Volume 4 of the SDM says that IA32_XSS is supported
if CPUID(EAX=0DH,ECX=1):EAX.XSS[bit 3] is set, so only the
X86_FEATURE_XSAVES check is necessary (X86_FEATURE_XSAVES is the Linux
name for CPUID(EAX=0DH,ECX=1):EAX.XSS[bit 3]).
Fixes: 4d763b168e9c5 ("KVM: VMX: check CPUID before allowing read/write of IA32_XSS")
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Change-Id: I9059b9f2e3595e4b09a4cdcf14b933b22ebad419
---
arch/x86/kvm/vmx/vmx.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 34525af44353..a9b070001c3e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1821,10 +1821,8 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index,
&msr_info->data);
case MSR_IA32_XSS:
- if (!vmx_xsaves_supported() ||
- (!msr_info->host_initiated &&
- !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
- guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))
return 1;
msr_info->data = vcpu->arch.ia32_xss;
break;
@@ -2064,10 +2062,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 1;
return vmx_set_vmx_msr(vcpu, msr_index, data);
case MSR_IA32_XSS:
- if (!vmx_xsaves_supported() ||
- (!msr_info->host_initiated &&
- !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
- guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))
return 1;
/*
* The only supported bit as of Skylake is bit 8, but
@@ -2076,11 +2072,13 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if (data != 0)
return 1;
vcpu->arch.ia32_xss = data;
- if (vcpu->arch.ia32_xss != host_xss)
- add_atomic_switch_msr(vmx, MSR_IA32_XSS,
- vcpu->arch.ia32_xss, host_xss, false);
- else
- clear_atomic_switch_msr(vmx, MSR_IA32_XSS);
+ if (vcpu->arch.xsaves_enabled) {
+ if (vcpu->arch.ia32_xss != host_xss)
+ add_atomic_switch_msr(vmx, MSR_IA32_XSS,
+ vcpu->arch.ia32_xss, host_xss, false);
+ else
+ clear_atomic_switch_msr(vmx, MSR_IA32_XSS);
+ }
break;
case MSR_IA32_RTIT_CTL:
if ((pt_mode != PT_MODE_HOST_GUEST) ||
--
2.23.0.866.gb869b98d4c-goog
