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authorMichael S. Tsirkin <mst@redhat.com>2012-11-13 12:23:23 +0200
committerStefan Hajnoczi <stefanha@redhat.com>2012-11-20 15:38:37 +0100
commit58ddcd50f30cb5c020bd4f9f36b01ee160a27cac (patch)
treebb00b80bdcb890d062dc4e9f479952fefc94650c /net/tap.c
parent1d2a67f89abee0cef4e3d8a8dec739ef0be77120 (diff)
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>
Diffstat (limited to 'net/tap.c')
-rw-r--r--net/tap.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/net/tap.c b/net/tap.c
index df89caaac6..1abfd44bd9 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -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;