/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *
 * Copyright (c) 2011, Microsoft Corporation.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 *   K. Y. Srinivasan <kys@microsoft.com>
 */

#ifndef _HYPERV_VMBUS_H
#define _HYPERV_VMBUS_H

#include <linux/list.h>
#include <linux/bitops.h>
#include <asm/sync_bitops.h>
#include <asm/mshyperv.h>
#include <linux/atomic.h>
#include <linux/hyperv.h>
#include <linux/interrupt.h>
#include <hyperv/hvhdk.h>

#include "hv_trace.h"

/*
 * Timeout for services such as KVP and fcopy.
 */
#define HV_UTIL_TIMEOUT 30

/*
 * Timeout for guest-host handshake for services.
 */
#define HV_UTIL_NEGO_TIMEOUT 55

void vmbus_isr(void);

/* Definitions for the monitored notification facility */
union hv_monitor_trigger_group {
        u64 as_uint64;
        struct {
                u32 pending;
                u32 armed;
        };
};

struct hv_monitor_parameter {
        union hv_connection_id connectionid;
        u16 flagnumber;
        u16 rsvdz;
};

union hv_monitor_trigger_state {
        u32 asu32;

        struct {
                u32 group_enable:4;
                u32 rsvdz:28;
        };
};

/* struct hv_monitor_page Layout */
/* ------------------------------------------------------ */
/* | 0   | TriggerState (4 bytes) | Rsvd1 (4 bytes)     | */
/* | 8   | TriggerGroup[0]                              | */
/* | 10  | TriggerGroup[1]                              | */
/* | 18  | TriggerGroup[2]                              | */
/* | 20  | TriggerGroup[3]                              | */
/* | 28  | Rsvd2[0]                                     | */
/* | 30  | Rsvd2[1]                                     | */
/* | 38  | Rsvd2[2]                                     | */
/* | 40  | NextCheckTime[0][0]    | NextCheckTime[0][1] | */
/* | ...                                                | */
/* | 240 | Latency[0][0..3]                             | */
/* | 340 | Rsvz3[0]                                     | */
/* | 440 | Parameter[0][0]                              | */
/* | 448 | Parameter[0][1]                              | */
/* | ...                                                | */
/* | 840 | Rsvd4[0]                                     | */
/* ------------------------------------------------------ */
struct hv_monitor_page {
        union hv_monitor_trigger_state trigger_state;
        u32 rsvdz1;

        union hv_monitor_trigger_group trigger_group[4];
        u64 rsvdz2[3];

        s32 next_checktime[4][32];

        u16 latency[4][32];
        u64 rsvdz3[32];

        struct hv_monitor_parameter parameter[4][32];

        u8 rsvdz4[1984];
};

#define HV_HYPERCALL_PARAM_ALIGN        sizeof(u64)

/* Definition of the hv_post_message hypercall input structure. */
struct hv_input_post_message {
        union hv_connection_id connectionid;
        u32 reserved;
        u32 message_type;
        u32 payload_size;
        u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
};


enum {
        VMBUS_MESSAGE_CONNECTION_ID     = 1,
        VMBUS_MESSAGE_CONNECTION_ID_4   = 4,
        VMBUS_MESSAGE_PORT_ID           = 1,
        VMBUS_EVENT_CONNECTION_ID       = 2,
        VMBUS_EVENT_PORT_ID             = 2,
        VMBUS_MONITOR_CONNECTION_ID     = 3,
        VMBUS_MONITOR_PORT_ID           = 3,
        VMBUS_MESSAGE_SINT              = 2,
};

/*
 * Per cpu state for channel handling
 */
struct hv_per_cpu_context {
        /*
         * SynIC pages for communicating with the host.
         *
         * These pages are accessible to the host partition and the hypervisor.
         * They may be used for exchanging data with the host partition and the
         * hypervisor even when they aren't trusted yet the guest partition
         * must be prepared to handle the malicious behavior.
         */
        void *hyp_synic_message_page;
        void *hyp_synic_event_page;
        /*
         * SynIC pages for communicating with the paravisor.
         *
         * These pages may be accessed from within the guest partition only in
         * CoCo VMs. Neither the host partition nor the hypervisor can access
         * these pages in that case; they are used for exchanging data with the
         * paravisor.
         */
        void *para_synic_message_page;
        void *para_synic_event_page;

