arch/x86/kvm/pmu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Kernel-based Virtual Machine -- Performance Monitoring Unit support
   4  *
   5  * Copyright 2015 Red Hat, Inc. and/or its affiliates.
   6  *
   7  * Authors:
   8  *   Avi Kivity   <[email protected]>
   9  *   Gleb Natapov <[email protected]>
  10  *   Wei Huang    <[email protected]>
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/kvm_host.h>
  15 #include <linux/perf_event.h>
  16 #include <asm/perf_event.h>
  17 #include "x86.h"
  18 #include "cpuid.h"
  19 #include "lapic.h"
  20 #include "pmu.h"
  21
  22 /* This is enough to filter the vast majority of currently defined events. */
  23 #define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300
  24
  25 /* NOTE:
  26  * - Each perf counter is defined as "struct kvm_pmc";
  27  * - There are two types of perf counters: general purpose (gp) and fixed.
  28  *   gp counters are stored in gp_counters[] and fixed counters are stored
  29  *   in fixed_counters[] respectively. Both of them are part of "struct
  30  *   kvm_pmu";
  31  * - pmu.c understands the difference between gp counters and fixed counters.
  32  *   However AMD doesn't support fixed-counters;
  33  * - There are three types of index to access perf counters (PMC):
  34  *     1. MSR (named msr): For example Intel has MSR_IA32_PERFCTRn and AMD
  35  *        has MSR_K7_PERFCTRn.
  36  *     2. MSR Index (named idx): This normally is used by RDPMC instruction.
  37  *        For instance AMD RDPMC instruction uses 0000_0003h in ECX to access
  38  *        C001_0007h (MSR_K7_PERCTR3). Intel has a similar mechanism, except
  39  *        that it also supports fixed counters. idx can be used to as index to
  40  *        gp and fixed counters.
  41  *     3. Global PMC Index (named pmc): pmc is an index specific to PMU
  42  *        code. Each pmc, stored in kvm_pmc.idx field, is unique across
  43  *        all perf counters (both gp and fixed). The mapping relationship
  44  *        between pmc and perf counters is as the following:
  45  *        * Intel: [0 .. INTEL_PMC_MAX_GENERIC-1] <=> gp counters
  46  *                 [INTEL_PMC_IDX_FIXED .. INTEL_PMC_IDX_FIXED + 2] <=> fixed
  47  *        * AMD:   [0 .. AMD64_NUM_COUNTERS-1] <=> gp counters
  48  */
  49
  50 static void kvm_pmi_trigger_fn(struct irq_work *irq_work)
  51 {
  52         struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work);
  53         struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu);
  54
  55         kvm_pmu_deliver_pmi(vcpu);
  56 }
  57
  58 static void kvm_perf_overflow(struct perf_event *perf_event,
  59                               struct perf_sample_data *data,
  60                               struct pt_regs *regs)
  61 {
  62         struct kvm_pmc *pmc = perf_event->overflow_handler_context;
  63         struct kvm_pmu *pmu = pmc_to_pmu(pmc);
  64
  65         if (!test_and_set_bit(pmc->idx,
  66                               (unsigned long *)&pmu->reprogram_pmi)) {
  67                 __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
  68                 kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
  69         }
  70 }
  71
  72 static void kvm_perf_overflow_intr(struct perf_event *perf_event,
  73                                    struct perf_sample_data *data,
  74                                    struct pt_regs *regs)
  75 {
  76         struct kvm_pmc *pmc = perf_event->overflow_handler_context;
  77         struct kvm_pmu *pmu = pmc_to_pmu(pmc);
  78
  79         if (!test_and_set_bit(pmc->idx,
  80                               (unsigned long *)&pmu->reprogram_pmi)) {
  81                 __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
  82                 kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
  83
  84                 /*
  85                  * Inject PMI. If vcpu was in a guest mode during NMI PMI
  86                  * can be ejected on a guest mode re-entry. Otherwise we can't
  87                  * be sure that vcpu wasn't executing hlt instruction at the
  88                  * time of vmexit and is not going to re-enter guest mode until
  89                  * woken up. So we should wake it, but this is impossible from
  90                  * NMI context. Do it from irq work instead.
