[PATCH 22/23] KVM: selftests: Fix PERF_METRICS test by checking FC3 availability

[Zide Chen]

IA32_PERF_CAPABILITIES.PERF_METRICS_AVAILABLE[bit 15] is not tied to
a particular PMU version, and userspace can enable it as long as it is
advertised.

On a PERF_METRICS capable host that supports fixed counter 3 through a
non-contiguous fixed counter bitmap, userspace may enable this capability
while configuring a guest PMU version lower than 5.

This scenario is unlikely on bare-metal systems, but it can occur with
PMU partitioning. For example, when kvm-intel is loaded with:

perfmon_mask=guest_fixed=1-3;perf_metrics

CPUID.0AH:ECX[4:0] is 0, and thus fixed counter 3 is not available
when the guest PMU version is below 5. Skip the test in this case.

Signed-off-by: Zide Chen <zide.chen@xxxxxxxxx>
---
 tools/testing/selftests/kvm/x86/pmu_counters_test.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/x86/pmu_counters_test.c b/tools/testing/selftests/kvm/x86/pmu_counters_test.c
index 2797d7e0e3a3..edcd04b4111c 100644
--- a/tools/testing/selftests/kvm/x86/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86/pmu_counters_test.c
@@ -678,7 +678,8 @@ static void __guest_test_perf_metrics(void)
 
 	if ((guest_get_pmu_version() < 2) ||	/* Does guest have GLOBAL_CTRL? */
 	    !this_cpu_has(X86_FEATURE_PDCM) ||
-	    !(rdmsr(MSR_IA32_PERF_CAPABILITIES) & PERF_CAP_PERF_METRICS))
+	    !(rdmsr(MSR_IA32_PERF_CAPABILITIES) & PERF_CAP_PERF_METRICS) ||
+	    !this_pmu_has(X86_PMU_FEATURE_TOPDOWN_SLOTS_FIXED))
 		return;
 
 	wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
-- 
2.55.0