// SPDX-License-Identifier: GPL-2.0-only
/*
 * virtio transport for vsock
 *
 * Copyright (C) 2013-2015 Red Hat, Inc.
 * Author: Asias He <asias@redhat.com>
 *         Stefan Hajnoczi <stefanha@redhat.com>
 *
 * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s
 * early virtio-vsock proof-of-concept bits.
 */
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/atomic.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
#include <linux/virtio_vsock.h>
#include <net/sock.h>
#include <linux/mutex.h>
#include <net/af_vsock.h>

static struct workqueue_struct *virtio_vsock_workqueue;
static struct virtio_vsock *the_virtio_vsock;
static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */

struct virtio_vsock {
        struct virtio_device *vdev;
        struct virtqueue *vqs[VSOCK_VQ_MAX];

        /* Virtqueue processing is deferred to a workqueue */
        struct work_struct tx_work;
        struct work_struct rx_work;
        struct work_struct event_work;

        /* The following fields are protected by tx_lock.  vqs[VSOCK_VQ_TX]
         * must be accessed with tx_lock held.
         */
        struct mutex tx_lock;
        bool tx_run;

        struct work_struct send_pkt_work;
        spinlock_t send_pkt_list_lock;
        struct list_head send_pkt_list;

        struct work_struct loopback_work;
        spinlock_t loopback_list_lock; /* protects loopback_list */
        struct list_head loopback_list;

        atomic_t queued_replies;

        /* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
         * must be accessed with rx_lock held.
         */
        struct mutex rx_lock;
        bool rx_run;
        int rx_buf_nr;
        int rx_buf_max_nr;

        /* The following fields are protected by event_lock.
         * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
         */
        struct mutex event_lock;
        bool event_run;
        struct virtio_vsock_event event_list[8];

        u32 guest_cid;
};

static u32 virtio_transport_get_local_cid(void)
{
        struct virtio_vsock *vsock;
        u32 ret;

        rcu_read_lock();
        vsock = rcu_dereference(the_virtio_vsock);
        if (!vsock) {
                ret = VMADDR_CID_ANY;
                goto out_rcu;
        }

        ret = vsock->guest_cid;
out_rcu:
        rcu_read_unlock();
        return ret;
}

static void virtio_transport_loopback_work(struct work_struct *work)
{
        struct virtio_vsock *vsock =
                container_of(work, struct virtio_vsock, loopback_work);
        LIST_HEAD(pkts);

        spin_lock_bh(&vsock->loopback_list_lock);
        list_splice_init(&vsock->loopback_list, &pkts);
        spin_unlock_bh(&vsock->loopback_list_lock);

        mutex_lock(&vsock->rx_lock);

        if (!vsock->rx_run)
                goto out;

        while (!list_empty(&pkts)) {
                struct virtio_vsock_pkt *pkt;

                pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
                list_del_init(&pkt->list);

                virtio_transport_recv_pkt(pkt);
        }
out:
        mutex_unlock(&vsock->rx_lock);
}

static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
                                              struct virtio_vsock_pkt *pkt)
{
        int len = pkt->len;

        spin_lock_bh(&vsock->loopback_list_lock);
        list_add_tail(&pkt->list, &vsock->loopback_list);
        spin_unlock_bh(&vsock->loopback_list_lock);

        queue_work(virtio_vsock_workqueue, &vsock->loopback_work);

        return len;
}

static void
virtio_transport_send_pkt_work(struct work_struct *work)
{
        struct virtio_vsock *vsock =
                container_of(work, struct virtio_vsock, send_pkt_work);
        struct virtqueue *vq;
        bool added = false;
        bool restart_rx = false;

        mutex_lock(&vsock->tx_lock);

        if (!vsock->tx_run)
                goto out;

        vq = vsock->vqs[VSOCK_VQ_TX];

        for (;;) {
                struct virtio_vsock_pkt *pkt;
                struct scatterlist hdr, buf, *sgs[2];
                int ret, in_sg = 0, out_sg = 0;
                bool reply;

                spin_lock_bh(&vsock->send_pkt_list_lock);
                if (list_empty(&vsock->send_pkt_list)) {
                        spin_unlock_bh(&vsock->send_pkt_list_lock);
                        break;
                }

                pkt = list_first_entry(&vsock->send_pkt_list,
                                       struct virtio_vsock_pkt, list);
                list_del_init(&pkt->list);
                spin_unlock_bh(&vsock->send_pkt_list_lock);

                virtio_transport_deliver_tap_pkt(pkt);

                reply = pkt->reply;

                sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
                sgs[out_sg++] = &hdr;
                if (pkt->buf) {
                        sg_init_one(&buf, pkt->buf, pkt->len);
                        sgs[out_sg++] = &buf;
                }

                ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
                /* Usually this means that there is no more space available in
                 * the vq
                 */
                if (ret < 0) {
                        spin_lock_bh(&vsock->send_pkt_list_lock);
                        list_add(&pkt->list, &vsock->send_pkt_list);
                        spin_unlock_bh(&vsock->send_pkt_list_lock);
                        break;
                }

                if (reply) {
                        struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
                        int val;

                        val = atomic_dec_return(&vsock->queued_replies);

                        /* Do we now have resources to resume rx processing? */
                        if (val + 1 == virtqueue_get_vring_size(rx_vq))
                                restart_rx = true;
                }

                added = true;
        }

        if (added)
                virtqueue_kick(vq);

out:
        mutex_unlock(&vsock->tx_lock);

        if (restart_rx)
                queue_work(virtio_vsock_workqueue, &vsock->rx_work);
}

static int
virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
{
        struct virtio_vsock *vsock;
        int len = pkt->len;

        rcu_read_lock();
        vsock = rcu_dereference(the_virtio_vsock);
        if (!vsock) {
                virtio_transport_free_pkt(pkt);
                len = -ENODEV;
                goto out_rcu;
        }

        if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
                len = virtio_transport_send_pkt_loopback(vsock, pkt);
                goto out_rcu;
        }

        if (pkt->reply)
                atomic_inc(&vsock->queued_replies);

        spin_lock_bh(&vsock->send_pkt_list_lock);
        list_add_tail(&pkt->list, &vsock->send_pkt_list);
        spin_unlock_bh(&vsock->send_pkt_list_lock);

        queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);

out_rcu:
        rcu_read_unlock();
        return len;
}

static int
virtio_transport_cancel_pkt(struct vsock_sock *vsk)
{
        struct virtio_vsock *vsock;
        struct virtio_vsock_pkt *pkt, *n;
        int cnt = 0, ret;
        LIST_HEAD(freeme);

        rcu_read_lock();
        vsock = rcu_dereference(the_virtio_vsock);
        if (!vsock) {
                ret = -ENODEV;
                goto out_rcu;
        }

        spin_lock_bh(&vsock->send_pkt_list_lock);
        list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
                if (pkt->vsk != vsk)
                        continue;
                list_move(&pkt->list, &freeme);
        }
        spin_unlock_bh(&vsock->send_pkt_list_lock);

        list_for_each_entry_safe(pkt, n, &freeme, list) {
                if (pkt->reply)
                        cnt++;
                list_del(&pkt->list);
                virtio_transport_free_pkt(pkt);
        }

        if (cnt) {
                struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
                int new_cnt;

                new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
                if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
                    new_cnt < virtqueue_get_vring_size(rx_vq))
                        queue_work(virtio_vsock_workqueue, &vsock->rx_work);
        }

        ret = 0;

out_rcu:
        rcu_read_unlock();
        return ret;
}

static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
{
        int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
        struct virtio_vsock_pkt *pkt;
        struct scatterlist hdr, buf, *sgs[2];
        struct virtqueue *vq;
        int ret;

        vq = vsock->vqs[VSOCK_VQ_RX];

        do {
                pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
                if (!pkt)
                        break;

                pkt->buf = kmalloc(buf_len, GFP_KERNEL);
                if (!pkt->buf) {
                        virtio_transport_free_pkt(pkt);
                        break;
                }

                pkt->len = buf_len;

                sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
                sgs[0] = &hdr;

                sg_init_one(&buf, pkt->buf, buf_len);
                sgs[1] = &buf;
                ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
                if (ret) {
                        virtio_transport_free_pkt(pkt);
                        break;
                }
                vsock->rx_buf_nr++;
        } while (vq->num_free);
        if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
                vsock->rx_buf_max_nr = vsock->rx_buf_nr;
        virtqueue_kick(vq);
}

static void virtio_transport_tx_work(struct work_struct *work)
{
        struct virtio_vsock *vsock =
                container_of(work, struct virtio_vsock, tx_work);
        struct virtqueue *vq;
        bool added = false;

        vq = vsock->vqs[VSOCK_VQ_TX];
        mutex_lock(&vsock->tx_lock);

        if (!vsock->tx_run)
                goto out;

        do {
                struct virtio_vsock_pkt *pkt;
                unsigned int len;

                virtqueue_disable_cb(vq);
                while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
                        virtio_transport_free_pkt(pkt);
                        added = true;
                }
        } while (!virtqueue_enable_cb(vq));

out:
        mutex_unlock(&vsock->tx_lock);

        if (added)
                queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
}

