From f5132b01386b5a67f1ff673bb2b96a507a3f7e41 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Thu, 10 Nov 2011 14:57:22 +0200 Subject: KVM: Expose a version 2 architectural PMU to a guests Use perf_events to emulate an architectural PMU, version 2. Based on PMU version 1 emulation by Avi Kivity. [avi: adjust for cpuid.c] [jan: fix anonymous field initialization for older gcc] Signed-off-by: Gleb Natapov Signed-off-by: Jan Kiszka Signed-off-by: Avi Kivity --- arch/x86/kvm/pmu.c | 533 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 533 insertions(+) create mode 100644 arch/x86/kvm/pmu.c (limited to 'arch/x86/kvm/pmu.c') diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c new file mode 100644 index 000000000000..7aad5446f393 --- /dev/null +++ b/arch/x86/kvm/pmu.c @@ -0,0 +1,533 @@ +/* + * Kernel-based Virtual Machine -- Performane Monitoring Unit support + * + * Copyright 2011 Red Hat, Inc. and/or its affiliates. + * + * Authors: + * Avi Kivity + * Gleb Natapov + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include +#include +#include +#include "x86.h" +#include "cpuid.h" +#include "lapic.h" + +static struct kvm_arch_event_perf_mapping { + u8 eventsel; + u8 unit_mask; + unsigned event_type; + bool inexact; +} arch_events[] = { + /* Index must match CPUID 0x0A.EBX bit vector */ + [0] = { 0x3c, 0x00, PERF_COUNT_HW_CPU_CYCLES }, + [1] = { 0xc0, 0x00, PERF_COUNT_HW_INSTRUCTIONS }, + [2] = { 0x3c, 0x01, PERF_COUNT_HW_BUS_CYCLES }, + [3] = { 0x2e, 0x4f, PERF_COUNT_HW_CACHE_REFERENCES }, + [4] = { 0x2e, 0x41, PERF_COUNT_HW_CACHE_MISSES }, + [5] = { 0xc4, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS }, + [6] = { 0xc5, 0x00, PERF_COUNT_HW_BRANCH_MISSES }, +}; + +/* mapping between fixed pmc index and arch_events array */ +int fixed_pmc_events[] = {1, 0, 2}; + +static bool pmc_is_gp(struct kvm_pmc *pmc) +{ + return pmc->type == KVM_PMC_GP; +} + +static inline u64 pmc_bitmask(struct kvm_pmc *pmc) +{ + struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu; + + return pmu->counter_bitmask[pmc->type]; +} + +static inline bool pmc_enabled(struct kvm_pmc *pmc) +{ + struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu; + return test_bit(pmc->idx, (unsigned long *)&pmu->global_ctrl); +} + +static inline struct kvm_pmc *get_gp_pmc(struct kvm_pmu *pmu, u32 msr, + u32 base) +{ + if (msr >= base && msr < base + pmu->nr_arch_gp_counters) + return &pmu->gp_counters[msr - base]; + return NULL; +} + +static inline struct kvm_pmc *get_fixed_pmc(struct kvm_pmu *pmu, u32 msr) +{ + int base = MSR_CORE_PERF_FIXED_CTR0; + if (msr >= base && msr < base + pmu->nr_arch_fixed_counters) + return &pmu->fixed_counters[msr - base]; + return NULL; +} + +static inline struct kvm_pmc *get_fixed_pmc_idx(struct kvm_pmu *pmu, int idx) +{ + return get_fixed_pmc(pmu, MSR_CORE_PERF_FIXED_CTR0 + idx); +} + +static struct kvm_pmc *global_idx_to_pmc(struct kvm_pmu *pmu, int idx) +{ + if (idx < X86_PMC_IDX_FIXED) + return get_gp_pmc(pmu, MSR_P6_EVNTSEL0 + idx, MSR_P6_EVNTSEL0); + else + return get_fixed_pmc_idx(pmu, idx - X86_PMC_IDX_FIXED); +} + +void kvm_deliver_pmi(struct kvm_vcpu *vcpu) +{ + if (vcpu->arch.apic) + kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC); +} + +static void trigger_pmi(struct irq_work *irq_work) +{ + struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, + irq_work); + struct kvm_vcpu *vcpu = container_of(pmu, struct