virtio-net: purge outstanding packets when starting vhost

whenever we start vhost, virtio could have outstanding packets
queued, when they complete later we'll modify the ring
while vhost is processing it.

To prevent this, purge outstanding packets on vhost start.

Cc: qemu-stable@nongnu.org
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 086abc1ccd)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
This commit is contained in:
Michael S. Tsirkin 2014-09-04 11:39:17 +03:00 committed by Michael Roth
parent 08743db463
commit cf29a88391
1 changed files with 14 additions and 1 deletions

View File

@ -125,10 +125,23 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)
return;
}
if (!n->vhost_started) {
int r;
int r, i;
if (!vhost_net_query(get_vhost_net(nc->peer), vdev)) {
return;
}
/* Any packets outstanding? Purge them to avoid touching rings
* when vhost is running.
*/
for (i = 0; i < queues; i++) {
NetClientState *qnc = qemu_get_subqueue(n->nic, i);
/* Purge both directions: TX and RX. */
qemu_net_queue_purge(qnc->peer->incoming_queue, qnc);
qemu_net_queue_purge(qnc->incoming_queue, qnc->peer);
}
n->vhost_started = 1;
r = vhost_net_start(vdev, n->nic->ncs, queues);
if (r < 0) {