blob: a504e2e003da58181e6fbf4e8276c8f4615e18f2 [file] [log] [blame]
/*
* vhost transport for vsock
*
* Copyright (C) 2013-2015 Red Hat, Inc.
* Author: Asias He <asias@redhat.com>
* Stefan Hajnoczi <stefanha@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2.
*/
#include <linux/miscdevice.h>
#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>
#include <net/sock.h>
#include <linux/virtio_vsock.h>
#include <linux/vhost.h>
#include <net/af_vsock.h>
#include "vhost.h"
#define VHOST_VSOCK_DEFAULT_HOST_CID 2
enum {
VHOST_VSOCK_FEATURES = VHOST_FEATURES,
};
/* Used to track all the vhost_vsock instances on the system. */
static DEFINE_SPINLOCK(vhost_vsock_lock);
static LIST_HEAD(vhost_vsock_list);
struct vhost_vsock {
struct vhost_dev dev;
struct vhost_virtqueue vqs[2];
/* Link to global vhost_vsock_list, protected by vhost_vsock_lock */
struct list_head list;
struct vhost_work send_pkt_work;
spinlock_t send_pkt_list_lock;
struct list_head send_pkt_list; /* host->guest pending packets */
atomic_t queued_replies;
u32 guest_cid;
};
static u32 vhost_transport_get_local_cid(void)
{
return VHOST_VSOCK_DEFAULT_HOST_CID;
}
static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
{
struct vhost_vsock *vsock;
spin_lock_bh(&vhost_vsock_lock);
list_for_each_entry(vsock, &vhost_vsock_list, list) {
u32 other_cid = vsock->guest_cid;
/* Skip instances that have no CID yet */
if (other_cid == 0)
continue;
if (other_cid == guest_cid) {
spin_unlock_bh(&vhost_vsock_lock);
return vsock;
}
}
spin_unlock_bh(&vhost_vsock_lock);
return NULL;
}
static void
vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
struct vhost_virtqueue *vq)
{
struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
bool added = false;
bool restart_tx = false;
mutex_lock(&vq->mutex);
if (!vq->private_data)
goto out;
/* Avoid further vmexits, we're already processing the virtqueue */
vhost_disable_notify(&vsock->dev, vq);
for (;;) {
struct virtio_vsock_pkt *pkt;
struct iov_iter iov_iter;
unsigned out, in;
size_t nbytes;
size_t len;
int head;
spin_lock_bh(&vsock->send_pkt_list_lock);
if (list_empty(&vsock->send_pkt_list)) {
spin_unlock_bh(&vsock->send_pkt_list_lock);
vhost_enable_notify(&vsock->dev, vq);
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);
head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
&out, &in, NULL, NULL);
if (head < 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 (head == vq->num) {
spin_lock_bh(&vsock->send_pkt_list_lock);
list_add(&pkt->list, &vsock->send_pkt_list);
spin_unlock_bh(&vsock->send_pkt_list_lock);
/* We cannot finish yet if more buffers snuck in while
* re-enabling notify.