        /*
         * The page is only used in hv_post_message() for a TDX VM (with the
         * paravisor) to post a messages to Hyper-V: when such a VM calls
         * HVCALL_POST_MESSAGE, it can't use the hyperv_pcpu_input_arg (which
         * is encrypted in such a VM) as the hypercall input page, because
         * the input page for HVCALL_POST_MESSAGE must be decrypted in such a
         * VM, so post_msg_page (which is decrypted in hv_synic_alloc()) is
         * introduced for this purpose. See hyperv_init() for more comments.
         */
        void *post_msg_page;

        /*
         * Starting with win8, we can take channel interrupts on any CPU;
         * we will manage the tasklet that handles events messages on a per CPU
         * basis.
         */
        struct tasklet_struct msg_dpc;
};

struct hv_context {
        /* We only support running on top of Hyper-V
         * So at this point this really can only contain the Hyper-V ID
         */
        u64 guestid;

        struct hv_per_cpu_context __percpu *cpu_context;

        /*
         * To manage allocations in a NUMA node.
         * Array indexed by numa node ID.
         */
        struct cpumask *hv_numa_map;
};

extern struct hv_context hv_context;

/* Hv Interface */

extern int hv_init(void);

extern int hv_post_message(union hv_connection_id connection_id,
                         enum hv_message_type message_type,
                         void *payload, size_t payload_size);

extern int hv_synic_alloc(void);

extern void hv_synic_free(void);

extern void hv_hyp_synic_enable_regs(unsigned int cpu);
extern int hv_synic_init(unsigned int cpu);

extern void hv_hyp_synic_disable_regs(unsigned int cpu);
extern int hv_synic_cleanup(unsigned int cpu);

/* Interface */

void hv_ringbuffer_pre_init(struct vmbus_channel *channel);

int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
                       struct page *pages, u32 pagecnt, u32 max_pkt_size,
                           bool confidential);

void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);

int hv_ringbuffer_write(struct vmbus_channel *channel,
                        const struct kvec *kv_list, u32 kv_count,
                        u64 requestid, u64 *trans_id);

int hv_ringbuffer_read(struct vmbus_channel *channel,
                       void *buffer, u32 buflen, u32 *buffer_actual_len,
                       u64 *requestid, bool raw);

/*
 * The Maximum number of channels (16384) is determined by the size of the
 * interrupt page, which is HV_HYP_PAGE_SIZE. 1/2 of HV_HYP_PAGE_SIZE is to
 * send endpoint interrupts, and the other is to receive endpoint interrupts.
 */
#define MAX_NUM_CHANNELS        ((HV_HYP_PAGE_SIZE >> 1) << 3)

/* The value here must be in multiple of 32 */
#define MAX_NUM_CHANNELS_SUPPORTED      256

#define MAX_CHANNEL_RELIDS                                      \
        max(MAX_NUM_CHANNELS_SUPPORTED, HV_EVENT_FLAGS_COUNT)

enum vmbus_connect_state {
        DISCONNECTED,
        CONNECTING,
        CONNECTED,
        DISCONNECTING
};

#define MAX_SIZE_CHANNEL_MESSAGE        HV_MESSAGE_PAYLOAD_BYTE_COUNT

/*
 * The CPU that Hyper-V will interrupt for VMBUS messages, such as
 * CHANNELMSG_OFFERCHANNEL and CHANNELMSG_RESCIND_CHANNELOFFER.
 */
#define VMBUS_CONNECT_CPU       0

struct vmbus_connection {
        u32 msg_conn_id;

        atomic_t offer_in_progress;

        enum vmbus_connect_state conn_state;

        atomic_t next_gpadl_handle;

        struct completion  unload_event;
        /*
         * Represents channel interrupts. Each bit position represents a
         * channel.  When a channel sends an interrupt via VMBUS, it finds its
         * bit in the sendInterruptPage, set it and calls Hv to generate a port
         * event. The other end receives the port event and parse the
         * recvInterruptPage to see which bit is set
         */
        void *int_page;
        void *send_int_page;
        void *recv_int_page;

        /*
         * 2 pages - 1st page for parent->child notification and 2nd
         * is child->parent notification
         */
        struct hv_monitor_page *monitor_pages[2];
        struct list_head chn_msg_list;
        spinlock_t channelmsg_lock;

        /* List of channels */
        struct list_head chn_list;
        struct mutex channel_mutex;

