On Sun, Feb 18, 2024, Yang Weijiang wrote: > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9eb5c8dbd4fb..b502d68a2576 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3926,16 +3926,23 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > } > break; > case MSR_IA32_XSS: > - if (!msr_info->host_initiated && > - !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES)) > + /* > + * If KVM reported support of XSS MSR, even guest CPUID doesn't > + * support XSAVES, still allow userspace to set default value(0) > + * to this MSR. > + */ > + if (!guest_cpuid_has(vcpu, X86_FEATURE_XSAVES) && > + !(msr_info->host_initiated && data == 0)) With my proposed MSR access cleanup[*], I think (hope?) this simply becomes: if (!guest_cpuid_has(vcpu, X86_FEATURE_XSAVES)) return KVM_MSR_RET_UNSUPPORTED; with no comment needed as the "host && !data" case is handled in common code. [*] https://lore.kernel.org/all/20240425181422.3250947-1-seanjc@xxxxxxxxxx