*/
if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
vhost_disable_notify(&vsock->dev, vq);
continue;
}
break;
}
if (out) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Expected 0 output buffers, got %u\n", out);
break;
}
len = iov_length(&vq->iov[out], in);
iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len);
nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
if (nbytes != sizeof(pkt->hdr)) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Faulted on copying pkt hdr\n");
break;
}
nbytes = copy_to_iter(pkt->buf, pkt->len, &iov_iter);
if (nbytes != pkt->len) {
virtio_transport_free_pkt(pkt);
vq_err(vq, "Faulted on copying pkt buf\n");
break;
}
vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len);
added = true;
if (pkt->reply) {
int val;
val = atomic_dec_return(&vsock->queued_replies);
/* Do we have resources to resume tx processing? */
if (val + 1 == tx_vq->num)
restart_tx = true;
}
virtio_transport_free_pkt(pkt);
}
if (added)
vhost_signal(&vsock->dev, vq);
out:
mutex_unlock(&vq->mutex);
if (restart_tx)
vhost_poll_queue(&tx_vq->poll);
}
static void vhost_transport_send_pkt_work(struct vhost_work *work)
{
struct vhost_virtqueue *vq;
struct vhost_vsock *vsock;
vsock = container_of(work, struct vhost_vsock, send_pkt_work);
vq = &vsock->vqs[VSOCK_VQ_RX];
vhost_transport_do_send_pkt(vsock, vq);
}
static int
vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
{
struct vhost_vsock *vsock;
struct vhost_virtqueue *vq;
int len = pkt->len;
/* Find the vhost_vsock according to guest context id */
vsock = vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid));
if (!vsock) {
virtio_transport_free_pkt(pkt);
return -ENODEV;
}
vq = &vsock->vqs[VSOCK_VQ_RX];
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);
vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
return len;
}
static struct virtio_vsock_pkt *
vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
unsigned int out, unsigned int in)
{
struct virtio_vsock_pkt *pkt;
struct iov_iter iov_iter;
size_t nbytes;
size_t len;
if (in != 0) {
vq_err(vq, "Expected 0 input buffers, got %u\n", in);
return NULL;
}
pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
if (!pkt)
return NULL;
len = iov_length(vq->iov, out);
iov_iter_init(&iov_iter, WRITE, vq->iov, out, len);
nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
if (nbytes != sizeof(pkt->hdr)) {
vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
sizeof(pkt->hdr), nbytes);
kfree(pkt);
return NULL;
}
if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM)
pkt->len = le32_to_cpu(pkt->hdr.len);
/* No payload */
if (!pkt->len)
return pkt;
/* The pkt is too big */
if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
kfree(pkt);
return NULL;
}
pkt->buf = kmalloc(pkt->len, GFP_KERNEL);
if (!pkt->buf) {
kfree(pkt);
return NULL;
}
nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
if (nbytes != pkt->len) {
vq_err(vq, "Expected %u byte payload, got %zu bytes\n",
pkt->len, nbytes);
virtio_transport_free_pkt(pkt);
return NULL;
}
return pkt;
}
/* Is there space left for replies to rx packets? */
static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
{
struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX];
int val;
smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
val = atomic_read(&vsock->queued_replies);
return val < vq->num;
}
static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
{
struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
poll.work);
struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
dev);
struct virtio_vsock_pkt *pkt;
int head;
unsigned int out, in;
bool added = false;
mutex_lock(&vq->mutex);
if (!vq->private_data)
goto out;
vhost_disable_notify(&vsock->dev, vq);
for (;;) {
u32 len;
if (!vhost_vsock_more_replies(vsock)) {
/* Stop tx until the device processes already
* pending replies. Leave tx virtqueue
* callbacks disabled.
*/
goto no_more_replies;
}
head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
&out, &in, NULL, NULL);