/* Is there space left for replies to rx packets? */
static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
{
        struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
        int val;

        smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
        val = atomic_read(&vsock->queued_replies);

        return val < virtqueue_get_vring_size(vq);
}

static void virtio_transport_rx_work(struct work_struct *work)
{
        struct virtio_vsock *vsock =
                container_of(work, struct virtio_vsock, rx_work);
        struct virtqueue *vq;

        vq = vsock->vqs[VSOCK_VQ_RX];

        mutex_lock(&vsock->rx_lock);

        if (!vsock->rx_run)
                goto out;

        do {
                virtqueue_disable_cb(vq);
                for (;;) {
                        struct virtio_vsock_pkt *pkt;
                        unsigned int len;

                        if (!virtio_transport_more_replies(vsock)) {
                                /* Stop rx until the device processes already
                                 * pending replies.  Leave rx virtqueue
                                 * callbacks disabled.
                                 */
                                goto out;
                        }

                        pkt = virtqueue_get_buf(vq, &len);
                        if (!pkt) {
                                break;
                        }

                        vsock->rx_buf_nr--;

                        /* Drop short/long packets */
                        if (unlikely(len < sizeof(pkt->hdr) ||
                                     len > sizeof(pkt->hdr) + pkt->len)) {
                                virtio_transport_free_pkt(pkt);
                                continue;
                        }

                        pkt->len = len - sizeof(pkt->hdr);
                        virtio_transport_deliver_tap_pkt(pkt);
                        virtio_transport_recv_pkt(pkt);
                }
        } while (!virtqueue_enable_cb(vq));

out:
        if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
                virtio_vsock_rx_fill(vsock);
        mutex_unlock(&vsock->rx_lock);
}

/* event_lock must be held */
static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
                                       struct virtio_vsock_event *event)
{
        struct scatterlist sg;
        struct virtqueue *vq;

        vq = vsock->vqs[VSOCK_VQ_EVENT];

        sg_init_one(&sg, event, sizeof(*event));

        return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
}

/* event_lock must be held */
static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
{
        size_t i;

        for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
                struct virtio_vsock_event *event = &vsock->event_list[i];

                virtio_vsock_event_fill_one(vsock, event);
        }

        virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
}

static void virtio_vsock_reset_sock(struct sock *sk)
{
        lock_sock(sk);
        sk->sk_state = TCP_CLOSE;
        sk->sk_err = ECONNRESET;
        sk->sk_error_report(sk);
        release_sock(sk);
}

static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
{
        struct virtio_device *vdev = vsock->vdev;
        __le64 guest_cid;

        vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
                          &guest_cid, sizeof(guest_cid));
        vsock->guest_cid = le64_to_cpu(guest_cid);
}

/* event_lock must be held */
static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
                                      struct virtio_vsock_event *event)
{
        switch (le32_to_cpu(event->id)) {
        case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
                virtio_vsock_update_guest_cid(vsock);
                vsock_for_each_connected_socket(virtio_vsock_reset_sock);
                break;
        }
}

static void virtio_transport_event_work(struct work_struct *work)
{
        struct virtio_vsock *vsock =
                container_of(work, struct virtio_vsock, event_work);
        struct virtqueue *vq;

        vq = vsock->vqs[VSOCK_VQ_EVENT];

        mutex_lock(&vsock->event_lock);

        if (!vsock->event_run)
                goto out;

        do {
                struct virtio_vsock_event *event;
                unsigned int len;

                virtqueue_disable_cb(vq);
                while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
                        if (len == sizeof(*event))
                                virtio_vsock_event_handle(vsock, event);

                        virtio_vsock_event_fill_one(vsock, event);
                }
        } while (!virtqueue_enable_cb(vq));

        virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
out:
        mutex_unlock(&vsock->event_lock);
}

static void virtio_vsock_event_done(struct virtqueue *vq)
{
        struct virtio_vsock *vsock = vq->vdev->priv;

        if (!vsock)
                return;
        queue_work(virtio_vsock_workqueue, &vsock->event_work);
}

static void virtio_vsock_tx_done(struct virtqueue *vq)
{
        struct virtio_vsock *vsock = vq->vdev->priv;

        if (!vsock)
                return;
        queue_work(virtio_vsock_workqueue, &vsock->tx_work);
}

static void virtio_vsock_rx_done(struct virtqueue *vq)
{
        struct virtio_vsock *vsock = vq->vdev->priv;

        if (!vsock)
                return;
        queue_work(virtio_vsock_workqueue, &vsock->rx_work);
}

static struct virtio_transport virtio_transport = {
        .transport = {
                .get_local_cid            = virtio_transport_get_local_cid,

