// SPDX-License-Identifier: GPL-2.0-only /* * Kernel-based Virtual Machine -- Performance Monitoring Unit support * * Copyright 2015 Red Hat, Inc. and/or its affiliates. * * Authors: * Avi Kivity * Gleb Natapov * Wei Huang */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include "x86.h" #include "cpuid.h" #include "lapic.h" #include "pmu.h" /* This is enough to filter the vast majority of currently defined events. */ #define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300 struct x86_pmu_capability __read_mostly kvm_pmu_cap; EXPORT_SYMBOL_GPL(kvm_pmu_cap); struct kvm_pmu_emulated_event_selectors __read_mostly kvm_pmu_eventsel; EXPORT_SYMBOL_GPL(kvm_pmu_eventsel); /* Precise Distribution of Instructions Retired (PDIR) */ static const struct x86_cpu_id vmx_pebs_pdir_cpu[] = { X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, NULL), X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, NULL), /* Instruction-Accurate PDIR (PDIR++) */ X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, NULL), {} }; /* Precise Distribution (PDist) */ static const struct x86_cpu_id vmx_pebs_pdist_cpu[] = { X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, NULL), {} }; /* NOTE: * - Each perf counter is defined as "struct kvm_pmc"; * - There are two types of perf counters: general purpose (gp) and fixed. * gp counters are stored in gp_counters[] and fixed counters are stored * in fixed_counters[] respectively. Both of them are part of "struct * kvm_pmu"; * - pmu.c understands the difference between gp counters and fixed counters. * However AMD doesn't support fixed-counters; * - There are three types of index to access perf counters (PMC): * 1. MSR (named msr): For example Intel has MSR_IA32_PERFCTRn and AMD * has MSR_K7_PERFCTRn and, for families 15H and later, * MSR_F15H_PERF_CTRn, where MSR_F15H_PERF_CTR[0-3] are * aliased to MSR_K7_PERFCTRn. * 2. MSR Index (named idx): This normally is used by RDPMC instruction. * For instance AMD RDPMC instruction uses 0000_0003h in ECX to access * C001_0007h (MSR_K7_PERCTR3). Intel has a similar mechanism, except * that it also supports fixed counters. idx can be used to as index to * gp and fixed counters. * 3. Global PMC Index (named pmc): pmc is an index specific to PMU * code. Each pmc, stored in kvm_pmc.idx field, is unique across * all perf counters (both gp and fixed). The mapping relationship * between pmc and perf counters is as the following: * * Intel: [0 .. KVM_INTEL_PMC_MAX_GENERIC-1] <=> gp counters * [KVM_FIXED_PMC_BASE_IDX .. KVM_FIXED_PMC_BASE_IDX + 2] <=> fixed * * AMD: [0 .. AMD64_NUM_COUNTERS-1] and, for families 15H * and later, [0 .. AMD64_NUM_COUNTERS_CORE-1] <=> gp counters */ static struct kvm_pmu_ops kvm_pmu_ops __read_mostly; #define KVM_X86_PMU_OP(func) \ DEFINE_STATIC_CALL_NULL(kvm_x86_pmu_##func, \ *(((struct kvm_pmu_ops *)0)->func)); #define KVM_X86_PMU_OP_OPTIONAL KVM_X86_PMU_OP #include void kvm_pmu_ops_update(const struct kvm_pmu_ops *pmu_ops) { memcpy(&kvm_pmu_ops, pmu_ops, sizeof(kvm_pmu_ops)); #define __KVM_X86_PMU_OP(func) \ static_call_update(kvm_x86_pmu_##func, kvm_pmu_ops.func); #define KVM_X86_PMU_OP(func) \ WARN_ON(!kvm_pmu_ops.func); __KVM_X86_PMU_OP(func) #define KVM_X86_PMU_OP_OPTIONAL __KVM_X86_PMU_OP #include #undef __KVM_X86_PMU_OP } static inline void __kvm_perf_overflow(struct kvm_pmc *pmc, bool in_pmi) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); bool skip_pmi = false; if (pmc->perf_event && pmc->perf_event->attr.precise_ip) { if (!in_pmi) { /* * TODO: KVM is currently _choosing_ to not generate records * for emulated instructions, avoiding BUFFER_OVF PMI when * there are no records. Strictly speaking, it should be done * as well in the right context to improve sampling accuracy. */ skip_pmi = true; } else { /* Indicate PEBS overflow PMI to guest. */ skip_pmi = __test_and_set_bit(GLOBAL_STATUS_BUFFER_OVF_BIT, (unsigned long *)&pmu->global_status); } } else { __set_bit(pmc->idx, (unsigned long *)&pmu->global_status); } if (pmc->intr && !skip_pmi) kvm_make_request(KVM_REQ_PMI, pmc->vcpu); } static void kvm_perf_overflow(struct perf_event *perf_event, struct perf_sample_data *data, struct pt_regs *regs) { struct kvm_pmc *pmc = perf_event->overflow_handler_context; /* * Ignore asynchronous overflow events for counters that are scheduled * to be reprogrammed, e.g. if a PMI for the previous event races with * KVM's handling of a related guest WRMSR. */ if (test_and_set_bit(pmc->idx, pmc_to_pmu(pmc)->reprogram_pmi)) return; __kvm_perf_overflow(pmc, true); kvm_make_request(KVM_REQ_PMU, pmc->vcpu); } static u64 pmc_get_pebs_precise_level(struct kvm_pmc *pmc) { /* * For some model specific pebs counters with special capabilities * (PDIR, PDIR++, PDIST), KVM needs to raise the event precise * level to the maximum value (currently 3, backwards compatible) * so that the perf subsystem would assign specific hardware counter * with that capability for vPMC. */ if ((pmc->idx == 0 && x86_match_cpu(vmx_pebs_pdist_cpu)) || (pmc->idx == 32 && x86_match_cpu(vmx_pebs_pdir_cpu))) return 3; /* * The non-zero precision level of guest event makes the ordinary * guest event becomes a guest PEBS event and triggers the host * PEBS PMI handler to determine whether the PEBS overflow PMI * comes from the host counters or the guest. */ return 1; } static u64 get_sample_period(struct kvm_pmc *pmc, u64 counter_value) { u64 sample_period = (-counter_value) & pmc_bitmask(pmc); if (!sample_period) sample_period = pmc_bitmask(pmc) + 1; return sample_period; } static int pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, u64 config, bool exclude_user, bool exclude_kernel, bool intr) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); struct perf_event *event; struct perf_event_attr attr = { .type = type, .size = sizeof(attr), .pinned = true, .exclude_idle = true, .exclude_host = 1, .exclude_user = exclude_user, .exclude_kernel = exclude_kernel, .config = config, }; bool pebs = test_bit(pmc->idx, (unsigned long *)&pmu->pebs_enable); attr.sample_period = get_sample_period(pmc, pmc->counter); if ((attr.config & HSW_IN_TX_CHECKPOINTED) && guest_cpuid_is_intel(pmc->vcpu)) { /* * HSW_IN_TX_CHECKPOINTED is not supported with nonzero * period. Just clear the sample period so at least * allocating the counter doesn't fail. */ attr.sample_period = 0; } if (pebs) { /* * For most PEBS hardware events, the difference in the software * precision levels of guest and host PEBS events will not affect * the accuracy of the PEBS profiling result, because the "event IP" * in the PEBS record is calibrated on the guest side. */ attr.precise_ip = pmc_get_pebs_precise_level(pmc); } event = perf_event_create_kernel_counter(&attr, -1, current, kvm_perf_overflow, pmc); if (IS_ERR(event)) { pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n", PTR_ERR(event), pmc->idx); return PTR_ERR(event); } pmc->perf_event = event; pmc_to_pmu(pmc)->event_count++; pmc->is_paused = false; pmc->intr = intr || pebs; return 0; } static bool pmc_pause_counter(struct kvm_pmc *pmc) { u64 counter = pmc->counter; u64 prev_counter; /* update counter, reset event value to avoid redundant accumulation */ if (pmc->perf_event && !pmc->is_paused) counter += perf_event_pause(pmc->perf_event, true); /* * Snapshot the previous counter *after* accumulating state from perf. * If overflow already happened, hardware (via perf) is responsible for * generating a PMI. KVM just needs to detect overflow on emulated * counter events that haven't yet been processed. */ prev_counter = counter & pmc_bitmask(pmc); counter += pmc->emulated_counter; pmc->counter = counter & pmc_bitmask(pmc); pmc->emulated_counter = 0; pmc->is_paused = true; return pmc->counter < prev_counter; } static bool pmc_resume_counter(struct kvm_pmc *pmc) { if (!pmc->perf_event) return false; /* recalibrate sample period and check if it's accepted by perf core */ if (is_sampling_event(pmc->perf_event) && perf_event_period(pmc->perf_event, get_sample_period(pmc, pmc->counter))) return false; if (test_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->pebs_enable) != (!!pmc->perf_event->attr.precise_ip)) return false; /* reuse perf_event to serve as pmc_reprogram_counter() does*/ perf_event_enable(pmc->perf_event); pmc->is_paused = false; return true; } static void pmc_release_perf_event(struct kvm_pmc *pmc) { if (pmc->perf_event) { perf_event_release_kernel(pmc->perf_event); pmc->perf_event = NULL; pmc->current_config = 0; pmc_to_pmu(pmc)->event_count--; } } static void pmc_stop_counter(struct kvm_pmc *pmc) { if (pmc->perf_event) { pmc->counter = pmc_read_counter(pmc); pmc_release_perf_event(pmc); } } static void pmc_update_sample_period(struct kvm_pmc *pmc) { if (!pmc->perf_event || pmc->is_paused || !is_sampling_event(pmc->perf_event)) return; perf_event_period(pmc->perf_event, get_sample_period(pmc, pmc->counter)); } void pmc_write_counter(struct kvm_pmc *pmc, u64 val) { /* * Drop any unconsumed accumulated counts, the WRMSR is a write, not a * read-modify-write. Adjust the counter value so that its value is * relative to the current count, as reading the current count from * perf is faster than pausing and repgrogramming the event in order to * reset it to '0'. Note, this very sneakily offsets the accumulated * emulated count too, by using pmc_read_counter()! */ pmc->emulated_counter = 0; pmc->counter += val - pmc_read_counter(pmc); pmc->counter &= pmc_bitmask(pmc); pmc_update_sample_period(pmc); } EXPORT_SYMBOL_GPL(pmc_write_counter); static int filter_cmp(const void *pa, const void *pb, u64 mask) { u64 a = *(u64 *)pa & mask; u64 b = *(u64 *)pb & mask; return (a > b) - (a < b); } static int filter_sort_cmp(const void *pa, const void *pb) { return filter_cmp(pa, pb, (KVM_PMU_MASKED_ENTRY_EVENT_SELECT | KVM_PMU_MASKED_ENTRY_EXCLUDE)); } /* * For the event filter, searching is done on the 'includes' list and * 'excludes' list separately rather than on the 'events' list (which * has both). As a result the exclude bit can be ignored. */ static int filter_event_cmp(const void *pa, const void *pb) { return filter_cmp(pa, pb, (KVM_PMU_MASKED_ENTRY_EVENT_SELECT)); } static int find_filter_index(u64 *events, u64 nevents, u64 key) { u64 *fe = bsearch(&key, events, nevents, sizeof(events[0]), filter_event_cmp); if (!fe) return -1; return fe - events; } static bool is_filter_entry_match(u64 