[PATCH v6 5/6] KVM: selftests: Test if event filter meets expectations on fixed counters

From: Jinrong Liang
Date: Thu Aug 10 2023 - 05:10:40 EST


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 | 80 +++++++++++++++++++
1 file changed, 80 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 8b8bfee11016..732c76c41bb0 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 +27,7 @@
#define ARCH_PERFMON_BRANCHES_RETIRED 5

#define NUM_BRANCHES 42
+#define INTEL_PMC_IDX_FIXED 32

/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */
#define MAX_FILTER_EVENTS 300
@@ -808,6 +809,84 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu)
TEST_ASSERT(!r, "Masking non-existent fixed counters should be allowed");
}

+static void intel_run_fixed_counter_guest_code(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 uint64_t test_with_fixed_counter_filter(struct kvm_vcpu *vcpu,
+ uint32_t action, uint32_t bitmap)
+{
+ struct __kvm_pmu_event_filter f = {
+ .action = action,
+ .fixed_counter_bitmap = bitmap,
+ };
+ do_vcpu_set_pmu_event_filter(vcpu, &f);
+
+ return run_vcpu_to_sync(vcpu);
+}
+
+static void __test_fixed_counter_bitmap(struct kvm_vcpu *vcpu, uint8_t idx,
+ uint8_t nr_fixed_counters)
+{
+ unsigned int i;
+ uint32_t bitmap;
+ uint64_t count;
+
+ TEST_ASSERT(nr_fixed_counters < sizeof(bitmap) * 8,
+ "Invalid nr_fixed_counters");
+
+ /*
+ * Check the fixed performance counter can count normally when KVM
+ * userspace doesn't set any pmu filter.
+ */
+ count = run_vcpu_to_sync(vcpu);
+ TEST_ASSERT(count, "Unexpected count value: %ld\n", count);
+
+ for (i = 0; i < BIT(nr_fixed_counters); i++) {
+ bitmap = BIT(i);
+ count = test_with_fixed_counter_filter(vcpu, KVM_PMU_EVENT_ALLOW,
+ bitmap);
+ TEST_ASSERT_EQ(!!count, !!(bitmap & BIT(idx)));
+
+ count = test_with_fixed_counter_filter(vcpu, KVM_PMU_EVENT_DENY,
+ bitmap);
+ TEST_ASSERT_EQ(!!count, !(bitmap & BIT(idx)));
+ }
+}
+
+static void test_fixed_counter_bitmap(void)
+{
+ uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+ uint8_t idx;
+
+ /*
+ * Check that pmu_event_filter works as expected when it's applied to
+ * fixed performance counters.
+ */
+ for (idx = 0; idx < nr_fixed_counters; idx++) {
+ vm = vm_create_with_one_vcpu(&vcpu,
+ intel_run_fixed_counter_guest_code);
+ vcpu_args_set(vcpu, 1, idx);
+ __test_fixed_counter_bitmap(vcpu, idx, nr_fixed_counters);
+ kvm_vm_free(vm);
+ }
+}
+
int main(int argc, char *argv[])
{
void (*guest_code)(void);
@@ -851,6 +930,7 @@ int main(int argc, char *argv[])
kvm_vm_free(vm);

test_pmu_config_disable(guest_code);
+ test_fixed_counter_bitmap();

return 0;
}
--
2.39.3