diff options
| -rw-r--r-- | tools/testing/selftests/kvm/Makefile | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/x86_64/pmu_counters_test.c | 321 |
2 files changed, 322 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 0f07ce8bd297..ce58098d80fd 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -81,6 +81,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_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/private_mem_conversions_test TEST_GEN_PROGS_x86_64 += x86_64/private_mem_kvm_exits_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..5b8687bb4639 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -0,0 +1,321 @@ +// 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" + +/* Number of LOOP instructions for the guest measurement payload. */ +#define NUM_BRANCHES 10 +/* + * Number of "extra" instructions that will be counted, i.e. the number of + * instructions that are needed to set up the loop and then disabled the + * counter. 2 MOV, 2 XOR, 1 WRMSR. + */ +#define NUM_EXTRA_INSNS 5 +#define NUM_INSNS_RETIRED (NUM_BRANCHES + NUM_EXTRA_INSNS) + +static uint8_t kvm_pmu_version; +static bool kvm_has_perf_caps; + +static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, + void *guest_code, + uint8_t pmu_version, + uint64_t perf_capabilities) +{ + struct kvm_vm *vm; + + vm = vm_create_with_one_vcpu(vcpu, guest_code); + vm_init_descriptor_tables(vm); + vcpu_init_descriptor_tables(*vcpu); + + sync_global_to_guest(vm, kvm_pmu_version); + + /* + * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling + * features via PERF_CAPABILITIES if the guest doesn't have a vPMU. + */ + if (kvm_has_perf_caps) + vcpu_set_msr(*vcpu, MSR_IA32_PERF_CAPABILITIES, perf_capabilities); + + vcpu_set_cpuid_property(*vcpu, X86_PROPERTY_PMU_VERSION, pmu_version); + 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_PRINTF: + pr_info("%s", uc.buffer); + break; + case UCALL_DONE: + break; + default: + TEST_FAIL("Unexpected ucall: %lu", uc.cmd); + } + } while (uc.cmd != UCALL_DONE); +} + +static uint8_t guest_get_pmu_version(void) +{ + /* + * Return the effective PMU version, i.e. the minimum between what KVM + * supports and what is enumerated to the guest. The host deliberately + * advertises a PMU version to the guest beyond what is actually + * supported by KVM to verify KVM doesn't freak out and do something + * bizarre with an architecturally valid, but unsupported, version. + */ + return min_t(uint8_t, kvm_pmu_version, this_cpu_property(X86_PROPERTY_PMU_VERSION)); +} + +/* + * If an architectural event is supported and guaranteed to generate at least + * one "hit, assert that its count is non-zero. If an event isn't supported or + * the test can't guarantee the associated action will occur, then all bets are + * off regarding the count, i.e. no checks can be done. + * + * Sanity check that in all cases, the event doesn't count when it's disabled, + * and that KVM correctly emulates the write of an arbitrary value. + */ +static void guest_assert_event_count(uint8_t idx, + struct kvm_x86_pmu_feature event, + uint32_t pmc, uint32_t pmc_msr) +{ + uint64_t count; + + count = _rdpmc(pmc); + if (!this_pmu_has(event)) + goto sanity_checks; + + switch (idx) { + case INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX: + GUEST_ASSERT_EQ(count, NUM_INSNS_RETIRED); + break; + case INTEL_ARCH_BRANCHES_RETIRED_INDEX: + GUEST_ASSERT_EQ(count, NUM_BRANCHES); + break; + case INTEL_ARCH_CPU_CYCLES_INDEX: + case INTEL_ARCH_REFERENCE_CYCLES_INDEX: + GUEST_ASSERT_NE(count, 0); + break; + default: + break; + } + +sanity_checks: + __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES})); + GUEST_ASSERT_EQ(_rdpmc(pmc), count); + + wrmsr(pmc_msr, 0xdead); + GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead); +} + +static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event, + uint32_t pmc, uint32_t pmc_msr, + uint32_t ctrl_msr, uint64_t ctrl_msr_value) +{ + wrmsr(pmc_msr, 0); + + /* + * Enable and disable the PMC in a monolithic asm blob to ensure that + * the compiler can't insert _any_ code into the measured sequence. + * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr, + * is restored before the end of the sequence. + */ + __asm__ __volatile__("wrmsr\n\t" + "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t" + "loop .