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) 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 }; 176 177 attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc); 178 179 event = perf_event_create_kernel_counter(&attr, -1, current, 180 intr ? kvm_perf_overflow_intr : 181 kvm_perf_overflow, pmc); 182 if (IS_ERR(event)) { 183 printk_once("kvm: pmu event creation failed %ld\n", 184 PTR_ERR(event)); 185 return; 186 } 187 188 pmc->perf_event = event; 189 clear_bit(pmc->idx, (unsigned long*)&pmc->vcpu->arch.pmu.reprogram_pmi); 190 } 191 192 static unsigned find_arch_event(struct kvm_pmu *pmu, u8 event_select, 193 u8 unit_mask) 194 { 195 int i; 196 197 for (i = 0; i < ARRAY_SIZE(arch_events); i++) 198 if (arch_events[i].eventsel == event_select 199 && arch_events[i].unit_mask == unit_mask 200 && (pmu->available_event_types & (1 << i))) 201 break; 202 203 if (i == ARRAY_SIZE(arch_events)) 204 return PERF_COUNT_HW_MAX; 205 206 return arch_events[i].event_type; 207 } 208 209 static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel) 210 { 211 unsigned config, type = PERF_TYPE_RAW; 212 u8 event_select, unit_mask; 213 214 if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL) 215 printk_once("kvm pmu: pin control bit is ignored\n"); 216 217 pmc->eventsel = eventsel; 218 219 stop_counter(pmc); 220 221 if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_enabled(pmc)) 222 return; 223 224 event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT; 225 unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8; 226 227 if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE | 228 ARCH_PERFMON_EVENTSEL_INV | 229 ARCH_PERFMON_EVENTSEL_CMASK))) { 230 config = find_arch_event(&pmc->vcpu->arch.pmu, event_select, 231 unit_mask); 232 if (config != PERF_COUNT_HW_MAX) 233 type = PERF_TYPE_HARDWARE; 234 } 235 236 if (type == PERF_TYPE_RAW) 237 config = eventsel & X86_RAW_EVENT_MASK; 238 239 reprogram_counter(pmc, type, config, 240 !(eventsel & ARCH_PERFMON_EVENTSEL_USR), 241 !(eventsel & ARCH_PERFMON_EVENTSEL_OS), 242 eventsel & ARCH_PERFMON_EVENTSEL_INT); 243 } 244 245 static void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 en_pmi, int idx) 246 { 247 unsigned en = en_pmi & 0x3; 248 bool pmi = en_pmi & 0x8; 249 250 stop_counter(pmc); 251 252 if (!en || !pmc_enabled(pmc)) 253 return; 254 255 reprogram_counter(pmc, PERF_TYPE_HARDWARE, 256 arch_events[fixed_pmc_events[idx]].event_type, 257 !(en & 0x2), /* exclude user */ 258 !(en & 0x1), /* exclude kernel */ 259 pmi); 260 } 261 262 static inline u8 fixed_en_pmi(u64 ctrl, int idx) 263 { 264 return (ctrl >> (idx * 4)) & 0xf; 265 } 266 267 static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) 268 { 269 int i; 270 271 for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { 272 u8 en_pmi = fixed_en_pmi(data, i); 273 struct kvm_pmc *pmc = get_fixed_pmc_idx(pmu, i); 274 275 if (fixed_en_pmi(pmu->fixed_ctr_ctrl, i) == en_pmi) 276 continue; 277 278 reprogram_fixed_counter(pmc, en_pmi, i); 279 } 280 281 pmu->fixed_ctr_ctrl = data; 282 } 283 284 static void reprogram_idx(struct kvm_pmu *pmu, int idx) 285 { 286 struct kvm_pmc *pmc = global_idx_to_pmc(pmu, idx); 287 288 if (!pmc) 289 return; 290 291 if (pmc_is_gp(pmc)) 292 reprogram_gp_counter(pmc, pmc->eventsel); 293 else { 294 int fidx = idx - INTEL_PMC_IDX_FIXED; 295 reprogram_fixed_counter(pmc, 