Re: [PATCH 15/19] kvm: x86: Save and restore guest XFD_ERR properly

Yang Zhong
2021-12-12T13:26:01Z

On Fri, Dec 10, 2021 at 11:01:15PM +0100, Paolo Bonzini wrote:
> On 12/8/21 01:03, Yang Zhong wrote:
> >--- a/arch/x86/kvm/cpuid.c
> >+++ b/arch/x86/kvm/cpuid.c
> >@@ -219,6 +219,11 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> > kvm_apic_set_version(vcpu);
> > }
> >+ /* Enable saving guest XFD_ERR */
> >+ best = kvm_find_cpuid_entry(vcpu, 7, 0);
> >+ if (best && cpuid_entry_has(best, X86_FEATURE_AMX_TILE))
> >+ vcpu->arch.guest_fpu.xfd_err = 0;
> >+
>
> This is incorrect. Instead it should check whether leaf 0xD
> includes any dynamic features.
>

Thanks Paolo, So ditto for "[PATCH 04/19] kvm: x86: Check guest xstate permissions when KVM_SET_CPUID2".

Yang

> Paolo