[libvirt] [PATCH] cpu: Add support for CPU vendor

Jiri Denemark jdenemar at redhat.com
Mon Jul 19 12:40:40 UTC 2010

> > By specifying <vendor> element in CPU requirements a guest can be
> > restricted to run only on CPUs by a given vendor. Host CPU vendor is
> > also specified in capabilities XML.
> > 
> > The vendor is checked when migrating a guest but it's not forced, i.e.,
> > a guest configured without <vendor> element can be freely migrated.
> >  src/cpu/cpu_map.xml         |    6 +
> Why did you add <vendor> tags to several of the models there? Does qemu
> (-no-kvm) have any problem emulating athlon on an Intel host?

Honestly, I don't know if qemu has any problems emulating them but it doesn't
really matter. The <vendor> emelement in cpu_map.xml is used when libvirt
decides what model should be used for describing host CPU.

> And how about adding policy='disable' attribute, so that I can ask
> virConnectCompareCPU to ignore this particular incompatibility, as I do
> with <feature> items?

Just don't use <vendor> tag in your XML.

In other words, if you specify <vendor> in domain XML (or it's cpu fragment
used by virConnectCompareCPU) and your host CPU is made by different vendor,
the CPUs won't match. If you don't specify <vendor>, you don't care about the
vendor and neither does libvirt.

I hope it's more clear now.


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