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

Paolo Bonzini
2021-12-10T22:01:30Z

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.

Paolo