arch/x86/kvm/pmu.c

   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
  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         [7] = { 0x00, 0x30, PERF_COUNT_HW_REF_CPU_CYCLES },
  37 };
  38
  39 /* mapping between fixed pmc index and arch_events array */
  40 int fixed_pmc_events[] = {1, 0, 7};
  41
  42 static bool pmc_is_gp(struct kvm_pmc *pmc)
  43 {
  44         return pmc->type == KVM_PMC_GP;
  45 }
  46
  47 static 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
  54 static 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
  60 static 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
  68 static 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
  76 static 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
  81 static 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
  89 void 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
  95 static 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
 105 static 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
 114 static 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
 137 static 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
 152 static 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
 161 static 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
 196 static 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
 213 static 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
 253 static 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
 270 static inline u8 fixed_en_pmi(u64 ctrl, int idx)
 271 {
 272         return (ctrl >> (idx * 4)) & 0xf;
 273 }
 274
 275 static 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
 292 static 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
 308 static 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
 319 bool 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
 340 int 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
 371 int 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
 428 int 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
 450 void 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
 498 void 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
 518 void 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
 537 void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
 538 {
 539         kvm_pmu_reset(vcpu);
 540 }
 541
 542 void 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 }