                .init                     = virtio_transport_do_socket_init,
                .destruct                 = virtio_transport_destruct,
                .release                  = virtio_transport_release,
                .connect                  = virtio_transport_connect,
                .shutdown                 = virtio_transport_shutdown,
                .cancel_pkt               = virtio_transport_cancel_pkt,

                .dgram_bind               = virtio_transport_dgram_bind,
                .dgram_dequeue            = virtio_transport_dgram_dequeue,
                .dgram_enqueue            = virtio_transport_dgram_enqueue,
                .dgram_allow              = virtio_transport_dgram_allow,

                .stream_dequeue           = virtio_transport_stream_dequeue,
                .stream_enqueue           = virtio_transport_stream_enqueue,
                .stream_has_data          = virtio_transport_stream_has_data,
                .stream_has_space         = virtio_transport_stream_has_space,
                .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
                .stream_is_active         = virtio_transport_stream_is_active,
                .stream_allow             = virtio_transport_stream_allow,

                .notify_poll_in           = virtio_transport_notify_poll_in,
                .notify_poll_out          = virtio_transport_notify_poll_out,
                .notify_recv_init         = virtio_transport_notify_recv_init,
                .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
                .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
                .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
                .notify_send_init         = virtio_transport_notify_send_init,
                .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
                .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
                .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,

                .set_buffer_size          = virtio_transport_set_buffer_size,
                .set_min_buffer_size      = virtio_transport_set_min_buffer_size,
                .set_max_buffer_size      = virtio_transport_set_max_buffer_size,
                .get_buffer_size          = virtio_transport_get_buffer_size,
                .get_min_buffer_size      = virtio_transport_get_min_buffer_size,
                .get_max_buffer_size      = virtio_transport_get_max_buffer_size,
        },

        .send_pkt = virtio_transport_send_pkt,
};

static int virtio_vsock_probe(struct virtio_device *vdev)
{
        vq_callback_t *callbacks[] = {
                virtio_vsock_rx_done,
                virtio_vsock_tx_done,
                virtio_vsock_event_done,
        };
        static const char * const names[] = {
                "rx",
                "tx",
                "event",
        };
        struct virtio_vsock *vsock = NULL;
        int ret;

        ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
        if (ret)
                return ret;

        /* Only one virtio-vsock device per guest is supported */
        if (rcu_dereference_protected(the_virtio_vsock,
                                lockdep_is_held(&the_virtio_vsock_mutex))) {
                ret = -EBUSY;
                goto out;
        }

        vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
        if (!vsock) {
                ret = -ENOMEM;
                goto out;
        }

        vsock->vdev = vdev;

        ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
                              vsock->vqs, callbacks, names,
                              NULL);
        if (ret < 0)
                goto out;

        virtio_vsock_update_guest_cid(vsock);

        vsock->rx_buf_nr = 0;
        vsock->rx_buf_max_nr = 0;
        atomic_set(&vsock->queued_replies, 0);

        mutex_init(&vsock->tx_lock);
        mutex_init(&vsock->rx_lock);
        mutex_init(&vsock->event_lock);
        spin_lock_init(&vsock->send_pkt_list_lock);
        INIT_LIST_HEAD(&vsock->send_pkt_list);
        spin_lock_init(&vsock->loopback_list_lock);
        INIT_LIST_HEAD(&vsock->loopback_list);
        INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
        INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
        INIT_WORK(&vsock->event_work, virtio_transport_event_work);
        INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
        INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);

        mutex_lock(&vsock->tx_lock);
        vsock->tx_run = true;
        mutex_unlock(&vsock->tx_lock);

        mutex_lock(&vsock->rx_lock);
        virtio_vsock_rx_fill(vsock);
        vsock->rx_run = true;
        mutex_unlock(&vsock->rx_lock);

        mutex_lock(&vsock->event_lock);
        virtio_vsock_event_fill(vsock);
        vsock->event_run = true;
        mutex_unlock(&vsock->event_lock);

        vdev->priv = vsock;
        rcu_assign_pointer(the_virtio_vsock, vsock);

        mutex_unlock(&the_virtio_vsock_mutex);
        return 0;

out:
        kfree(vsock);
        mutex_unlock(&the_virtio_vsock_mutex);
        return ret;
}

static void virtio_vsock_remove(struct virtio_device *vdev)
{
        struct virtio_vsock *vsock = vdev->priv;
        struct virtio_vsock_pkt *pkt;

        mutex_lock(&the_virtio_vsock_mutex);

        vdev->priv = NULL;
        rcu_assign_pointer(the_virtio_vsock, NULL);
        synchronize_rcu();

