linux/arch/x86/kvm/pmu.c
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   1/*
   2 * Kernel-based Virtual Machine -- Performance Monitoring Unit support
   3 *
   4 * Copyright 2011 Red Hat, Inc. and/or its affiliates.
   5 *
   6 * Authors:
   7 *   Avi Kivity   <avi@redhat.com>
   8 *   Gleb Natapov <gleb@redhat.com>
   9 *
  10 * This work is licensed under the terms of the GNU GPL, version 2.  See
  11 * the COPYING file in the top-level directory.
  12 *
  13 */
  14
  15#include <linux/types.h>
  16#include <linux/kvm_host.h>
  17#include <linux/perf_event.h>
  18#include "x86.h"
  19#include "cpuid.h"
  20#include "lapic.h"
  21
  22static struct kvm_arch_event_perf_mapping {
  23        u8 eventsel;
  24        u8 unit_mask;
  25        unsigned event_type;
  26        bool inexact;
  27} arch_events[] = {
  28        /* Index must match CPUID 0x0A.EBX bit vector */
  29        [0] = { 0x3c, 0x00, PERF_COUNT_HW_CPU_CYCLES },
  30        [1] = { 0xc0, 0x00, PERF_COUNT_HW_INSTRUCTIONS },
  31        [2] = { 0x3c, 0x01, PERF_COUNT_HW_BUS_CYCLES  },
  32        [3] = { 0x2e, 0x4f, PERF_COUNT_HW_CACHE_REFERENCES },
  33        [4] = { 0x2e, 0x41, PERF_COUNT_HW_CACHE_MISSES },
  34        [5] = { 0xc4, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
  35        [6] = { 0xc5, 0x00, PERF_COUNT_HW_BRANCH_MISSES },
  36        [7] = { 0x00, 0x30, PERF_COUNT_HW_REF_CPU_CYCLES },
  37};
  38
  39/* mapping between fixed pmc index and arch_events array */
  40int fixed_pmc_events[] = {1, 0, 7};
  41
  42static bool pmc_is_gp(struct kvm_pmc *pmc)
  43{
  44        return pmc->type == KVM_PMC_GP;
  45}
  46
  47static inline u64 pmc_bitmask(struct kvm_pmc *pmc)
  48{
  49        struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
  50
  51        return pmu->counter_bitmask[pmc->type];
  52}
  53
  54static inline bool pmc_enabled(struct kvm_pmc *pmc)
  55{
  56        struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
  57        return test_bit(pmc->idx, (unsigned long *)&pmu->global_ctrl);
  58}
  59
  60static inline struct kvm_pmc *get_gp_pmc(struct kvm_pmu *pmu, u32 msr,
  61                                         u32 base)
  62{
  63        if (msr >= base && msr < base + pmu->nr_arch_gp_counters)
  64                return &pmu->gp_counters[msr - base];
  65        return NULL;
  66}
  67
  68static inline struct kvm_pmc *get_fixed_pmc(struct kvm_pmu *pmu, u32 msr)
  69{
  70        int base = MSR_CORE_PERF_FIXED_CTR0;
  71        if (msr >= base && msr < base + pmu->nr_arch_fixed_counters)
  72                return &pmu->fixed_counters[msr - base];
  73        return NULL;
  74}
  75
  76static inline struct kvm_pmc *get_fixed_pmc_idx(struct kvm_pmu *pmu, int idx)
  77{
  78        return get_fixed_pmc(pmu, MSR_CORE_PERF_FIXED_CTR0 + idx);
  79}
  80
  81static struct kvm_pmc *global_idx_to_pmc(struct kvm_pmu *pmu, int idx)
  82{
  83        if (idx < INTEL_PMC_IDX_FIXED)
  84                return get_gp_pmc(pmu, MSR_P6_EVNTSEL0 + idx, MSR_P6_EVNTSEL0);
  85        else
  86                return get_fixed_pmc_idx(pmu, idx - INTEL_PMC_IDX_FIXED);
  87}
  88
  89void kvm_deliver_pmi(struct kvm_vcpu *vcpu)
  90{
  91        if (vcpu->arch.apic)
  92                kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
  93}
  94
  95static void trigger_pmi(struct irq_work *irq_work)
  96{
  97        struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu,
  98                        irq_work);
  99        struct kvm_vcpu *vcpu = container_of(pmu, struct kvm_vcpu,
 100                        arch.pmu);
 101
 102        kvm_deliver_pmi(vcpu);
 103}
 104
 105static void kvm_perf_overflow(struct perf_event *perf_event,
 106                              struct perf_sample_data *data,
 107                              struct pt_regs *regs)
 108{
 109        struct kvm_pmc *pmc = perf_event->overflow_handler_context;
 110        struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
 111        __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
 112}
 113
 114static void kvm_perf_overflow_intr(struct perf_event *perf_event,
 115                struct perf_sample_data *data, struct pt_regs *regs)
 116{
 117        struct kvm_pmc *pmc = perf_event->overflow_handler_context;
