From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:53556) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tap6C-0002n7-Jf for qemu-devel@nongnu.org; Tue, 20 Nov 2012 09:47:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Tap65-00011X-R8 for qemu-devel@nongnu.org; Tue, 20 Nov 2012 09:46:52 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25495) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tap65-00010n-JS for qemu-devel@nongnu.org; Tue, 20 Nov 2012 09:46:45 -0500 From: Stefan Hajnoczi Date: Tue, 20 Nov 2012 15:46:38 +0100 Message-Id: <1353422798-30741-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1353422798-30741-1-git-send-email-stefanha@redhat.com> References: <1353422798-30741-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH 1/1] tap: reset vnet header size on open List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: qemu-devel@nongnu.org, Stefan Hajnoczi , "Michael S. Tsirkin" From: "Michael S. Tsirkin" 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 Tested-by: Alexander Graf Signed-off-by: Stefan Hajnoczi --- net/tap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/tap.c b/net/tap.c index df89caa..1abfd44 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; -- 1.8.0