> -----Original Message-----
> From: Eduardo Habkost [mailto:ehabk...@redhat.com]
> Sent: Wednesday, June 13, 2018 1:18 PM
> To: Moger, Babu <babu.mo...@amd.com>
> Cc: m...@redhat.com; marcel.apfelb...@gmail.com; pbonz...@redhat.com;
> r...@twiddle.net; mtosa...@redhat.com; qemu-devel@nongnu.org;
> k...@vger.kernel.org; k...@tripleback.net; ge...@hostfission.com; Jiri
> Denemark <jdene...@redhat.com>
> Subject: Re: [PATCH v13 3/5] i386: Enable TOPOEXT feature on AMD EPYC
> CPU
>
> On Wed, Jun 13, 2018 at 06:10:30PM +0000, Moger, Babu wrote:
> > > -----Original Message-----
> > > From: Eduardo Habkost [mailto:ehabk...@redhat.com]
> > > Sent: Wednesday, June 13, 2018 12:18 PM
> > > To: Moger, Babu <babu.mo...@amd.com>
> > > Cc: m...@redhat.com; marcel.apfelb...@gmail.com;
> pbonz...@redhat.com;
> > > r...@twiddle.net; mtosa...@redhat.com; qemu-devel@nongnu.org;
> > > k...@vger.kernel.org; k...@tripleback.net; ge...@hostfission.com; Jiri
> > > Denemark <jdene...@redhat.com>
> > > Subject: Re: [PATCH v13 3/5] i386: Enable TOPOEXT feature on AMD EPYC
> > > CPU
> > >
> > > On Wed, Jun 13, 2018 at 04:52:18PM +0000, Moger, Babu wrote:
> > > [...]
> > > > > What do you think our options are here?
> > > >
> > > > Should we drop automatic topoext completely and move forward?
> > > > What are your thoughts?
> > >
> > > Let's drop automatic topoext by now, and see if we find solutions
> > > later. I don't want to hold the rest of the patches because of
> > > this.
> >
> > Ok. I will drop topoext.
> >
> > >
> > > I'm thinking we could simply make kvm_arch_get_supported_cpuid()
> > > always return TOPOEXT on AMD CPUs, because the feature flag don't
> > > really depend on any KVM code to work (is that correct?).
> >
> > Yes, that is correct. I don't see any dependent code on TOPOEXT in KVM
> driver.
> >
> > Ok. Let me add TOPOEXT flag for all the AMD cpus and see how it goes.
>
> Hmm, this could actually solve all of our problems, then:
>
> We can forget about auto-topoext: just add TOPOEXT in
> kvm_arch_get_supported_cpuid(), add TOPOEXT unconditionally to
> the CPU models where you are interested into (EPYC only?), and
> add topoext=off to pc-2.12 compat_props.
>
Ok Sure.
> Sorry for not noticing that before. I was incorrectly assuming
No problem.
> that TOPOEXT was safe to enable only if it was returned by
> GET_SUPPORTED_CPUID.
>
> --
> Eduardo
