| Message ID | 20171116184835.28556-3-maxime.coquelin@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtio-net: Fix TX data discard on backend disconnection | expand |
On Thu, Nov 16, 2017 at 06:48:35PM +0000, Maxime Coquelin wrote: >vhost_virtqueue_stop() gets avail index value from the backend, >except if the backend is not responding. > >It happens when the backend crashes, and in this case, internal >state of the virtio queue is inconsistent, making packets >to corrupt the vring state. > >With a Linux guest, it results in following error message on >backend reconnection: > >[ 22.444905] virtio_net virtio0: output.0:id 0 is not a head! >[ 22.446746] net enp0s3: Unexpected TXQ (0) queue failure: -5 >[ 22.476360] net enp0s3: Unexpected TXQ (0) queue failure: -5 > >Fixes: 283e2c2adcb8 ("net: virtio-net discards TX data after link down") >Cc: qemu-stable@nongnu.org >Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> >--- > hw/virtio/vhost.c | 4 ++++ > 1 file changed, 4 insertions(+) > Reviewed-by: Jens Freimann <jfreimann@redhat.com>
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index ddc42f0f93..54041948cf 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -1138,6 +1138,10 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, r = dev->vhost_ops->vhost_get_vring_base(dev, &state); if (r < 0) { VHOST_OPS_DEBUG("vhost VQ %d ring restore failed: %d", idx, r); + /* Connection to the backend is broken, so let's sync internal + * last avail idx to the device used idx. + */ + virtio_queue_restore_last_avail_idx(vdev, idx); } else { virtio_queue_set_last_avail_idx(vdev, idx, state.num); }
vhost_virtqueue_stop() gets avail index value from the backend, except if the backend is not responding. It happens when the backend crashes, and in this case, internal state of the virtio queue is inconsistent, making packets to corrupt the vring state. With a Linux guest, it results in following error message on backend reconnection: [ 22.444905] virtio_net virtio0: output.0:id 0 is not a head! [ 22.446746] net enp0s3: Unexpected TXQ (0) queue failure: -5 [ 22.476360] net enp0s3: Unexpected TXQ (0) queue failure: -5 Fixes: 283e2c2adcb8 ("net: virtio-net discards TX data after link down") Cc: qemu-stable@nongnu.org Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> --- hw/virtio/vhost.c | 4 ++++ 1 file changed, 4 insertions(+)