filter_event, u64 umask) { u64 mask = filter_event >> (KVM_PMU_MASKED_ENTRY_UMASK_MASK_SHIFT - 8); u64 match = filter_event & KVM_PMU_MASKED_ENTRY_UMASK_MATCH; BUILD_BUG_ON((KVM_PMU_ENCODE_MASKED_ENTRY(0, 0xff, 0, false) >> (KVM_PMU_MASKED_ENTRY_UMASK_MASK_SHIFT - 8)) != ARCH_PERFMON_EVENTSEL_UMASK); return (umask & mask) == match; } static bool filter_contains_match(u64 *events, u64 nevents, u64 eventsel) { u64 event_select = eventsel & kvm_pmu_ops.EVENTSEL_EVENT; u64 umask = eventsel & ARCH_PERFMON_EVENTSEL_UMASK; int i, index; index = find_filter_index(events, nevents, event_select); if (index < 0) return false; /* * Entries are sorted by the event select. Walk the list in both * directions to process all entries with the targeted event select. */ for (i = index; i < nevents; i++) { if (filter_event_cmp(&events[i], &event_select)) break; if (is_filter_entry_match(events[i], umask)) return true; } for (i = index - 1; i >= 0; i--) { if (filter_event_cmp(&events[i], &event_select)) break; if (is_filter_entry_match(events[i], umask)) return true; } return false; } static bool is_gp_event_allowed(struct kvm_x86_pmu_event_filter *f, u64 eventsel) { if (filter_contains_match(f->includes, f->nr_includes, eventsel) && !filter_contains_match(f->excludes, f->nr_excludes, eventsel)) return f->action == KVM_PMU_EVENT_ALLOW; return f->action == KVM_PMU_EVENT_DENY; } static bool is_fixed_event_allowed(struct kvm_x86_pmu_event_filter *filter, int idx) { int fixed_idx = idx - KVM_FIXED_PMC_BASE_IDX; if (filter->action == KVM_PMU_EVENT_DENY && test_bit(fixed_idx, (ulong *)&filter->fixed_counter_bitmap)) return false; if (filter->action == KVM_PMU_EVENT_ALLOW && !test_bit(fixed_idx, (ulong *)&filter->fixed_counter_bitmap)) return false; return true; } static bool check_pmu_event_filter(struct kvm_pmc *pmc) { struct kvm_x86_pmu_event_filter *filter; struct kvm *kvm = pmc->vcpu->kvm; filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu); if (!filter) return true; if (pmc_is_gp(pmc)) return is_gp_event_allowed(filter, pmc->eventsel); return is_fixed_event_allowed(filter, pmc->idx); } static bool pmc_event_is_allowed(struct kvm_pmc *pmc) { return pmc_is_globally_enabled(pmc) && pmc_speculative_in_use(pmc) && check_pmu_event_filter(pmc); } static int reprogram_counter(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); u64 eventsel = pmc->eventsel; u64 new_config = eventsel; bool emulate_overflow; u8 fixed_ctr_ctrl; emulate_overflow = pmc_pause_counter(pmc); if (!pmc_event_is_allowed(pmc)) return 0; if (emulate_overflow) __kvm_perf_overflow(pmc, false); if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL) printk_once("kvm pmu: pin control bit is ignored\n"); if (pmc_is_fixed(pmc)) { fixed_ctr_ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl, pmc->idx - KVM_FIXED_PMC_BASE_IDX); if (fixed_ctr_ctrl & 0x1) eventsel |= ARCH_PERFMON_EVENTSEL_OS; if (fixed_ctr_ctrl & 0x2) eventsel |= ARCH_PERFMON_EVENTSEL_USR; if (fixed_ctr_ctrl & 0x8) eventsel |= ARCH_PERFMON_EVENTSEL_INT; new_config = (u64)fixed_ctr_ctrl; } if (pmc->current_config == new_config && pmc_resume_counter(pmc)) return 0; pmc_release_perf_event(pmc); pmc->current_config = new_config; return pmc_reprogram_counter(pmc, PERF_TYPE_RAW, (eventsel & pmu->raw_event_mask), !(eventsel & ARCH_PERFMON_EVENTSEL_USR), !