        /* Array of channels */
        struct vmbus_channel **channels;

        /*
         * An offer message is handled first on the work_queue, and then
         * is further handled on handle_primary_chan_wq or
         * handle_sub_chan_wq.
         */
        struct workqueue_struct *work_queue;
        struct workqueue_struct *handle_primary_chan_wq;
        struct workqueue_struct *handle_sub_chan_wq;
        struct workqueue_struct *rescind_work_queue;

        /*
         * On suspension of the vmbus, the accumulated offer messages
         * must be dropped.
         */
        bool ignore_any_offer_msg;

        /*
         * The number of sub-channels and hv_sock channels that should be
         * cleaned up upon suspend: sub-channels will be re-created upon
         * resume, and hv_sock channels should not survive suspend.
         */
        atomic_t nr_chan_close_on_suspend;
        /*
         * vmbus_bus_suspend() waits for "nr_chan_close_on_suspend" to
         * drop to zero.
         */
        struct completion ready_for_suspend_event;

        /*
         * Completed once the host has offered all boot-time channels.
         * Note that some channels may still be under process on a workqueue.
         */
        struct completion all_offers_delivered_event;
};


struct vmbus_msginfo {
        /* Bookkeeping stuff */
        struct list_head msglist_entry;

        /* The message itself */
        unsigned char msg[];
};


extern struct vmbus_connection vmbus_connection;

int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version);

static inline void vmbus_send_interrupt(u32 relid)
{
        sync_set_bit(relid, vmbus_connection.send_int_page);
}

enum vmbus_message_handler_type {
        /* The related handler can sleep. */
        VMHT_BLOCKING = 0,

        /* The related handler must NOT sleep. */
        VMHT_NON_BLOCKING = 1,
};

struct vmbus_channel_message_table_entry {
        enum vmbus_channel_message_type message_type;
        enum vmbus_message_handler_type handler_type;
        void (*message_handler)(struct vmbus_channel_message_header *msg);
        u32 min_payload_len;
};

extern const struct vmbus_channel_message_table_entry
        channel_message_table[CHANNELMSG_COUNT];


/* General vmbus interface */

bool vmbus_is_confidential(void);

#if IS_ENABLED(CONFIG_HYPERV_VMBUS)
/* Free the message slot and signal end-of-message if required */
static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
{
        /*
         * On crash we're reading some other CPU's message page and we need
         * to be careful: this other CPU may already had cleared the header
         * and the host may already had delivered some other message there.
         * In case we blindly write msg->header.message_type we're going
         * to lose it. We can still lose a message of the same type but
         * we count on the fact that there can only be one
         * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
         * on crash.
         */
        if (!try_cmpxchg(&msg->header.message_type,
                         &old_msg_type, HVMSG_NONE))
                return;

        /*
         * The cmpxchg() above does an implicit memory barrier to
         * ensure the write to MessageType (ie set to
         * HVMSG_NONE) happens before we read the
         * MessagePending and EOMing. Otherwise, the EOMing
         * will not deliver any more messages since there is
         * no empty slot
         */
        if (msg->header.message_flags.msg_pending) {
                /*
                 * This will cause message queue rescan to
                 * possibly deliver another msg from the
                 * hypervisor
                 */
                if (vmbus_is_confidential())
                        hv_para_set_synic_register(HV_MSR_EOM, 0);
                else
                        hv_set_msr(HV_MSR_EOM, 0);
        }
}

extern int vmbus_interrupt;
extern int vmbus_irq;
#endif /* CONFIG_HYPERV_VMBUS */

struct hv_device *vmbus_device_create(const guid_t *type,
                                      const guid_t *instance,
                                      struct vmbus_channel *channel);

int vmbus_device_register(struct hv_device *child_device_obj);
void vmbus_device_unregister(struct hv_device *device_obj);
int vmbus_add_channel_kobj(struct hv_device *device_obj,
                           struct vmbus_channel *channel);

void vmbus_remove_channel_attr_group(struct vmbus_channel *channel);

void vmbus_channel_map_relid(struct vmbus_channel *channel);
void vmbus_channel_unmap_relid(struct vmbus_channel *channel);

struct vmbus_channel *relid2channel(u32 relid);

void vmbus_free_channels(void);

