Commit 086abc1c authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Stefan Hajnoczi
Browse files

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: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent ca77d85e

hw/net/virtio-net.c

+14 −1
Original line number Diff line number Diff line
@@ -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) {