(eventsel & ARCH_PERFMON_EVENTSEL_OS), eventsel & ARCH_PERFMON_EVENTSEL_INT); } void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) { DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; int bit; bitmap_copy(bitmap, pmu->reprogram_pmi, X86_PMC_IDX_MAX); /* * The reprogramming bitmap can be written asynchronously by something * other than the task that holds vcpu->mutex, take care to clear only * the bits that will actually processed. */ BUILD_BUG_ON(sizeof(bitmap) != sizeof(atomic64_t)); atomic64_andnot(*(s64 *)bitmap, &pmu->__reprogram_pmi); kvm_for_each_pmc(pmu, pmc, bit, bitmap) { /* * If reprogramming fails, e.g. due to contention, re-set the * regprogram bit set, i.e. opportunistically try again on the * next PMU refresh. Don't make a new request as doing so can * stall the guest if reprogramming repeatedly fails. */ if (reprogram_counter(pmc)) set_bit(pmc->idx, pmu->reprogram_pmi); } /* * Unused perf_events are only released if the corresponding MSRs * weren't accessed during the last vCPU time slice. kvm_arch_sched_in * triggers KVM_REQ_PMU if cleanup is needed. */ if (unlikely(pmu->need_cleanup)) kvm_pmu_cleanup(vcpu); } int kvm_pmu_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) { /* * On Intel, VMX interception has priority over RDPMC exceptions that * aren't already handled by the emulator, i.e. there are no additional * check needed for Intel PMUs. * * On AMD, _all_ exceptions on RDPMC have priority over SVM intercepts, * i.e. an invalid PMC results in a #GP, not #VMEXIT. */ if (!kvm_pmu_ops.check_rdpmc_early) return 0; return static_call(kvm_x86_pmu_check_rdpmc_early)(vcpu, idx); } bool is_vmware_backdoor_pmc(u32 pmc_idx) { switch (pmc_idx) { case VMWARE_BACKDOOR_PMC_HOST_TSC: case VMWARE_BACKDOOR_PMC_REAL_TIME: case VMWARE_BACKDOOR_PMC_APPARENT_TIME: return true; } return false; } static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) { u64 ctr_val; switch (idx) { case VMWARE_BACKDOOR_PMC_HOST_TSC: ctr_val = rdtsc(); break; case VMWARE_BACKDOOR_PMC_REAL_TIME: ctr_val = ktime_get_boottime_ns(); break; case VMWARE_BACKDOOR_PMC_APPARENT_TIME: ctr_val = ktime_get_boottime_ns() + vcpu->kvm->arch.kvmclock_offset; break; default: return 1; } *data = ctr_val; return 0; } int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; u64 mask = ~0ull; if (!pmu->version) return 1; if (is_vmware_backdoor_pmc(idx)) return kvm_pmu_rdpmc_vmware(vcpu, idx, data); pmc = static_call(kvm_x86_pmu_rdpmc_ecx_to_pmc)(vcpu, idx, &mask); if (!pmc) return 1; if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_PCE) && (static_call(kvm_x86_get_cpl)(vcpu) != 0) && kvm_is_cr0_bit_set(vcpu, X86_CR0_PE)) return 1; *data = pmc_read_counter(pmc) & mask; return 0; } void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu) { if (lapic_in_kernel(vcpu)) { static_call_cond(kvm_x86_pmu_deliver_pmi)(vcpu); kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC); } } bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) { switch (msr) { case MSR_CORE_PERF_GLOBAL_STATUS: case MSR_CORE_PERF_GLOBAL_CTRL: case MSR_CORE_PERF_GLOBAL_OVF_CTRL: return kvm_pmu_has_perf_global_ctrl(vcpu_to_pmu(vcpu)); default: break; } return static_call(kvm_x86_pmu_msr_idx_to_pmc)(vcpu, msr) || static_call(kvm_x86_pmu_is_valid_msr)(vcpu, msr); } static void kvm_pmu_mark_pmc_in_use(struct kvm_vcpu *vcpu, u32 msr) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc = static_call(kvm_x86_pmu_msr_idx_to_pmc)(vcpu, msr); if (pmc) __set_bit(pmc->idx, pmu->pmc_in_use); } int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); u32 msr = msr_info->index; switch (msr) { case MSR_CORE_PERF_GLOBAL_STATUS: case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS: msr_info->data = pmu->global_status; break; case MSR_AMD64_PERF_CNTR_GLOBAL_CTL: case MSR_CORE_PERF_GLOBAL_CTRL: msr_info->data = pmu->global_ctrl; break; case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR: case MSR_CORE_PERF_GLOBAL_OVF_CTRL: msr_info->data = 0; break; default: return static_call(kvm_x86_pmu_get_msr)(vcpu, msr_info); } return 0; } int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); u32 msr = msr_info->index; u64 data = msr_info->data; u64 diff; /* * Note, AMD ignores writes to reserved bits and read-only PMU MSRs, * whereas Intel generates #GP on attempts to write reserved/RO MSRs. */ switch (msr) { case MSR_CORE_PERF_GLOBAL_STATUS: if (!msr_info->host_initiated) return 1; /* RO MSR */ fallthrough; case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS: /* Per PPR, Read-only MSR. Writes are ignored. */ if (!msr_info->host_initiated) break; if (data & pmu->global_status_mask) return 1; pmu->global_status = data; break; case MSR_AMD64_PERF_CNTR_GLOBAL_CTL: data &= ~pmu->global_ctrl_mask; fallthrough; case MSR_CORE_PERF_GLOBAL_CTRL: if (!kvm_valid_perf_global_ctrl(pmu, data)) return 1; if (pmu->global_ctrl != data) { diff = pmu->global_ctrl ^ data; pmu->global_ctrl = data; reprogram_counters(pmu, diff); } break; case MSR_CORE_PERF_GLOBAL_OVF_CTRL: /* * GLOBAL_OVF_CTRL, a.k.a. GLOBAL STATUS_RESET, clears bits in * GLOBAL_STATUS, and so the set of reserved bits is the same. */ if (data & pmu->global_status_mask) return 1; fallthrough; case MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR: if (!msr_info->host_initiated) pmu->global_status &= ~data; break; default: kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index); return static_call(kvm_x86_pmu_set_msr)(vcpu, msr_info); } return 0; } static void kvm_pmu_reset(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; int i; pmu->need_cleanup = false; bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) { pmc_stop_counter(pmc); pmc->counter = 0; pmc->emulated_counter = 0; if (pmc_is_gp(pmc)) pmc->eventsel = 0; } pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = 0; static_call_cond(kvm_x86_pmu_reset)(vcpu); } /* * Refresh the PMU configuration for the vCPU, e.g. if userspace changes CPUID * and/or PERF_CAPABILITIES. */ void kvm_pmu_refresh(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); if (KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm)) return; /* * Stop/release all existing counters/events before realizing the new * vPMU model. */ kvm_pmu_reset(vcpu); pmu->version = 0; pmu->nr_arch_gp_counters = 0; pmu->nr_arch_fixed_counters = 0; pmu->counter_bitmask[KVM_PMC_GP] = 0; pmu->counter_bitmask[KVM_PMC_FIXED] = 0; pmu->reserved_bits = 0xffffffff00200000ull; pmu->raw_event_mask = X86_RAW_EVENT_MASK; pmu->global_ctrl_mask = ~0ull; pmu->global_status_mask = ~0ull; pmu->fixed_ctr_ctrl_mask = ~0ull; pmu->pebs_enable_mask = ~0ull; pmu->pebs_data_cfg_mask = ~0ull; bitmap_zero(pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX); if (!vcpu->kvm->arch.enable_pmu) return; static_call(kvm_x86_pmu_refresh)(vcpu); /* * At RESET, both Intel and AMD CPUs set all enable bits for general * purpose counters in IA32_PERF_GLOBAL_CTRL (so that software that * was written for v1 PMUs don't unknowingly leave GP counters disabled * in the global controls). Emulate that behavior when