// SPDX-License-Identifier: GPL-2.0-only
/*
* virtio transport for vsock
*
* Copyright (C) 2013-2015 Red Hat, Inc.
* Author: Asias He <[email protected]>
* Stefan Hajnoczi <[email protected]>
*
* Some of the code is take from Gerd Hoffmann <[email protected]>'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 __rcu *the_virtio_vsock;
static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
static struct virtio_transport virtio_transport; /* forward declaration */
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;
struct sk_buff_head send_pkt_queue;
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;
bool seqpacket_allow;
/* These fields are used only in tx path in function
* 'virtio_transport_send_pkt_work()', so to save
* stack space in it, place both of them here. Each
* pointer from 'out_sgs' points to the corresponding
* element in 'out_bufs' - this is initialized in
* 'virtio_vsock_probe()'. Both fields are protected
* by 'tx_lock'. +1 is needed for packet header.
*/
struct scatterlist *out_sgs[MAX_SKB_FRAGS + 1];
struct scatterlist out_bufs[MAX_SKB_FRAGS + 1];
};
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;
}
/* Caller need to hold vsock->tx_lock on vq */
static int virtio_transport_send_skb(struct sk_buff *skb, struct virtqueue *vq,
struct virtio_vsock *vsock)
{
int ret, in_sg = 0, out_sg = 0;
struct scatterlist **sgs;
sgs = vsock->out_sgs;
sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb),
sizeof(*virtio_vsock_hdr(skb)));
out_sg++;
if (!skb_is_nonlinear(skb)) {
if (skb->len > 0) {
sg_init_one(sgs[out_sg], skb->data, skb->len);
out_sg++;
}
} else {
struct skb_shared_info *si;
int i;
/* If skb is nonlinear, then its buffer must contain
* only header and nothing more. Data is stored in
* the fragged part.
*/
WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb)));
si = skb_shinfo(skb);
for (i = 0; i < si->nr_frags; i++) {
skb_frag_t *skb_frag = &si->frags[i];
void *va;
/* We will use 'page_to_virt()' for the userspace page
* here, because virtio or dma-mapping layers will call
* 'virt_to_phys()' later to fill the buffer descriptor.
* We don't touch memory at "virtual" address of this page.
*/
va = page_to_virt(skb_frag_page(skb_frag));
sg_init_one(sgs[out_sg],
va + skb_frag_off(skb_frag),
skb_frag_size(skb_frag));
out_sg++;
}
}
ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
/* Usually this means that there is no more space available in
* the vq
*/
if (ret < 0)
return ret;
virtio_transport_deliver_tap_pkt(skb);
return 0;
}
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 sk_buff *skb;
bool reply;
int ret;
skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue);
if (!skb)
break;
reply = virtio_vsock_skb_reply(skb);
ret = virtio_transport_send_skb(skb, vq, vsock);
if (ret < 0) {
virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb);
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);
}
/* Caller need to hold RCU for vsock.
* Returns 0 if the packet is successfully put on the vq.
*/
static int virtio_transport_send_skb_fast_path(struct virtio_vsock *vsock, struct sk_buff *skb)
{
struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX];
int ret;
/* Inside RCU, can't sleep! */
ret = mutex_trylock(&vsock->tx_lock);
if (unlikely(ret == 0))
return -EBUSY;
ret = virtio_transport_send_skb(skb, vq, vsock);
if (ret == 0)
virtqueue_kick(vq);
mutex_unlock(&vsock->tx_lock);
return ret;
}
static int
virtio_transport_send_pkt(struct sk_buff *skb)
{
struct virtio_vsock_hdr *hdr;
struct virtio_vsock *vsock;
int len = skb->len;
hdr = virtio_vsock_hdr(skb);
rcu_read_lock();
vsock = rcu_dereference(the_virtio_vsock);
if (!vsock) {
kfree_skb(skb);
len = -ENODEV;
goto out_rcu;
}
if (le64_to_cpu(hdr->dst_cid) == vsock->guest_cid) {
kfree_skb(skb);
len = -ENODEV;
goto out_rcu;
}
/* If send_pkt_queue is empty, we can safely bypass this queue
* because packet order is maintained and (try) to put the packet
* on the virtqueue using virtio_transport_send_skb_fast_path.
* If this fails we simply put the packet on the intermediate
* queue and schedule the worker.