kvm_vcpu, + arch.pmu); + + kvm_deliver_pmi(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; + struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu; + __set_bit(pmc->idx, (unsigned long *)&pmu->global_status); +} + +static void kvm_perf_overflow_intr(struct perf_event *perf_event, + struct perf_sample_data *data, struct pt_regs *regs) +{ + struct kvm_pmc *pmc = perf_event->overflow_handler_context; + struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu; + if (!test_and_set_bit(pmc->idx, (unsigned long *)&pmu->reprogram_pmi)) { + kvm_perf_overflow(perf_event, data, regs); + kvm_make_request(KVM_REQ_PMU, pmc->vcpu); + /* + * Inject PMI. If vcpu was in a guest mode during NMI PMI + * can be ejected on a guest mode re-entry. Otherwise we can't + * be sure that vcpu wasn't executing hlt instruction at the + * time of vmexit and is not going to re-enter guest mode until, + * woken up. So we should wake it, but this is impossible from + * NMI context. Do it from irq work instead. + */ + if (!kvm_is_in_guest()) + irq_work_queue(&pmc->vcpu->arch.pmu.irq_work); + else + kvm_make_request(KVM_REQ_PMI, pmc->vcpu); + } +} + +static u64 read_pmc(struct kvm_pmc *pmc) +{ + u64 counter, enabled, running; + + counter = pmc->counter; + + if (pmc->perf_event) + counter += perf_event_read_value(pmc->perf_event, + &enabled, &running); + + /* FIXME: Scaling needed? */ + + return counter & pmc_bitmask(pmc); +} + +static void stop_counter(struct kvm_pmc *pmc) +{ + if (pmc->perf_event) { + pmc->counter = read_pmc(pmc); + perf_event_release_kernel(pmc->perf_event); + pmc->perf_event = NULL; + } +} + +static void reprogram_counter(struct kvm_pmc *pmc, u32 type, + unsigned config, bool exclude_user, bool exclude_kernel, + bool intr) +{ + 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, + }; + + attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc); + + event = perf_event_create_kernel_counter(&attr, -1, current, + intr ? kvm_perf_overflow_intr : + kvm_perf_overflow, pmc); + if (IS_ERR(event)) { + printk_once("kvm: pmu event creation failed %ld\n", + PTR_ERR(event)); + return; + } + + pmc->perf_event = event; + clear_bit(pmc->idx, (unsigned long*)&pmc->vcpu->arch.pmu.reprogram_pmi); +} + +static unsigned find_arch_event(struct kvm_pmu *pmu, u8 event_select, + u8 unit_mask) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(arch_events); i++) + if (arch_events[i].eventsel == event_select + && arch_events[i].unit_mask == unit_mask + && (pmu->available_event_types & (1 << i))) + break; + + if (i == ARRAY_SIZE(arch_events)) + return PERF_COUNT_HW_MAX; + + return arch_events[i].event_type; +} + +static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel) +{ + unsigned config, type = PERF_TYPE_RAW; + u8 event_select, unit_mask; + + pmc->eventsel = eventsel; + + stop_counter(pmc); + + if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_enabled(pmc)) + return; + + event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT; + unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8; + + if (!(event_select & (ARCH_PERFMON_EVENTSEL_EDGE | + ARCH_PERFMON_EVENTSEL_INV | + ARCH_PERFMON_EVENTSEL_CMASK))) { + config = find_arch_event(&pmc->vcpu->arch.pmu, event_select, + unit_mask); + if (config != PERF_COUNT_HW_MAX) + type = PERF_TYPE_HARDWARE; + } + + if (type == PERF_TYPE_RAW) + config = eventsel & X86_RAW_EVENT_MASK; + + reprogram_counter(pmc, type, config, + !(eventsel & ARCH_PERFMON_EVENTSEL_USR), + !