[PATCH v4 38/38] KVM: Selftests: Fix pmu_counters_test error for mediated vPMU

[Mingwei Zhang <mizhang@google.com>]

From: Dapeng Mi <dapeng1.mi@linux.intel.com>

As previous patch commit 'f8905c638eb7 ("KVM: x86/pmu: Check PMU cpuid
configuration from user space")', KVM would check if user space configured
pmu version is larger than KVM supported maximum pmu version for
mediated vPMU, or if fixed counter bitmap is configured incorrectly,
if so, KVM would return an error.

This enhanced check would lead to pmu_counters_test fails, thus limit
pmu_counters_test only validate KVM supported pmu versions for mediated
vPMU and only validate 0 fixed counter bitmap if pmu version is less than
5.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 .../selftests/kvm/include/x86/processor.h     |  8 ++++++++
 .../selftests/kvm/x86/pmu_counters_test.c     | 20 ++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
index d60da8966772..7db34f48427a 100644
--- a/tools/testing/selftests/kvm/include/x86/processor.h
+++ b/tools/testing/selftests/kvm/include/x86/processor.h
@@ -1311,6 +1311,14 @@ static inline bool kvm_is_pmu_enabled(void)
 	return get_kvm_param_bool("enable_pmu");
 }
 
+static inline bool kvm_is_mediated_pmu_enabled(void)
+{
+	if (host_cpu_is_intel)
+		return get_kvm_intel_param_bool("enable_mediated_pmu");
+	else
+		return get_kvm_amd_param_bool("enable_mediated_pmu");
+}
+
 static inline bool kvm_is_forced_emulation_enabled(void)
 {
 	return !!get_kvm_param_integer("force_emulation_prefix");
diff --git a/tools/testing/selftests/kvm/x86/pmu_counters_test.c b/tools/testing/selftests/kvm/x86/pmu_counters_test.c
index 441c66f314fb..4745f82ce860 100644
--- a/tools/testing/selftests/kvm/x86/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86/pmu_counters_test.c
@@ -564,8 +564,14 @@ static void test_intel_counters(void)
 	 * Test up to PMU v5, which is the current maximum version defined by
 	 * Intel, i.e. is the last version that is guaranteed to be backwards
 	 * compatible with KVM's existing behavior.
+	 *
+	 * Whereas for mediated vPMU, limit max_pmu_version to KVM supported
+	 * maximum pmu version since KVM rejects PMU versions larger than KVM
+	 * supported maximum PMU version to avoid guest to manipulate unsupported
+	 * or unallowed PMU MSRs directly.
 	 */
-	uint8_t max_pmu_version = max_t(typeof(pmu_version), pmu_version, 5);
+	uint8_t max_pmu_version = kvm_is_mediated_pmu_enabled() ?
+				  pmu_version : max_t(typeof(pmu_version), pmu_version, 5);
 
 	/*
 	 * Detect the existence of events that aren't supported by selftests.
@@ -622,8 +628,16 @@ static void test_intel_counters(void)
 			pr_info("Testing fixed counters, PMU version %u, perf_caps = %lx\n",
 				v, perf_caps[i]);
 			for (j = 0; j <= nr_fixed_counters; j++) {
-				for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++)
-					test_fixed_counters(v, perf_caps[i], j, k);
+				/*
+				 * pmu version less than 5 doesn't support fixed counter
+				 * bitmap, so only set fixed counter bitamp to 0.
+				 */
+				if (v < 5) {
+					test_fixed_counters(v, perf_caps[i], j, 0);
+				} else {
+					for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++)
+						test_fixed_counters(v, perf_caps[i], j, k);
+				}
 			}
 		}
 	}
-- 
2.49.0.395.g12beb8f557-goog