> -----Original Message-----
> From: Eduardo Habkost [mailto:ehabk...@redhat.com]
> Sent: Wednesday, June 13, 2018 9:22 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
> Subject: Re: [PATCH v14 1/6] i386: Set TOPOEXT unconditionally for
> comapatibility
>
> On Wed, Jun 13, 2018 at 09:18:22PM -0400, Babu Moger wrote:
> > Enabling TOPOEXT feature might cause compatibility issues if
> > older kernels does not set this feature. Lets set this feature
> > unconditionally.
> >
> > Signed-off-by: Babu Moger <babu.mo...@amd.com>
> > ---
> > target/i386/kvm.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> > index 445e0e0..6f2cca7 100644
> > --- a/target/i386/kvm.c
> > +++ b/target/i386/kvm.c
> > @@ -372,6 +372,12 @@ uint32_t
> kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
> > if (host_tsx_blacklisted()) {
> > ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE);
> > }
> > + } else if (function == 0x80000001 && reg == R_ECX) {
> > + /* Enabling topoext feature might cause compatibility issues if
> > + * older kernel does not set this feature. Lets set this feature
> > + * unconditionally.
> > + */
>
> Thanks. I will apply and rewrite the comment as:
Sure. Thanks
>
> /*
> * It's safe to enable TOPOEXT even if it's not returned
> * by GET_SUPPORTED_CPUID. Unconditionally enabling
> * TOPOEXT here let us keep CPU models runnable on
> * older kernels even when TOPOEXT is enabled.
> */
>
> > + ret |= CPUID_EXT3_TOPOEXT;
> > } else if (function == 0x80000001 && reg == R_EDX) {
> > /* On Intel, kvm returns cpuid according to the Intel spec,
> > * so add missing bits according to the AMD spec:
> > --
> > 1.8.3.1
> >
>
> --
> Eduardo