  91                  */
  92                 if (!kvm_is_in_guest())
  93                         irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
  94                 else
  95                         kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
  96         }
  97 }
  98
  99 static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
 100                                   unsigned config, bool exclude_user,
 101                                   bool exclude_kernel, bool intr,
 102                                   bool in_tx, bool in_tx_cp)
 103 {
 104         struct perf_event *event;
 105         struct perf_event_attr attr = {
 106                 .type = type,
 107                 .size = sizeof(attr),
 108                 .pinned = true,
 109                 .exclude_idle = true,
 110                 .exclude_host = 1,
 111                 .exclude_user = exclude_user,
 112                 .exclude_kernel = exclude_kernel,
 113                 .config = config,
 114         };
 115
 116         attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc);
 117
 118         if (in_tx)
 119                 attr.config |= HSW_IN_TX;
 120         if (in_tx_cp) {
 121                 /*
 122                  * HSW_IN_TX_CHECKPOINTED is not supported with nonzero
 123                  * period. Just clear the sample period so at least
 124                  * allocating the counter doesn't fail.
 125                  */
 126                 attr.sample_period = 0;
 127                 attr.config |= HSW_IN_TX_CHECKPOINTED;
 128         }
 129
 130         event = perf_event_create_kernel_counter(&attr, -1, current,
 131                                                  intr ? kvm_perf_overflow_intr :
 132                                                  kvm_perf_overflow, pmc);
 133         if (IS_ERR(event)) {
 134                 pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
 135                             PTR_ERR(event), pmc->idx);
 136                 return;
 137         }
 138
 139         pmc->perf_event = event;
 140         clear_bit(pmc->idx, (unsigned long*)&pmc_to_pmu(pmc)->reprogram_pmi);
 141 }
 142
 143 void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
 144 {
 145         unsigned config, type = PERF_TYPE_RAW;
 146         u8 event_select, unit_mask;
 147         struct kvm *kvm = pmc->vcpu->kvm;
 148         struct kvm_pmu_event_filter *filter;
 149         int i;
 150         bool allow_event = true;
 151
 152         if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
 153                 printk_once("kvm pmu: pin control bit is ignored\n");
 154
 155         pmc->eventsel = eventsel;
 156
 157         pmc_stop_counter(pmc);
 158
 159         if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_is_enabled(pmc))
 160                 return;
 161
 162         filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
 163         if (filter) {
 164                 for (i = 0; i < filter->nevents; i++)
 165                         if (filter->events[i] ==
 166                             (eventsel & AMD64_RAW_EVENT_MASK_NB))
 167                                 break;
 168                 if (filter->action == KVM_PMU_EVENT_ALLOW &&
 169                     i == filter->nevents)
 170                         allow_event = false;
 171                 if (filter->action == KVM_PMU_EVENT_DENY &&
 172                     i < filter->nevents)
 173                         allow_event = false;
 174         }
 175         if (!allow_event)
 176                 return;
 177
 178         event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
 179         unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 180
 181         if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
 182                           ARCH_PERFMON_EVENTSEL_INV |
 183                           ARCH_PERFMON_EVENTSEL_CMASK |
 184                           HSW_IN_TX |
 185                           HSW_IN_TX_CHECKPOINTED))) {
 186                 config = kvm_x86_ops->pmu_ops->find_arch_event(pmc_to_pmu(pmc),
 187                                                       event_select,
