arch/x86/kvm/pmu.c

   1 /*
   2  * Kernel-based Virtual Machine -- Performane 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
  22 static 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 };
  37
  38 /* mapping between fixed pmc index and arch_events array */
  39 int fixed_pmc_events[] = {1, 0, 2};
  40
  41 static bool pmc_is_gp(struct kvm_pmc *pmc)
  42 {
  43         return pmc->type == KVM_PMC_GP;
  44 }
  45
  46 static inline u64 pmc_bitmask(struct kvm_pmc *pmc)
  47 {
  48         struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
  49
  50         return pmu->counter_bitmask[pmc->type];
  51 }
  52
  53 static inline bool pmc_enabled(struct kvm_pmc *pmc)
  54 {
  55         struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
  56         return test_bit(pmc->idx, (unsigned long *)&pmu->global_ctrl);
  57 }
  58
  59 static inline struct kvm_pmc *get_gp_pmc(struct kvm_pmu *pmu, u32 msr,
  60                                          u32 base)
  61 {
  62         if (msr >= base && msr < base + pmu->nr_arch_gp_counters)
  63                 return &pmu->gp_counters[msr - base];
  64         return NULL;
  65 }
  66
  67 static inline struct kvm_pmc *get_fixed_pmc(struct kvm_pmu *pmu, u32 msr)
  68 {
  69         int base = MSR_CORE_PERF_FIXED_CTR0;
  70         if (msr >= base && msr < base + pmu->nr_arch_fixed_counters)
  71                 return &pmu->fixed_counters[msr - base];
  72         return NULL;
  73 }
  74
  75 static inline struct kvm_pmc *get_fixed_pmc_idx(struct kvm_pmu *pmu, int idx)
  76 {
  77         return get_fixed_pmc(pmu, MSR_CORE_PERF_FIXED_CTR0 + idx);
  78 }
  79
  80 static struct kvm_pmc *global_idx_to_pmc(struct kvm_pmu *pmu, int idx)
  81 {
  82         if (idx < X86_PMC_IDX_FIXED)
  83                 return get_gp_pmc(pmu, MSR_P6_EVNTSEL0 + idx, MSR_P6_EVNTSEL0);
  84         else
  85                 return get_fixed_pmc_idx(pmu, idx - X86_PMC_IDX_FIXED);
  86 }
  87
  88 void kvm_deliver_pmi(struct kvm_vcpu *vcpu)
  89 {
  90         if (vcpu->arch.apic)
  91                 kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
  92 }
  93
  94 static void trigger_pmi(struct irq_work *irq_work)
  95 {
  96         struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu,
  97                         irq_work);
  98         struct kvm_vcpu *vcpu = container_of(pmu, struct kvm_vcpu,
  99                         arch.pmu);
 100
 101         kvm_deliver_pmi(vcpu);
 102 }
 103
 104 static void kvm_perf_overflow(struct perf_event *perf_event,
 105                               struct perf_sample_data *data,
 106                               struct pt_regs *regs)
 107 {
 108         struct kvm_pmc *pmc = perf_event->overflow_handler_context;
 109         struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
 110         __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
 111 }
 112
 113 static void kvm_perf_overflow_intr(struct perf_event *perf_event,
 114                 struct perf_sample_data *data, struct pt_regs *regs)
 115 {
 116         struct kvm_pmc *pmc = perf_event->overflow_handler_context;
 117         struct kvm_pmu *pmu = &pmc->vcpu->arch.pmu;
 118         if (!test_and_set_bit(pmc->idx, (unsigned long *)&pmu->reprogram_pmi)) {
 119                 kvm_perf_overflow(perf_event, data, regs);
 120                 kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
 121                 /*
 122                  * Inject PMI. If vcpu was in a guest mode during NMI PMI
 123                  * can be ejected on a guest mode re-entry. Otherwise we can't
 124                  * be sure that vcpu wasn't executing hlt instruction at the
 125                  * time of vmexit and is not going to re-enter guest mode until,
 126                  * woken up. So we should wake it, but this is impossible from
 127                  * NMI context. Do it from irq work instead.
