Messages in this thread | | | Date | Tue, 24 Oct 2023 19:49:26 +0800 | Subject | Re: [PATCH v5 13/13] KVM: selftests: Extend PMU counters test to permute on vPMU version | From | JinrongLiang <> |
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在 2023/10/24 08:26, Sean Christopherson 写道: > Extent the PMU counters test to verify that KVM emulates the vPMU (or > not) according to the vPMU version exposed to the guest. KVM's ABI (which > does NOT reflect Intel's architectural behavior) is that GP counters are > available if the PMU version is >0, and that fixed counters and > PERF_GLOBAL_CTRL are available if the PMU version is >1. > > Test up to vPMU version 5, i.e. the current architectural max. KVM only > officially supports up to version 2, but the behavior of the counters is > backwards compatible, i.e. KVM shouldn't do something completely different > for a higher, architecturally-defined vPMU version. > > Verify KVM behavior against the effective vPMU version, e.g. advertising > vPMU 5 when KVM only supports vPMU 2 shouldn't magically unlock vPMU 5 > features. > > Suggested-by: Like Xu <likexu@tencent.com> > Suggested-by: Jinrong Liang <cloudliang@tencent.com> > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > .../selftests/kvm/x86_64/pmu_counters_test.c | 60 +++++++++++++++---- > 1 file changed, 47 insertions(+), 13 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 1c392ad156f4..85b01dd5b2cd 100644 > --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c > +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c > @@ -12,6 +12,8 @@ > /* Guest payload for any performance counter counting */ > #define NUM_BRANCHES 10 > > +static uint8_t kvm_pmu_version; > + > static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, > void *guest_code) > { > @@ -21,6 +23,8 @@ static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, > vm_init_descriptor_tables(vm); > vcpu_init_descriptor_tables(*vcpu); > > + sync_global_to_guest(vm, kvm_pmu_version); > + > return vm; > } > > @@ -97,6 +101,19 @@ static bool pmu_is_null_feature(struct kvm_x86_pmu_feature event) > return !(*(u64 *)&event); > } > > +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 counters test > + * 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)); > +} > + > static void guest_measure_loop(uint8_t idx) > { > const struct { > @@ -121,7 +138,7 @@ static void guest_measure_loop(uint8_t idx) > }; > > uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); > - uint32_t pmu_version = this_cpu_property(X86_PROPERTY_PMU_VERSION); > + uint32_t pmu_version = guest_get_pmu_version(); > struct kvm_x86_pmu_feature gp_event, fixed_event; > uint32_t counter_msr; > unsigned int i; > @@ -270,9 +287,12 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters > > static void guest_test_gp_counters(void) > { > - uint8_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); > + 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 (rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES) > base_msr = MSR_IA32_PMC0; > else > @@ -282,7 +302,8 @@ static void guest_test_gp_counters(void) > GUEST_DONE(); > } > > -static void test_gp_counters(uint8_t nr_gp_counters, uint64_t perf_cap) > +static void test_gp_counters(uint8_t pmu_version, uint8_t nr_gp_counters,
The parameter pmu_version is not used in this function.
> + uint64_t perf_cap) > { > struct kvm_vcpu *vcpu; > struct kvm_vm *vm; > @@ -305,16 +326,17 @@ static void guest_test_fixed_counters(void) > uint8_t i; > > /* KVM provides fixed counters iff the vPMU version is 2+. */ > - if (this_cpu_property(X86_PROPERTY_PMU_VERSION) >= 2) > + if (guest_get_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) > + if (guest_get_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); > > @@ -345,7 +367,7 @@ static void guest_test_fixed_counters(void) > GUEST_DONE(); > } > > -static void test_fixed_counters(uint8_t nr_fixed_counters, > +static void test_fixed_counters(uint8_t pmu_version, uint8_t nr_fixed_counters,
The parameter pmu_version is not used in this function.
> uint32_t supported_bitmask, uint64_t perf_cap) > { > struct kvm_vcpu *vcpu; > @@ -368,22 +390,32 @@ 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); > + uint8_t max_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); > unsigned int i; > + uint8_t j, v; > uint32_t k; > - uint8_t j; > > const uint64_t perf_caps[] = { > 0, > PMU_CAP_FW_WRITES, > }; > > - for (i = 0; i < ARRAY_SIZE(perf_caps); i++) { > - for (j = 0; j <= nr_gp_counters; j++) > - test_gp_counters(j, perf_caps[i]); > + /* > + * 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. > + */ > + max_pmu_version = max_t(typeof(max_pmu_version), max_pmu_version, 5); > > - 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]); > + for (v = 0; v <= max_pmu_version; v++) { > + for (i = 0; i < ARRAY_SIZE(perf_caps) + 1; i++) { > + for (j = 0; j <= nr_gp_counters; j++) > + test_gp_counters(v, 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(v, j, k, perf_caps[i]); > + } > } > } > } > @@ -397,6 +429,8 @@ int main(int argc, char *argv[]) > TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0); > TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM)); > > + kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); > + > test_intel_arch_events(); > test_intel_counters(); >
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