(eventsel & ARCH_PERFMON_EVENTSEL_OS), + eventsel & ARCH_PERFMON_EVENTSEL_INT); +} + +static void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 en_pmi, int idx) +{ + unsigned en = en_pmi & 0x3; + bool pmi = en_pmi & 0x8; + + stop_counter(pmc); + + if (!en || !pmc_enabled(pmc)) + return; + + reprogram_counter(pmc, PERF_TYPE_HARDWARE, + arch_events[fixed_pmc_events[idx]].event_type, + !(en & 0x2), /* exclude user */ + !(en & 0x1), /* exclude kernel */ + pmi); +} + +static inline u8 fixed_en_pmi(u64 ctrl, int idx) +{ + return (ctrl >> (idx * 4)) & 0xf; +} + +static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) +{ + int i; + + for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { + u8 en_pmi = fixed_en_pmi(data, i); + struct kvm_pmc *pmc = get_fixed_pmc_idx(pmu, i); + + if (fixed_en_pmi(pmu->fixed_ctr_ctrl, i) == en_pmi) + continue; + + reprogram_fixed_counter(pmc, en_pmi, i); + } + + pmu->fixed_ctr_ctrl = data; +} + +static void reprogram_idx(struct kvm_pmu *pmu, int idx) +{ + struct kvm_pmc *pmc = global_idx_to_pmc(pmu, idx); + + if (!pmc) + return; + + if (pmc_is_gp(pmc)) + reprogram_gp_counter(pmc, pmc->eventsel); + else { + int fidx = idx - X86_PMC_IDX_FIXED; + reprogram_fixed_counter(pmc, + fixed_en_pmi(pmu->fixed_ctr_ctrl, fidx), fidx); + } +} + +static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data) +{ + int bit; + u64 diff = pmu->global_ctrl ^ data; + + pmu->global_ctrl = data; + + for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX) + reprogram_idx(pmu, bit); +} + +bool kvm_pmu_msr(struct kvm_vcpu *vcpu, u32 msr) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + int ret; + + switch (msr) { + case MSR_CORE_PERF_FIXED_CTR_CTRL: + case MSR_CORE_PERF_GLOBAL_STATUS: + case MSR_CORE_PERF_GLOBAL_CTRL: + case MSR_CORE_PERF_GLOBAL_OVF_CTRL: + ret = pmu->version > 1; + break; + default: + ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) + || get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) + || get_fixed_pmc(pmu, msr); + break; + } + return ret; +} + +int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + struct kvm_pmc *pmc; + + switch (index) { + case MSR_CORE_PERF_FIXED_CTR_CTRL: + *data = pmu->fixed_ctr_ctrl; + return 0; + case MSR_CORE_PERF_GLOBAL_STATUS: + *data = pmu->global_status; + return 0; + case MSR_CORE_PERF_GLOBAL_CTRL: + *data = pmu->global_ctrl; + return 0; + case MSR_CORE_PERF_GLOBAL_OVF_CTRL: + *data = pmu->global_ovf_ctrl; + return 0; + default: + if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) || + (pmc = get_fixed_pmc(pmu, index))) { + *data = read_pmc(pmc); + return 0; + } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) { + *data = pmc->eventsel; + return 0; + } + } + return 1; +} + +int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + struct kvm_pmc *pmc; + + switch (index) { + case MSR_CORE_PERF_FIXED_CTR_CTRL: + if (pmu->fixed_ctr_ctrl == data) + return 0; + if (!(data & 0xfffffffffffff444)) { + reprogram_fixed_counters(pmu, data); + return 0; + } + break; + case MSR_CORE_PERF_GLOBAL_STATUS: + break; /* RO MSR */ + case MSR_CORE_PERF_GLOBAL_CTRL: + if (pmu->global_ctrl == data) + return 0; + if (!(data & pmu->global_ctrl_mask)) { + global_ctrl_changed(pmu, data); + return 0; + } + break; + case MSR_CORE_PERF_GLOBAL_OVF_CTRL: + if (!