[PATCH v5 08/13] KVM: selftests: Test Intel PMU architectural events on gp counters

Sean Christopherson
2023-10-24T00:27:11Z

From: Jinrong Liang <cloudliang@tencent.com>

Add test cases to check if different Architectural events are available
after it's marked as unavailable via CPUID. It covers vPMU event filtering
logic based on Intel CPUID, which is a complement to pmu_event_filter.

According to Intel SDM, the number of architectural events is reported
through CPUID.0AH:EAX[31:24] and the architectural event x is supported
if EBX[x]=0 && EAX[31:24]>x.

Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/pmu_counters_test.c | 189 ++++++++++++++++++
2 files changed, 190 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/pmu_counters_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index ed1c17cabc07..4c024fb845b4 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -82,6 +82,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test
TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test
TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
+TEST_GEN_PROGS_x86_64 += x86_64/pmu_counters_test
TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test
TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
new file mode 100644
index 000000000000..2a6336b994d5
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023, Tencent, Inc.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <x86intrin.h>
+
+#include "pmu.h"
+#include "processor.h"
+
+/* Guest payload for any performance counter counting */
+#define NUM_BRANCHES 10
+
+static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
+ void *guest_code)
+{
+ struct kvm_vm *vm;
+
+ vm = vm_create_with_one_vcpu(vcpu, guest_code);
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(*vcpu);
+
+ return vm;
+}
+
+static void run_vcpu(struct kvm_vcpu *vcpu)
+{
+ struct ucall uc;
+
+ do {
+ vcpu_run(vcpu);
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_SYNC:
+ break;
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_DONE:
+ break;
+ default:
+ TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
+ }
+ } while (uc.cmd != UCALL_DONE);
+}
+
+static bool pmu_is_intel_event_stable(uint8_t idx)
+{
+ switch (idx) {
+ case INTEL_ARCH_CPU_CYCLES:
+ case INTEL_ARCH_INSTRUCTIONS_RETIRED:
+ case INTEL_ARCH_REFERENCE_CYCLES:
+ case INTEL_ARCH_BRANCHES_RETIRED:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static void guest_measure_pmu_v1(struct kvm_x86_pmu_feature event,
+ uint32_t counter_msr, uint32_t nr_gp_counters)
+{
+ uint8_t idx = event.f.bit;
+ unsigned int i;
+
+ for (i = 0; i < nr_gp_counters; i++) {
+ wrmsr(counter_msr + i, 0);
+ wrmsr(MSR_P6_EVNTSEL0 + i, ARCH_PERFMON_EVENTSEL_OS |
+ ARCH_PERFMON_EVENTSEL_ENABLE | intel_pmu_arch_events[idx]);
+ __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+
+ if (pmu_is_intel_event_stable(idx))
+ GUEST_ASSERT_EQ(this_pmu_has(event), !!_rdpmc(i));
+
+ wrmsr(MSR_P6_EVNTSEL0 + i, ARCH_PERFMON_EVENTSEL_OS |
+ !ARCH_PERFMON_EVENTSEL_ENABLE |
+ intel_pmu_arch_events[idx]);
+ wrmsr(counter_msr + i, 0);
+ __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+
+ if (pmu_is_intel_event_stable(idx))
+ GUEST_ASSERT(!_rdpmc(i));
+ }
+
+ GUEST_DONE();
+}
+
+static void guest_measure_loop(uint8_t idx)
+{
+ const struct {
+ struct kvm_x86_pmu_feature gp_event;
+ } intel_event_to_feature[] = {
+ [INTEL_ARCH_CPU_CYCLES] = { X86_PMU_FEATURE_CPU_CYCLES },
+ [INTEL_ARCH_INSTRUCTIONS_RETIRED] = { X86_PMU_FEATURE_INSNS_RETIRED },
+ [INTEL_ARCH_REFERENCE_CYCLES] = { X86_PMU_FEATURE_REFERENCE_CYCLES },
+ [INTEL_ARCH_LLC_REFERENCES] = { X86_PMU_FEATURE_LLC_REFERENCES },
+ [INTEL_ARCH_LLC_MISSES] = { X86_PMU_FEATURE_LLC_MISSES },
+ [INTEL_ARCH_BRANCHES_RETIRED] = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED },
+ [INTEL_ARCH_BRANCHES_MISPREDICTED] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED },
+ };
+
+ uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
+ uint32_t pmu_version = this_cpu_property(X86_PROPERTY_PMU_VERSION);
+ struct kvm_x86_pmu_feature gp_event;
+ uint32_t counter_msr;
+ unsigned int i;
+
+ if (rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES)
+ counter_msr = MSR_IA32_PMC0;
+ else
+ counter_msr = MSR_IA32_PERFCTR0;
+
+ gp_event = intel_event_to_feature[idx].gp_event;
+ TEST_ASSERT_EQ(idx, gp_event.f.bit);
+
+ if (pmu_version < 2) {
+ guest_measure_pmu_v1(gp_event, counter_msr, nr_gp_counters);
+ return;
+ }
+
+ for (i = 0; i < nr_gp_counters; i++) {
+ wrmsr(counter_msr + i, 0);
+ wrmsr(MSR_P6_EVNTSEL0 + i, ARCH_PERFMON_EVENTSEL_OS |
+ ARCH_PERFMON_EVENTSEL_ENABLE |
+ intel_pmu_arch_events[idx]);
+
+ wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, BIT_ULL(i));
+ __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+ wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+
+ if (pmu_is_intel_event_stable(idx))
+ GUEST_ASSERT_EQ(this_pmu_has(gp_event), !!_rdpmc(i));
+ }
+
+ GUEST_DONE();
+}
+
+static void test_arch_events_cpuid(uint8_t i, uint8_t j, uint8_t idx)
+{
+ uint8_t arch_events_unavailable_mask = BIT_ULL(j);
+ uint8_t arch_events_bitmap_size = BIT_ULL(i);
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+
+ vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_measure_loop);
+
+ vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH,
+ arch_events_bitmap_size);
+ vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EVENTS_MASK,
+ arch_events_unavailable_mask);
+
+ vcpu_args_set(vcpu, 1, idx);
+
+ run_vcpu(vcpu);
+
+ kvm_vm_free(vm);
+}
+
+static void test_intel_arch_events(void)
+{
+ uint8_t idx, i, j;
+
+ for (idx = 0; idx < NR_INTEL_ARCH_EVENTS; idx++) {
+ /*
+ * A brute force iteration of all combinations of values is
+ * likely to exhaust the limit of the single-threaded thread
+ * fd nums, so it's test by iterating through all valid
+ * single-bit values.
+ */
+ for (i = 0; i < NR_INTEL_ARCH_EVENTS; i++) {
+ for (j = 0; j < NR_INTEL_ARCH_EVENTS; j++)
+ test_arch_events_cpuid(i, j, idx);
+ }
+ }
+}
+
+int main(int argc, char *argv[])
+{
+ TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+
+ TEST_REQUIRE(host_cpu_is_intel);
+ TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
+ TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
+ TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
+
+ test_intel_arch_events();
+
+ return 0;
+}
--
2.42.0.758.gaed0368e0e-goog