diff options
Diffstat (limited to 'arch/x86/kvm/pmu.c')
| -rw-r--r-- | arch/x86/kvm/pmu.c | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c new file mode 100644 index 000000000..20cd746cf --- /dev/null +++ b/arch/x86/kvm/pmu.c @@ -0,0 +1,623 @@ +// 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 <avi@redhat.com> + * Gleb Natapov <gleb@redhat.com> + * Wei Huang <wei@redhat.com> + */ + +#include <linux/types.h> +#include <linux/kvm_host.h> +#include <linux/perf_event.h> +#include <linux/bsearch.h> +#include <linux/sort.h> +#include <asm/perf_event.h> +#include <asm/cpu_device_id.h> +#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); + +static const struct x86_cpu_id vmx_icl_pebs_cpu[] = { + X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, NULL), + X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_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 + * [INTEL_PMC_IDX_FIXED .. INTEL_PMC_IDX_FIXED + 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 <asm/kvm-x86-pmu-ops.h> + +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 <asm/kvm-x86-pmu-ops.h> +#undef __KVM_X86_PMU_OP +} + +static inline bool pmc_is_enabled(struct kvm_pmc *pmc) +{ + return static_call(kvm_x86_pmu_pmc_is_enabled)(pmc); +} + +static void kvm_pmi_trigger_fn(struct irq_work *irq_work) +{ + struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work); + struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu); + + kvm_pmu_deliver_pmi(vcpu); +} + +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; + + /* Ignore counters that have been reprogrammed already. */ + if (test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) + return; + + 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); + } + kvm_make_request(KVM_REQ_PMU, pmc->vcpu); + + if (!pmc->intr || skip_pmi) + return; + + /* + * 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 (in_pmi && !kvm_handling_nmi_from_guest(pmc->vcpu)) + irq_work_queue(&pmc_to_pmu(pmc)->irq_work); + else + 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; + + __kvm_perf_overflow(pmc, true); +} + +static void 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) { + /* + * 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. + * + * 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. + * + * On Icelake everything is fine. Other hardware (GLC+, TNT+) that + * could possibly care here is unsupported and needs changes. + */ + attr.precise_ip = 1; + if (x86_match_cpu(vmx_icl_pebs_cpu) && pmc->idx == 32) + attr.precise_ip = 3; + } + + 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; + } + + pmc->perf_event = event; + pmc_to_pmu(pmc)->event_count++; + clear_bit(pmc->idx, pmc_to_pmu(pmc)->reprogram_pmi); + pmc->is_paused = false; + pmc->intr = intr || pebs; +} + +static void pmc_pause_counter(struct kvm_pmc *pmc) +{ + u64 counter = pmc->counter; + + if (!pmc->perf_event || pmc->is_paused) + return; + + /* update counter, reset event value to avoid redundant accumulation */ + counter += perf_event_pause(pmc->perf_event, true); + pmc->counter = counter & pmc_bitmask(pmc); + pmc->is_paused = true; +} + +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 (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; + + clear_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->reprogram_pmi); + return true; +} + +static int cmp_u64(const void *pa, const void *pb) +{ + u64 a = *(u64 *)pa; + u64 b = *(u64 *)pb; + + return (a > b) - (a < b); +} + +static bool check_pmu_event_filter(struct kvm_pmc *pmc) +{ + struct kvm_pmu_event_filter *filter; + struct kvm *kvm = pmc->vcpu->kvm; + bool allow_event = true; + __u64 key; + int idx; + + if (!static_call(kvm_x86_pmu_hw_event_available)(pmc)) + return false; + + filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu); + if (!filter) + goto out; + + if (pmc_is_gp(pmc)) { + key = pmc->eventsel & AMD64_RAW_EVENT_MASK_NB; + if (bsearch(&key, filter->events, filter->nevents, + sizeof(__u64), cmp_u64)) + allow_event = filter->action == KVM_PMU_EVENT_ALLOW; + else + allow_event = filter->action == KVM_PMU_EVENT_DENY; + } else { + idx = pmc->idx - INTEL_PMC_IDX_FIXED; + if (filter->action == KVM_PMU_EVENT_DENY && + test_bit(idx, (ulong *)&filter->fixed_counter_bitmap)) + allow_event = false; + if (filter->action == KVM_PMU_EVENT_ALLOW && + !