On 5/2/2024 4:43 AM, Sean Christopherson wrote:
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.
Right, I'll change this part after the cleanup series is merged. Thanks!
[*] https://lore.kernel.org/all/20240425181422.3250947-1-seanjc@xxxxxxxxxx
