Re: [PATCH] KVM: X86: Expose KVM_HINTS_REALTIME in KVM_GET_SUPPORTED_CPUID

[Xiaoyao Li]

On 10/22/2020 10:06 PM, Paolo Bonzini wrote:
> On 22/10/20 15:31, Xiaoyao Li wrote:
> > > It's common for userspace to copy all supported CPUID bits to
> > > KVM_SET_CPUID2, I don't think this is the right behavior for
> > > KVM_HINTS_REALTIME.
> >
> > It reminds of X86_FEATURE_WAITPKG, which is added to supported CPUID
> > recently as a fix but QEMU exposes it to guest only when "-overcommit
> > cpu-pm"
>
> WAITPKG is not included in KVM_GET_SUPPORTED_CPUID either.  QEMU detects
> it through the MSR_IA32_UMWAIT register.

Doesn't 0abcc8f65cc2 ("KVM: VMX: enable X86_FEATURE_WAITPKG in KVM 
capabilities") add WAITPKG to KVM_GET_SUPPORTED_CPUID?

> Paolo