[PATCH 3/7] KVM: selftests: Test unavailable event filters are rejected

[Jinrong Liang]

From: Jinrong Liang <cloudliang@xxxxxxxxxxx>

Adds unsupported input test cases for PMU filter. Specifically,
it tests the input of unsupported "action" values, unsupported
"flags" values, and unsupported "nevents" values, which should
all return an error, as they are currently unsupported by the
filter. Additionally, the patch tests setting non-exist fixed
counters in the fixed bitmap doesn't fail.

This change aims to improve the testing of the PMU filter and
ensure that it functions correctly in all supported use cases.
The patch has been tested and verified to function correctly.

Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx>
---
 .../kvm/x86_64/pmu_event_filter_test.c        | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index 4e87eea6986b..a3d5c30ce914 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -27,6 +27,10 @@
 #define ARCH_PERFMON_BRANCHES_RETIRED		5
 
 #define NUM_BRANCHES 42
+#define FIXED_CTR_NUM_MASK				GENMASK_ULL(4, 0)
+#define PMU_EVENT_FILTER_INVALID_ACTION		(KVM_PMU_EVENT_DENY + 1)
+#define PMU_EVENT_FILTER_INVALID_FLAGS			(KVM_PMU_EVENT_FLAG_MASKED_EVENTS + 1)
+#define PMU_EVENT_FILTER_INVALID_NEVENTS		(MAX_FILTER_EVENTS + 1)
 
 /*
  * This is how the event selector and unit mask are stored in an AMD
@@ -743,10 +747,22 @@ static int run_filter_test(struct kvm_vcpu *vcpu, const uint64_t *events,
 	return r;
 }
 
+static uint8_t get_kvm_supported_fixed_num(void)
+{
+	const struct kvm_cpuid_entry2 *kvm_entry;
+
+	if (host_cpu_is_amd)
+		return 0;
+
+	kvm_entry = get_cpuid_entry(kvm_get_supported_cpuid(), 0xa, 0);
+	return kvm_entry->edx & FIXED_CTR_NUM_MASK;
+}
+
 static void test_filter_ioctl(struct kvm_vcpu *vcpu)
 {
 	uint64_t e = ~0ul;
 	int r;
+	uint8_t max_fixed_num = get_kvm_supported_fixed_num();
 
 	/*
 	 * Unfortunately having invalid bits set in event data is expected to
@@ -763,6 +779,42 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu)
 	r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS,
 			    KVM_PMU_EVENT_ALLOW, 0);
 	TEST_ASSERT(r == 0, "Valid PMU Event Filter is failing");
+
+	/*
+	 * Test input of unsupported "action" values should return an error.
+	 * The only values currently supported are 0 or 1.
+	 */
+	r = run_filter_test(vcpu, 0, 0, 0, PMU_EVENT_FILTER_INVALID_ACTION, 0);
+	TEST_ASSERT(r != 0, "Set invalid action is expected to fail.");
+
+	/*
+	 * Test input of unsupported "flags" values should return an error.
+	 * The only values currently supported are 0 or 1.
+	 */
+	r = run_filter_test(vcpu, 0, 0, PMU_EVENT_FILTER_INVALID_FLAGS,
+			    KVM_PMU_EVENT_ALLOW, 0);
+	TEST_ASSERT(r != 0, "Set invalid flags is expected to fail.");
+
+	/*
+	 * Test input of unsupported "nevents" values should return an error.
+	 * The only values currently supported are those less than or equal to
+	 * MAX_FILTER_EVENTS.
+	 */
+	r = run_filter_test(vcpu, event_list, PMU_EVENT_FILTER_INVALID_NEVENTS,
+			    0, KVM_PMU_EVENT_ALLOW, 0);
+	TEST_ASSERT(r != 0,
+		    "Setting PMU event filters that exceeds the maximum supported value should fail");
+
+	/*
+	 * In this case, set non-exist fixed counters in the fixed bitmap
+	 * doesn't fail.
+	 */
+	if (max_fixed_num) {
+		r = run_filter_test(vcpu, 0, 0, 0, KVM_PMU_EVENT_ALLOW,
+				    ~GENMASK_ULL(max_fixed_num, 0));
+		TEST_ASSERT(r == 0,
+			    "Set invalid or non-exist fixed cunters in the fixed bitmap fail.");
+	}
 }
 
 int main(int argc, char *argv[])
-- 
2.31.1