 118        struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
 119        if (!test_and_set_bit(pmc->idx, (unsigned long *)&pmu->reprogram_pmi)) {
 120                kvm_perf_overflow(perf_event, data, regs);
 121                kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
 122                /*
 123                 * Inject PMI. If vcpu was in a guest mode during NMI PMI
 124                 * can be ejected on a guest mode re-entry. Otherwise we can't
 125                 * be sure that vcpu wasn't executing hlt instruction at the
 126                 * time of vmexit and is not going to re-enter guest mode until,
 127                 * woken up. So we should wake it, but this is impossible from
 128                 * NMI context. Do it from irq work instead.
 129                 */
 130                if (!kvm_is_in_guest())
 131                        irq_work_queue(&pmc->vcpu->arch.pmu.irq_work);
 132                else
 133                        kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
 134        }
 135}
 136
 137static u64 read_pmc(struct kvm_pmc *pmc)
 138{
 139        u64 counter, enabled, running;
 140
 141        counter = pmc->counter;
 142
 143        if (pmc->perf_event)
 144                counter += perf_event_read_value(pmc->perf_event,
 145                                                 &enabled, &running);
 146
 147        /* FIXME: Scaling needed? */
 148
 149        return counter & pmc_bitmask(pmc);
 150}
 151
 152static void stop_counter(struct kvm_pmc *pmc)
 153{
 154        if (pmc->perf_event) {
 155                pmc->counter = read_pmc(pmc);
 156                perf_event_release_kernel(pmc->perf_event);
 157                pmc->perf_event = NULL;
 158        }
 159}
 160
 161static void reprogram_counter(struct kvm_pmc *pmc, u32 type,
 162                unsigned config, bool exclude_user, bool exclude_kernel,
 163                bool intr, bool in_tx, bool in_tx_cp)
 164{
 165        struct perf_event *event;
 166        struct perf_event_attr attr = {
 167                .type = type,
 168                .size = sizeof(attr),
 169                .pinned = true,
 170                .exclude_idle = true,
 171                .exclude_host = 1,
 172                .exclude_user = exclude_user,
 173                .exclude_kernel = exclude_kernel,
 174                .config = config,
 175        };
 176        if (in_tx)
 177                attr.config |= HSW_IN_TX;
 178        if (in_tx_cp)
 179                attr.config |= HSW_IN_TX_CHECKPOINTED;
 180
 181        attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc);
 182
 183        event = perf_event_create_kernel_counter(&attr, -1, current,
 184                                                 intr ? kvm_perf_overflow_intr :
 185                                                 kvm_perf_overflow, pmc);
 186        if (IS_ERR(event)) {
 187                printk_once("kvm: pmu event creation failed %ld\n",
 188                                PTR_ERR(event));
 189                return;
 190        }
 191
 192        pmc->perf_event = event;
 193        clear_bit(pmc->idx, (unsigned long*)&pmc->vcpu->arch.pmu.reprogram_pmi);
 194}
 195
 196static unsigned find_arch_event(struct kvm_pmu *pmu, u8 event_select,
 197                u8 unit_mask)
 198{
 199        int i;
 200
 201        for (i = 0; i < ARRAY_SIZE(arch_events); i++)
 202                if (arch_events[i].eventsel == event_select
 203                                && arch_events[i].unit_mask == unit_mask
 204                                && (pmu->available_event_types & (1 << i)))
 205                        break;
 206
 207        if (i == ARRAY_SIZE(arch_events))
 208                return PERF_COUNT_HW_MAX;
 209
 210        return arch_events[i].event_type;
 211}
 212
 213static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
 214{
 215        unsigned config, type = PERF_TYPE_RAW;
 216        u8 event_select, unit_mask;
 217
 218        if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
 219                printk_once("kvm pmu: pin control bit is ignored\n");
 220
 221        pmc->eventsel = eventsel;
 222
 223        stop_counter(pmc);
 224
 225        if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_enabled(pmc))
