Re: KVM: x86: expose HINTS_REALTIME ablility to qemu

Aili Yao
2021-08-16T06:10:28Z

On Fri, 13 Aug 2021 17:54:20 +0800
Aili Yao <yaoaili@kingsoft.com> wrote:

> When I do a test that try to enable hint-dedicated for one VM, but qemu
> says "warning: host doesn't support requested feature:
> CPUID.40000001H:EDX.kvm-hint-dedicated [bit 0]".
>
> It seems the kernel hasn't expose this ability even when supporting it;
> So expose it.

Sorry, I check it again:
Ihe issue I met is because of my qemu's mis-backport,

In qemu, kvm_arch_get_supported_cpuid() will set the feature bit:
if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
ret |= KVM_HINTS_DEDICATED;
found = 1;
}
But I have mis-ported the KVM_HINTS_DEDICATED and KVM_HINTS_REALTIME macro; And it lead to
the error I met;

And it's right that kernel don't expose this ability!

Sorry again!