/* Connection interface */

int vmbus_connect(void);
void vmbus_disconnect(void);

int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep);

void vmbus_on_event(unsigned long data);
void vmbus_on_msg_dpc(unsigned long data);

int hv_kvp_init(struct hv_util_service *srv);
int hv_kvp_init_transport(void);
void hv_kvp_deinit(void);
int hv_kvp_pre_suspend(void);
int hv_kvp_pre_resume(void);
void hv_kvp_onchannelcallback(void *context);

int hv_vss_init(struct hv_util_service *srv);
int hv_vss_init_transport(void);
void hv_vss_deinit(void);
int hv_vss_pre_suspend(void);
int hv_vss_pre_resume(void);
void hv_vss_onchannelcallback(void *context);
void vmbus_initiate_unload(bool crash);

static inline void hv_poll_channel(struct vmbus_channel *channel,
                                   void (*cb)(void *))
{
        if (!channel)
                return;
        cb(channel);
}

enum hvutil_device_state {
        HVUTIL_DEVICE_INIT = 0,  /* driver is loaded, waiting for userspace */
        HVUTIL_READY,            /* userspace is registered */
        HVUTIL_HOSTMSG_RECEIVED, /* message from the host was received */
        HVUTIL_USERSPACE_REQ,    /* request to userspace was sent */
        HVUTIL_USERSPACE_RECV,   /* reply from userspace was received */
        HVUTIL_DEVICE_DYING,     /* driver unload is in progress */
};

enum delay {
        INTERRUPT_DELAY = 0,
        MESSAGE_DELAY   = 1,
};

extern const struct vmbus_device vmbus_devs[];

static inline bool hv_is_perf_channel(struct vmbus_channel *channel)
{
        return vmbus_devs[channel->device_id].perf_device;
}

static inline size_t hv_dev_ring_size(struct vmbus_channel *channel)
{
        return vmbus_devs[channel->device_id].pref_ring_size;
}

static inline bool hv_is_allocated_cpu(unsigned int cpu)
{
        struct vmbus_channel *channel, *sc;

        lockdep_assert_held(&vmbus_connection.channel_mutex);
        /*
         * List additions/deletions as well as updates of the target CPUs are
         * protected by channel_mutex.
         */
        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
                if (!hv_is_perf_channel(channel))
                        continue;
                if (channel->target_cpu == cpu)
                        return true;
                list_for_each_entry(sc, &channel->sc_list, sc_list) {
                        if (sc->target_cpu == cpu)
                                return true;
                }
        }
        return false;
}

static inline void hv_set_allocated_cpu(unsigned int cpu)
{
        cpumask_set_cpu(cpu, &hv_context.hv_numa_map[cpu_to_node(cpu)]);
}

static inline void hv_clear_allocated_cpu(unsigned int cpu)
{
        if (hv_is_allocated_cpu(cpu))
                return;
        cpumask_clear_cpu(cpu, &hv_context.hv_numa_map[cpu_to_node(cpu)]);
}

static inline void hv_update_allocated_cpus(unsigned int old_cpu,
                                          unsigned int new_cpu)
{
        hv_set_allocated_cpu(new_cpu);
        hv_clear_allocated_cpu(old_cpu);
}

#ifdef CONFIG_HYPERV_TESTING

int hv_debug_add_dev_dir(struct hv_device *dev);
void hv_debug_rm_dev_dir(struct hv_device *dev);
void hv_debug_rm_all_dir(void);
int hv_debug_init(void);
void hv_debug_delay_test(struct vmbus_channel *channel, enum delay delay_type);

#else /* CONFIG_HYPERV_TESTING */

static inline void hv_debug_rm_dev_dir(struct hv_device *dev) {};
static inline void hv_debug_rm_all_dir(void) {};
static inline void hv_debug_delay_test(struct vmbus_channel *channel,
                                       enum delay delay_type) {};
static inline int hv_debug_init(void)
{
        return -1;
}

static inline int hv_debug_add_dev_dir(struct hv_device *dev)
{
        return -1;
}

#endif /* CONFIG_HYPERV_TESTING */

/* Create and remove sysfs entry for memory mapped ring buffers for a channel */
int hv_create_ring_sysfs(struct vmbus_channel *channel,
                         int (*hv_mmap_ring_buffer)(struct vmbus_channel *channel,
                                                    struct vm_area_struct *vma));
int hv_remove_ring_sysfs(struct vmbus_channel *channel);

#endif /* _HYPERV_VMBUS_H */