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

From: Paolo Bonzini
Date: Thu Oct 22 2020 - 09:02:27 EST


On 22/10/20 03:34, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>
> Per KVM_GET_SUPPORTED_CPUID ioctl documentation:
>
> This ioctl returns x86 cpuid features which are supported by both the
> hardware and kvm in its default configuration.
>
> A well-behaved userspace should not set the bit if it is not supported.
>
> Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx>
> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>

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.

(But maybe this was discussed already; if so, please point me to the
previous discussion).

Paolo