(data & (pmu->global_ctrl_mask & ~(3ull<<62)))) { + pmu->global_status &= ~data; + pmu->global_ovf_ctrl = data; + return 0; + } + break; + default: + if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) || + (pmc = get_fixed_pmc(pmu, index))) { + data = (s64)(s32)data; + pmc->counter += data - read_pmc(pmc); + return 0; + } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) { + if (data == pmc->eventsel) + return 0; + if (!(data & 0xffffffff00200000ull)) { + reprogram_gp_counter(pmc, data); + return 0; + } + } + } + return 1; +} + +int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + bool fast_mode = pmc & (1u << 31); + bool fixed = pmc & (1u << 30); + struct kvm_pmc *counters; + u64 ctr; + + pmc &= (3u << 30) - 1; + if (!fixed && pmc >= pmu->nr_arch_gp_counters) + return 1; + if (fixed && pmc >= pmu->nr_arch_fixed_counters) + return 1; + counters = fixed ? pmu->fixed_counters : pmu->gp_counters; + ctr = read_pmc(&counters[pmc]); + if (fast_mode) + ctr = (u32)ctr; + *data = ctr; + + return 0; +} + +void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + struct kvm_cpuid_entry2 *entry; + unsigned bitmap_len; + + 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->version = 0; + + entry = kvm_find_cpuid_entry(vcpu, 0xa, 0); + if (!entry) + return; + + pmu->version = entry->eax & 0xff; + if (!pmu->version) + return; + + pmu->nr_arch_gp_counters = min((int)(entry->eax >> 8) & 0xff, + X86_PMC_MAX_GENERIC); + pmu->counter_bitmask[KVM_PMC_GP] = + ((u64)1 << ((entry->eax >> 16) & 0xff)) - 1; + bitmap_len = (entry->eax >> 24) & 0xff; + pmu->available_event_types = ~entry->ebx & ((1ull << bitmap_len) - 1); + + if (pmu->version == 1) { + pmu->global_ctrl = (1 << pmu->nr_arch_gp_counters) - 1; + return; + } + + pmu->nr_arch_fixed_counters = min((int)(entry->edx & 0x1f), + X86_PMC_MAX_FIXED); + pmu->counter_bitmask[KVM_PMC_FIXED] = + ((u64)1 << ((entry->edx >> 5) & 0xff)) - 1; + pmu->global_ctrl_mask = ~(((1 << pmu->nr_arch_gp_counters) - 1) + | (((1ull << pmu->nr_arch_fixed_counters) - 1) + << X86_PMC_IDX_FIXED)); +} + +void kvm_pmu_init(struct kvm_vcpu *vcpu) +{ + int i; + struct kvm_pmu *pmu = &vcpu->arch.pmu; + + memset(pmu, 0, sizeof(*pmu)); + for (i = 0; i < X86_PMC_MAX_GENERIC; i++) { + pmu->gp_counters[i].type = KVM_PMC_GP; + pmu->gp_counters[i].vcpu = vcpu; + pmu->gp_counters[i].idx = i; + } + for (i = 0; i < X86_PMC_MAX_FIXED; i++) { + pmu->fixed_counters[i].type = KVM_PMC_FIXED; + pmu->fixed_counters[i].vcpu = vcpu; + pmu->fixed_counters[i].idx = i + X86_PMC_IDX_FIXED; + } + init_irq_work(&pmu->irq_work, trigger_pmi); + kvm_pmu_cpuid_update(vcpu); +} + +void kvm_pmu_reset(struct kvm_vcpu *vcpu) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + int i; + + irq_work_sync(&pmu->irq_work); + for (i = 0; i < X86_PMC_MAX_GENERIC; i++) { + struct kvm_pmc *pmc = &pmu->gp_counters[i]; + stop_counter(pmc); + pmc->counter = pmc->eventsel = 0; + } + + for (i = 0; i < X86_PMC_MAX_FIXED; i++) + stop_counter(&pmu->fixed_counters[i]); + + pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = + pmu->global_ovf_ctrl = 0; +} + +void kvm_pmu_destroy(struct kvm_vcpu *vcpu) +{ + kvm_pmu_reset(vcpu); +} + +void kvm_handle_pmu_event(struct kvm_vcpu *vcpu) +{ + struct kvm_pmu *pmu = &vcpu->arch.pmu; + u64 bitmask; + int bit; + + bitmask = pmu->reprogram_pmi; + + for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) { + struct kvm_pmc *pmc = global_idx_to_pmc(pmu, bit); + + if (unlikely(!pmc || !pmc->perf_event)) { + clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi); + continue; + } + + reprogram_idx(pmu, bit); + } +} -- cgit v1.2.1