From b31880ca2f41dc2196e31d97e498b0fa884c2b2a Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:50 -0800 Subject: [PATCH] KVM: x86/pmu: Move pmc_idx => pmc translation helper to common code Add a common helper for *internal* PMC lookups, and delete the ops hook and Intel's implementation. Keep AMD's implementation, but rename it to amd_pmu_get_pmc() to make it somewhat more obvious that it's suited for both KVM-internal and guest-initiated lookups. Because KVM tracks all counters in a single bitmap, getting a counter when iterating over a bitmap, e.g. of all valid PMCs, requires a small amount of math, that while simple, isn't super obvious and doesn't use the same semantics as PMC lookups from RDPMC! Although AMD doesn't support fixed counters, the common PMU code still behaves as if there a split, the high half of which just happens to always be empty. Opportunstically add a comment to explain both what is going on, and why KVM uses a single bitmap, e.g. the boilerplate for iterating over separate bitmaps could be done via macros, so it's not (just) about deduplicating code. Link: https://lore.kernel.org/r/20231110022857.1273836-4-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 - arch/x86/kvm/pmu.c | 8 +++---- arch/x86/kvm/pmu.h | 29 +++++++++++++++++++++++++- arch/x86/kvm/svm/pmu.c | 7 +++---- arch/x86/kvm/vmx/pmu_intel.c | 15 +------------ 5 files changed, 36 insertions(+), 24 deletions(-) diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h index f0cd48222133..f852b13aeefe 100644 --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h @@ -12,7 +12,6 @@ BUILD_BUG_ON(1) * a NULL definition, for example if "static_call_cond()" will be used * at the call sites. */ -KVM_X86_PMU_OP(pmc_idx_to_pmc) KVM_X86_PMU_OP(rdpmc_ecx_to_pmc) KVM_X86_PMU_OP(msr_idx_to_pmc) KVM_X86_PMU_OP_OPTIONAL(check_rdpmc_early) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 67d589ac9363..0873937c90bc 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -505,7 +505,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) int bit; for_each_set_bit(bit, pmu->reprogram_pmi, X86_PMC_IDX_MAX) { - struct kvm_pmc *pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, bit); + struct kvm_pmc *pmc = kvm_pmc_idx_to_pmc(pmu, bit); if (unlikely(!pmc)) { clear_bit(bit, pmu->reprogram_pmi); @@ -725,7 +725,7 @@ static void kvm_pmu_reset(struct kvm_vcpu *vcpu) bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { - pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + pmc = kvm_pmc_idx_to_pmc(pmu, i); if (!pmc) continue; @@ -801,7 +801,7 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu) pmu->pmc_in_use, X86_PMC_IDX_MAX); for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) { - pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + pmc = kvm_pmc_idx_to_pmc(pmu, i); if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc)) pmc_stop_counter(pmc); @@ -856,7 +856,7 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) int i; for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { - pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + pmc = kvm_pmc_idx_to_pmc(pmu, i); if (!pmc || !pmc_event_is_allowed(pmc)) continue; diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index e8c6a1f4b8e8..56e8e665e1af 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -4,6 +4,8 @@ #include +#include + #define vcpu_to_pmu(vcpu) (&(vcpu)->arch.pmu) #define pmu_to_vcpu(pmu) (container_of((pmu), struct kvm_vcpu, arch.pmu)) #define pmc_to_pmu(pmc) (&(pmc)->vcpu->arch.pmu) @@ -21,7 +23,6 @@ #define KVM_FIXED_PMC_BASE_IDX INTEL_PMC_IDX_FIXED struct kvm_pmu_ops { - struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx); struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask); struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, u32 msr); @@ -56,6 +57,32 @@ static inline bool kvm_pmu_has_perf_global_ctrl(struct kvm_pmu *pmu) return pmu->version > 1; } +/* + * KVM tracks all counters in 64-bit bitmaps, with general purpose counters + * mapped to bits 31:0 and fixed counters mapped to 63:32, e.g. fixed counter 0 + * is tracked internally via index 32. On Intel, (AMD doesn't support fixed + * counters), this mirrors how fixed counters are mapped to PERF_GLOBAL_CTRL + * and similar MSRs, i.e. tracking fixed counters at base index 32 reduces the + * amounter of boilerplate needed to iterate over PMCs *and* simplifies common + * enabling/disable/reset operations. + * + * WARNING! This helper is only for lookups that are initiated by KVM, it is + * NOT safe for guest lookups, e.g. will do the wrong thing if passed a raw + * ECX value from RDPMC (fixed counters are accessed by setting bit 30 in ECX + * for RDPMC, not by adding 32 to the fixed counter index). + */ +static inline struct kvm_pmc *kvm_pmc_idx_to_pmc(struct kvm_pmu *pmu, int idx) +{ + if (idx < pmu->nr_arch_gp_counters) + return &pmu->gp_counters[idx]; + + idx -= KVM_FIXED_PMC_BASE_IDX; + if (idx >= 0 && idx < pmu->nr_arch_fixed_counters) + return &pmu->fixed_counters[idx]; + + return NULL; +} + static inline u64 pmc_bitmask(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index e886300f0f97..dfcc38bd97d3 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -25,7 +25,7 @@ enum pmu_type { PMU_TYPE_EVNTSEL, }; -static struct kvm_pmc *amd_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) +static struct kvm_pmc *amd_pmu_get_pmc(struct kvm_pmu *pmu, int pmc_idx) { unsigned int num_counters = pmu->nr_arch_gp_counters; @@ -70,7 +70,7 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr, return NULL; } - return amd_pmc_idx_to_pmc(pmu, idx); + return amd_pmu_get_pmc(pmu, idx); } static int amd_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) @@ -87,7 +87,7 @@ static int amd_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { - return amd_pmc_idx_to_pmc(vcpu_to_pmu(vcpu), idx); + return amd_pmu_get_pmc(vcpu_to_pmu(vcpu), idx); } static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr) @@ -229,7 +229,6 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu) } struct kvm_pmu_ops amd_pmu_ops __initdata = { - .pmc_idx_to_pmc = amd_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = amd_msr_idx_to_pmc, .check_rdpmc_early = amd_check_rdpmc_early, diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index fe7a2ba51e1b..845a964f22a6 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -55,18 +55,6 @@ static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) } } -static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) -{ - if (pmc_idx < KVM_FIXED_PMC_BASE_IDX) { - return get_gp_pmc(pmu, MSR_P6_EVNTSEL0 + pmc_idx, - MSR_P6_EVNTSEL0); - } else { - u32 idx = pmc_idx - KVM_FIXED_PMC_BASE_IDX; - - return get_fixed_pmc(pmu, idx + MSR_CORE_PERF_FIXED_CTR0); - } -} - static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { @@ -718,7 +706,7 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu) for_each_set_bit(bit, (unsigned long *)&pmu->global_ctrl, X86_PMC_IDX_MAX) { - pmc = intel_pmc_idx_to_pmc(pmu, bit); + pmc = kvm_pmc_idx_to_pmc(pmu, bit); if (!pmc || !pmc_speculative_in_use(pmc) || !pmc_is_globally_enabled(pmc) || !pmc->perf_event) @@ -735,7 +723,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu) } struct kvm_pmu_ops intel_pmu_ops __initdata = { - .pmc_idx_to_pmc = intel_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = intel_msr_idx_to_pmc, .is_valid_msr = intel_is_valid_msr,