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Fix test_fixed_counters() to derive supported fixed counters using the above formula instead of relying solely on EDX[4:0]. This allows the test to cover non-contiguous fixed counter configurations. Update this_pmu_has() to take the PMU version into consideration. Without this fix, it could return incorrect results in test cases such as test_arch_events(), which configure a PMU version different from the one originally advertised by KVM without explicitly updating CPUID.0AH.{ECX,EDX} to match the new PMU version. For example, after downgrading a guest from PMU v5 to PMU v2, this_pmu_has() would still consult CPUID.0AH.ECX while KVM ignores it, resulting in a mismatch in the reported fixed counter capabilities. Signed-off-by: Dapeng Mi Co-developed-by: Zide Chen Signed-off-by: Zide Chen --- v3: - use the BIT() macro instead of an open-coded left shift. (Sashiko) - Simplified ternary condition in this_pmu_has(). (Sashiko) - Also test legacy EDX contiguous counts with ECX=0 in test_fixed_counters(). (Sashiko) v2: - Fix this_pmu_has() to honor the guest's configured PMU version. - Update the pmu_vm_create_with_vcpus() calls after rebasing. --- .../selftests/kvm/include/x86/processor.h | 6 +++- .../selftests/kvm/x86/pmu_counters_test.c | 28 +++++++++++++++---- 2 files changed, 28 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h index ffec2291b1e1..21381db1c4ca 100644 --- a/tools/testing/selftests/kvm/include/x86/processor.h +++ b/tools/testing/selftests/kvm/include/x86/processor.h @@ -836,6 +836,7 @@ static __always_inline bool this_cpu_has_p(struct kvm_x86_cpu_property property) static inline bool this_pmu_has(struct kvm_x86_pmu_feature feature) { + u8 pmu_version; u32 nr_bits; if (feature.f.reg == KVM_CPUID_EBX) { @@ -845,7 +846,10 @@ static inline bool this_pmu_has(struct kvm_x86_pmu_feature feature) GUEST_ASSERT(feature.f.reg == KVM_CPUID_ECX); nr_bits = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS); - return nr_bits > feature.f.bit || this_cpu_has(feature.f); + pmu_version = this_cpu_property(X86_PROPERTY_PMU_VERSION); + + return nr_bits > feature.f.bit || + (pmu_version >= 5 && this_cpu_has(feature.f)); } static __always_inline u64 this_cpu_supported_xcr0(void) diff --git a/tools/testing/selftests/kvm/x86/pmu_counters_test.c b/tools/testing/selftests/kvm/x86/pmu_counters_test.c index c3e784e16348..77d67fa6e3fc 100644 --- a/tools/testing/selftests/kvm/x86/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86/pmu_counters_test.c @@ -3,6 +3,7 @@ * Copyright (C) 2023, Tencent, Inc. */ #include +#include #include "pmu.h" #include "processor.h" @@ -631,25 +632,42 @@ static void __test_fixed_counters(struct kvm_vcpu *vcpu, u8 nr_fixed_counters, static void test_fixed_counters(u8 pmu_version, u64 perf_capabilities) { u8 nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS); + unsigned long fixed_subset; struct kvm_vcpu **vcpus; struct kvm_vm *vm; + u32 fixed_bitmap; int i = 0; - u32 k; u8 j; pr_info("Testing %u fixed counters, PMU version %u, perf_caps = %lx\n", nr_fixed_counters, pmu_version, perf_capabilities); + fixed_bitmap = BIT_ULL(nr_fixed_counters) - 1; + if (pmu_version >= 5) + fixed_bitmap |= kvm_cpu_property(X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK); - vm = pmu_vm_create_with_vcpus((nr_fixed_counters + 1) * BIT(nr_fixed_counters), + vm = pmu_vm_create_with_vcpus(BIT(__builtin_popcount(fixed_bitmap)) + nr_fixed_counters, guest_test_fixed_counters, pmu_version, perf_capabilities, &vcpus); - for (j = 0; j <= nr_fixed_counters; j++) { - for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++) - __test_fixed_counters(vcpus[i++], j, k); + for (fixed_subset = 0; fixed_subset <= fixed_bitmap; fixed_subset++) { + u32 nr_contiguous; + + /* + * The loop walks all values from 0 to fixed_bitmap, so skip any + * value that is not a subset of fixed_bitmap. + */ + if (fixed_subset & ~fixed_bitmap) + continue; + + nr_contiguous = find_first_zero_bit(&fixed_subset, + MAX_NR_FIXED_COUNTERS); + __test_fixed_counters(vcpus[i++], nr_contiguous, fixed_subset); } + for (j = 1; j <= nr_fixed_counters; j++) + __test_fixed_counters(vcpus[i++], j, 0); + pmu_vm_free(vm, vcpus); } -- 2.56.0