/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _VHOST_H
#define _VHOST_H

#include <linux/eventfd.h>
#include <linux/vhost.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/atomic.h>
#include <linux/vhost_iotlb.h>
#include <linux/irqbypass.h>
#include <linux/unroll.h>

struct vhost_work;
struct vhost_task;
typedef void (*vhost_work_fn_t)(struct vhost_work *work);

#define VHOST_WORK_QUEUED 1
struct vhost_work {
        struct llist_node       node;
        vhost_work_fn_t         fn;
        unsigned long           flags;
};

struct vhost_worker;
struct vhost_dev;

struct vhost_worker_ops {
        int (*create)(struct vhost_worker *worker, struct vhost_dev *dev,
                      const char *name);
        void (*stop)(struct vhost_worker *worker);
        void (*wakeup)(struct vhost_worker *worker);
};

struct vhost_worker {
        struct task_struct *kthread_task;
        struct vhost_task       *vtsk;
        struct vhost_dev        *dev;
        /* Used to serialize device wide flushing with worker swapping. */
        struct mutex            mutex;
        struct llist_head       work_list;
        u64                     kcov_handle;
        u32                     id;
        int                     attachment_cnt;
        bool                    killed;
        const struct vhost_worker_ops *ops;
};

/* Poll a file (eventfd or socket) */
/* Note: there's nothing vhost specific about this structure. */
struct vhost_poll {
        poll_table              table;
        wait_queue_head_t       *wqh;
        wait_queue_entry_t      wait;
        struct vhost_work       work;
        __poll_t                mask;
        struct vhost_dev        *dev;
        struct vhost_virtqueue  *vq;
};

void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
                     __poll_t mask, struct vhost_dev *dev,
                     struct vhost_virtqueue *vq);
int vhost_poll_start(struct vhost_poll *poll, struct file *file);
void vhost_poll_stop(struct vhost_poll *poll);
void vhost_poll_queue(struct vhost_poll *poll);

void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
void vhost_dev_flush(struct vhost_dev *dev);

struct vhost_log {
        u64 addr;
        u64 len;
};

enum vhost_uaddr_type {
        VHOST_ADDR_DESC = 0,
        VHOST_ADDR_AVAIL = 1,
        VHOST_ADDR_USED = 2,
        VHOST_NUM_ADDRS = 3,
};

struct vhost_vring_call {
        struct eventfd_ctx *ctx;
        struct irq_bypass_producer producer;
};

/* The virtqueue structure describes a queue attached to a device. */
struct vhost_virtqueue {
        struct vhost_dev *dev;
        struct vhost_worker __rcu *worker;

        /* The actual ring of buffers. */
        struct mutex mutex;
        unsigned int num;
        vring_desc_t __user *desc;
        vring_avail_t __user *avail;
        vring_used_t __user *used;
        const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
        struct file *kick;
        struct vhost_vring_call call_ctx;
        struct eventfd_ctx *error_ctx;
        struct eventfd_ctx *log_ctx;

        struct vhost_poll poll;

        /* The routine to call when the Guest pings us, or timeout. */
        vhost_work_fn_t handle_kick;

        /* Last available index we saw.
         * Values are limited to 0x7fff, and the high bit is used as
         * a wrap counter when using VIRTIO_F_RING_PACKED. */
        u16 last_avail_idx;
        /* Next avail ring head when VIRTIO_F_IN_ORDER is negoitated */
        u16 next_avail_head;

        /* Caches available index value from user. */
        u16 avail_idx;

        /* Last index we used.
         * Values are limited to 0x7fff, and the high bit is used as
         * a wrap counter when using VIRTIO_F_RING_PACKED. */
        u16 last_used_idx;

        /* Used flags */
        u16 used_flags;

        /* Last used index value we have signalled on */
        u16 signalled_used;

        /* Last used index value we have signalled on */
        bool signalled_used_valid;

        /* Log writes to used structure. */
        bool log_used;
        u64 log_addr;

        struct iovec iov[UIO_MAXIOV];
        struct iovec iotlb_iov[64];
        struct iovec *indirect;
        struct vring_used_elem *heads;
        u16 *nheads;
        /* Protected by virtqueue mutex. */
        struct vhost_iotlb *umem;
        struct vhost_iotlb *iotlb;
        void *private_data;
        VIRTIO_DECLARE_FEATURES(acked_features);
        u64 acked_backend_features;
        /* Log write descriptors */
        void __user *log_base;
        struct vhost_log *log;
        struct iovec log_iov[64];

        /* Ring endianness. Defaults to legacy native endianness.
         * Set to true when starting a modern virtio device. */
        bool is_le;
#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
        /* Ring endianness requested by userspace for cross-endian support. */
        bool user_be;
#endif
        u32 busyloop_timeout;
};

struct vhost_msg_node {
  union {
          struct vhost_msg msg;
          struct vhost_msg_v2 msg_v2;
  };
  struct vhost_virtqueue *vq;
  struct list_head node;
};