296 fixed_en_pmi(pmu->fixed_ctr_ctrl, fidx), fidx); 297 } 298 } 299 300 static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data) 301 { 302 int bit; 303 u64 diff = pmu->global_ctrl ^ data; 304 305 pmu->global_ctrl = data; 306 307 for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX) 308 reprogram_idx(pmu, bit); 309 } 310 311 bool kvm_pmu_msr(struct kvm_vcpu *vcpu, u32 msr) 312 { 313 struct kvm_pmu *pmu = &vcpu->arch.pmu; 314 int ret; 315 316 switch (msr) { 317 case MSR_CORE_PERF_FIXED_CTR_CTRL: 318 case MSR_CORE_PERF_GLOBAL_STATUS: 319 case MSR_CORE_PERF_GLOBAL_CTRL: 320 case MSR_CORE_PERF_GLOBAL_OVF_CTRL: 321 ret = pmu->version > 1; 322 break; 323 default: 324 ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) 325 || get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) 326 || get_fixed_pmc(pmu, msr); 327 break; 328 } 329 return ret; 330 } 331 332 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data) 333 { 334 struct kvm_pmu *pmu = &vcpu->arch.pmu; 335 struct kvm_pmc *pmc; 336 337 switch (index) { 338 case MSR_CORE_PERF_FIXED_CTR_CTRL: 339 *data = pmu->fixed_ctr_ctrl; 340 return 0; 341 case MSR_CORE_PERF_GLOBAL_STATUS: 342 *data = pmu->global_status; 343 return 0; 344 case MSR_CORE_PERF_GLOBAL_CTRL: 345 *data = pmu->global_ctrl; 346 return 0; 347 case MSR_CORE_PERF_GLOBAL_OVF_CTRL: 348 *data = pmu->global_ovf_ctrl; 349 return 0; 350 default: 351 if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) || 352 (pmc = get_fixed_pmc(pmu, index))) { 353 *data = read_pmc(pmc); 354 return 0; 355 } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) { 356 *data = pmc->eventsel; 357 return 0; 358 } 359 } 360 return 1; 361 } 362 363 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 364 { 365 struct kvm_pmu *pmu = &vcpu->arch.pmu; 366 struct kvm_pmc *pmc; 367 u32 index = msr_info->index; 368 u64 data = msr_info->data; 369 370 switch (index) { 371 case MSR_CORE_PERF_FIXED_CTR_CTRL: 372 if (pmu->fixed_ctr_ctrl == data) 373 return 0; 374 if (!(data & 0xfffffffffffff444ull)) { 375 reprogram_fixed_counters(pmu, data); 376 return 0; 377 } 378 break; 379 case MSR_CORE_PERF_GLOBAL_STATUS: 380 if (msr_info->host_initiated) { 381 pmu->global_status = data; 382 return 0; 383 } 384 break; /* RO MSR */ 385 case MSR_CORE_PERF_GLOBAL_CTRL: 386 if (pmu->global_ctrl == data) 387 return 0; 388 if (!(data & pmu->global_ctrl_mask)) { 389 global_ctrl_changed(pmu, data); 390 return 0; 391 } 392 break; 393 case MSR_CORE_PERF_GLOBAL_OVF_CTRL: 394 if (!(data & (pmu->global_ctrl_mask & ~(3ull<<62)))) { 395 if (!msr_info->host_initiated) 396 pmu->global_status &= ~data; 397 pmu->global_ovf_ctrl = data; 398 return 0; 399 } 400 break; 401 default: 402 if ((pmc = get_gp_pmc(pmu, index, MSR_IA32_PERFCTR0)) || 403 (pmc = get_fixed_pmc(pmu, index))) { 404 if (!msr_info->host_initiated) 405 data = (s64)(s32)data; 406 pmc->counter += data - read_pmc(pmc); 407 return 0; 408 } else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) { 409 if (data == pmc->eventsel) 410 return 0; 411 if (!