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 bool is_vmware_backdoor_pmc(u32 pmc_idx) 248 { 249 switch (pmc_idx) { 250 case VMWARE_BACKDOOR_PMC_HOST_TSC: 251 case VMWARE_BACKDOOR_PMC_REAL_TIME: 252 case VMWARE_BACKDOOR_PMC_APPARENT_TIME: 253 return true; 254 } 255 return false; 256 } 257 258 static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) 259 { 260 u64 ctr_val; 261 262 switch (idx) { 263 case VMWARE_BACKDOOR_PMC_HOST_TSC: 264 ctr_val = rdtsc(); 265 break; 266 case VMWARE_BACKDOOR_PMC_REAL_TIME: 267 ctr_val = ktime_get_boot_ns(); 268 break; 269 case VMWARE_BACKDOOR_PMC_APPARENT_TIME: 270 ctr_val = ktime_get_boot_ns() + 271 vcpu->kvm->arch.kvmclock_offset; 272 break; 273 default: 274 return 1; 275 } 276 277 *data = ctr_val; 278 return 0; 279 } 280 281 int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) 282 { 283 bool fast_mode = idx & (1u << 31); 284 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); 285 struct kvm_pmc *pmc; 286 u64 mask = fast_mode ? ~0u : ~0ull; 287 288 if (!pmu->version) 289 return 1; 290 291 if (is_vmware_backdoor_pmc(idx)) 292 return kvm_pmu_rdpmc_vmware(vcpu, idx, data); 293 294 pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx, &mask); 295 if (!pmc) 296 return 1; 297 298 *data = pmc_read_counter(pmc) & mask; 299 return 0; 300 } 301 302 void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu) 303 { 304 if (lapic_in_kernel(vcpu)) 305 kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC); 306 } 307 308 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr) 309 { 310 return kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr); 311 } 312 313 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data) 314 { 315 return kvm_x86_ops->pmu_ops->get_msr(vcpu, msr, data); 316 } 317 318 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 319 { 320 return kvm_x86_ops->pmu_ops->set_msr(vcpu, msr_info); 321 } 322 323 /* refresh PMU settings. This function generally is called when underlying 324 * settings are changed (such as changes of PMU CPUID by guest VMs), which 325 * should rarely happen. 326 */ 327 void kvm_pmu_refresh(struct kvm_vcpu *vcpu) 328 { 329 kvm_x86_ops->pmu_ops->refresh(vcpu); 330 } 331 332 void kvm_pmu_reset(struct kvm_vcpu *vcpu) 333 { 334 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); 335 336 irq_work_sync(&pmu->irq_work); 337 kvm_x86_ops->pmu_ops->reset(vcpu); 338 } 339 340 void kvm_pmu_init(struct kvm_vcpu *vcpu) 341 { 342 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); 343 344 memset(pmu, 0, sizeof(*pmu)); 345 kvm_x86_ops->pmu_ops->init(vcpu); 346 init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn); 347 kvm_pmu_refresh(vcpu); 348 } 349 350 void kvm_pmu_destroy(struct kvm_vcpu *vcpu) 351 { 352 kvm_pmu_reset(vcpu); 353 } 354