refreshing the * PMU so that userspace doesn't need to manually set PERF_GLOBAL_CTRL. */ if (kvm_pmu_has_perf_global_ctrl(pmu) && pmu->nr_arch_gp_counters) pmu->global_ctrl = GENMASK_ULL(pmu->nr_arch_gp_counters - 1, 0); } void kvm_pmu_init(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); memset(pmu, 0, sizeof(*pmu)); static_call(kvm_x86_pmu_init)(vcpu); kvm_pmu_refresh(vcpu); } /* Release perf_events for vPMCs that have been unused for a full time slice. */ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc = NULL; DECLARE_BITMAP(bitmask, X86_PMC_IDX_MAX); int i; pmu->need_cleanup = false; bitmap_andnot(bitmask, pmu->all_valid_pmc_idx, pmu->pmc_in_use, X86_PMC_IDX_MAX); kvm_for_each_pmc(pmu, pmc, i, bitmask) { if (pmc->perf_event && !pmc_speculative_in_use(pmc)) pmc_stop_counter(pmc); } static_call_cond(kvm_x86_pmu_cleanup)(vcpu); bitmap_zero(pmu->pmc_in_use, X86_PMC_IDX_MAX); } void kvm_pmu_destroy(struct kvm_vcpu *vcpu) { kvm_pmu_reset(vcpu); } static void kvm_pmu_incr_counter(struct kvm_pmc *pmc) { pmc->emulated_counter++; kvm_pmu_request_counter_reprogram(pmc); } static inline bool cpl_is_matched(struct kvm_pmc *pmc) { bool select_os, select_user; u64 config; if (pmc_is_gp(pmc)) { config = pmc->eventsel; select_os = config & ARCH_PERFMON_EVENTSEL_OS; select_user = config & ARCH_PERFMON_EVENTSEL_USR; } else { config = fixed_ctrl_field(pmc_to_pmu(pmc)->fixed_ctr_ctrl, pmc->idx - KVM_FIXED_PMC_BASE_IDX); select_os = config & 0x1; select_user = config & 0x2; } /* * Skip the CPL lookup, which isn't free on Intel, if the result will * be the same regardless of the CPL. */ if (select_os == select_user) return select_os; return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? select_os : select_user; } void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 eventsel) { DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; int i; BUILD_BUG_ON(sizeof(pmu->global_ctrl) * BITS_PER_BYTE != X86_PMC_IDX_MAX); if (!kvm_pmu_has_perf_global_ctrl(pmu)) bitmap_copy(bitmap, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX); else if (!bitmap_and(bitmap, pmu->all_valid_pmc_idx, (unsigned long *)&pmu->global_ctrl, X86_PMC_IDX_MAX)) return; kvm_for_each_pmc(pmu, pmc, i, bitmap) { /* * Ignore checks for edge detect (all events currently emulated * but KVM are always rising edges), pin control (unsupported * by modern CPUs), and counter mask and its invert flag (KVM * doesn't emulate multiple events in a single clock cycle). * * Note, the uppermost nibble of AMD's mask overlaps Intel's * IN_TX (bit 32) and IN_TXCP (bit 33), as well as two reserved * bits (bits 35:34). Checking the "in HLE/RTM transaction" * flags is correct as the vCPU can't be in a transaction if * KVM is emulating an instruction. Checking the reserved bits * might be wrong if they are defined in the future, but so * could ignoring them, so do the simple thing for now. */ if (((pmc->eventsel ^ eventsel) & AMD64_RAW_EVENT_MASK_NB) || !pmc_event_is_allowed(pmc) || !cpl_is_matched(pmc)) continue; kvm_pmu_incr_counter(pmc); } } EXPORT_SYMBOL_GPL(kvm_pmu_trigger_event); static bool is_masked_filter_valid(const struct kvm_x86_pmu_event_filter *filter) { u64 mask = kvm_pmu_ops.EVENTSEL_EVENT | KVM_PMU_MASKED_ENTRY_UMASK_MASK | KVM_PMU_MASKED_ENTRY_UMASK_MATCH | KVM_PMU_MASKED_ENTRY_EXCLUDE; int i; for (i = 0; i < filter->nevents; i++) { if (filter->events[i] & ~mask) return false; } return true; } static void convert_to_masked_filter(struct