Comment 41 for bug 1561019

(In reply to Richard W.M. Jones from comment #22)
> (In reply to Zeeshan Ali from comment #20)
> > From Boxes bug https://bugzilla.gnome.org/show_bug.cgi?id=720798
> >
> > "When I run qemu with the '-cpu host' parameter instead, GNOME Shell starts
> > correctly."
> >
> > Shouldn't libvirt just use that option of qemu for 'host-model' config?
>
> host-passthrough maps to the qemu '-cpu host' parameter.
>
> host-model is as convoluted as it is so that live migration can
> be supported. ie. You start a guest on host A with host-model,
> then migrate it to host B. What you DON'T want to happen is
> that -cpu host is used on host B, since likely host A and host B
> have different CPUs, so the guest will see a sudden change in CPU
> capabilities and probably crash / get inconsistent results.
> Instead host-model tries to create a full description of host A's
> CPU, and after live migration the guest sees the same (host A)
> CPU features.
>
> AIUI host-passthrough disables or prevents live migration in some way.

Ah, in that case I think we are actually better off using host-model in Boxes, at least for now. We don't have live migration support and if hardware changes, user will loose any saved state on the VMs.