[libvirt] [RFC] Host CPU passthrough

Jiri Denemark jdenemar at redhat.com
Tue Aug 16 20:55:32 UTC 2011


On Mon, Aug 08, 2011 at 13:48:59 +0200, Jiri Denemark wrote:
> Hi,
> 
> AFAIK this topic is not new but I think we still do not have a good solution
> for it. Libvirt already supports specifying what CPU and its features a guest
> should see but imagine one wants to run a guest on the best possible CPU. The
> current way is to copy the <cpu> element from capabilities XML into domain
> XML. This approach is fine since it provides reproducible environment and such
> domain can even be migrated to a different host. But the CPU shown provided to
> a guest is not the same as the real host CPU. It's based on a model which
> doesn't reflect all aspects of real CPUs. Ideally, we would model everything
> but that's quite complicated and may need updating anytime a new CPU is
> introduced.

There have been no comments on this so far. Perhaps the topic is not so
controversial as I thought it was. But more likely it's just that people are
busy with other things. IIRC, Daniel used to have a strong opinion on this
matter, is that right?

Jirka




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