[libvirt] X86CPU "feature-words" property on QEMU (was Re: [PATCH v3 1/3] x86: Data structure changes to support MSR based) features

[Paolo Bonzini]

On 17/08/2018 19:48, Eduardo Habkost wrote:
> So let's do what's necessary to remove it.  But I don't think the
> removal of "feature-words" should block the inclusion of this
> series.
> 
> Now, should QOM properties follow our feature deprecation policy,
> or they were never a supported external API and we can remove it
> immediately?
> 
> CCing Jiri and libvir-list, because I just found that there's
> code on libvirt that uses it, but I don't know exactly it does
> with that info.

It is used to check whether the host supports invtsc and pv-unhalt and
avoid changing the guest ABI when migrating: see
https://marc.info/?l=libvir-list&m=152445761414746&w=2 for a patch that
introduces one user.

I think we should extend it to MSRs, not remove it.

Paolo