struct vhost_dev {
        struct mm_struct *mm;
        struct mutex mutex;
        struct vhost_virtqueue **vqs;
        int nvqs;
        struct eventfd_ctx *log_ctx;
        struct vhost_iotlb *umem;
        struct vhost_iotlb *iotlb;
        spinlock_t iotlb_lock;
        struct list_head read_list;
        struct list_head pending_list;
        wait_queue_head_t wait;
        int iov_limit;
        int weight;
        int byte_weight;
        struct xarray worker_xa;
        bool use_worker;
        /*
         * If fork_owner is true we use vhost_tasks to create
         * the worker so all settings/limits like cgroups, NPROC,
         * scheduler, etc are inherited from the owner. If false,
         * we use kthreads and only attach to the same cgroups
         * as the owner for compat with older kernels.
         * here we use true as default value.
         * The default value is set by fork_from_owner_default
         */
        bool fork_owner;
        int (*msg_handler)(struct vhost_dev *dev, u32 asid,
                           struct vhost_iotlb_msg *msg);
};

bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
                    int nvqs, int iov_limit, int weight, int byte_weight,
                    bool use_worker,
                    int (*msg_handler)(struct vhost_dev *dev, u32 asid,
                                       struct vhost_iotlb_msg *msg));
long vhost_dev_set_owner(struct vhost_dev *dev);
bool vhost_dev_has_owner(struct vhost_dev *dev);
long vhost_dev_check_owner(struct vhost_dev *);
struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
void vhost_dev_cleanup(struct vhost_dev *);
void vhost_dev_stop(struct vhost_dev *);
long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
                        void __user *argp);
bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
bool vhost_log_access_ok(struct vhost_dev *);
void vhost_clear_msg(struct vhost_dev *dev);

int vhost_get_vq_desc(struct vhost_virtqueue *,
                      struct iovec iov[], unsigned int iov_size,
                      unsigned int *out_num, unsigned int *in_num,
                      struct vhost_log *log, unsigned int *log_num);

int vhost_get_vq_desc_n(struct vhost_virtqueue *vq,
                        struct iovec iov[], unsigned int iov_size,
                        unsigned int *out_num, unsigned int *in_num,
                        struct vhost_log *log, unsigned int *log_num,
                        unsigned int *ndesc);

void vhost_discard_vq_desc(struct vhost_virtqueue *, int nbuf,
                           unsigned int ndesc);

bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work);
bool vhost_vq_has_work(struct vhost_virtqueue *vq);
bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
int vhost_vq_init_access(struct vhost_virtqueue *);
int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
                     u16 *nheads, unsigned count);
void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
                               unsigned int id, int len);
void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
                                 struct vring_used_elem *heads, u16 *nheads,
                                 unsigned count);
void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);

int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
                    unsigned int log_num, u64 len,
                    struct iovec *iov, int count);
int vq_meta_prefetch(struct vhost_virtqueue *vq);

struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
void vhost_enqueue_msg(struct vhost_dev *dev,
                       struct list_head *head,
                       struct vhost_msg_node *node);
struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
                                         struct list_head *head);
void vhost_set_backend_features(struct vhost_dev *dev, u64 features);

__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
                            poll_table *wait);
ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
                            int noblock);
ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
                             struct iov_iter *from);
int vhost_init_device_iotlb(struct vhost_dev *d);

void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
                          struct vhost_iotlb_map *map);

#define vq_err(vq, fmt, ...) do {                                  \
                pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
                if ((vq)->error_ctx)                               \
                                eventfd_signal((vq)->error_ctx);\
        } while (0)

#define VHOST_FEATURES \
        VIRTIO_F_NOTIFY_ON_EMPTY, \
        VIRTIO_RING_F_INDIRECT_DESC, \
        VIRTIO_RING_F_EVENT_IDX, \
        VHOST_F_LOG_ALL, \
        VIRTIO_F_ANY_LAYOUT, \
        VIRTIO_F_VERSION_1

static inline u64 vhost_features_u64(const int *features, int size, int idx)
{
        u64 res = 0;

        unrolled_count(VIRTIO_FEATURES_BITS)
        for (int i = 0; i < size; ++i) {
                int bit = features[i];

                if (virtio_features_chk_bit(bit) && VIRTIO_U64(bit) == idx)
                        res |= VIRTIO_BIT(bit);
        }
        return res;
}

#define VHOST_FEATURES_U64(features, idx) \
        vhost_features_u64(features, ARRAY_SIZE(features), idx)

#define DEFINE_VHOST_FEATURES_ARRAY_ENTRY(idx, features) \
        [idx] = VHOST_FEATURES_U64(features, idx),

#define DEFINE_VHOST_FEATURES_ARRAY(array, features) \
        u64 array[VIRTIO_FEATURES_U64S] = { \
                UNROLL(VIRTIO_FEATURES_U64S, \
                       DEFINE_VHOST_FEATURES_ARRAY_ENTRY, features) \
        }

/**
 * vhost_vq_set_backend - Set backend.
 *
 * @vq            Virtqueue.
 * @private_data  The private data.
 *
 * Context: Need to call with vq->mutex acquired.
 */
static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
                                        void *private_data)
{
        vq->private_data = private_data;
}

/**
 * vhost_vq_get_backend - Get backend.
 *
 * @vq            Virtqueue.
 *
 * Context: Need to call with vq->mutex acquired.
 * Return: Private data previously set with vhost_vq_set_backend.
 */
static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
{
        return vq->private_data;
}

static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
{
        return virtio_features_test_bit(vq->acked_features_array, bit);
}

static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
{
        return vq->acked_backend_features & (1ULL << bit);
}

#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
{
        return vq->is_le;
}
#else
static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
{
        return virtio_legacy_is_little_endian() || vq->is_le;
}
#endif

/* Memory accessors */
static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
{
        return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
}

static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
{
        return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
}

static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
{
        return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
}

static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
{
        return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
}

static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
{
        return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
}

static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
{
        return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
}
#endif