio_net_config,
                                              mtu));
                if (mtu < dev->min_mtu) {
                        /* Should never trigger: MTU was previously validated
                         * in virtnet_validate.
                         */
                        dev_err(&vdev->dev,
                                "device MTU appears to have changed it is now %d < %d",
                                mtu, dev->min_mtu);
                        err = -EINVAL;
                        goto free;
                }

                dev->mtu = mtu;
                dev->max_mtu = mtu;
        }

        virtnet_set_big_packets(vi, mtu);

        if (vi->any_header_sg)
                dev->needed_headroom = vi->hdr_len;

        /* Enable multiqueue by default */
        if (num_online_cpus() >= max_queue_pairs)
                vi->curr_queue_pairs = max_queue_pairs;
        else
                vi->curr_queue_pairs = num_online_cpus();
        vi->max_queue_pairs = max_queue_pairs;

        /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
        err = init_vqs(vi);
        if (err)
                goto free;

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {
                vi->intr_coal_rx.max_usecs = 0;
                vi->intr_coal_tx.max_usecs = 0;
                vi->intr_coal_rx.max_packets = 0;

                /* Keep the default values of the coalescing parameters
                 * aligned with the default napi_tx state.
                 */
                if (vi->sq[0].napi.weight)
                        vi->intr_coal_tx.max_packets = 1;
                else
                        vi->intr_coal_tx.max_packets = 0;
        }

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
                /* The reason is the same as VIRTIO_NET_F_NOTF_COAL. */
                for (i = 0; i < vi->max_queue_pairs; i++)
                        if (vi->sq[i].napi.weight)
                                vi->sq[i].intr_coal.max_packets = 1;

                err = virtnet_init_irq_moder(vi);
                if (err)
                        goto free;
        }

#ifdef CONFIG_SYSFS
        if (vi->mergeable_rx_bufs)
                dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
#endif
        netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
        netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);

        virtnet_init_settings(dev);

        if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) {
                vi->failover = net_failover_create(vi->dev);
                if (IS_ERR(vi->failover)) {
                        err = PTR_ERR(vi->failover);
                        goto free_vqs;
                }
        }

        if (vi->has_rss || vi->has_rss_hash_report)
                virtnet_init_default_rss(vi);

        enable_rx_mode_work(vi);

        /* serialize netdev register + virtio_device_ready() with ndo_open() */
        rtnl_lock();

        err = register_netdevice(dev);
        if (err) {
                pr_debug("virtio_net: registering device failed\n");
                rtnl_unlock();
                goto free_failover;
        }

        /* Disable config change notification until ndo_open. */
        virtio_config_driver_disable(vi->vdev);

        virtio_device_ready(vdev);

        if (vi->has_rss || vi->has_rss_hash_report) {
                if (!virtnet_commit_rss_command(vi)) {
                        dev_warn(&vdev->dev, "RSS disabled because committing failed.\n");
                        dev->hw_features &= ~NETIF_F_RXHASH;
                        vi->has_rss_hash_report = false;
                        vi->has_rss = false;
                }
        }

        virtnet_set_queues(vi, vi->curr_queue_pairs);

        /* a random MAC address has been assigned, notify the device.
         * We don't fail probe if VIRTIO_NET_F_CTRL_MAC_ADDR is not there
         * because many devices work fine without getting MAC explicitly
         */
        if (!virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
            virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
                struct scatterlist sg;

                sg_init_one(&sg, dev->dev_addr, dev->addr_len);
                if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
                                          VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
                        pr_debug("virtio_net: setting MAC address failed\n");
                        rtnl_unlock();
                        err = -EINVAL;
                        goto free_unregister_netdev;
                }
        }

        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_DEVICE_STATS)) {
                struct virtio_net_stats_capabilities *stats_cap  __free(kfree) = NULL;
                struct scatterlist sg;
                __le64 v;

                stats_cap = kzalloc_obj(*stats_cap);
                if (!stats_cap) {
                        rtnl_unlock();
                        err = -ENOMEM;
                        goto free_unregister_netdev;
                }

                sg_init_one(&sg, stats_cap, sizeof(*stats_cap));

                if (!virtnet_send_command_reply(vi, VIRTIO_NET_CTRL_STATS,
                                                VIRTIO_NET_CTRL_STATS_QUERY,
                                                NULL, &sg)) {
                        pr_debug("virtio_net: fail to get stats capability\n");
                        rtnl_unlock();
                        err = -EINVAL;
                        goto free_unregister_netdev;
                }

                v = stats_cap->supported_stats_types[0];
                vi->device_stats_cap = le64_to_cpu(v);
        }

        /* Assume link up if device can't report link status,
           otherwise get link status from config. */
        netif_carrier_off(dev);
        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
                virtio_config_changed(vi->vdev);
        } else {
                vi->status = VIRTIO_NET_S_LINK_UP;
                virtnet_update_settings(vi);
                netif_carrier_on(dev);
        }

        for (i = 0; i < ARRAY_SIZE(guest_offloads); i++) {
                unsigned int fbit;

                fbit = virtio_offload_to_feature(guest_offloads[i]);
                if (virtio_has_feature(vi->vdev, fbit))
                        set_bit(guest_offloads[i], &vi->guest_offloads);
        }
        vi->guest_offloads_capable = vi->guest_offloads;

        rtnl_unlock();

        err = virtnet_cpu_notif_add(vi);
        if (err) {
                pr_debug("virtio_net: registering cpu notifier failed\n");
                goto free_unregister_netdev;
        }

        pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
                 dev->name, max_queue_pairs);

        return 0;

free_unregister_netdev:
        unregister_netdev(dev);
free_failover:
        net_failover_destroy(vi->failover);
free_vqs:
        virtio_reset_device(vdev);
        free_receive_page_frags(vi);
        virtnet_del_vqs(vi);
free:
        free_netdev(dev);
        return err;
}

static void remove_vq_common(struct virtnet_info *vi)
{
        int i;

        virtio_reset_device(vi->vdev);

