tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Test for VMX-pmu perf capability msr
   4  *
   5  * Copyright (C) 2021 Intel Corporation
   6  *
   7  * Test to check the effect of various CPUID settings on
   8  * MSR_IA32_PERF_CAPABILITIES MSR, and check that what
   9  * we write with KVM_SET_MSR is _not_ modified by the guest
  10  * and check it can be retrieved with KVM_GET_MSR, also test
  11  * the invalid LBR formats are rejected.
  12  */
  13
  14 #define _GNU_SOURCE /* for program_invocation_short_name */
  15 #include <sys/ioctl.h>
  16
  17 #include "kvm_util.h"
  18 #include "vmx.h"
  19
  20 #define PMU_CAP_FW_WRITES       (1ULL << 13)
  21 #define PMU_CAP_LBR_FMT         0x3f
  22
  23 union perf_capabilities {
  24         struct {
  25                 u64     lbr_format:6;
  26                 u64     pebs_trap:1;
  27                 u64     pebs_arch_reg:1;
  28                 u64     pebs_format:4;
  29                 u64     smm_freeze:1;
  30                 u64     full_width_write:1;
  31                 u64 pebs_baseline:1;
  32                 u64     perf_metrics:1;
  33                 u64     pebs_output_pt_available:1;
  34                 u64     anythread_deprecated:1;
  35         };
  36         u64     capabilities;
  37 };
  38
  39 static void guest_code(void)
  40 {
  41         wrmsr(MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
  42 }
  43
  44 /*
  45  * Verify KVM allows writing PERF_CAPABILITIES with all KVM-supported features
  46  * enabled, as well as '0' (to disable all features).
  47  */
  48 static void test_basic_perf_capabilities(union perf_capabilities host_cap)
  49 {
  50         struct kvm_vcpu *vcpu;
  51         struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
  52
  53         vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0);
  54         ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), 0);
  55
  56         vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
  57         ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);
  58
  59         kvm_vm_free(vm);
  60 }
  61
  62 static void test_fungible_perf_capabilities(union perf_capabilities host_cap)
  63 {
  64         struct kvm_vcpu *vcpu;
  65         struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, guest_code);
  66
  67         /* testcase 1, set capabilities when we have PDCM bit */
  68         vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_FW_WRITES);
  69
  70         /* check capabilities can be retrieved with KVM_GET_MSR */
  71         ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);
  72
  73         /* check whatever we write with KVM_SET_MSR is _not_ modified */
  74         vcpu_run(vcpu);
  75         ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);
  76
  77         kvm_vm_free(vm);
  78 }
  79
  80 static void test_immutable_perf_capabilities(union perf_capabilities host_cap)
  81 {
  82         struct kvm_vcpu *vcpu;
  83         struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
  84         uint64_t val;
  85         int ret;
  86
  87         /*
  88          * KVM only supports the host's native LBR format, as well as '0' (to
  89          * disable LBR support).  Verify KVM rejects all other LBR formats.
  90          */
  91         for (val = 1; val <= PMU_CAP_LBR_FMT; val++) {
  92                 if (val == (host_cap.capabilities & PMU_CAP_LBR_FMT))
  93                         continue;
  94
  95                 ret = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, val);
  96                 TEST_ASSERT(!ret, "Bad LBR FMT = 0x%lx didn't fail", val);
  97         }
  98         kvm_vm_free(vm);
  99 }
 100
 101 int main(int argc, char *argv[])
 102 {
 103         union perf_capabilities host_cap;
 104
 105         TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
 106
 107         TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
 108         TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
 109
 110         host_cap.capabilities = kvm_get_feature_msr(MSR_IA32_PERF_CAPABILITIES);
 111         host_cap.capabilities &= (PMU_CAP_FW_WRITES | PMU_CAP_LBR_FMT);
 112
 113         TEST_ASSERT(host_cap.full_width_write,
 114                     "Full-width writes should always be supported");
 115
 116         test_basic_perf_capabilities(host_cap);
 117         test_fungible_perf_capabilities(host_cap);
 118         test_immutable_perf_capabilities(host_cap);
 119
 120         printf("Completed perf capability tests.\n");
 121 }