[PATCH v2 5/7] KVM: selftests: Check if pmu_event_filter meets expectations on fixed ctrs

Jinrong Liang
2023-04-20T10:49:21Z

From: Jinrong Liang <cloudliang@tencent.com>

From: Jinrong Liang <cloudliang@tencent.com>

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@tencent.com>
---
.../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