On Thu, 2009-10-29 at 09:39 -0500, Anthony Liguori wrote: > Mark McLoughlin wrote: > > On Thu, 2009-10-29 at 09:11 -0500, Anthony Liguori wrote: > > > >> 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 <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162> > >> 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 <rusty@xxxxxxxxxxxxxxx> > >> Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx> > >> > >> 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. > >> > > > > If it's not acking VBAD_FEATURE, then it doesn't sound like the same > > issue > > > > It was acking VBAD_FEATURE when I tested it. > > But if you look at the patch, it whitelists the following features: > > features |= (1 << VIRTIO_NET_F_MAC); > features |= (1 << VIRTIO_NET_F_GUEST_CSUM); > features |= (1 << VIRTIO_NET_F_GUEST_TSO4); > features |= (1 << VIRTIO_NET_F_GUEST_TSO6); > features |= (1 << VIRTIO_NET_F_GUEST_ECN); Ah, it all makes sense now. I was getting confused between HOST_* and GUEST_* this should have been: features |= (1 << VIRTIO_NET_F_MAC); features |= (1 << VIRTIO_NET_F_HOST_CSUM); features |= (1 << VIRTIO_NET_F_HOST_TSO4); features |= (1 << VIRTIO_NET_F_HOST_TSO6); features |= (1 << VIRTIO_NET_F_HOST_ECN); Could you try that Dustin? > Which is why it's ack'ing TSO4. Removing TSO4 didn't seem to fix it > for me. Odd. Cheers, Mark. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
