Re: [PATCH v5 11/13] KVM: selftests: Test consistency of CPUID with num of fixed counters

JinrongLiang
2023-10-24T12:15:54Z

在 2023/10/24 08:26, Sean Christopherson 写道:
> From: Jinrong Liang <cloudliang@tencent.com>
>
> Extend the PMU counters test to verify KVM emulation of fixed counters in
> addition to general purpose counters. Fixed counters add an extra wrinkle
> in the form of an extra supported bitmask. Thus quoth the SDM:
>
> fixed-function performance counter 'i' is supported if ECX[i] || (EDX[4:0] > i)
>
> Test that KVM handles a counter being available through either method.
>
> 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>
> ---
> .../selftests/kvm/x86_64/pmu_counters_test.c | 58 ++++++++++++++++++-
> 1 file changed, 55 insertions(+), 3 deletions(-)
>
> 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 274b7f4d4b53..f1d9cdd69a17 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -227,13 +227,19 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector, \
> expect_gp ? "#GP" : "no fault", msr, vector) \
>
> static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters,
> - uint8_t nr_counters)
> + uint8_t nr_counters, uint32_t or_mask)
> {
> uint8_t i;
>
> for (i = 0; i < nr_possible_counters; i++) {
> const uint32_t msr = base_msr + i;
> - const bool expect_success = i < nr_counters;
> +
> + /*
> + * Fixed counters are supported if the counter is less than the
> + * number of enumerated contiguous counters *or* the counter is
> + * explicitly enumerated in the supported counters mask.
> + */
> + const bool expect_success = i < nr_counters || (or_mask & BIT(i));
>
> /*
> * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are
> @@ -273,7 +279,7 @@ static void guest_test_gp_counters(void)
> else
> base_msr = MSR_IA32_PERFCTR0;
>
> - guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters);
> + guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0);
> }
>
> static void test_gp_counters(uint8_t nr_gp_counters, uint64_t perf_cap)
> @@ -292,10 +298,51 @@ static void test_gp_counters(uint8_t nr_gp_counters, uint64_t perf_cap)
> kvm_vm_free(vm);
> }
>
> +static void guest_test_fixed_counters(void)
> +{
> + uint64_t supported_bitmask = 0;
> + uint8_t nr_fixed_counters = 0;
> +
> + /* KVM provides fixed counters iff the vPMU version is 2+. */

s/iff/if/

> + if (this_cpu_property(X86_PROPERTY_PMU_VERSION) >= 2)
> + nr_fixed_counters = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
> +
> + /*
> + * The supported bitmask for fixed counters was introduced in PMU
> + * version 5.
> + */
> + if (this_cpu_property(X86_PROPERTY_PMU_VERSION) >= 5)
> + supported_bitmask = this_cpu_property(X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK);
> +
> + guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS,
> + nr_fixed_counters, supported_bitmask);
> +}
> +
> +static void test_fixed_counters(uint8_t nr_fixed_counters,
> + uint32_t supported_bitmask, uint64_t perf_cap)
> +{
> + struct kvm_vcpu *vcpu;
> + struct kvm_vm *vm;
> +
> + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_fixed_counters);
> +
> + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK,
> + supported_bitmask);
> + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_FIXED_COUNTERS,
> + nr_fixed_counters);
> + vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, perf_cap);
> +
> + run_vcpu(vcpu);
> +
> + kvm_vm_free(vm);
> +}
> +
> static void test_intel_counters(void)
> {
> + uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
> uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
> unsigned int i;
> + uint32_t k;
> uint8_t j;
>
> const uint64_t perf_caps[] = {
> @@ -306,6 +353,11 @@ static void test_intel_counters(void)
> for (i = 0; i < ARRAY_SIZE(perf_caps); i++) {
> for (j = 0; j <= nr_gp_counters; j++)
> test_gp_counters(j, perf_caps[i]);
> +
> + for (j = 0; j <= nr_fixed_counters; j++) {
> + for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++)
> + test_fixed_counters(j, k, perf_caps[i]);
> + }
> }
> }
>