(data & 0xffffffff00200000ull)) { 412 reprogram_gp_counter(pmc, data); 413 return 0; 414 } 415 } 416 } 417 return 1; 418 } 419 420 int kvm_pmu_read_pmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data) 421 { 422 struct kvm_pmu *pmu = &vcpu->arch.pmu; 423 bool fast_mode = pmc & (1u << 31); 424 bool fixed = pmc & (1u << 30); 425 struct kvm_pmc *counters; 426 u64 ctr; 427 428 pmc &= ~(3u << 30); 429 if (!fixed && pmc >= pmu->nr_arch_gp_counters) 430 return 1; 431 if (fixed && pmc >= pmu->nr_arch_fixed_counters) 432 return 1; 433 counters = fixed ? pmu->fixed_counters : pmu->gp_counters; 434 ctr = read_pmc(&counters[pmc]); 435 if (fast_mode) 436 ctr = (u32)ctr; 437 *data = ctr; 438 439 return 0; 440 } 441 442 void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu) 443 { 444 struct kvm_pmu *pmu = &vcpu->arch.pmu; 445 struct kvm_cpuid_entry2 *entry; 446 unsigned bitmap_len; 447 448 pmu->nr_arch_gp_counters = 0; 449 pmu->nr_arch_fixed_counters = 0; 450 pmu->counter_bitmask[KVM_PMC_GP] = 0; 451 pmu->counter_bitmask[KVM_PMC_FIXED] = 0; 452 pmu->version = 0; 453 454 entry = kvm_find_cpuid_entry(vcpu, 0xa, 0); 455 if (!entry) 456 return; 457 458 pmu->version = entry->eax & 0xff; 459 if (!pmu->version) 460 return; 461 462 pmu->nr_arch_gp_counters = min((int)(entry->eax >> 8) & 0xff, 463 INTEL_PMC_MAX_GENERIC); 464 pmu->counter_bitmask[KVM_PMC_GP] = 465 ((u64)1 << ((entry->eax >> 16) & 0xff)) - 1; 466 bitmap_len = (entry->eax >> 24) & 0xff; 467 pmu->available_event_types = ~entry->ebx & ((1ull << bitmap_len) - 1); 468 469 if (pmu->version == 1) { 470 pmu->nr_arch_fixed_counters = 0; 471 } else { 472 pmu->nr_arch_fixed_counters = min((int)(entry->edx & 0x1f), 473 INTEL_PMC_MAX_FIXED); 474 pmu->counter_bitmask[KVM_PMC_FIXED] = 475 ((u64)1 << ((entry->edx >> 5) & 0xff)) - 1; 476 } 477 478 pmu->global_ctrl = ((1 << pmu->nr_arch_gp_counters) - 1) | 479 (((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED); 480 pmu->global_ctrl_mask = ~pmu->global_ctrl; 481 } 482 483 void kvm_pmu_init(struct kvm_vcpu *vcpu) 484 { 485 int i; 486 struct kvm_pmu *pmu = &vcpu->arch.pmu; 487 488 memset(pmu, 0, sizeof(*pmu)); 489 for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) { 490 pmu->gp_counters[i].type = KVM_PMC_GP; 491 pmu->gp_counters[i].vcpu = vcpu; 492 pmu->gp_counters[i].idx = i; 493 } 494 for (i = 0; i < INTEL_PMC_MAX_FIXED; i++) { 495 pmu->fixed_counters[i].type = KVM_PMC_FIXED; 496 pmu->fixed_counters[i].vcpu = vcpu; 497 pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED; 498 } 499 init_irq_work(&pmu->irq_work, trigger_pmi); 500 kvm_pmu_cpuid_update(vcpu); 501 } 502 503 void kvm_pmu_reset(struct kvm_vcpu *vcpu) 504 { 505 struct kvm_pmu *pmu = &vcpu->arch.pmu; 506 int i; 507 508 irq_work_sync(&pmu->irq_work); 509 for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) { 510 struct kvm_pmc *pmc = &pmu->gp_counters[i]; 511 stop_counter(pmc); 512 pmc->counter = pmc->eventsel = 0; 513 } 514 515 for (i = 0; i < INTEL_PMC_MAX_FIXED; i++) 516 stop_counter(&pmu->fixed_counters[i]); 517 518 pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = 519 pmu->global_ovf_ctrl = 0; 520 } 521 522 void kvm_pmu_destroy(struct kvm_vcpu *vcpu) 523 { 524 kvm_pmu_reset(vcpu); 525 } 526 527 void kvm_handle_pmu_event(struct kvm_vcpu *vcpu) 528 { 529 struct kvm_pmu *pmu = &vcpu->arch.pmu; 530 u64 bitmask; 531 int bit; 532 533 bitmask = pmu->reprogram_pmi; 534 535 for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) { 536 struct kvm_pmc *pmc = global_idx_to_pmc(pmu, bit); 537 538 if (unlikely(!pmc || !pmc->perf_event)) { 539 clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi); 540 continue; 541 } 542 543 reprogram_idx(pmu, bit); 544 } 545 } 546