On Wed, Sep 03, 2014 at 02:17:02AM +0400, Andrey Korolyov wrote: > On Wed, Sep 3, 2014 at 2:09 AM, Andrey Korolyov <and...@xdel.ru> wrote: > > On Wed, Sep 3, 2014 at 1:51 AM, Michael S. Tsirkin <m...@redhat.com> wrote: > >> On Wed, Sep 03, 2014 at 01:29:29AM +0400, Andrey Korolyov wrote: > >>> On Wed, Sep 3, 2014 at 1:03 AM, Michael S. Tsirkin <m...@redhat.com> > >>> wrote: > >>> >> bad one is the > >>> >> > >>> >> Author: Jason Wang <jasow...@redhat.com> > >>> >> Date: Tue Sep 2 18:07:46 2014 +0300 > >>> >> > >>> >> vhost_net: start/stop guest notifiers properly > >>> > > >>> > > >>> > > >>> > upstream has this (pull request sent today): > >>> > vhost_net: cleanup start/stop condition > >>> > > >>> > Could you apply it and see if it helps please? > >>> > > >>> > Michael, if it helps it should be before start/stop guest notifiers > >>> > ideally to avoid bisect problems. > >>> > >>> It is already applied as shown from the list in the previous message > >>> (there are some aio fixes too on top of 2.1 I picked before but they > >>> should not impact vhost-net interaction in any mean). The symptoms are > >>> a bit interesting - VM crashes only at PCI device initalization (e.g. > >>> grub stage after reset and initrd unpacking are passing well, but then > >>> things getting ugly). I am running 3.14 guest i686-pae kernel from > >>> debian backports in guest, so it may be version-specific after all. If > >>> it`ll be hard to reproduce, I can try 64bit, expecting same behavior. > >>> Please find args in attached file. > >> > >> > >> > >> ok just to make sure - which tree do I clone exactly? > >> > > > > https://github.com/mdroth/qemu.git stable-2.1-staging showing same > > behavior for me with those patches > > Forgot to mention important detail - I am playing with -mq now, so > actually virtio-net working in a bit different way than it may > expected (it also shown in args list from above, but someone may miss > it): > ... > qemu-system-x86_64: unable to start vhost net: 95: falling back on > userspace virtio > qemu-system-x86_64: unable to start vhost net: 95: falling back on > userspace virtio > ...
Okay, so there's some bug in the error handling then. I'll dig into it - meanwhile can you please strace the binary to figure out which ioctl is failing? Or just trace it by hand: I am guessing vhost_net_start_one is the one failing here, add printfs there and check (note to self: we need more error messages in that function).
