arch/x86/kvm/pmu.c

   1 /*
   2  * Kernel-based Virtual Machine -- Performance Monitoring Unit support
   3  *
   4  * Copyright 2015 Red Hat, Inc. and/or its affiliates.
   5  *
   6  * Authors:
   7  *   Avi Kivity   <avi@redhat.com>
   8  *   Gleb Natapov <gleb@redhat.com>
   9  *   Wei Huang    <wei@redhat.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2.  See
  12  * the COPYING file in the top-level directory.
  13  *
  14  */
  15
  16 #include <linux/types.h>
  17 #include <linux/kvm_host.h>
  18 #include <linux/perf_event.h>
  19 #include <asm/perf_event.h>
  20 #include "x86.h"
  21 #include "cpuid.h"
  22 #include "lapic.h"
  23 #include "pmu.h"
  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                 printk_once("kvm_pmu: event creation failed %ld\n",
 135                             PTR_ERR(event));
 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
 148         if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
 149                 printk_once("kvm pmu: pin control bit is ignored\n");
 150
 151         pmc->eventsel = eventsel;
 152
 153         pmc_stop_counter(pmc);
 154
 155         if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_is_enabled(pmc))
 156                 return;
 157
 158         event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
 159         unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 160
 161         if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
 162                           ARCH_PERFMON_EVENTSEL_INV |
 163                           ARCH_PERFMON_EVENTSEL_CMASK |
 164                           HSW_IN_TX |
 165                           HSW_IN_TX_CHECKPOINTED))) {
 166                 config = kvm_x86_ops->pmu_ops->find_arch_event(pmc_to_pmu(pmc),
 167                                                       event_select,
 168                                                       unit_mask);
 169                 if (config != PERF_COUNT_HW_MAX)
 170                         type = PERF_TYPE_HARDWARE;
 171         }
 172
 173         if (type == PERF_TYPE_RAW)
 174                 config = eventsel & X86_RAW_EVENT_MASK;
 175
 176         pmc_reprogram_counter(pmc, type, config,
 177                               !(eventsel & ARCH_PERFMON_EVENTSEL_USR),
 178                               !(eventsel & ARCH_PERFMON_EVENTSEL_OS),
 179                               eventsel & ARCH_PERFMON_EVENTSEL_INT,
 180                               (eventsel & HSW_IN_TX),
 181                               (eventsel & HSW_IN_TX_CHECKPOINTED));
 182 }
 183 EXPORT_SYMBOL_GPL(reprogram_gp_counter);
 184
 185 void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
 186 {
 187         unsigned en_field = ctrl & 0x3;
 188         bool pmi = ctrl & 0x8;
 189
 190         pmc_stop_counter(pmc);
 191
 192         if (!en_field || !pmc_is_enabled(pmc))
 193                 return;
 194
 195         pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
 196                               kvm_x86_ops->pmu_ops->find_fixed_event(idx),
 197                               !(en_field & 0x2), /* exclude user */
 198                               !(en_field & 0x1), /* exclude kernel */
 199                               pmi, false, false);
 200 }
 201 EXPORT_SYMBOL_GPL(reprogram_fixed_counter);
 202
 203 void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx)
 204 {
 205         struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->pmc_idx_to_pmc(pmu, pmc_idx);
 206
 207         if (!pmc)
 208                 return;
 209
 210         if (pmc_is_gp(pmc))
 211                 reprogram_gp_counter(pmc, pmc->eventsel);
 212         else {
 213                 int idx = pmc_idx - INTEL_PMC_IDX_FIXED;
 214                 u8 ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl, idx);
 215
 216                 reprogram_fixed_counter(pmc, ctrl, idx);
 217         }
 218 }
 219 EXPORT_SYMBOL_GPL(reprogram_counter);
 220
 221 void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
 222 {
 223         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 224         u64 bitmask;
 225         int bit;
 226
 227         bitmask = pmu->reprogram_pmi;
 228
 229         for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) {
 230                 struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->pmc_idx_to_pmc(pmu, bit);
 231
 232                 if (unlikely(!pmc || !pmc->perf_event)) {
 233                         clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi);
 234                         continue;
 235                 }
 236
 237                 reprogram_counter(pmu, bit);
 238         }
 239 }
 240
 241 /* check if idx is a valid index to access PMU */
 242 int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
 243 {
 244         return kvm_x86_ops->pmu_ops->is_valid_msr_idx(vcpu, idx);
 245 }
 246
 247 int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 248 {
 249         bool fast_mode = idx & (1u << 31);
 250         struct kvm_pmc *pmc;
 251         u64 ctr_val;
 252
 253         pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx);
 254         if (!pmc)
 255                 return 1;
 256
 257         ctr_val = pmc_read_counter(pmc);
 258         if (fast_mode)
 259                 ctr_val = (u32)ctr_val;
 260
 261         *data = ctr_val;
 262         return 0;
 263 }
 264
 265 void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
 266 {
 267         if (lapic_in_kernel(vcpu))
 268                 kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
 269 }
 270
 271 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 272 {
 273         return kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr);
 274 }
 275
 276 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 277 {
 278         return kvm_x86_ops->pmu_ops->get_msr(vcpu, msr, data);
 279 }
 280
 281 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 282 {
 283         return kvm_x86_ops->pmu_ops->set_msr(vcpu, msr_info);
 284 }
 285
 286 /* refresh PMU settings. This function generally is called when underlying
 287  * settings are changed (such as changes of PMU CPUID by guest VMs), which
 288  * should rarely happen.
 289  */
 290 void kvm_pmu_refresh(struct kvm_vcpu *vcpu)
 291 {
 292         kvm_x86_ops->pmu_ops->refresh(vcpu);
 293 }
 294
 295 void kvm_pmu_reset(struct kvm_vcpu *vcpu)
 296 {
 297         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 298
 299         irq_work_sync(&pmu->irq_work);
 300         kvm_x86_ops->pmu_ops->reset(vcpu);
 301 }
 302
 303 void kvm_pmu_init(struct kvm_vcpu *vcpu)
 304 {
 305         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 306
 307         memset(pmu, 0, sizeof(*pmu));
 308         kvm_x86_ops->pmu_ops->init(vcpu);
 309         init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn);
 310         kvm_pmu_refresh(vcpu);
 311 }
 312
 313 void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
 314 {
 315         kvm_pmu_reset(vcpu);
 316 }