 188                                                       unit_mask);
 189                 if (config != PERF_COUNT_HW_MAX)
 190                         type = PERF_TYPE_HARDWARE;
 191         }
 192
 193         if (type == PERF_TYPE_RAW)
 194                 config = eventsel & X86_RAW_EVENT_MASK;
 195
 196         pmc_reprogram_counter(pmc, type, config,
 197                               !(eventsel & ARCH_PERFMON_EVENTSEL_USR),
 198                               !(eventsel & ARCH_PERFMON_EVENTSEL_OS),
 199                               eventsel & ARCH_PERFMON_EVENTSEL_INT,
 200                               (eventsel & HSW_IN_TX),
 201                               (eventsel & HSW_IN_TX_CHECKPOINTED));
 202 }
 203 EXPORT_SYMBOL_GPL(reprogram_gp_counter);
 204
 205 void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
 206 {
 207         unsigned en_field = ctrl & 0x3;
 208         bool pmi = ctrl & 0x8;
 209         struct kvm_pmu_event_filter *filter;
 210         struct kvm *kvm = pmc->vcpu->kvm;
 211
 212         pmc_stop_counter(pmc);
 213
 214         if (!en_field || !pmc_is_enabled(pmc))
 215                 return;
 216
 217         filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
 218         if (filter) {
 219                 if (filter->action == KVM_PMU_EVENT_DENY &&
 220                     test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
 221                         return;
 222                 if (filter->action == KVM_PMU_EVENT_ALLOW &&
 223                     !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
 224                         return;
 225         }
 226
 227         pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
 228                               kvm_x86_ops->pmu_ops->find_fixed_event(idx),
 229                               !(en_field & 0x2), /* exclude user */
 230                               !(en_field & 0x1), /* exclude kernel */
 231                               pmi, false, false);
 232 }
 233 EXPORT_SYMBOL_GPL(reprogram_fixed_counter);
 234
 235 void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx)
 236 {
 237         struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->pmc_idx_to_pmc(pmu, pmc_idx);
 238
 239         if (!pmc)
 240                 return;
 241
 242         if (pmc_is_gp(pmc))
 243                 reprogram_gp_counter(pmc, pmc->eventsel);
 244         else {
 245                 int idx = pmc_idx - INTEL_PMC_IDX_FIXED;
 246                 u8 ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl, idx);
 247
 248                 reprogram_fixed_counter(pmc, ctrl, idx);
 249         }
 250 }
 251 EXPORT_SYMBOL_GPL(reprogram_counter);
 252
 253 void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
 254 {
 255         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 256         u64 bitmask;
 257         int bit;
 258
 259         bitmask = pmu->reprogram_pmi;
 260
 261         for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) {
 262                 struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->pmc_idx_to_pmc(pmu, bit);
 263
 264                 if (unlikely(!pmc || !pmc->perf_event)) {
 265                         clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi);
 266                         continue;
 267                 }
 268
 269                 reprogram_counter(pmu, bit);
 270         }
 271 }
 272
 273 /* check if idx is a valid index to access PMU */
 274 int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
 275 {
 276         return kvm_x86_ops->pmu_ops->is_valid_msr_idx(vcpu, idx);
 277 }
 278
 279 bool is_vmware_backdoor_pmc(u32 pmc_idx)
 280 {
 281         switch (pmc_idx) {
 282         case VMWARE_BACKDOOR_PMC_HOST_TSC:
 283         case VMWARE_BACKDOOR_PMC_REAL_TIME:
 284         case VMWARE_BACKDOOR_PMC_APPARENT_TIME:
 285                 return true;
 286         }
 287         return false;
 288 }
 289
 290 static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 291 {
 292         u64 ctr_val;
 293
 294         switch (idx) {
 295         case VMWARE_BACKDOOR_PMC_HOST_TSC:
 296                 ctr_val = rdtsc();
 297                 break;
