[PATCH v2 8/8] KVM: selftests: Test consistency of PMU MSRs with Intel PMU version

[Jinrong Liang]

From: Jinrong Liang <cloudliang@xxxxxxxxxxx>

KVM user sapce may control the Intel guest PMU version number via
CPUID.0AH:EAX[07:00]. A test is added to check if a typical PMU register
that is not available at the current version number is leaking.

Co-developed-by: Like Xu <likexu@xxxxxxxxxxx>
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx>
---
 .../kvm/x86_64/pmu_basic_functionality_test.c | 64 +++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c b/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
index 108cfe254095..7da3eaf9ab5a 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
@@ -368,11 +368,75 @@ static void intel_test_fixed_counters(void)
 	}
 }
 
+static void intel_guest_check_pmu_version(uint8_t version)
+{
+	switch (version) {
+	case 0:
+		GUEST_SYNC(wrmsr_safe(MSR_INTEL_ARCH_PMU_GPCTR, 0xffffull));
+	case 1:
+		GUEST_SYNC(wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL, 0x1ull));
+	case 2:
+		/*
+		 * AnyThread Bit is only supported in version 3
+		 *
+		 * The strange thing is that when version=0, writing ANY-Any
+		 * Thread bit (bit 21) in MSR_P6_EVNTSEL0 and MSR_P6_EVNTSEL1
+		 * will not generate #GP. While writing ANY-Any Thread bit
+		 * (bit 21) in MSR_P6_EVNTSEL0+x (MAX_GP_CTR_NUM > x > 2) to
+		 * ANY-Any Thread bit (bit 21) will generate #GP.
+		 */
+		if (version == 0)
+			break;
+
+		GUEST_SYNC(wrmsr_safe(MSR_P6_EVNTSEL0, EVENTSEL_ANY));
+		break;
+	default:
+		/* KVM currently supports up to pmu version 2 */
+		GUEST_SYNC(GP_VECTOR);
+	}
+
+	GUEST_DONE();
+}
+
+static void test_pmu_version_setup(struct kvm_vcpu *vcpu, uint8_t version,
+				   uint64_t expected)
+{
+	struct kvm_cpuid_entry2 *entry;
+	uint64_t msr_val;
+
+	entry = vcpu_get_cpuid_entry(vcpu, 0xa);
+	entry->eax = (entry->eax & ~PMU_VERSION_MASK) | version;
+	vcpu_set_cpuid(vcpu);
+
+	vcpu_args_set(vcpu, 1, version);
+	while (run_vcpu(vcpu, &msr_val) != UCALL_DONE) {
+		TEST_ASSERT(msr_val == expected,
+			    "Something beyond this PMU version is leaked.");
+	}
+}
+
+static void intel_test_pmu_version(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	uint8_t version, unsupported_version = X86_INTEL_PMU_VERSION + 1;
+
+	TEST_REQUIRE(X86_INTEL_MAX_FIXED_CTR_NUM > 2);
+
+	for (version = 0; version <= unsupported_version; version++) {
+		vm = pmu_vm_create_with_one_vcpu(&vcpu,
+						 intel_guest_check_pmu_version);
+		test_pmu_version_setup(vcpu, version, GP_VECTOR);
+		kvm_vm_free(vm);
+	}
+}
+
 static void intel_test_pmu_cpuid(void)
 {
 	intel_test_arch_events();
 	intel_test_counters_num();
 	intel_test_fixed_counters();
+	intel_test_pmu_version();
 }
 
 int main(int argc, char *argv[])
-- 
2.31.1