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

From: Paolo Bonzini
Date: Thu Oct 22 2020 - 10:06:53 EST


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.

Paolo