[libvirt] [PATCH] qemu: Starting a domain with custom model and allowed-fallback failed when host lacks some CPU features

Jiri Denemark jdenemar at redhat.com
Tue Jun 6 17:56:02 UTC 2017

On Tue, Jun 06, 2017 at 12:23:01 -0400, Yi Wang wrote:
> An attemp to start a domain requesting a custom CPU model, core2duo, for
> example, will fail if some feature that the model needs doesn't exist in that
> host, even though fallback attibute is set allow:
> "error: the CPU is incompatible with host CPU: Host CPU does not provide
> required features: monitor"
> Of course we can start that domain through forbidding that feature, but
> that may not be flexible.

NACK, it works exactly as designed. The fallback attribute would make a
difference only if core2duo CPU model was not supported by QEMU, then
libvirt would translate it into a different supported one.


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