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Message-Id: <20230530134248.23998-4-cloudliang@tencent.com>
Date: Tue, 30 May 2023 21:42:43 +0800
From: Jinrong Liang <ljr.kernel@...il.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, Like Xu <likexu@...cent.com>,
David Matlack <dmatlack@...gle.com>,
Aaron Lewis <aaronlewis@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jinrong Liang <cloudliang@...cent.com>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/8] KVM: selftests: Test Intel PMU architectural events on gp counters
From: Like Xu <likexu@...cent.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: Jinrong Liang <cloudliang@...cent.com>
Signed-off-by: Jinrong Liang <cloudliang@...cent.com>
Signed-off-by: Like Xu <likexu@...cent.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../kvm/x86_64/pmu_basic_functionality_test.c | 168 ++++++++++++++++++
2 files changed, 169 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 18cadc669798..f636968709c4 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -78,6 +78,7 @@ 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_basic_functionality_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_basic_functionality_test.c b/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
new file mode 100644
index 000000000000..1f100fd94d67
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test the consistency of the PMU's CPUID and its features
+ *
+ * Copyright (C) 2023, Tencent, Inc.
+ *
+ * Check that the VM's PMU behaviour is consistent with the
+ * VM CPUID definition.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <x86intrin.h>
+
+#include "pmu.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 uint64_t run_vcpu(struct kvm_vcpu *vcpu, uint64_t *ucall_arg)
+{
+ struct ucall uc;
+
+ vcpu_run(vcpu);
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_SYNC:
+ *ucall_arg = uc.args[1];
+ break;
+ case UCALL_DONE:
+ break;
+ default:
+ TEST_ASSERT(false, "Unexpected exit: %s",
+ exit_reason_str(vcpu->run->exit_reason));
+ }
+ return uc.cmd;
+}
+
+static void intel_guest_run_arch_event(uint8_t version, uint8_t max_gp_num,
+ uint32_t ctr_base_msr, uint64_t evt_code)
+{
+ uint32_t global_msr = MSR_CORE_PERF_GLOBAL_CTRL;
+ unsigned int i;
+
+ for (i = 0; i < max_gp_num; i++) {
+ wrmsr(ctr_base_msr + i, 0);
+ wrmsr(MSR_P6_EVNTSEL0 + i, EVENTSEL_OS | EVENTSEL_EN | evt_code);
+ if (version > 1)
+ wrmsr(global_msr, BIT_ULL(i));
+
+ __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+
+ if (version > 1)
+ wrmsr(global_msr, 0);
+
+ GUEST_SYNC(_rdpmc(i));
+ }
+
+ GUEST_DONE();
+}
+
+static void test_arch_events_cpuid(struct kvm_vcpu *vcpu, uint8_t evt_vector,
+ uint8_t unavl_mask, uint8_t idx)
+{
+ struct kvm_cpuid_entry2 *entry;
+ uint32_t ctr_msr = MSR_IA32_PERFCTR0;
+ bool is_supported;
+ uint64_t counter_val = 0;
+
+ entry = vcpu_get_cpuid_entry(vcpu, 0xa);
+ entry->eax = (entry->eax & ~EVT_LEN_MASK) |
+ (evt_vector << EVT_LEN_OFS_BIT);
+ entry->ebx = (entry->ebx & ~EVENTS_MASK) | unavl_mask;
+ vcpu_set_cpuid(vcpu);
+
+ if (vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES)
+ ctr_msr = MSR_IA32_PMC0;
+
+ /* Arch event x is supported if EBX[x]=0 && EAX[31:24]>x */
+ is_supported = !(entry->ebx & BIT_ULL(idx)) &&
+ (((entry->eax & EVT_LEN_MASK) >> EVT_LEN_OFS_BIT) > idx);
+
+ vcpu_args_set(vcpu, 4, X86_INTEL_PMU_VERSION, X86_INTEL_MAX_GP_CTR_NUM,
+ ctr_msr, arch_events[idx]);
+
+ while (run_vcpu(vcpu, &counter_val) != UCALL_DONE)
+ TEST_ASSERT(is_supported == !!counter_val,
+ "Unavailable arch event is counting.");
+}
+
+static void intel_check_arch_event_is_unavl(uint8_t idx)
+{
+ uint8_t eax_evt_vec, ebx_unavl_mask, i, j;
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+
+ /*
+ * 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
+ * tested here by iterating through all valid values on a single bit.
+ */
+ for (i = 0; i < ARRAY_SIZE(arch_events); i++) {
+ eax_evt_vec = BIT_ULL(i);
+ for (j = 0; j < ARRAY_SIZE(arch_events); j++) {
+ ebx_unavl_mask = BIT_ULL(j);
+ vm = pmu_vm_create_with_one_vcpu(&vcpu,
+ intel_guest_run_arch_event);
+ test_arch_events_cpuid(vcpu, eax_evt_vec,
+ ebx_unavl_mask, idx);
+
+ kvm_vm_free(vm);
+ }
+ }
+}
+
+static void intel_test_arch_events(void)
+{
+ uint8_t idx;
+
+ for (idx = 0; idx < ARRAY_SIZE(arch_events); idx++) {
+ /*
+ * Given the stability of performance event recurrence,
+ * only these arch events are currently being tested:
+ *
+ * - Core cycle event (idx = 0)
+ * - Instruction retired event (idx = 1)
+ * - Reference cycles event (idx = 2)
+ * - Branch instruction retired event (idx = 5)
+ *
+ * Note that reference cycles is one event that actually cannot
+ * be successfully virtualized.
+ */
+ if (idx > 2 && idx != 5)
+ continue;
+
+ intel_check_arch_event_is_unavl(idx);
+ }
+}
+
+static void intel_test_pmu_cpuid(void)
+{
+ intel_test_arch_events();
+}
+
+int main(int argc, char *argv[])
+{
+ TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+
+ if (host_cpu_is_intel) {
+ TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
+ TEST_REQUIRE(X86_INTEL_PMU_VERSION > 0);
+ TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
+
+ intel_test_pmu_cpuid();
+ }
+
+ return 0;
+}
--
2.31.1
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