kvm_x86_pmu_event_filter *filter) { int i, j; for (i = 0, j = 0; i < filter->nevents; i++) { /* * Skip events that are impossible to match against a guest * event. When filtering, only the event select + unit mask * of the guest event is used. To maintain backwards * compatibility, impossible filters can't be rejected :-( */ if (filter->events[i] & ~(kvm_pmu_ops.EVENTSEL_EVENT | ARCH_PERFMON_EVENTSEL_UMASK)) continue; /* * Convert userspace events to a common in-kernel event so * only one code path is needed to support both events. For * the in-kernel events use masked events because they are * flexible enough to handle both cases. To convert to masked * events all that's needed is to add an "all ones" umask_mask, * (unmasked filter events don't support EXCLUDE). */ filter->events[j++] = filter->events[i] | (0xFFULL << KVM_PMU_MASKED_ENTRY_UMASK_MASK_SHIFT); } filter->nevents = j; } static int prepare_filter_lists(struct kvm_x86_pmu_event_filter *filter) { int i; if (!(filter->flags & KVM_PMU_EVENT_FLAG_MASKED_EVENTS)) convert_to_masked_filter(filter); else if (!is_masked_filter_valid(filter)) return -EINVAL; /* * Sort entries by event select and includes vs. excludes so that all * entries for a given event select can be processed efficiently during * filtering. The EXCLUDE flag uses a more significant bit than the * event select, and so the sorted list is also effectively split into * includes and excludes sub-lists. */ sort(&filter->events, filter->nevents, sizeof(filter->events[0]), filter_sort_cmp, NULL); i = filter->nevents; /* Find the first EXCLUDE event (only supported for masked events). */ if (filter->flags & KVM_PMU_EVENT_FLAG_MASKED_EVENTS) { for (i = 0; i < filter->nevents; i++) { if (filter->events[i] & KVM_PMU_MASKED_ENTRY_EXCLUDE) break; } } filter->nr_includes = i; filter->nr_excludes = filter->nevents - filter->nr_includes; filter->includes = filter->events; filter->excludes = filter->events + filter->nr_includes; return 0; } int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp) { struct kvm_pmu_event_filter __user *user_filter = argp; struct kvm_x86_pmu_event_filter *filter; struct kvm_pmu_event_filter tmp; struct kvm_vcpu *vcpu; unsigned long i; size_t size; int r; if (copy_from_user(&tmp, user_filter, sizeof(tmp))) return -EFAULT; if (tmp.action != KVM_PMU_EVENT_ALLOW && tmp.action != KVM_PMU_EVENT_DENY) return -EINVAL; if (tmp.flags & ~KVM_PMU_EVENT_FLAGS_VALID_MASK) return -EINVAL; if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS) return -E2BIG; size = struct_size(filter, events, tmp.nevents); filter = kzalloc(size, GFP_KERNEL_ACCOUNT); if (!filter) return -ENOMEM; filter->action = tmp.action; filter->nevents = tmp.nevents; filter->fixed_counter_bitmap = tmp.fixed_counter_bitmap; filter->flags = tmp.flags; r = -EFAULT; if (copy_from_user(filter->events, user_filter->events, sizeof(filter->events[0]) * filter->nevents)) goto cleanup; r = prepare_filter_lists(filter); if (r) goto cleanup; mutex_lock(&kvm->lock); filter = rcu_replace_pointer(kvm->arch.pmu_event_filter, filter, mutex_is_locked(&kvm->lock)); mutex_unlock(&kvm->lock); synchronize_srcu_expedited(&kvm->srcu); BUILD_BUG_ON(sizeof(((struct kvm_pmu *)0)->reprogram_pmi) > sizeof(((struct kvm_pmu *)0)->__reprogram_pmi)); kvm_for_each_vcpu(i, vcpu, kvm) atomic64_set(&vcpu_to_pmu(vcpu)->__reprogram_pmi, -1ull); kvm_make_all_cpus_request(kvm, KVM_REQ_PMU); r = 0; cleanup: kfree(filter); return r; }