\n\t" + "mov %%edi, %%ecx\n\t" + "xor %%eax, %%eax\n\t" + "xor %%edx, %%edx\n\t" + "wrmsr\n\t" + :: "a"((uint32_t)ctrl_msr_value), + "d"(ctrl_msr_value >> 32), + "c"(ctrl_msr), "D"(ctrl_msr) + ); + + guest_assert_event_count(idx, event, pmc, pmc_msr); +} + +static void guest_test_arch_event(uint8_t idx) +{ + const struct { + struct kvm_x86_pmu_feature gp_event; + } intel_event_to_feature[] = { + [INTEL_ARCH_CPU_CYCLES_INDEX] = { X86_PMU_FEATURE_CPU_CYCLES }, + [INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX] = { X86_PMU_FEATURE_INSNS_RETIRED }, + [INTEL_ARCH_REFERENCE_CYCLES_INDEX] = { X86_PMU_FEATURE_REFERENCE_CYCLES }, + [INTEL_ARCH_LLC_REFERENCES_INDEX] = { X86_PMU_FEATURE_LLC_REFERENCES }, + [INTEL_ARCH_LLC_MISSES_INDEX] = { X86_PMU_FEATURE_LLC_MISSES }, + [INTEL_ARCH_BRANCHES_RETIRED_INDEX] = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED }, + [INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED }, + [INTEL_ARCH_TOPDOWN_SLOTS_INDEX] = { X86_PMU_FEATURE_TOPDOWN_SLOTS }, + }; + + uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); + uint32_t pmu_version = guest_get_pmu_version(); + /* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */ + bool guest_has_perf_global_ctrl = pmu_version >= 2; + struct kvm_x86_pmu_feature gp_event; + uint32_t base_pmc_msr; + unsigned int i; + + /* The host side shouldn't invoke this without a guest PMU. */ + GUEST_ASSERT(pmu_version); + + if (this_cpu_has(X86_FEATURE_PDCM) && + rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES) + base_pmc_msr = MSR_IA32_PMC0; + else + base_pmc_msr = MSR_IA32_PERFCTR0; + + gp_event = intel_event_to_feature[idx].gp_event; + GUEST_ASSERT_EQ(idx, gp_event.f.bit); + + GUEST_ASSERT(nr_gp_counters); + + for (i = 0; i < nr_gp_counters; i++) { + uint64_t eventsel = ARCH_PERFMON_EVENTSEL_OS | + ARCH_PERFMON_EVENTSEL_ENABLE | + intel_pmu_arch_events[idx]; + + wrmsr(MSR_P6_EVNTSEL0 + i, 0); + if (guest_has_perf_global_ctrl) + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, BIT_ULL(i)); + + __guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i, + MSR_P6_EVNTSEL0 + i, eventsel); + } +} + +static void guest_test_arch_events(void) +{ + uint8_t i; + + for (i = 0; i < NR_INTEL_ARCH_EVENTS; i++) + guest_test_arch_event(i); + + GUEST_DONE(); +} + +static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities, + uint8_t length, uint8_t unavailable_mask) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + /* Testing arch events requires a vPMU (there are no negative tests). */ + if (!pmu_version) + return; + + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_arch_events, + pmu_version, perf_capabilities); + + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH, + length); + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EVENTS_MASK, + unavailable_mask); + + 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 pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); + unsigned int i; + uint8_t v, j; + uint32_t k; + + const uint64_t perf_caps[] = { + 0, + PMU_CAP_FW_WRITES, + }; + + /* + * Test up to PMU v5, which is the current maximum version defined by + * Intel, i.e. is the last version that is guaranteed to be backwards + * compatible with KVM's existing behavior. + */ + uint8_t max_pmu_version = max_t(typeof(pmu_version), pmu_version, 5); + + /* + * Detect the existence of events that aren't supported by selftests. + * This will (obviously) fail any time the kernel adds support for a + * new event, but it's worth paying that price to keep the test fresh. + */ + TEST_ASSERT(nr_arch_events <= NR_INTEL_ARCH_EVENTS, + "New architectural event(s) detected; please update this test (length = %u, mask = %x)", + nr_arch_events, kvm_cpu_property(X86_PROPERTY_PMU_EVENTS_MASK)); + + /* + * Force iterating over known arch events regardless of whether or not + * KVM/hardware supports a given event. + */ + nr_arch_events = max_t(typeof(nr_arch_events), nr_arch_events, NR_INTEL_ARCH_EVENTS); + + for (v = 0; v <= max_pmu_version; v++) { + for (i = 0; i < ARRAY_SIZE(perf_caps); i++) { + if (!kvm_has_perf_caps && perf_caps[i]) + continue; + + pr_info("Testing arch events, PMU version %u, perf_caps = %lx\n", + v, perf_caps[i]); + /* + * To keep the total runtime reasonable, test every + * possible non-zero, non-reserved bitmap combination + * only with the native PMU version and the full bit + * vector length. + */ + if (v == pmu_version) { + for (k = 1; k < (BIT(nr_arch_events) - 1); k++) + test_arch_events(v, perf_caps[i], nr_arch_events, k); + } + /* + * Test single bits for all PMU version and lengths up + * the number of events +1 (to verify KVM doesn't do + * weird things if the guest length is greater than the + * host length). Explicitly test a mask of '0' and all + * ones i.e. all events being available and unavailable. + */ + for (j = 0; j <= nr_arch_events + 1; j++) { + test_arch_events(v, perf_caps[i], j, 0); + test_arch_events(v, perf_caps[i], j, 0xff); + + for (k = 0; k < nr_arch_events; k++) + test_arch_events(v, perf_caps[i], j, BIT(k)); + } + } + } +} + +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); + + kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); + kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM); + + test_intel_counters(); + + return 0; +} |