From c59a1f106f5cd4843c097069ff1bb2ad72103a67 Mon Sep 17 00:00:00 2001 From: Like Xu Date: Mon, 11 Apr 2022 18:19:36 +0800 Subject: [PATCH] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS If IA32_PERF_CAPABILITIES.PEBS_BASELINE [bit 14] is set, the IA32_PEBS_ENABLE MSR exists and all architecturally enumerated fixed and general-purpose counters have corresponding bits in IA32_PEBS_ENABLE that enable generation of PEBS records. The general-purpose counter bits start at bit IA32_PEBS_ENABLE[0], and the fixed counter bits start at bit IA32_PEBS_ENABLE[32]. When guest PEBS is enabled, the IA32_PEBS_ENABLE MSR will be added to the perf_guest_switch_msr() and atomically switched during the VMX transitions just like CORE_PERF_GLOBAL_CTRL MSR. Based on whether the platform supports x86_pmu.pebs_ept, it has also refactored the way to add more msrs to arr[] in intel_guest_get_msrs() for extensibility. Originally-by: Andi Kleen Co-developed-by: Kan Liang Signed-off-by: Kan Liang Co-developed-by: Luwei Kang Signed-off-by: Luwei Kang Signed-off-by: Like Xu Acked-by: Peter Zijlstra (Intel) Message-Id: <20220411101946.20262-8-likexu@tencent.com> Signed-off-by: Paolo Bonzini --- arch/x86/events/intel/core.c | 75 ++++++++++++++++++++++++++++++---------- arch/x86/include/asm/kvm_host.h | 3 ++ arch/x86/include/asm/msr-index.h | 6 ++++ arch/x86/kvm/vmx/pmu_intel.c | 31 +++++++++++++++++ arch/x86/kvm/x86.c | 1 + 5 files changed, 98 insertions(+), 18 deletions(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 8c9cb41..70a5c66 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3969,33 +3969,72 @@ static int intel_pmu_hw_config(struct perf_event *event) return 0; } +/* + * Currently, the only caller of this function is the atomic_switch_perf_msrs(). + * The host perf conext helps to prepare the values of the real hardware for + * a set of msrs that need to be switched atomically in a vmx transaction. + * + * For example, the pseudocode needed to add a new msr should look like: + * + * arr[(*nr)++] = (struct perf_guest_switch_msr){ + * .msr = the hardware msr address, + * .host = the value the hardware has when it doesn't run a guest, + * .guest = the value the hardware has when it runs a guest, + * }; + * + * These values have nothing to do with the emulated values the guest sees + * when it uses {RD,WR}MSR, which should be handled by the KVM context, + * specifically in the intel_pmu_{get,set}_msr(). + */ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr, void *data) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct perf_guest_switch_msr *arr = cpuc->guest_switch_msrs; u64 intel_ctrl = hybrid(cpuc->pmu, intel_ctrl); + u64 pebs_mask = cpuc->pebs_enabled & x86_pmu.pebs_capable; + int global_ctrl, pebs_enable; + + *nr = 0; + global_ctrl = (*nr)++; + arr[global_ctrl] = (struct perf_guest_switch_msr){ + .msr = MSR_CORE_PERF_GLOBAL_CTRL, + .host = intel_ctrl & ~cpuc->intel_ctrl_guest_mask, + .guest = intel_ctrl & (~cpuc->intel_ctrl_host_mask | ~pebs_mask), + }; - arr[0].msr = MSR_CORE_PERF_GLOBAL_CTRL; - arr[0].host = intel_ctrl & ~cpuc->intel_ctrl_guest_mask; - arr[0].guest = intel_ctrl & ~cpuc->intel_ctrl_host_mask; - arr[0].guest &= ~(cpuc->pebs_enabled & x86_pmu.pebs_capable); - *nr = 1; + if (!x86_pmu.pebs) + return arr; - if (x86_pmu.pebs && x86_pmu.pebs_no_isolation) { - /* - * If PMU counter has PEBS enabled it is not enough to - * disable counter on a guest entry since PEBS memory - * write can overshoot guest entry and corrupt guest - * memory. Disabling PEBS solves the problem. - * - * Don't do this if the CPU already enforces it. - */ - arr[1].msr = MSR_IA32_PEBS_ENABLE; - arr[1].host = cpuc->pebs_enabled; - arr[1].guest = 0; - *nr = 2; + /* + * If PMU counter has PEBS enabled it is not enough to + * disable counter on a guest entry since PEBS memory + * write can overshoot guest entry and corrupt guest + * memory. Disabling PEBS solves the problem. + * + * Don't do this if the CPU already enforces it. + */ + if (x86_pmu.pebs_no_isolation) { + arr[(*nr)++] = (struct perf_guest_switch_msr){ + .msr = MSR_IA32_PEBS_ENABLE, + .host = cpuc->pebs_enabled, + .guest = 0, + }; + return arr; } + if (!x86_pmu.pebs_ept) + return arr; + pebs_enable = (*nr)++; + + arr[pebs_enable] = (struct perf_guest_switch_msr){ + .msr = MSR_IA32_PEBS_ENABLE, + .host = cpuc->pebs_enabled & ~cpuc->intel_ctrl_guest_mask, + .guest = pebs_mask & ~cpuc->intel_ctrl_host_mask, + }; + + /* Set hw GLOBAL_CTRL bits for PEBS counter when it runs for guest */ + arr[0].guest |= arr[*nr].guest; + return arr; } diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7458abe..36a5650 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -521,6 +521,9 @@ struct kvm_pmu { DECLARE_BITMAP(all_valid_pmc_idx, X86_PMC_IDX_MAX); DECLARE_BITMAP(pmc_in_use, X86_PMC_IDX_MAX); + u64 pebs_enable; + u64 pebs_enable_mask; + /* * The gate to release perf_events not marked in * pmc_in_use only once in a vcpu time slice. diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index c194995..bd1861c 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -196,6 +196,12 @@ #define PERF_CAP_PT_IDX 16 #define MSR_PEBS_LD_LAT_THRESHOLD 0x000003f6 +#define PERF_CAP_PEBS_TRAP BIT_ULL(6) +#define PERF_CAP_ARCH_REG BIT_ULL(7) +#define PERF_CAP_PEBS_FORMAT 0xf00 +#define PERF_CAP_PEBS_BASELINE BIT_ULL(14) +#define PERF_CAP_PEBS_MASK (PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \ + PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE) #define MSR_IA32_RTIT_CTL 0x00000570 #define RTIT_CTL_TRACEEN BIT(0) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index c04d123..2cd4f8a 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -214,6 +214,9 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) case MSR_CORE_PERF_GLOBAL_OVF_CTRL: ret = pmu->version > 1; break; + case MSR_IA32_PEBS_ENABLE: + ret = vcpu->arch.perf_capabilities & PERF_CAP_PEBS_FORMAT; + break; default: ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) || get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) || @@ -361,6 +364,9 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_CORE_PERF_GLOBAL_OVF_CTRL: msr_info->data = 0; return 0; + case MSR_IA32_PEBS_ENABLE: + msr_info->data = pmu->pebs_enable; + return 0; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) { @@ -421,6 +427,14 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 0; } break; + case MSR_IA32_PEBS_ENABLE: + if (pmu->pebs_enable == data) + return 0; + if (!(data & pmu->pebs_enable_mask)) { + pmu->pebs_enable = data; + return 0; + } + break; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) { @@ -489,6 +503,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->reserved_bits = 0xffffffff00200000ull; pmu->raw_event_mask = X86_RAW_EVENT_MASK; pmu->fixed_ctr_ctrl_mask = ~0ull; + pmu->pebs_enable_mask = ~0ull; entry = kvm_find_cpuid_entry(vcpu, 0xa, 0); if (!entry || !vcpu->kvm->arch.enable_pmu) @@ -560,6 +575,22 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) if (lbr_desc->records.nr) bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1); + + if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_FORMAT) { + if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_BASELINE) { + pmu->pebs_enable_mask = ~pmu->global_ctrl; + pmu->reserved_bits &= ~ICL_EVENTSEL_ADAPTIVE; + for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { + pmu->fixed_ctr_ctrl_mask &= + ~(1ULL << (INTEL_PMC_IDX_FIXED + i * 4)); + } + } else { + pmu->pebs_enable_mask = + ~((1ull << pmu->nr_arch_gp_counters) - 1); + } + } else { + vcpu->arch.perf_capabilities &= ~PERF_CAP_PEBS_MASK; + } } static void intel_pmu_init(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 68ec5cb..12183c7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1448,6 +1448,7 @@ static const u32 msrs_to_save_all[] = { MSR_ARCH_PERFMON_EVENTSEL0 + 12, MSR_ARCH_PERFMON_EVENTSEL0 + 13, MSR_ARCH_PERFMON_EVENTSEL0 + 14, MSR_ARCH_PERFMON_EVENTSEL0 + 15, MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17, + MSR_IA32_PEBS_ENABLE, MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3, MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3, -- 2.7.4