tap: reset vnet header size on open

For tap, we currently assume the vnet header size is 10
(the default value) but that might not be the case
if tap is persistent and has been used by qemu previously.
To fix, set host header size in tap device on open.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2012-11-13 12:23:23 +02:00 committed by Stefan Hajnoczi
parent 1d2a67f89a
commit 58ddcd50f3
1 changed files with 7 additions and 0 deletions

View File

@ -341,6 +341,13 @@ static TAPState *net_tap_fd_init(NetClientState *peer,
s->using_vnet_hdr = 0;
s->has_ufo = tap_probe_has_ufo(s->fd);
tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
/*
* Make sure host header length is set correctly in tap:
* it might have been modified by another instance of qemu.
*/
if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
}
tap_read_poll(s, 1);
s->vhost_net = NULL;
return s;