 226                return;
 227
 228        event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
 229        unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 230
 231        if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
 232                                ARCH_PERFMON_EVENTSEL_INV |
 233                                ARCH_PERFMON_EVENTSEL_CMASK |
 234                                HSW_IN_TX |
 235                                HSW_IN_TX_CHECKPOINTED))) {
 236                config = find_arch_event(&pmc->vcpu->arch.pmu, event_select,
 237                                unit_mask);
 238                if (config != PERF_COUNT_HW_MAX)
 239                        type = PERF_TYPE_HARDWARE;
 240        }
 241
 242        if (type == PERF_TYPE_RAW)
 243                config = eventsel & X86_RAW_EVENT_MASK;
 244
 245        reprogram_counter(pmc, type, config,
 246                        !(eventsel & ARCH_PERFMON_EVENTSEL_USR),
 247                        !(eventsel & ARCH_PERFMON_EVENTSEL_OS),
 248                        eventsel & ARCH_PERFMON_EVENTSEL_INT,
 249                        (eventsel & HSW_IN_TX),
 250                        (eventsel & HSW_IN_TX_CHECKPOINTED));
 251}
 252
 253static void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 en_pmi, int idx)
 254{
 255        unsigned en = en_pmi & 0x3;
 256        bool pmi = en_pmi & 0x8;
 257
 258        stop_counter(pmc);
 259
 260        if (!en || !pmc_enabled(pmc))
 261                return;
 262
 263        reprogram_counter(pmc, PERF_TYPE_HARDWARE,
 264                        arch_events[fixed_pmc_events[idx]].event_type,
 265                        !(en & 0x2), /* exclude user */
 266                        !(en & 0x1), /* exclude kernel */
 267                        pmi, false, false);
 268}
 269
 270static inline u8 fixed_en_pmi(u64 ctrl, int idx)
 271{
 272        return (ctrl >> (idx * 4)) & 0xf;
 273}
 274
 275static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
 276{
 277        int i;
 278
 279        for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
 280                u8 en_pmi = fixed_en_pmi(data, i);
 281                struct kvm_pmc *pmc = get_fixed_pmc_idx(pmu, i);
 282
 283                if (fixed_en_pmi(pmu->fixed_ctr_ctrl, i) == en_pmi)
 284                        continue;
 285
 286                reprogram_fixed_counter(pmc, en_pmi, i);
 287        }
 288
 289        pmu->fixed_ctr_ctrl = data;
 290}
 291
 292static void reprogram_idx(struct kvm_pmu *pmu, int idx)
 293{
 294        struct kvm_pmc *pmc = global_idx_to_pmc(pmu, idx);
 295
 296        if (!pmc)
 297                return;
 298
 299        if (pmc_is_gp(pmc))
 300                reprogram_gp_counter(pmc, pmc->eventsel);
 301        else {
 302                int fidx = idx - INTEL_PMC_IDX_FIXED;
 303                reprogram_fixed_counter(pmc,
 304                                fixed_en_pmi(pmu->fixed_ctr_ctrl, fidx), fidx);
 305        }
 306}
 307
 308static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data)
 309{
 310        int bit;
 311        u64 diff = pmu->global_ctrl ^ data;
 312
 313        pmu->global_ctrl = data;
 314
 315        for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX)
 316                reprogram_idx(pmu, bit);
 317}
 318
 319bool kvm_pmu_msr(struct kvm_vcpu *vcpu, u32 msr)
 320{
 321        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 322        int ret;
 323
 324        switch (msr) {
 325        case MSR_CORE_PERF_FIXED_CTR_CTRL:
 326        case MSR_CORE_PERF_GLOBAL_STATUS:
 327        case MSR_CORE_PERF_GLOBAL_CTRL:
 328        case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 329                ret = pmu->version > 1;
 330                break;
 331        default:
 332                ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)
 333                        || get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0)
 334                        || get_fixed_pmc(pmu, msr);
 335                break;
 336        }
 337        return ret;
 338}
 339
 340int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data)
 341{
 342        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 343        struct kvm_pmc *pmc;
 344