 128                  */
 129                 if (!kvm_is_in_guest())
 130                         irq_work_queue(&pmc->vcpu->arch.pmu.irq_work);
 131                 else
 132                         kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
 133         }
 134 }
 135
 136 static u64 read_pmc(struct kvm_pmc *pmc)
 137 {
 138         u64 counter, enabled, running;
 139
 140         counter = pmc->counter;
 141
 142         if (pmc->perf_event)
 143                 counter += perf_event_read_value(pmc->perf_event,
 144                                                  &enabled, &running);
 145
 146         /* FIXME: Scaling needed? */
 147
 148         return counter & pmc_bitmask(pmc);
 149 }
 150
 151 static void stop_counter(struct kvm_pmc *pmc)
 152 {
 153         if (pmc->perf_event) {
 154                 pmc->counter = read_pmc(pmc);
 155                 perf_event_release_kernel(pmc->perf_event);
 156                 pmc->perf_event = NULL;
 157         }
 158 }
 159
 160 static void reprogram_counter(struct kvm_pmc *pmc, u32 type,
 161                 unsigned config, bool exclude_user, bool exclude_kernel,
 162                 bool intr)
 163 {
 164         struct perf_event *event;
 165         struct perf_event_attr attr = {
 166                 .type = type,
 167                 .size = sizeof(attr),
 168                 .pinned = true,
 169                 .exclude_idle = true,
 170                 .exclude_host = 1,
 171                 .exclude_user = exclude_user,
 172                 .exclude_kernel = exclude_kernel,
 173                 .config = config,
 174         };
 175
 176         attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc);
 177
 178         event = perf_event_create_kernel_counter(&attr, -1, current,
 179                                                  intr ? kvm_perf_overflow_intr :
 180                                                  kvm_perf_overflow, pmc);
 181         if (IS_ERR(event)) {
 182                 printk_once("kvm: pmu event creation failed %ld\n",
 183                                 PTR_ERR(event));
 184                 return;
 185         }
 186
 187         pmc->perf_event = event;
 188         clear_bit(pmc->idx, (unsigned long*)&pmc->vcpu->arch.pmu.reprogram_pmi);
 189 }
 190
 191 static unsigned find_arch_event(struct kvm_pmu *pmu, u8 event_select,
 192                 u8 unit_mask)
 193 {
 194         int i;
 195
 196         for (i = 0; i < ARRAY_SIZE(arch_events); i++)
 197                 if (arch_events[i].eventsel == event_select
 198                                 && arch_events[i].unit_mask == unit_mask
 199                                 && (pmu->available_event_types & (1 << i)))
 200                         break;
 201
 202         if (i == ARRAY_SIZE(arch_events))
 203                 return PERF_COUNT_HW_MAX;
 204
 205         return arch_events[i].event_type;
 206 }
 207
 208 static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
 209 {
 210         unsigned config, type = PERF_TYPE_RAW;
 211         u8 event_select, unit_mask;
 212
 213         pmc->eventsel = eventsel;
 214
 215         stop_counter(pmc);
 216
 217         if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_enabled(pmc))
 218                 return;
 219
 220         event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
 221         unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 222
 223         if (!(event_select & (ARCH_PERFMON_EVENTSEL_EDGE |
 224                                 ARCH_PERFMON_EVENTSEL_INV |
 225                                 ARCH_PERFMON_EVENTSEL_CMASK))) {
 226                 config = find_arch_event(&pmc->vcpu->arch.pmu, event_select,
 227                                 unit_mask);
 228                 if (config != PERF_COUNT_HW_MAX)
 229                         type = PERF_TYPE_HARDWARE;
 230         }
 231
 232         if (type == PERF_TYPE_RAW)
 233                 config = eventsel & X86_RAW_EVENT_MASK;
 234
 235         reprogram_counter(pmc, type, config,
 236                         !(eventsel & ARCH_PERFMON_EVENTSEL_USR),
 237                         !(eventsel & ARCH_PERFMON_EVENTSEL_OS),
 238                         eventsel & ARCH_PERFMON_EVENTSEL_INT);
 239 }
 240
 241 static void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 en_pmi, int idx)
 242 {
 243         unsigned en = en_pmi & 0x3;
 244         bool pmi = en_pmi & 0x8;
 245
 246         stop_counter(pmc);
 247
 248         if (!en || !pmc_enabled(pmc))
 249                 return;
 250
 251         reprogram_counter(pmc, PERF_TYPE_HARDWARE,
 252                         arch_events[fixed_pmc_events[idx]].event_type,
 253                         !(en & 0x2), /* exclude user */
 254                         !(en & 0x1), /* exclude kernel */
 255                         pmi);
 256 }
 257
 258 static inline u8 fixed_en_pmi(u64 ctrl, int idx)
 259 {
 260         return (ctrl >> (idx * 4)) & 0xf;
 261 }
 262
 263 static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
 264 {
 265         int i;
 266