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap)) + allow_event = false; + } + +out: + return allow_event; +} + +void reprogram_counter(struct kvm_pmc *pmc) +{ + struct kvm_pmu *pmu = pmc_to_pmu(pmc); + u64 eventsel = pmc->eventsel; + u64 new_config = eventsel; + u8 fixed_ctr_ctrl; + + pmc_pause_counter(pmc); + + if (!pmc_speculative_in_use(pmc) || !pmc_is_enabled(pmc)) + return; + + if (!check_pmu_event_filter(pmc)) + return; + + 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 - INTEL_PMC_IDX_FIXED); + 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; + + pmc_release_perf_event(pmc); + + pmc->current_config = new_config; + 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); +} +EXPORT_SYMBOL_GPL(reprogram_counter); + +void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) +{ + struct kvm_pmu *pmu = vcpu_to_pmu(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); + + if (unlikely(!pmc || !pmc->perf_event)) { + clear_bit(bit, pmu->reprogram_pmi); + continue; + } + reprogram_counter(pmc); + } + + /* + * 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); +} + +/* check if idx is a valid index to access PMU */ +bool kvm_pmu_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) +{ + return static_call(kvm_x86_pmu_is_valid_rdpmc_ecx)(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) +{ + bool fast_mode = idx & (1u << 31); + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + struct kvm_pmc *pmc; + u64 mask = fast_mode ? ~0u : ~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_read_cr4_bits(vcpu, X86_CR4_PCE)) && + (static_call(kvm_x86_get_cpl)(vcpu) != 0) && + (kvm_read_cr0_bits(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) +{ + 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) +{ + return static_call(kvm_x86_pmu_get_msr)(vcpu, msr_info); +} + +int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) +{ + kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index); + return static_call(kvm_x86_pmu_set_msr)(vcpu, msr_info); +} + +/* refresh PMU settings. This function generally is called when underlying + * settings are changed (such as changes of PMU CPUID by guest VMs), which + * should rarely happen. + */ +void kvm_pmu_refresh(struct kvm_vcpu *vcpu) +{ + static_call(kvm_x86_pmu_refresh)(vcpu); +} + +void kvm_pmu_reset(struct kvm_vcpu *vcpu) +{ + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + + irq_work_sync(&pmu->irq_work); + static_call(kvm_x86_pmu_reset)(vcpu); +} + +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); + init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn); + pmu->event_count = 0; + pmu->need_cleanup = false; + 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); + + for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) { + pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + + if (pmc && 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) +{ + u64 prev_count; + + prev_count = pmc->counter; + pmc->counter = (pmc->counter + 1) & pmc_bitmask(pmc); + + reprogram_counter(pmc); + if (pmc->counter < prev_count) + __kvm_perf_overflow(pmc, false); +} + +static inline bool eventsel_match_perf_hw_id(struct kvm_pmc *pmc, + unsigned int perf_hw_id) +{ + return !((pmc->eventsel ^ perf_get_hw_event_config(perf_hw_id)) & + AMD64_RAW_EVENT_MASK_NB); +} + +static inline bool cpl_is_matched(struct kvm_pmc *pmc) +{ + bool select_os, select_user; + u64 config = pmc->current_config; + + if (pmc_is_gp(pmc)) { + select_os = config & ARCH_PERFMON_EVENTSEL_OS; + select_user = config & ARCH_PERFMON_EVENTSEL_USR; + } else { + select_os = config & 0x1; + select_user = config & 0x2; + } + + return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? select_os : select_user; +} + +void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) +{ + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + struct kvm_pmc *pmc; + 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); + + if (!pmc || !pmc_is_enabled(pmc) || !pmc_speculative_in_use(pmc)) + continue; + + /* Ignore checks for edge detect, pin control, invert and CMASK bits */ + if (eventsel_match_perf_hw_id(pmc, perf_hw_id) && cpl_is_matched(pmc)) + kvm_pmu_incr_counter(pmc); + } +} +EXPORT_SYMBOL_GPL(kvm_pmu_trigger_event); + +int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp) +{ + struct kvm_pmu_event_filter tmp, *filter; + size_t size; + int r; + + if (copy_from_user(&tmp, argp, sizeof(tmp))) + return -EFAULT; + + if (tmp.action != KVM_PMU_EVENT_ALLOW && + tmp.action != KVM_PMU_EVENT_DENY) + return -EINVAL; + + if (tmp.flags != 0) + return -EINVAL; + + if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS) + return -E2BIG; + + size = struct_size(filter, events, tmp.nevents); + filter = kmalloc(size, GFP_KERNEL_ACCOUNT); + if (!filter) + return -ENOMEM; + + r = -EFAULT; + if (copy_from_user(filter, argp, size)) + goto cleanup; + + /* Ensure nevents can't be changed between the user copies. */ + *filter = tmp; + + /* + * Sort the in-kernel list so that we can search it with bsearch. + */ + sort(&filter->events, filter->nevents, sizeof(__u64), cmp_u64, NULL); + + 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); + r = 0; +cleanup: + kfree(filter); + return r; +} |