        /* Free unused buffers in both send and recv, if any. */
        free_unused_bufs(vi);

        /*
         * Rule of thumb is netdev_tx_reset_queue() should follow any
         * skb freeing not followed by netdev_tx_completed_queue()
         */
        for (i = 0; i < vi->max_queue_pairs; i++)
                netdev_tx_reset_queue(netdev_get_tx_queue(vi->dev, i));

        free_receive_bufs(vi);

        free_receive_page_frags(vi);

        virtnet_del_vqs(vi);
}

static void virtnet_remove(struct virtio_device *vdev)
{
        struct virtnet_info *vi = vdev->priv;

        virtnet_cpu_notif_remove(vi);

        /* Make sure no work handler is accessing the device. */
        flush_work(&vi->config_work);
        disable_rx_mode_work(vi);
        flush_work(&vi->rx_mode_work);

        virtnet_free_irq_moder(vi);

        unregister_netdev(vi->dev);

        net_failover_destroy(vi->failover);

        remove_vq_common(vi);

        free_netdev(vi->dev);
}

static __maybe_unused int virtnet_freeze(struct virtio_device *vdev)
{
        struct virtnet_info *vi = vdev->priv;

        virtnet_cpu_notif_remove(vi);
        virtnet_freeze_down(vdev);
        remove_vq_common(vi);

        return 0;
}

static __maybe_unused int virtnet_restore(struct virtio_device *vdev)
{
        struct virtnet_info *vi = vdev->priv;
        int err;

        err = virtnet_restore_up(vdev);
        if (err)
                return err;
        virtnet_set_queues(vi, vi->curr_queue_pairs);

        err = virtnet_cpu_notif_add(vi);
        if (err) {
                virtnet_freeze_down(vdev);
                remove_vq_common(vi);
                return err;
        }

        return 0;
}

static struct virtio_device_id id_table[] = {
        { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
        { 0 },
};

#define VIRTNET_FEATURES \
        VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM, \
        VIRTIO_NET_F_MAC, \
        VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \
        VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \
        VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO, \
        VIRTIO_NET_F_HOST_USO, VIRTIO_NET_F_GUEST_USO4, VIRTIO_NET_F_GUEST_USO6, \
        VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ, \
        VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, \
        VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
        VIRTIO_NET_F_CTRL_MAC_ADDR, \
        VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
        VIRTIO_NET_F_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \
        VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT, VIRTIO_NET_F_NOTF_COAL, \
        VIRTIO_NET_F_VQ_NOTF_COAL, \
        VIRTIO_NET_F_GUEST_HDRLEN, VIRTIO_NET_F_DEVICE_STATS

static unsigned int features[] = {
        VIRTNET_FEATURES,
        VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO,
        VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM,
        VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO,
        VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO_CSUM,
};

static unsigned int features_legacy[] = {
        VIRTNET_FEATURES,
        VIRTIO_NET_F_GSO,
        VIRTIO_F_ANY_LAYOUT,
};

static struct virtio_driver virtio_net_driver = {
        .feature_table = features,
        .feature_table_size = ARRAY_SIZE(features),
        .feature_table_legacy = features_legacy,
        .feature_table_size_legacy = ARRAY_SIZE(features_legacy),
        .driver.name =  KBUILD_MODNAME,
        .id_table =     id_table,
        .validate =     virtnet_validate,
        .probe =        virtnet_probe,
        .remove =       virtnet_remove,
        .config_changed = virtnet_config_changed,
#ifdef CONFIG_PM_SLEEP
        .freeze =       virtnet_freeze,
        .restore =      virtnet_restore,
#endif
};

static __init int virtio_net_driver_init(void)
{
        int ret;

        ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "virtio/net:online",
                                      virtnet_cpu_online,
                                      virtnet_cpu_down_prep);
        if (ret < 0)
                goto out;
        virtionet_online = ret;
        ret = cpuhp_setup_state_multi(CPUHP_VIRT_NET_DEAD, "virtio/net:dead",
                                      NULL, virtnet_cpu_dead);
        if (ret)
                goto err_dead;
        ret = register_virtio_driver(&virtio_net_driver);
        if (ret)
                goto err_virtio;
        return 0;
err_virtio:
        cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
err_dead:
        cpuhp_remove_multi_state(virtionet_online);
out:
        return ret;
}
module_init(virtio_net_driver_init);

static __exit void virtio_net_driver_exit(void)
{
        unregister_virtio_driver(&virtio_net_driver);
        cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
        cpuhp_remove_multi_state(virtionet_online);
}
module_exit(virtio_net_driver_exit);

MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio network driver");
MODULE_LICENSE("GPL");