 267         for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
 268                 u8 en_pmi = fixed_en_pmi(data, i);
 269                 struct kvm_pmc *pmc = get_fixed_pmc_idx(pmu, i);
 270
 271                 if (fixed_en_pmi(pmu->fixed_ctr_ctrl, i) == en_pmi)
 272                         continue;
 273
 274                 reprogram_fixed_counter(pmc, en_pmi, i);
 275         }
 276
 277         pmu->fixed_ctr_ctrl = data;
 278 }
 279
 280 static void reprogram_idx(struct kvm_pmu *pmu, int idx)
 281 {
 282         struct kvm_pmc *pmc = global_idx_to_pmc(pmu, idx);
 283
 284         if (!pmc)
 285                 return;
 286
 287         if (pmc_is_gp(pmc))
 288                 reprogram_gp_counter(pmc, pmc->eventsel);
 289         else {
 290                 int fidx = idx - X86_PMC_IDX_FIXED;
 291                 reprogram_fixed_counter(pmc,
 292                                 fixed_en_pmi(pmu->fixed_ctr_ctrl, fidx), fidx);
 293         }
 294 }
 295
 296 static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data)
 297 {
 298         int bit;
 299         u64 diff = pmu->global_ctrl ^ data;
 300
 301         pmu->global_ctrl = data;
 302
 303         for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX)
 304                 reprogram_idx(pmu, bit);
 305 }
 306
 307 bool kvm_pmu_msr(struct kvm_vcpu *vcpu, u32 msr)
 308 {
 309         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 310         int ret;
 311
 312         switch (msr) {
 313         case MSR_CORE_PERF_FIXED_CTR_CTRL:
 314         case MSR_CORE_PERF_GLOBAL_STATUS:
 315         case MSR_CORE_PERF_GLOBAL_CTRL:
 316         case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 317                 ret = pmu->version > 1;
 318                 break;
 319         default:
 320                 ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)
 321                         || get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0)
 322                         || get_fixed_pmc(pmu, msr);
 323                 break;
 324         }
 325         return ret;
 326 }
 327
 328 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data)
 329 {
 330         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 331         struct kvm_pmc *pmc;
 332
 333         switch (index) {
 334         case MSR_CORE_PERF_FIXED_CTR_CTRL:
 335                 *data = pmu->fixed_ctr_ctrl;
 336                 return 0;
 337         case MSR_CORE_PERF_GLOBAL_STATUS:
 338                 *data = pmu->global_status;
 339                 return 0;
 340         case MSR_CORE_PERF_GLOBAL_CTRL:
 341                 *data = pmu->global_ctrl;
 342                 return 0;
 343         case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 344                 *data = pmu->global_ovf_ctrl;
 345                 return 0;
 346         default:
 347                 if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) ||
 348                                 (pmc = get_fixed_pmc(pmu, index))) {
 349                         *data = read_pmc(pmc);
 350                         return 0;
 351                 } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) {
 352                         *data = pmc->eventsel;
 353                         return 0;
 354                 }
 355         }
 356         return 1;
 357 }
 358
 359 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
 360 {
 361         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 362         struct kvm_pmc *pmc;
 363
 364         switch (index) {
 365         case MSR_CORE_PERF_FIXED_CTR_CTRL:
 366                 if (pmu->fixed_ctr_ctrl == data)
 367                         return 0;
 368                 if (!(data & 0xfffffffffffff444)) {
 369                         reprogram_fixed_counters(pmu, data);
 370                         return 0;
 371                 }
 372                 break;
 373         case MSR_CORE_PERF_GLOBAL_STATUS:
 374                 break; /* RO MSR */
 375         case MSR_CORE_PERF_GLOBAL_CTRL:
 376                 if (pmu->global_ctrl == data)
 377                         return 0;
 378                 if (!(data & pmu->global_ctrl_mask)) {
 379                         global_ctrl_changed(pmu, data);
 380                         return 0;
 381                 }
 382                 break;
 383         case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 384                 if (!(data & (pmu->global_ctrl_mask & ~(3ull<<62)))) {
 385                         pmu->global_status &= ~data;
 386                         pmu->global_ovf_ctrl = data;
 387                         return 0;
 388                 }
 389                 break;
 390         default:
 391                 if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) ||
 392                                 (pmc = get_fixed_pmc(pmu, index))) {
 393                         data = (s64)(s32)data;
 394                         pmc->counter += data - read_pmc(pmc);
 395                         return 0;
 396                 } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) {
