[libvirt] [PATCH] treat host models as case-insensitive strings

Daniel P. Berrange berrange at redhat.com
Wed Dec 20 09:50:31 UTC 2017

On Tue, Dec 19, 2017 at 02:24:47PM -0600, Scott Garfinkle wrote:
> On Tue, 2017-12-19 at 20:05 +0100, Jiri Denemark wrote:
> > On Tue, Dec 19, 2017 at 12:39:26 -0600, Scott Garfinkle wrote:
> > > Qemu now allows case-insensitive specification of CPU models. This fixes the
> > > resulting problems on POWER arch machines. I believe a similar change is needed
> > > in src/cpu/cpu_x86.c but I don't have a way to test this.
> > 
> > I believe this change is not needed or even acceptable at all. What kind
> > of issue are you trying to solve?
> So, the problem is that as of qemu 2.11, Power arch guests don't start,
> since libvirt ppc code is looking for the string POWER to determine
> whether the system supports the model at hand. 
> Comment from our qemu maintainer: "There was a rework in QEMU side to
> allow case-insensitive specification of CPU models. As a side-effect of
> that some models no longer show up as all caps in -cpu ? /
> query-cpu-definitions. This requires libvirt changes to avoid relying on
> specific capitalized models."
> Are you concerned that we SHOULD be looking for case-sensitive models in
> libvirt? Is this a problem absent qemu?

You need to dinstinguish what libvirt does internally from what it does
in the public XML/APIs.   Your change affected both, so it is wrong. Any
fix should only apply to libvirt's internal communication with QEMU, and
not affect what's done in the public XML/APIs.

|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

More information about the libvir-list mailing list