[libvirt] cpuset / numa and qemu in TCG mode

Guido Günther agx at sigxcpu.org
Tue May 12 16:46:28 UTC 2015

On Tue, May 12, 2015 at 11:14:09AM +0200, Martin Kletzander wrote:
> On Tue, May 12, 2015 at 05:27:34PM +1000, Tony Breeds wrote:
> >On Mon, May 11, 2015 at 01:14:58PM +0200, Martin Kletzander wrote:
> >
> >>Determining this by version might not be reliable, but more
> >>importantly working around bug in underlying software is something
> >>that shouldn't be done at all IMHO.  Let the maintainers backport
> >>whatever needs to be done.
> >
> >I agree with you in an ideal world but there are times when we do need
> >to add work arounds in $project_x to work around issues in $project_y.
> >
> >>>Ther nova side will be pretty easy regardless.
> >>>
> >>>I'd say the best solution would be to back port the 'fix' but that seems like a
> >>>lot of effort given the number of distros and libvirt versions potentiall
> >>>involved.
> >>>
> >>
> >>If you want the fix to be distro-agnostic, there's nothing easier than
> >>back-porting the fix into our upstream maintenance branches.  Those
> >>should make the life of distro maintainers easy (although it looks
> >>like not many distros use it).
> >
> >And this is part of the problem.  If I understand correctly Ubuntu cloud-archive
> >is using libvirt 1.2.12 which is *NOT* a maintenance release so that leaves us
> >with doing an additional backport to 1.2.12 and getting the cloud-archive team
> >to take it[1]  or Adding a hack to nova.  And that's just Ubuntu It's hard to
> >say for sure that some vendor isn't running libvirt 1.2.12 also.
> >
> >>Having said that I'm not sure which commit(s) are those that need to
> >>be back-ported.  Having known your libvirt version, it shouldn't be
> >>too hard looking for the differences and finding the right commit.
> >>When back-porting request is made on the list, it is usually acted
> >>upon.  If you can't find the exact commit, let me know and I'll do my
> >>best to help.
> >
> >So a git bisect points at:
> >---
> >commit a103bb105c0c189c3973311ff1826972b5bc6ad6
> >Author: Daniel P. Berrange <berrange at redhat.com>
> >Date:   Tue Feb 10 15:59:57 2015 +0000
> >
> >   qemu: fix setting of VM CPU affinity with TCG
> >---
> >
> >A small amount of reading implies to me that we'd be looking at backporting
> >a103bb105c0c189c3973311ff1826972b5bc6ad6 to any maintenance branch that contains
> >b07f3d821dfb11a118ee75ea275fd6ab737d9500.  Which I think is 1.2.13 only, but I
> >could be wrong.
> >
> 1.2.13 has the commit already in the release and 1.2.12-maint has it
> as a first back-port right after release.  The problem is that there
> was no maintenance release of 1.2.12 yet.  Maybe they would use
> if it existed.
> I Cc'd Guido as an upstream debian maintainer, maybe he'll have some
> insights.  @Guido: would it help if we created a maintenance release
> from the v1.2.12-maint branch?  Or is the only thing missing the fact
> that the launchpad bug is not moved to libvirt?

Basically Ubuntu takes the version that is in Debian testing, unstable
or experimental at time of their release and adds pathes. There's little
to no sync unfortunately (except for the awesome efforts to sync the
apparmor stuff)

Debian itself is not using 1.2.12 anywhere. Current stable has 1.2.9 +
maintenance patches (which I intend to switch over to the maintenance
releases soonish and support hopefully Cole with these), oldstable has and unstable/sid has 1.2.15 (and will keep following the

I've added Serge since he might to jump onto maintenance

I'm happy about any additional notifications for things that should go
into distributions.

 -- Guido

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