Commit d5675bd2 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin

vhost: break out of polling loop on error

When ring parsing fails, we currently handle this
as ring empty condition. This means that we enable
kicks and recheck ring empty: if this not empty,
we re-start polling which of course will fail again.

Instead, let's return a negative error code and stop polling.
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 38000a94
......@@ -98,7 +98,8 @@ static void tx_poll_start(struct vhost_net *net, struct socket *sock)
static void handle_tx(struct vhost_net *net)
{
struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
unsigned head, out, in, s;
unsigned out, in, s;
int head;
struct msghdr msg = {
.msg_name = NULL,
.msg_namelen = 0,
......@@ -135,6 +136,9 @@ static void handle_tx(struct vhost_net *net)
ARRAY_SIZE(vq->iov),
&out, &in,
NULL, NULL);
/* On error, stop handling until the next kick. */
if (head < 0)
break;
/* Nothing new? Wait for eventfd to tell us they refilled. */
if (head == vq->num) {
wmem = atomic_read(&sock->sk->sk_wmem_alloc);
......@@ -192,7 +196,8 @@ static void handle_tx(struct vhost_net *net)
static void handle_rx(struct vhost_net *net)
{
struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
unsigned head, out, in, log, s;
unsigned out, in, log, s;
int head;
struct vhost_log *vq_log;
struct msghdr msg = {
.msg_name = NULL,
......@@ -228,6 +233,9 @@ static void handle_rx(struct vhost_net *net)
ARRAY_SIZE(vq->iov),
&out, &in,
vq_log, &log);
/* On error, stop handling until the next kick. */
if (head < 0)
break;
/* OK, now we need to know about added descriptors. */
if (head == vq->num) {
if (unlikely(vhost_enable_notify(vq))) {
......
......@@ -873,12 +873,13 @@ static unsigned get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq,
* number of output then some number of input descriptors, it's actually two
* iovecs, but we pack them into one and note how many of each there were.
*
* This function returns the descriptor number found, or vq->num (which
* is never a valid descriptor number) if none was found. */
unsigned vhost_get_vq_desc(struct vhost_dev *dev, 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)
* This function returns the descriptor number found, or vq->num (which is
* never a valid descriptor number) if none was found. A negative code is
* returned on error. */
int vhost_get_vq_desc(struct vhost_dev *dev, 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)
{
struct vring_desc desc;
unsigned int i, head, found = 0;
......@@ -890,13 +891,13 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
if (get_user(vq->avail_idx, &vq->avail->idx)) {
vq_err(vq, "Failed to access avail idx at %p\n",
&vq->avail->idx);
return vq->num;
return -EFAULT;
}
if ((u16)(vq->avail_idx - last_avail_idx) > vq->num) {
vq_err(vq, "Guest moved used index from %u to %u",
last_avail_idx, vq->avail_idx);
return vq->num;
return -EFAULT;
}
/* If there's nothing new since last we looked, return invalid. */
......@@ -912,14 +913,14 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
vq_err(vq, "Failed to read head: idx %d address %p\n",
last_avail_idx,
&vq->avail->ring[last_avail_idx % vq->num]);
return vq->num;
return -EFAULT;
}
/* If their number is silly, that's an error. */
if (head >= vq->num) {
vq_err(vq, "Guest says index %u > %u is available",
head, vq->num);
return vq->num;
return -EINVAL;
}
/* When we start there are none of either input nor output. */
......@@ -933,19 +934,19 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
if (i >= vq->num) {
vq_err(vq, "Desc index is %u > %u, head = %u",
i, vq->num, head);
return vq->num;
return -EINVAL;
}
if (++found > vq->num) {
vq_err(vq, "Loop detected: last one at %u "
"vq size %u head %u\n",
i, vq->num, head);
return vq->num;
return -EINVAL;
}
ret = copy_from_user(&desc, vq->desc + i, sizeof desc);
if (ret) {
vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
i, vq->desc + i);
return vq->num;
return -EFAULT;
}
if (desc.flags & VRING_DESC_F_INDIRECT) {
ret = get_indirect(dev, vq, iov, iov_size,
......@@ -954,7 +955,7 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
if (ret < 0) {
vq_err(vq, "Failure detected "
"in indirect descriptor at idx %d\n", i);
return vq->num;
return ret;
}
continue;
}
......@@ -964,7 +965,7 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
if (ret < 0) {
vq_err(vq, "Translation failure %d descriptor idx %d\n",
ret, i);
return vq->num;
return ret;
}
if (desc.flags & VRING_DESC_F_WRITE) {
/* If this is an input descriptor,
......@@ -981,7 +982,7 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
if (*in_num) {
vq_err(vq, "Descriptor has out after in: "
"idx %d\n", i);
return vq->num;
return -EINVAL;
}
*out_num += ret;
}
......
......@@ -120,10 +120,10 @@ long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
int vhost_vq_access_ok(struct vhost_virtqueue *vq);
int vhost_log_access_ok(struct vhost_dev *);
unsigned vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
struct iovec iov[], unsigned int iov_count,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num);
int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
struct iovec iov[], unsigned int iov_count,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num);
void vhost_discard_vq_desc(struct vhost_virtqueue *);
int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
......
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