 345        switch (index) {
 346        case MSR_CORE_PERF_FIXED_CTR_CTRL:
 347                *data = pmu->fixed_ctr_ctrl;
 348                return 0;
 349        case MSR_CORE_PERF_GLOBAL_STATUS:
 350                *data = pmu->global_status;
 351                return 0;
 352        case MSR_CORE_PERF_GLOBAL_CTRL:
 353                *data = pmu->global_ctrl;
 354                return 0;
 355        case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 356                *data = pmu->global_ovf_ctrl;
 357                return 0;
 358        default:
 359                if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) ||
 360                                (pmc = get_fixed_pmc(pmu, index))) {
 361                        *data = read_pmc(pmc);
 362                        return 0;
 363                } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) {
 364                        *data = pmc->eventsel;
 365                        return 0;
 366                }
 367        }
 368        return 1;
 369}
 370
 371int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 372{
 373        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 374        struct kvm_pmc *pmc;
 375        u32 index = msr_info->index;
 376        u64 data = msr_info->data;
 377
 378        switch (index) {
 379        case MSR_CORE_PERF_FIXED_CTR_CTRL:
 380                if (pmu->fixed_ctr_ctrl == data)
 381                        return 0;
 382                if (!(data & 0xfffffffffffff444ull)) {
 383                        reprogram_fixed_counters(pmu, data);
 384                        return 0;
 385                }
 386                break;
 387        case MSR_CORE_PERF_GLOBAL_STATUS:
 388                if (msr_info->host_initiated) {
 389                        pmu->global_status = data;
 390                        return 0;
 391                }
 392                break; /* RO MSR */
 393        case MSR_CORE_PERF_GLOBAL_CTRL:
 394                if (pmu->global_ctrl == data)
 395                        return 0;
 396                if (!(data & pmu->global_ctrl_mask)) {
 397                        global_ctrl_changed(pmu, data);
 398                        return 0;
 399                }
 400                break;
 401        case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 402                if (!(data & (pmu->global_ctrl_mask & ~(3ull<<62)))) {
 403                        if (!msr_info->host_initiated)
 404                                pmu->global_status &= ~data;
 405                        pmu->global_ovf_ctrl = data;
 406                        return 0;
 407                }
 408                break;
 409        default:
 410                if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) ||
 411                                (pmc = get_fixed_pmc(pmu, index))) {
 412                        if (!msr_info->host_initiated)
 413                                data = (s64)(s32)data;
 414                        pmc->counter += data - read_pmc(pmc);
 415                        return 0;
 416                } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) {
 417                        if (data == pmc->eventsel)
 418                                return 0;
 419                        if (!(data & pmu->reserved_bits)) {
 420                                reprogram_gp_counter(pmc, data);
 421                                return 0;
 422                        }
 423                }
 424        }
 425        return 1;
 426}
 427
 428int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data)
 429{
 430        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 431        bool fast_mode = pmc & (1u << 31);
 432        bool fixed = pmc & (1u << 30);
 433        struct kvm_pmc *counters;
 434        u64 ctr;
 435
 436        pmc &= ~(3u << 30);
 437        if (!fixed && pmc >= pmu->nr_arch_gp_counters)
 438                return 1;
 439        if (fixed && pmc >= pmu->nr_arch_fixed_counters)
 440                return 1;
 441        counters = fixed ? pmu->fixed_counters : pmu->gp_counters;
 442        ctr = read_pmc(&counters[pmc]);
 443        if (fast_mode)
 444                ctr = (u32)ctr;
 445        *data = ctr;
 446
 447        return 0;
 448}
 449
