[PATCH 5/7] KVM: selftests: Check if pmu_event_filter meets expectations on fixed ctrs

[Jinrong Liang]

From: Jinrong Liang <cloudliang@xxxxxxxxxxx>

Add tests to cover that pmu_event_filter works as expected when
it's applied to fixed performance counters, even if there is none
fixed counter exists (e.g. Intel guest pmu version=1 or AMD guest).

Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx>
---
 .../kvm/x86_64/pmu_event_filter_test.c        | 109 ++++++++++++++++++
 1 file changed, 109 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 a3d5c30ce914..0f54c53d7fff 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
@@ -31,6 +31,7 @@
 #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)
+#define INTEL_PMC_IDX_FIXED 32
 
 /*
  * This is how the event selector and unit mask are stored in an AMD
@@ -817,6 +818,113 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu)
 	}
 }
 
+static void intel_guest_run_fixed_counters(uint8_t fixed_ctr_idx)
+{
+	for (;;) {
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx, 0);
+
+		/* Only OS_EN bit is enabled for fixed counter[idx]. */
+		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, BIT_ULL(4 * fixed_ctr_idx));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL,
+		      BIT_ULL(INTEL_PMC_IDX_FIXED + fixed_ctr_idx));
+		__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+
+		GUEST_SYNC(rdmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx));
+	}
+}
+
+static struct kvm_vcpu *new_vcpu(void *guest_code)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vcpu);
+
+	return vcpu;
+}
+
+static void free_vcpu(struct kvm_vcpu *vcpu)
+{
+	kvm_vm_free(vcpu->vm);
+}
+
+static uint64_t test_fixed_ctr_without_filter(struct kvm_vcpu *vcpu)
+{
+	return run_vcpu_to_sync(vcpu);
+}
+
+static const uint32_t actions[] = {
+	KVM_PMU_EVENT_ALLOW,
+	KVM_PMU_EVENT_DENY,
+};
+
+static uint64_t test_fixed_ctr_with_filter(struct kvm_vcpu *vcpu,
+					   uint32_t action,
+					   uint32_t bitmap)
+{
+	struct kvm_pmu_event_filter *f;
+	uint64_t r;
+
+	f = create_pmu_event_filter(0, 0, action, 0, bitmap);
+	r = test_with_filter(vcpu, f);
+	free(f);
+	return r;
+}
+
+static bool fixed_ctr_is_allowed(uint8_t idx, uint32_t action, uint32_t bitmap)
+{
+	return (action == KVM_PMU_EVENT_ALLOW && (bitmap & BIT_ULL(idx))) ||
+		(action == KVM_PMU_EVENT_DENY && !(bitmap & BIT_ULL(idx)));
+}
+
+static void test_fixed_ctr_action_and_bitmap(struct kvm_vcpu *vcpu,
+					     uint8_t fixed_ctr_idx,
+					     uint8_t max_fixed_num)
+{
+	uint8_t i;
+	uint32_t bitmap;
+	uint64_t count;
+	bool expected;
+
+	/*
+	 * Check the fixed performance counter can count normally works when
+	 * KVM userspace doesn't set any pmu filter.
+	 */
+	TEST_ASSERT(max_fixed_num && test_fixed_ctr_without_filter(vcpu),
+		    "Fixed counter does not exist or does not work as expected.");
+
+	for (i = 0; i < ARRAY_SIZE(actions); i++) {
+		for (bitmap = 0; bitmap < BIT_ULL(max_fixed_num); bitmap++) {
+			expected = fixed_ctr_is_allowed(fixed_ctr_idx, actions[i], bitmap);
+			count = test_fixed_ctr_with_filter(vcpu, actions[i], bitmap);
+
+			TEST_ASSERT(expected == !!count,
+				    "Fixed event filter does not work as expected.");
+		}
+	}
+}
+
+static void test_fixed_counter_bitmap(void)
+{
+	struct kvm_vcpu *vcpu;
+	uint8_t idx, max_fixed_num = get_kvm_supported_fixed_num();
+
+	/*
+	 * Check that pmu_event_filter works as expected when it's applied to
+	 * fixed performance counters.
+	 */
+	for (idx = 0; idx < max_fixed_num; idx++) {
+		vcpu = new_vcpu(intel_guest_run_fixed_counters);
+		vcpu_args_set(vcpu, 1, idx);
+		test_fixed_ctr_action_and_bitmap(vcpu, idx, max_fixed_num);
+		free_vcpu(vcpu);
+	}
+}
+
 int main(int argc, char *argv[])
 {
 	void (*guest_code)(void);
@@ -860,6 +968,7 @@ int main(int argc, char *argv[])
 	kvm_vm_free(vm);
 
 	test_pmu_config_disable(guest_code);
+	test_fixed_counter_bitmap();
 
 	return 0;
 }
-- 
2.31.1