 397                         if (data == pmc->eventsel)
 398                                 return 0;
 399                         if (!(data & 0xffffffff00200000ull)) {
 400                                 reprogram_gp_counter(pmc, data);
 401                                 return 0;
 402                         }
 403                 }
 404         }
 405         return 1;
 406 }
 407
 408 int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data)
 409 {
 410         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 411         bool fast_mode = pmc & (1u << 31);
 412         bool fixed = pmc & (1u << 30);
 413         struct kvm_pmc *counters;
 414         u64 ctr;
 415
 416         pmc &= (3u << 30) - 1;
 417         if (!fixed && pmc >= pmu->nr_arch_gp_counters)
 418                 return 1;
 419         if (fixed && pmc >= pmu->nr_arch_fixed_counters)
 420                 return 1;
 421         counters = fixed ? pmu->fixed_counters : pmu->gp_counters;
 422         ctr = read_pmc(&counters[pmc]);
 423         if (fast_mode)
 424                 ctr = (u32)ctr;
 425         *data = ctr;
 426
 427         return 0;
 428 }
 429
 430 void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu)
 431 {
 432         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 433         struct kvm_cpuid_entry2 *entry;
 434         unsigned bitmap_len;
 435
 436         pmu->nr_arch_gp_counters = 0;
 437         pmu->nr_arch_fixed_counters = 0;
 438         pmu->counter_bitmask[KVM_PMC_GP] = 0;
 439         pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
 440         pmu->version = 0;
 441
 442         entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
 443         if (!entry)
 444                 return;
 445
 446         pmu->version = entry->eax & 0xff;
 447         if (!pmu->version)
 448                 return;
 449
 450         pmu->nr_arch_gp_counters = min((int)(entry->eax >> 8) & 0xff,
 451                         X86_PMC_MAX_GENERIC);
 452         pmu->counter_bitmask[KVM_PMC_GP] =
 453                 ((u64)1 << ((entry->eax >> 16) & 0xff)) - 1;
 454         bitmap_len = (entry->eax >> 24) & 0xff;
 455         pmu->available_event_types = ~entry->ebx & ((1ull << bitmap_len) - 1);
 456
 457         if (pmu->version == 1) {
 458                 pmu->global_ctrl = (1 << pmu->nr_arch_gp_counters) - 1;
 459                 return;
 460         }
 461
 462         pmu->nr_arch_fixed_counters = min((int)(entry->edx & 0x1f),
 463                         X86_PMC_MAX_FIXED);
 464         pmu->counter_bitmask[KVM_PMC_FIXED] =
 465                 ((u64)1 << ((entry->edx >> 5) & 0xff)) - 1;
 466         pmu->global_ctrl_mask = ~(((1 << pmu->nr_arch_gp_counters) - 1)
 467                         | (((1ull << pmu->nr_arch_fixed_counters) - 1)
 468                                 << X86_PMC_IDX_FIXED));
 469 }
 470
 471 void kvm_pmu_init(struct kvm_vcpu *vcpu)
 472 {
 473         int i;
 474         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 475
 476         memset(pmu, 0, sizeof(*pmu));
 477         for (i = 0; i < X86_PMC_MAX_GENERIC; i++) {
 478                 pmu->gp_counters[i].type = KVM_PMC_GP;
 479                 pmu->gp_counters[i].vcpu = vcpu;
 480                 pmu->gp_counters[i].idx = i;
 481         }
 482         for (i = 0; i < X86_PMC_MAX_FIXED; i++) {
 483                 pmu->fixed_counters[i].type = KVM_PMC_FIXED;
 484                 pmu->fixed_counters[i].vcpu = vcpu;
 485                 pmu->fixed_counters[i].idx = i + X86_PMC_IDX_FIXED;
 486         }
 487         init_irq_work(&pmu->irq_work, trigger_pmi);
 488         kvm_pmu_cpuid_update(vcpu);
 489 }
 490
 491 void kvm_pmu_reset(struct kvm_vcpu *vcpu)
 492 {
 493         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 494         int i;
 495
 496         irq_work_sync(&pmu->irq_work);
 497         for (i = 0; i < X86_PMC_MAX_GENERIC; i++) {
 498                 struct kvm_pmc *pmc = &pmu->gp_counters[i];
 499                 stop_counter(pmc);
 500                 pmc->counter = pmc->eventsel = 0;
 501         }
 502
 503         for (i = 0; i < X86_PMC_MAX_FIXED; i++)
 504                 stop_counter(&pmu->fixed_counters[i]);
 505
 506         pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status =
 507                 pmu->global_ovf_ctrl = 0;
 508 }
 509
 510 void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
 511 {
 512         kvm_pmu_reset(vcpu);
 513 }
 514
 515 void kvm_handle_pmu_event(struct kvm_vcpu *vcpu)
 516 {
 517         struct kvm_pmu *pmu = &vcpu->arch.pmu;
 518         u64 bitmask;
 519         int bit;
 520
 521         bitmask = pmu->reprogram_pmi;
 522
 523         for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) {
 524                 struct kvm_pmc *pmc = global_idx_to_pmc(pmu, bit);
 525
 526                 if (unlikely(!pmc || !pmc->perf_event)) {
 527                         clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi);
 528                         continue;
 529                 }
 530
 531                 reprogram_idx(pmu, bit);
 532         }
 533 }