From: Jinrong Liang <cloudliang@xxxxxxxxxxx> Add a test to verify that KVM correctly emulates MSR-based accesses to general purpose counters based on guest CPUID, e.g. that accesses to non-existent counters #GP and accesses to existent counters succeed. Note, for compatibility reasons, KVM does not emulate #GP when MSR_P6_PERFCTR[0|1] is not present (writes should be dropped). Co-developed-by: Like Xu <likexu@xxxxxxxxxxx> Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx> Co-developed-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- .../selftests/kvm/x86_64/pmu_counters_test.c | 99 +++++++++++++++++++ 1 file changed, 99 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index 663e8fbe7ff8..863418842ef8 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -270,9 +270,103 @@ static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities, kvm_vm_free(vm); } +/* + * Limit testing to MSRs that are actually defined by Intel (in the SDM). MSRs + * that aren't defined counter MSRs *probably* don't exist, but there's no + * guarantee that currently undefined MSR indices won't be used for something + * other than PMCs in the future. + */ +#define MAX_NR_GP_COUNTERS 8 +#define MAX_NR_FIXED_COUNTERS 3 + +#define GUEST_ASSERT_PMC_MSR_ACCESS(insn, msr, expect_gp, vector) \ +__GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector, \ + "Expected %s on " #insn "(0x%x), got vector %u", \ + expect_gp ? "#GP" : "no fault", msr, vector) \ + +#define GUEST_ASSERT_PMC_VALUE(insn, msr, val, expected) \ + __GUEST_ASSERT(val == expected_val, \ + "Expected " #insn "(0x%x) to yield 0x%lx, got 0x%lx", \ + msr, expected_val, val); + +static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters, + uint8_t nr_counters) +{ + uint8_t i; + + for (i = 0; i < nr_possible_counters; i++) { + /* + * TODO: Test a value that validates full-width writes and the + * width of the counters. + */ + const uint64_t test_val = 0xffff; + const uint32_t msr = base_msr + i; + const bool expect_success = i < nr_counters; + + /* + * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are + * unsupported, i.e. doesn't #GP and reads back '0'. + */ + const uint64_t expected_val = expect_success ? test_val : 0; + const bool expect_gp = !expect_success && msr != MSR_P6_PERFCTR0 && + msr != MSR_P6_PERFCTR1; + uint8_t vector; + uint64_t val; + + vector = wrmsr_safe(msr, test_val); + GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector); + + vector = rdmsr_safe(msr, &val); + GUEST_ASSERT_PMC_MSR_ACCESS(RDMSR, msr, expect_gp, vector); + + /* On #GP, the result of RDMSR is undefined. */ + if (!expect_gp) + GUEST_ASSERT_PMC_VALUE(RDMSR, msr, val, expected_val); + + vector = wrmsr_safe(msr, 0); + GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector); + } + GUEST_DONE(); +} + +static void guest_test_gp_counters(void) +{ + uint8_t nr_gp_counters = 0; + uint32_t base_msr; + + if (guest_get_pmu_version()) + nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); + + if (this_cpu_has(X86_FEATURE_PDCM) && + rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES) + base_msr = MSR_IA32_PMC0; + else + base_msr = MSR_IA32_PERFCTR0; + + guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters); +} + +static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities, + uint8_t nr_gp_counters) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_gp_counters, + pmu_version, perf_capabilities); + + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_GP_COUNTERS, + nr_gp_counters); + + run_vcpu(vcpu); + + kvm_vm_free(vm); +} + static void test_intel_counters(void) { uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); unsigned int i; uint8_t v, j; @@ -336,6 +430,11 @@ static void test_intel_counters(void) for (k = 0; k < nr_arch_events; k++) test_arch_events(v, perf_caps[i], j, BIT(k)); } + + pr_info("Testing GP counters, PMU version %u, perf_caps = %lx\n", + v, perf_caps[i]); + for (j = 0; j <= nr_gp_counters; j++) + test_gp_counters(v, perf_caps[i], j); } } } -- 2.42.0.869.gea05f2083d-goog