[libvirt-users] LibVirt query CPU Model support and restore operation

[Jiri Denemark]

On Tue, Jan 24, 2017 at 16:21:14 +0530, akhilesh rawat wrote:
> hi,
> 
> yes we are talking about same host here.
> 
> You could've just used -cpu host-model-only
> >> I dont want to host model ( it is working with host model) .
> 
> AS KVM seems to allow support Haswell with native commands . Does this mean
> in my case KVM is allowing software emulated cpu model.

No, QEMU will just drop the features which are not supported on your
host. Although there are some rare exceptions, such as x2apic, which can
be emulated even with KVM.

Anyway, starting QEMU directly should print several warnings about
features which are dropped. And when you start QEMU with
-cpu Haswell,enforce it should refuse to start.

> Can libvirt allow  software-emulated for non host model ?  if yes how .

You can bypass the libvirt check for specific features by setting the
feature policy to "force" (no idea if this can be done with
virt-install), but QEMU will still do the check itself and either drop
the features or refuse to start (with enforce) if they cannot be used on
the host.

Jirka