From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network Date: Thu, 29 Oct 2009 09:11:37 -0500 Message-ID: <4AE9A299.5060003@codemonkey.ws> References: <1256807803.10825.39.camel@blaa> <1256815818-sup-7805@xpc65.scottt> <1256818566.10825.58.camel@blaa> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Scott Tsai , Dustin Kirkland , qemu-devel , kvm To: Mark McLoughlin Return-path: Received: from mail-yx0-f187.google.com ([209.85.210.187]:58989 "EHLO mail-yx0-f187.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754388AbZJ2OLf (ORCPT ); Thu, 29 Oct 2009 10:11:35 -0400 Received: by yxe17 with SMTP id 17so1683599yxe.33 for ; Thu, 29 Oct 2009 07:11:40 -0700 (PDT) In-Reply-To: <1256818566.10825.58.camel@blaa> Sender: kvm-owner@vger.kernel.org List-ID: Mark McLoughlin wrote: > >> tap_set_offload(csum: 1, tso4: 1, tso6: 1, ecn: 1) >> being called and get an mtu of 1500 on virbr0 using his birdge.sh script. >> >> virtio_net_receive2 was trying to transfer a 1534 byte packet (1524 'size' + 10 'virtio_net_hdr') >> and the guest only had 1524 bytes of space in its input descriptors. >> > > Okay, that sounds like a bug in Dustin's version of the guest virtio-net > driver - if it is only supplying 1524 byte buffers, it should not be > saying it supports the VIRTIO_NET_F_GUEST_TSO4 feature > See: commit 8eca6b1bc770982595db2f7207c65051572436cb Author: aliguori Date: Sun Apr 5 17:40:08 2009 +0000 Fix oops on 2.6.25 guest (Rusty Russell) I believe this is behind the following: https://bugs.edge.launchpad.net/ubuntu/jaunty/+source/linux/+bug/331128 virtio_pci in 2.6.25 didn't do feature negotiation correctly: it acked every bit. Fortunately, we can detect this. Signed-off-by: Rusty Russell Signed-off-by: Anthony Liguori It looks like Rusty's fix wasn't enough. If I change virtio-net to only advertise F_MAC, we don't run into this problem. Regards, Anthony Liguori From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1N3VjB-00047B-To for qemu-devel@nongnu.org; Thu, 29 Oct 2009 10:11:50 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1N3Vj5-00044z-8W for qemu-devel@nongnu.org; Thu, 29 Oct 2009 10:11:48 -0400 Received: from [199.232.76.173] (port=41252 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N3Vj3-00044j-PP for qemu-devel@nongnu.org; Thu, 29 Oct 2009 10:11:42 -0400 Received: from mail-yw0-f176.google.com ([209.85.211.176]:52700) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1N3Vj3-0001lx-Hy for qemu-devel@nongnu.org; Thu, 29 Oct 2009 10:11:41 -0400 Received: by ywh6 with SMTP id 6so1679852ywh.4 for ; Thu, 29 Oct 2009 07:11:40 -0700 (PDT) Message-ID: <4AE9A299.5060003@codemonkey.ws> Date: Thu, 29 Oct 2009 09:11:37 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network References: <1256807803.10825.39.camel@blaa> <1256815818-sup-7805@xpc65.scottt> <1256818566.10825.58.camel@blaa> In-Reply-To: <1256818566.10825.58.camel@blaa> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mark McLoughlin Cc: Scott Tsai , qemu-devel , kvm , Dustin Kirkland Mark McLoughlin wrote: > >> tap_set_offload(csum: 1, tso4: 1, tso6: 1, ecn: 1) >> being called and get an mtu of 1500 on virbr0 using his birdge.sh script. >> >> virtio_net_receive2 was trying to transfer a 1534 byte packet (1524 'size' + 10 'virtio_net_hdr') >> and the guest only had 1524 bytes of space in its input descriptors. >> > > Okay, that sounds like a bug in Dustin's version of the guest virtio-net > driver - if it is only supplying 1524 byte buffers, it should not be > saying it supports the VIRTIO_NET_F_GUEST_TSO4 feature > See: commit 8eca6b1bc770982595db2f7207c65051572436cb Author: aliguori Date: Sun Apr 5 17:40:08 2009 +0000 Fix oops on 2.6.25 guest (Rusty Russell) I believe this is behind the following: https://bugs.edge.launchpad.net/ubuntu/jaunty/+source/linux/+bug/331128 virtio_pci in 2.6.25 didn't do feature negotiation correctly: it acked every bit. Fortunately, we can detect this. Signed-off-by: Rusty Russell Signed-off-by: Anthony Liguori It looks like Rusty's fix wasn't enough. If I change virtio-net to only advertise F_MAC, we don't run into this problem. Regards, Anthony Liguori