if (head < 0)
break;
if (head == vq->num) {
if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
vhost_disable_notify(&vsock->dev, vq);
continue;
}
break;
}
pkt = vhost_vsock_alloc_pkt(vq, out, in);
if (!pkt) {
vq_err(vq, "Faulted on pkt\n");
continue;
}
len = pkt->len;
/* Only accept correctly addressed packets */
if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid)
virtio_transport_recv_pkt(pkt);
else
virtio_transport_free_pkt(pkt);
vhost_add_used(vq, head, sizeof(pkt->hdr) + len);
added = true;
}
no_more_replies:
if (added)
vhost_signal(&vsock->dev, vq);
out:
mutex_unlock(&vq->mutex);
}
static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
{
struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
poll.work);
struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
dev);
vhost_transport_do_send_pkt(vsock, vq);
}
static int vhost_vsock_start(struct vhost_vsock *vsock)
{
size_t i;
int ret;
mutex_lock(&vsock->dev.mutex);
ret = vhost_dev_check_owner(&vsock->dev);
if (ret)
goto err;
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
struct vhost_virtqueue *vq = &vsock->vqs[i];
mutex_lock(&vq->mutex);
if (!vhost_vq_access_ok(vq)) {
ret = -EFAULT;
mutex_unlock(&vq->mutex);
goto err_vq;
}
if (!vq->private_data) {
vq->private_data = vsock;
vhost_vq_init_access(vq);
}
mutex_unlock(&vq->mutex);
}
mutex_unlock(&vsock->dev.mutex);
return 0;
err_vq:
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
struct vhost_virtqueue *vq = &vsock->vqs[i];
mutex_lock(&vq->mutex);
vq->private_data = NULL;
mutex_unlock(&vq->mutex);
}
err:
mutex_unlock(&vsock->dev.mutex);
return ret;
}
static int vhost_vsock_stop(struct vhost_vsock *vsock)
{
size_t i;
int ret;
mutex_lock(&vsock->dev.mutex);
ret = vhost_dev_check_owner(&vsock->dev);
if (ret)
goto err;
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
struct vhost_virtqueue *vq = &vsock->vqs[i];
mutex_lock(&vq->mutex);
vq->private_data = NULL;
mutex_unlock(&vq->mutex);
}
err:
mutex_unlock(&vsock->dev.mutex);
return ret;
}
static void vhost_vsock_free(struct vhost_vsock *vsock)
{
kvfree(vsock);
}
static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
{
struct vhost_virtqueue **vqs;
struct vhost_vsock *vsock;
int ret;
/* This struct is large and allocation could fail, fall back to vmalloc
* if there is no other way.
*/
vsock = kzalloc(sizeof(*vsock), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
if (!vsock) {
vsock = vmalloc(sizeof(*vsock));
if (!vsock)
return -ENOMEM;
}
vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL);
if (!vqs) {
ret = -ENOMEM;
goto out;
}
atomic_set(&vsock->queued_replies, 0);
vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];
vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];
vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs));
file->private_data = vsock;
spin_lock_init(&vsock->send_pkt_list_lock);
INIT_LIST_HEAD(&vsock->send_pkt_list);
vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
spin_lock_bh(&vhost_vsock_lock);
list_add_tail(&vsock->list, &vhost_vsock_list);
spin_unlock_bh(&vhost_vsock_lock);
return 0;
out:
vhost_vsock_free(vsock);
return ret;
}
static void vhost_vsock_flush(struct vhost_vsock *vsock)
{
int i;
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++)
if (vsock->vqs[i].handle_kick)
vhost_poll_flush(&vsock->vqs[i].poll);
vhost_work_flush(&vsock->dev, &vsock->send_pkt_work);
}
static void vhost_vsock_reset_orphans(struct sock *sk)
{
struct vsock_sock *vsk = vsock_sk(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.
*/
if (!vhost_vsock_get(vsk->remote_addr.svm_cid)) {
sock_set_flag(sk, SOCK_DONE);
vsk->peer_shutdown = SHUTDOWN_MASK;
sk->sk_state = SS_UNCONNECTED;
sk->sk_err = ECONNRESET;
sk->sk_error_report(sk);
}
}
static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
{
struct vhost_vsock *vsock = file->private_data;
spin_lock_bh(&vhost_vsock_lock);
list_del(&vsock->list);
spin_unlock_bh(&vhost_vsock_lock);
/* Iterating over all connections for all CIDs to find orphans is
