[v3,07/11] KVM: selftests: Test Intel supported fixed counters bit mask

Commit Message

Jinrong Liang Aug. 14, 2023, 11:51 a.m. UTC

From: Jinrong Liang <[e-mail]>

Add a test to check that fixed counters enabled via guest
CPUID.0xA.ECX (instead of EDX[04:00]) work as normal as usual.

Co-developed-by: Like Xu <[e-mail]>
Signed-off-by: Like Xu <[e-mail]>
Signed-off-by: Jinrong Liang <[e-mail]>
---
 .../kvm/x86_64/pmu_basic_functionality_test.c | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)

Comments

Sean Christopherson Aug. 17, 2023, 11:19 p.m. UTC | #1

On Mon, Aug 14, 2023, Jinrong Liang wrote:
> +static void intel_test_fixed_counters(void)
> +{
> +	uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
> +	struct kvm_vcpu *vcpu;
> +	struct kvm_vm *vm;
> +	uint32_t ecx;
> +	uint8_t edx;
> +
> +	for (edx = 0; edx <= nr_fixed_counters; edx++) {
> +		/* KVM doesn't emulate more fixed counters than it can support. */
> +		for (ecx = 0; ecx <= (BIT_ULL(nr_fixed_counters) - 1); ecx++) {
> +			vm = pmu_vm_create_with_one_vcpu(&vcpu,
> +							 intel_guest_run_fixed_counters);
> +			test_fixed_counters_setup(vcpu, ecx, edx);
> +			kvm_vm_free(vm);

Same comments as a previous patch, either use a helper or open code, don't mix
both.

> +		}
> +	}
> +}
> +
>  int main(int argc, char *argv[])
>  {
>  	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
> @@ -293,6 +352,7 @@ int main(int argc, char *argv[])
>  
>  	intel_test_arch_events();
>  	intel_test_counters_num();
> +	intel_test_fixed_counters();
>  
>  	return 0;
>  }
> -- 
> 2.39.3
>

Patch

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 db1c1230700a..3bbf3bd2846b 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
@@ -282,6 +282,65 @@  static void intel_test_counters_num(void)
 	}
 }
 
+static void intel_guest_run_fixed_counters(void)
+{
+	uint64_t supported_bitmask = this_cpu_property(X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK);
+	uint32_t nr_fixed_counter = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
+	uint64_t msr_val;
+	unsigned int i;
+	bool expected;
+
+	for (i = 0; i < nr_fixed_counter; i++) {
+		expected = supported_bitmask & BIT_ULL(i) || i < nr_fixed_counter;
+
+		wrmsr_safe(MSR_CORE_PERF_FIXED_CTR0 + i, 0);
+		wrmsr_safe(MSR_CORE_PERF_FIXED_CTR_CTRL, BIT_ULL(4 * i));
+		wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL, BIT_ULL(INTEL_PMC_IDX_FIXED + i));
+		__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+		wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+		rdmsr_safe(MSR_CORE_PERF_FIXED_CTR0 + i, &msr_val);
+
+		GUEST_ASSERT(expected == !!msr_val);
+	}
+
+	GUEST_DONE();
+}
+
+static void test_fixed_counters_setup(struct kvm_vcpu *vcpu,
+				      uint32_t fixed_bitmask,
+				      uint8_t edx_fixed_num)
+{
+	int ret;
+
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK,
+				fixed_bitmask);
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_FIXED_COUNTERS,
+				edx_fixed_num);
+
+	do {
+		ret = run_vcpu(vcpu, NULL);
+	} while (ret != UCALL_DONE);
+}
+
+static void intel_test_fixed_counters(void)
+{
+	uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	uint32_t ecx;
+	uint8_t edx;
+
+	for (edx = 0; edx <= nr_fixed_counters; edx++) {
+		/* KVM doesn't emulate more fixed counters than it can support. */
+		for (ecx = 0; ecx <= (BIT_ULL(nr_fixed_counters) - 1); ecx++) {
+			vm = pmu_vm_create_with_one_vcpu(&vcpu,
+							 intel_guest_run_fixed_counters);
+			test_fixed_counters_setup(vcpu, ecx, edx);
+			kvm_vm_free(vm);
+		}
+	}
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
@@ -293,6 +352,7 @@  int main(int argc, char *argv[])
 
 	intel_test_arch_events();
 	intel_test_counters_num();
+	intel_test_fixed_counters();
 
 	return 0;
 }