*/
if (!skb_queue_empty_lockless(&vsock->send_pkt_queue) ||
virtio_transport_send_skb_fast_path(vsock, skb)) {
if (virtio_vsock_skb_reply(skb))
atomic_inc(&vsock->queued_replies);
virtio_vsock_skb_queue_tail(&vsock->send_pkt_queue, skb);
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;
int cnt = 0, ret;
rcu_read_lock();
vsock = rcu_dereference(the_virtio_vsock);
if (!vsock) {
ret = -ENODEV;
goto out_rcu;
}
cnt = virtio_transport_purge_skbs(vsk, &vsock->send_pkt_queue);
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 total_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM;
struct scatterlist pkt, *p;
struct virtqueue *vq;
struct sk_buff *skb;
int ret;
vq = vsock->vqs[VSOCK_VQ_RX];
do {
skb = virtio_vsock_alloc_skb(total_len, GFP_KERNEL);
if (!skb)
break;
memset(skb->head, 0, VIRTIO_VSOCK_SKB_HEADROOM);
sg_init_one(&pkt, virtio_vsock_hdr(skb), total_len);
p = &pkt;
ret = virtqueue_add_sgs(vq, &p, 0, 1, skb, GFP_KERNEL);
if (ret < 0) {
kfree_skb(skb);
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 sk_buff *skb;
unsigned int len;
virtqueue_disable_cb(vq);
while ((skb = virtqueue_get_buf(vq, &len)) != NULL) {
virtio_transport_consume_skb_sent(skb, true);
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);
}
/* 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)
{
/* vmci_transport.c doesn't take sk_lock here either. At least we're
* under vsock_table_lock so the sock cannot disappear while we're
* executing.
*/
sk->sk_state = TCP_CLOSE;
sk->sk_err = ECONNRESET;
sk_error_report(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_transport.transport,
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 bool virtio_transport_can_msgzerocopy(int bufs_num)
{
struct virtio_vsock *vsock;
bool res = false;
rcu_read_lock();
vsock = rcu_dereference(the_virtio_vsock);
if (vsock) {
struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX];
/* Check that tx queue is large enough to keep whole
* data to send. This is needed, because when there is
* not enough free space in the queue, current skb to
* send will be reinserted to the head of tx list of
* the socket to retry transmission later, so if skb
* is bigger than whole queue, it will be reinserted
* again and again, thus blocking other skbs to be sent.
* Each page of the user provided buffer will be added
* as a single buffer to the tx virtqueue, so compare
* number of pages against maximum capacity of the queue.
*/
if (bufs_num <= vq->num_max)
res = true;
}
rcu_read_unlock();
return res;
}
static bool virtio_transport_msgzerocopy_allow(void)
{
return true;
}
static bool virtio_transport_seqpacket_allow(u32 remote_cid);
static struct virtio_transport virtio_transport = {
.transport = {
.module = THIS_MODULE,
.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,
.seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
.seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
.seqpacket_allow = virtio_transport_seqpacket_allow,
.seqpacket_has_data = virtio_transport_seqpacket_has_data,
.msgzerocopy_allow = virtio_transport_msgzerocopy_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,
.notify_buffer_size = virtio_transport_notify_buffer_size,
.notify_set_rcvlowat = virtio_transport_notify_set_rcvlowat,
.unsent_bytes = virtio_transport_unsent_bytes,
.read_skb = virtio_transport_read_skb,
},
.send_pkt = virtio_transport_send_pkt,
.can_msgzerocopy = virtio_transport_can_msgzerocopy,
};
static bool virtio_transport_seqpacket_allow(u32 remote_cid)
{
struct virtio_vsock *vsock;
bool seqpacket_allow;
seqpacket_allow = false;
rcu_read_lock();
vsock = rcu_dereference(the_virtio_vsock);
if (vsock)
seqpacket_allow = vsock->seqpacket_allow;
rcu_read_unlock();
return seqpacket_allow;
}
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 sk_buff *skb;
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;
}
skb = virtqueue_get_buf(vq, &len);
if (!skb)
break;
vsock->rx_buf_nr--;
/* Drop short/long packets */
if (unlikely(len < sizeof(struct virtio_vsock_hdr) ||
len > virtio_vsock_skb_len(skb))) {
kfree_skb(skb);
continue;
}
virtio_vsock_skb_rx_put(skb);
virtio_transport_deliver_tap_pkt(skb);
virtio_transport_recv_pkt(&virtio_transport, skb);
}
} 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);
}
static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
{
struct virtio_device *vdev = vsock->vdev;
struct virtqueue_info vqs_info[] = {
{ "rx", virtio_vsock_rx_done },
{ "tx", virtio_vsock_tx_done },
{ "event", virtio_vsock_event_done },
};
int ret;
ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, vqs_info, NULL);
if (ret < 0)
return ret;
virtio_vsock_update_guest_cid(vsock);
virtio_device_ready(vdev);
return 0;
}
static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
{
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);
/* virtio_transport_send_pkt() can queue packets once
* the_virtio_vsock is set, but they won't be processed until
* vsock->tx_run is set to true. We queue vsock->send_pkt_work
* when initialization finishes to send those packets queued
* earlier.