* inefficient. Room for improvement here. */
vsock_for_each_connected_socket(vhost_vsock_reset_orphans);
vhost_vsock_stop(vsock);
vhost_vsock_flush(vsock);
vhost_dev_stop(&vsock->dev);
spin_lock_bh(&vsock->send_pkt_list_lock);
while (!list_empty(&vsock->send_pkt_list)) {
struct virtio_vsock_pkt *pkt;
pkt = list_first_entry(&vsock->send_pkt_list,
struct virtio_vsock_pkt, list);
list_del_init(&pkt->list);
virtio_transport_free_pkt(pkt);
}
spin_unlock_bh(&vsock->send_pkt_list_lock);
vhost_dev_cleanup(&vsock->dev, false);
kfree(vsock->dev.vqs);
vhost_vsock_free(vsock);
return 0;
}
static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
{
struct vhost_vsock *other;
/* Refuse reserved CIDs */
if (guest_cid <= VMADDR_CID_HOST ||
guest_cid == U32_MAX)
return -EINVAL;
/* 64-bit CIDs are not yet supported */
if (guest_cid > U32_MAX)
return -EINVAL;
/* Refuse if CID is already in use */
other = vhost_vsock_get(guest_cid);
if (other && other != vsock)
return -EADDRINUSE;
spin_lock_bh(&vhost_vsock_lock);
vsock->guest_cid = guest_cid;
spin_unlock_bh(&vhost_vsock_lock);
return 0;
}
static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
{
struct vhost_virtqueue *vq;
int i;
if (features & ~VHOST_VSOCK_FEATURES)
return -EOPNOTSUPP;
mutex_lock(&vsock->dev.mutex);
if ((features & (1 << VHOST_F_LOG_ALL)) &&
!vhost_log_access_ok(&vsock->dev)) {
mutex_unlock(&vsock->dev.mutex);
return -EFAULT;
}
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
vq = &vsock->vqs[i];
mutex_lock(&vq->mutex);
vq->acked_features = features;
mutex_unlock(&vq->mutex);
}
mutex_unlock(&vsock->dev.mutex);
return 0;
}
static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
unsigned long arg)
{
struct vhost_vsock *vsock = f->private_data;
void __user *argp = (void __user *)arg;
u64 guest_cid;
u64 features;
int start;
int r;
switch (ioctl) {
case VHOST_VSOCK_SET_GUEST_CID:
if (copy_from_user(&guest_cid, argp, sizeof(guest_cid)))
return -EFAULT;
return vhost_vsock_set_cid(vsock, guest_cid);
case VHOST_VSOCK_SET_RUNNING:
if (copy_from_user(&start, argp, sizeof(start)))
return -EFAULT;
if (start)
return vhost_vsock_start(vsock);
else
return vhost_vsock_stop(vsock);
case VHOST_GET_FEATURES:
features = VHOST_VSOCK_FEATURES;
if (copy_to_user(argp, &features, sizeof(features)))
return -EFAULT;
return 0;
case VHOST_SET_FEATURES:
if (copy_from_user(&features, argp, sizeof(features)))
return -EFAULT;
return vhost_vsock_set_features(vsock, features);
default:
mutex_lock(&vsock->dev.mutex);
r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);
if (r == -ENOIOCTLCMD)
r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);
else
vhost_vsock_flush(vsock);
mutex_unlock(&vsock->dev.mutex);
return r;
}
}
static const struct file_operations vhost_vsock_fops = {
.owner = THIS_MODULE,
.open = vhost_vsock_dev_open,
.release = vhost_vsock_dev_release,
.llseek = noop_llseek,
.unlocked_ioctl = vhost_vsock_dev_ioctl,
};
static struct miscdevice vhost_vsock_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = "vhost-vsock",
.fops = &vhost_vsock_fops,
};
static struct virtio_transport vhost_transport = {
.transport = {
.get_local_cid = vhost_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,
.dgram_enqueue = virtio_transport_dgram_enqueue,
.dgram_dequeue = virtio_transport_dgram_dequeue,
.dgram_bind = virtio_transport_dgram_bind,
.dgram_allow = virtio_transport_dgram_allow,
.stream_enqueue = virtio_transport_stream_enqueue,
.stream_dequeue = virtio_transport_stream_dequeue,
.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 = vhost_transport_send_pkt,
};
static int __init vhost_vsock_init(void)
{
int ret;
ret = vsock_core_init(&vhost_transport.transport);
if (ret < 0)
return ret;
return misc_register(&vhost_vsock_misc);
};
static void __exit vhost_vsock_exit(void)
{
misc_deregister(&vhost_vsock_misc);
vsock_core_exit();
};
module_init(vhost_vsock_init);
module_exit(vhost_vsock_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Asias He");
MODULE_DESCRIPTION("vhost transport for vsock ");