[PATCH v4 5/5] KVM: selftests: Update hwcr_msr_test for CPUID faulting bit
From: Jim Mattson
Date: Wed May 27 2026 - 13:44:56 EST
Add BIT_ULL(35) (CpuidUserDis) to the valid mask in hwcr_msr_test, now that
KVM accepts writes to this bit when the guest CPUID advertises
CpuidUserDis.
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
---
tools/testing/selftests/kvm/include/x86/processor.h | 1 +
tools/testing/selftests/kvm/x86/hwcr_msr_test.c | 9 +++++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
index 06878e7c7347..513e4a1075fa 100644
--- a/tools/testing/selftests/kvm/include/x86/processor.h
+++ b/tools/testing/selftests/kvm/include/x86/processor.h
@@ -226,6 +226,7 @@ struct kvm_x86_cpu_feature {
#define X86_FEATURE_SEV KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 1)
#define X86_FEATURE_SEV_ES KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 3)
#define X86_FEATURE_SEV_SNP KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 4)
+#define X86_FEATURE_GP_ON_USER_CPUID KVM_X86_CPU_FEATURE(0x80000021, 0, EAX, 17)
#define X86_FEATURE_PERFMON_V2 KVM_X86_CPU_FEATURE(0x80000022, 0, EAX, 0)
#define X86_FEATURE_LBR_PMC_FREEZE KVM_X86_CPU_FEATURE(0x80000022, 0, EAX, 2)
diff --git a/tools/testing/selftests/kvm/x86/hwcr_msr_test.c b/tools/testing/selftests/kvm/x86/hwcr_msr_test.c
index 8e20a03b3329..53b7971aa072 100644
--- a/tools/testing/selftests/kvm/x86/hwcr_msr_test.c
+++ b/tools/testing/selftests/kvm/x86/hwcr_msr_test.c
@@ -11,12 +11,17 @@
void test_hwcr_bit(struct kvm_vcpu *vcpu, unsigned int bit)
{
const u64 ignored = BIT_ULL(3) | BIT_ULL(6) | BIT_ULL(8);
- const u64 valid = BIT_ULL(18) | BIT_ULL(24);
- const u64 legal = ignored | valid;
+ u64 valid = BIT_ULL(18) | BIT_ULL(24);
u64 val = BIT_ULL(bit);
u64 actual;
+ u64 legal;
int r;
+ if (kvm_cpu_has(X86_FEATURE_GP_ON_USER_CPUID))
+ valid |= BIT_ULL(35);
+
+ legal = ignored | valid;
+
r = _vcpu_set_msr(vcpu, MSR_K7_HWCR, val);
TEST_ASSERT(val & ~legal ? !r : r == 1,
"Expected KVM_SET_MSRS(MSR_K7_HWCR) = 0x%lx to %s",
--
2.54.0.794.g4f17f83d09-goog