* We don't need to queue the other workers (rx, event) because
* as long as we don't fill the queues with empty buffers, the
* host can't send us any notification.
*/
queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
}
static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
{
struct virtio_device *vdev = vsock->vdev;
struct sk_buff *skb;
/* Reset all connected sockets when the VQs disappear */
vsock_for_each_connected_socket(&virtio_transport.transport,
virtio_vsock_reset_sock);
/* Stop all work handlers to make sure no one is accessing the device,
* so we can safely call virtio_reset_device().
*/
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.
*/
virtio_reset_device(vdev);
mutex_lock(&vsock->rx_lock);
while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
kfree_skb(skb);
mutex_unlock(&vsock->rx_lock);
mutex_lock(&vsock->tx_lock);
while ((skb = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
kfree_skb(skb);
mutex_unlock(&vsock->tx_lock);
virtio_vsock_skb_queue_purge(&vsock->send_pkt_queue);
/* Delete virtqueues and flush outstanding callbacks if any */
vdev->config->del_vqs(vdev);
}
static int virtio_vsock_probe(struct virtio_device *vdev)
{
struct virtio_vsock *vsock = NULL;
int ret;
int i;
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;
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);
skb_queue_head_init(&vsock->send_pkt_queue);
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);
if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
vsock->seqpacket_allow = true;
vdev->priv = vsock;
ret = virtio_vsock_vqs_init(vsock);
if (ret < 0)
goto out;
for (i = 0; i < ARRAY_SIZE(vsock->out_sgs); i++)
vsock->out_sgs[i] = &vsock->out_bufs[i];
rcu_assign_pointer(the_virtio_vsock, vsock);
virtio_vsock_vqs_start(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;
mutex_lock(&the_virtio_vsock_mutex);
vdev->priv = NULL;
rcu_assign_pointer(the_virtio_vsock, NULL);
synchronize_rcu();
virtio_vsock_vqs_del(vsock);
/* 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->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);
}
#ifdef CONFIG_PM_SLEEP
static int virtio_vsock_freeze(struct virtio_device *vdev)
{
struct virtio_vsock *vsock = vdev->priv;
mutex_lock(&the_virtio_vsock_mutex);
rcu_assign_pointer(the_virtio_vsock, NULL);
synchronize_rcu();
virtio_vsock_vqs_del(vsock);
mutex_unlock(&the_virtio_vsock_mutex);
return 0;
}
static int virtio_vsock_restore(struct virtio_device *vdev)
{
struct virtio_vsock *vsock = vdev->priv;
int ret;
mutex_lock(&the_virtio_vsock_mutex);
/* 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;
}
ret = virtio_vsock_vqs_init(vsock);
if (ret < 0)
goto out;
rcu_assign_pointer(the_virtio_vsock, vsock);
virtio_vsock_vqs_start(vsock);
out:
mutex_unlock(&the_virtio_vsock_mutex);
return ret;
}
#endif /* CONFIG_PM_SLEEP */
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
{ 0 },
};
static unsigned int features[] = {
VIRTIO_VSOCK_F_SEQPACKET
};
static struct virtio_driver virtio_vsock_driver = {
.feature_table = features,
.feature_table_size = ARRAY_SIZE(features),
.driver.name = KBUILD_MODNAME,
.id_table = id_table,
.probe = virtio_vsock_probe,
.remove = virtio_vsock_remove,
#ifdef CONFIG_PM_SLEEP
.freeze = virtio_vsock_freeze,
.restore = virtio_vsock_restore,
#endif
};
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_register(&virtio_transport.transport,
VSOCK_TRANSPORT_F_G2H);
if (ret)
goto out_wq;
ret = register_virtio_driver(&virtio_vsock_driver);
if (ret)
goto out_vci;
return 0;
out_vci:
vsock_core_unregister(&virtio_transport.transport);
out_wq:
destroy_workqueue(virtio_vsock_workqueue);
return ret;
}
static void __exit virtio_vsock_exit(void)
{
unregister_virtio_driver(&virtio_vsock_driver);
vsock_core_unregister(&virtio_transport.transport);
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);
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