        /* Reset all connected sockets when the device disappear */
        vsock_for_each_connected_socket(virtio_vsock_reset_sock);

        /* Stop all work handlers to make sure no one is accessing the device,
         * so we can safely call vdev->config->reset().
         */
        mutex_lock(&vsock->rx_lock);
        vsock->rx_run = false;
        mutex_unlock(&vsock->rx_lock);

        mutex_lock(&vsock->tx_lock);
        vsock->tx_run = false;
        mutex_unlock(&vsock->tx_lock);

        mutex_lock(&vsock->event_lock);
        vsock->event_run = false;
        mutex_unlock(&vsock->event_lock);

        /* Flush all device writes and interrupts, device will not use any
         * more buffers.
         */
        vdev->config->reset(vdev);

        mutex_lock(&vsock->rx_lock);
        while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
                virtio_transport_free_pkt(pkt);
        mutex_unlock(&vsock->rx_lock);

        mutex_lock(&vsock->tx_lock);
        while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
                virtio_transport_free_pkt(pkt);
        mutex_unlock(&vsock->tx_lock);

        spin_lock_bh(&vsock->send_pkt_list_lock);
        while (!list_empty(&vsock->send_pkt_list)) {
                pkt = list_first_entry(&vsock->send_pkt_list,
                                       struct virtio_vsock_pkt, list);
                list_del(&pkt->list);
                virtio_transport_free_pkt(pkt);
        }
        spin_unlock_bh(&vsock->send_pkt_list_lock);

        spin_lock_bh(&vsock->loopback_list_lock);
        while (!list_empty(&vsock->loopback_list)) {
                pkt = list_first_entry(&vsock->loopback_list,
                                       struct virtio_vsock_pkt, list);
                list_del(&pkt->list);
                virtio_transport_free_pkt(pkt);
        }
        spin_unlock_bh(&vsock->loopback_list_lock);

        /* Delete virtqueues and flush outstanding callbacks if any */
        vdev->config->del_vqs(vdev);

        /* Other works can be queued before 'config->del_vqs()', so we flush
         * all works before to free the vsock object to avoid use after free.
         */
        flush_work(&vsock->loopback_work);
        flush_work(&vsock->rx_work);
        flush_work(&vsock->tx_work);
        flush_work(&vsock->event_work);
        flush_work(&vsock->send_pkt_work);

        mutex_unlock(&the_virtio_vsock_mutex);

        kfree(vsock);
}

static struct virtio_device_id id_table[] = {
        { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
        { 0 },
};

static unsigned int features[] = {
};

static struct virtio_driver virtio_vsock_driver = {
        .feature_table = features,
        .feature_table_size = ARRAY_SIZE(features),
        .driver.name = KBUILD_MODNAME,
        .driver.owner = THIS_MODULE,
        .id_table = id_table,
        .probe = virtio_vsock_probe,
        .remove = virtio_vsock_remove,
};

static int __init virtio_vsock_init(void)
{
        int ret;

        virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
        if (!virtio_vsock_workqueue)
                return -ENOMEM;

        ret = vsock_core_init(&virtio_transport.transport);
        if (ret)
                goto out_wq;

        ret = register_virtio_driver(&virtio_vsock_driver);
        if (ret)
                goto out_vci;

        return 0;

out_vci:
        vsock_core_exit();
out_wq:
        destroy_workqueue(virtio_vsock_workqueue);
        return ret;
}

static void __exit virtio_vsock_exit(void)
{
        unregister_virtio_driver(&virtio_vsock_driver);
        vsock_core_exit();
        destroy_workqueue(virtio_vsock_workqueue);
}

module_init(virtio_vsock_init);
module_exit(virtio_vsock_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Asias He");
MODULE_DESCRIPTION("virtio transport for vsock");
MODULE_DEVICE_TABLE(virtio, id_table);