 298         case VMWARE_BACKDOOR_PMC_REAL_TIME:
 299                 ctr_val = ktime_get_boottime_ns();
 300                 break;
 301         case VMWARE_BACKDOOR_PMC_APPARENT_TIME:
 302                 ctr_val = ktime_get_boottime_ns() +
 303                         vcpu->kvm->arch.kvmclock_offset;
 304                 break;
 305         default:
 306                 return 1;
 307         }
 308
 309         *data = ctr_val;
 310         return 0;
 311 }
 312
 313 int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 314 {
 315         bool fast_mode = idx & (1u << 31);
 316         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 317         struct kvm_pmc *pmc;
 318         u64 mask = fast_mode ? ~0u : ~0ull;
 319
 320         if (!pmu->version)
 321                 return 1;
 322
 323         if (is_vmware_backdoor_pmc(idx))
 324                 return kvm_pmu_rdpmc_vmware(vcpu, idx, data);
 325
 326         pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx, &mask);
 327         if (!pmc)
 328                 return 1;
 329
 330         *data = pmc_read_counter(pmc) & mask;
 331         return 0;
 332 }
 333
 334 void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
 335 {
 336         if (lapic_in_kernel(vcpu))
 337                 kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
 338 }
 339
 340 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 341 {
 342         return kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr);
 343 }
 344
 345 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 346 {
 347         return kvm_x86_ops->pmu_ops->get_msr(vcpu, msr, data);
 348 }
 349
 350 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 351 {
 352         return kvm_x86_ops->pmu_ops->set_msr(vcpu, msr_info);
 353 }
 354
 355 /* refresh PMU settings. This function generally is called when underlying
 356  * settings are changed (such as changes of PMU CPUID by guest VMs), which
 357  * should rarely happen.
 358  */
 359 void kvm_pmu_refresh(struct kvm_vcpu *vcpu)
 360 {
 361         kvm_x86_ops->pmu_ops->refresh(vcpu);
 362 }
 363
 364 void kvm_pmu_reset(struct kvm_vcpu *vcpu)
 365 {
 366         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 367
 368         irq_work_sync(&pmu->irq_work);
 369         kvm_x86_ops->pmu_ops->reset(vcpu);
 370 }
 371
 372 void kvm_pmu_init(struct kvm_vcpu *vcpu)
 373 {
 374         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 375
 376         memset(pmu, 0, sizeof(*pmu));
 377         kvm_x86_ops->pmu_ops->init(vcpu);
 378         init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn);
 379         kvm_pmu_refresh(vcpu);
 380 }
 381
 382 void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
 383 {
 384         kvm_pmu_reset(vcpu);
 385 }
 386
 387 int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
 388 {
 389         struct kvm_pmu_event_filter tmp, *filter;
 390         size_t size;
 391         int r;
 392
 393         if (copy_from_user(&tmp, argp, sizeof(tmp)))
 394                 return -EFAULT;
 395
 396         if (tmp.action != KVM_PMU_EVENT_ALLOW &&
 397             tmp.action != KVM_PMU_EVENT_DENY)
 398                 return -EINVAL;
 399
 400         if (tmp.flags != 0)
 401                 return -EINVAL;
 402
 403         if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS)
 404                 return -E2BIG;
 405
 406         size = struct_size(filter, events, tmp.nevents);
 407         filter = kmalloc(size, GFP_KERNEL_ACCOUNT);
 408         if (!filter)
 409                 return -ENOMEM;
 410
 411         r = -EFAULT;
 412         if (copy_from_user(filter, argp, size))
 413                 goto cleanup;
 414
 415         /* Ensure nevents can't be changed between the user copies. */
 416         *filter = tmp;
 417
 418         mutex_lock(&kvm->lock);
 419         rcu_swap_protected(kvm->arch.pmu_event_filter, filter,
 420                            mutex_is_locked(&kvm->lock));
 421         mutex_unlock(&kvm->lock);
 422
 423         synchronize_srcu_expedited(&kvm->srcu);
 424         r = 0;
 425 cleanup:
 426         kfree(filter);
 427         return r;
 428 }