 450void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu)
 451{
 452        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 453        struct kvm_cpuid_entry2 *entry;
 454        unsigned bitmap_len;
 455
 456        pmu->nr_arch_gp_counters = 0;
 457        pmu->nr_arch_fixed_counters = 0;
 458        pmu->counter_bitmask[KVM_PMC_GP] = 0;
 459        pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
 460        pmu->version = 0;
 461        pmu->reserved_bits = 0xffffffff00200000ull;
 462
 463        entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
 464        if (!entry)
 465                return;
 466
 467        pmu->version = entry->eax & 0xff;
 468        if (!pmu->version)
 469                return;
 470
 471        pmu->nr_arch_gp_counters = min((int)(entry->eax >> 8) & 0xff,
 472                        INTEL_PMC_MAX_GENERIC);
 473        pmu->counter_bitmask[KVM_PMC_GP] =
 474                ((u64)1 << ((entry->eax >> 16) & 0xff)) - 1;
 475        bitmap_len = (entry->eax >> 24) & 0xff;
 476        pmu->available_event_types = ~entry->ebx & ((1ull << bitmap_len) - 1);
 477
 478        if (pmu->version == 1) {
 479                pmu->nr_arch_fixed_counters = 0;
 480        } else {
 481                pmu->nr_arch_fixed_counters = min((int)(entry->edx & 0x1f),
 482                                INTEL_PMC_MAX_FIXED);
 483                pmu->counter_bitmask[KVM_PMC_FIXED] =
 484                        ((u64)1 << ((entry->edx >> 5) & 0xff)) - 1;
 485        }
 486
 487        pmu->global_ctrl = ((1 << pmu->nr_arch_gp_counters) - 1) |
 488                (((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED);
 489        pmu->global_ctrl_mask = ~pmu->global_ctrl;
 490
 491        entry = kvm_find_cpuid_entry(vcpu, 7, 0);
 492        if (entry &&
 493            (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
 494            (entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM)))
 495                pmu->reserved_bits ^= HSW_IN_TX|HSW_IN_TX_CHECKPOINTED;
 496}
 497
 498void kvm_pmu_init(struct kvm_vcpu *vcpu)
 499{
 500        int i;
 501        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 502
 503        memset(pmu, 0, sizeof(*pmu));
 504        for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) {
 505                pmu->gp_counters[i].type = KVM_PMC_GP;
 506                pmu->gp_counters[i].vcpu = vcpu;
 507                pmu->gp_counters[i].idx = i;
 508        }
 509        for (i = 0; i < INTEL_PMC_MAX_FIXED; i++) {
 510                pmu->fixed_counters[i].type = KVM_PMC_FIXED;
 511                pmu->fixed_counters[i].vcpu = vcpu;
 512                pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
 513        }
 514        init_irq_work(&pmu->irq_work, trigger_pmi);
 515        kvm_pmu_cpuid_update(vcpu);
 516}
 517
 518void kvm_pmu_reset(struct kvm_vcpu *vcpu)
 519{
 520        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 521        int i;
 522
 523        irq_work_sync(&pmu->irq_work);
 524        for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) {
 525                struct kvm_pmc *pmc = &pmu->gp_counters[i];
 526                stop_counter(pmc);
 527                pmc->counter = pmc->eventsel = 0;
 528        }
 529
 530        for (i = 0; i < INTEL_PMC_MAX_FIXED; i++)
 531                stop_counter(&pmu->fixed_counters[i]);
 532
 533        pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status =
 534                pmu->global_ovf_ctrl = 0;
 535}
 536
 537void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
 538{
 539        kvm_pmu_reset(vcpu);
 540}
 541
 542void kvm_handle_pmu_event(struct kvm_vcpu *vcpu)
 543{
 544        struct kvm_pmu *pmu = &vcpu->arch.pmu;
 545        u64 bitmask;
 546        int bit;
 547
 548        bitmask = pmu->reprogram_pmi;
 549
 550        for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) {
 551                struct kvm_pmc *pmc = global_idx_to_pmc(pmu, bit);
 552
 553                if (unlikely(!pmc || !pmc->perf_event)) {
 554                        clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi);
 555                        continue;
 556                }
 557
 558                reprogram_idx(pmu, bit);
 559        }
 560}
 561