1 // SPDX-License-Identifier: GPL-2.0-only
3 * Kernel-based Virtual Machine -- Performance Monitoring Unit support
5 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
8 * Avi Kivity <avi@redhat.com>
9 * Gleb Natapov <gleb@redhat.com>
10 * Wei Huang <wei@redhat.com>
13 #include <linux/types.h>
14 #include <linux/kvm_host.h>
15 #include <linux/perf_event.h>
16 #include <asm/perf_event.h>
22 /* This is enough to filter the vast majority of currently defined events. */
23 #define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300
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
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
50 static void kvm_pmi_trigger_fn(struct irq_work *irq_work)
52 struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work);
53 struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu);
55 kvm_pmu_deliver_pmi(vcpu);
58 static void kvm_perf_overflow(struct perf_event *perf_event,
59 struct perf_sample_data *data,
62 struct kvm_pmc *pmc = perf_event->overflow_handler_context;
63 struct kvm_pmu *pmu = pmc_to_pmu(pmc);
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);
72 static void kvm_perf_overflow_intr(struct perf_event *perf_event,
73 struct perf_sample_data *data,
76 struct kvm_pmc *pmc = perf_event->overflow_handler_context;
77 struct kvm_pmu *pmu = pmc_to_pmu(pmc);
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);
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.
92 if (!kvm_is_in_guest())
93 irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
95 kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
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)
104 struct perf_event *event;
105 struct perf_event_attr attr = {
107 .size = sizeof(attr),
109 .exclude_idle = true,
111 .exclude_user = exclude_user,
112 .exclude_kernel = exclude_kernel,
116 attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc);
119 attr.config |= HSW_IN_TX;
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.
126 attr.sample_period = 0;
127 attr.config |= HSW_IN_TX_CHECKPOINTED;
130 event = perf_event_create_kernel_counter(&attr, -1, current,
131 intr ? kvm_perf_overflow_intr :
132 kvm_perf_overflow, pmc);
134 pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
135 PTR_ERR(event), pmc->idx);
139 pmc->perf_event = event;
140 clear_bit(pmc->idx, (unsigned long*)&pmc_to_pmu(pmc)->reprogram_pmi);
143 void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
145 unsigned config, type = PERF_TYPE_RAW;
146 struct kvm *kvm = pmc->vcpu->kvm;
147 struct kvm_pmu_event_filter *filter;
149 bool allow_event = true;
151 if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
152 printk_once("kvm pmu: pin control bit is ignored\n");
154 pmc->eventsel = eventsel;
156 pmc_stop_counter(pmc);
158 if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_is_enabled(pmc))
161 filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
163 for (i = 0; i < filter->nevents; i++)
164 if (filter->events[i] ==
165 (eventsel & AMD64_RAW_EVENT_MASK_NB))
167 if (filter->action == KVM_PMU_EVENT_ALLOW &&
168 i == filter->nevents)
170 if (filter->action == KVM_PMU_EVENT_DENY &&
177 if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
178 ARCH_PERFMON_EVENTSEL_INV |
179 ARCH_PERFMON_EVENTSEL_CMASK |
181 HSW_IN_TX_CHECKPOINTED))) {
182 config = kvm_x86_ops->pmu_ops->pmc_perf_hw_id(pmc);
183 if (config != PERF_COUNT_HW_MAX)
184 type = PERF_TYPE_HARDWARE;
187 if (type == PERF_TYPE_RAW)
188 config = eventsel & AMD64_RAW_EVENT_MASK;
190 pmc_reprogram_counter(pmc, type, config,
191 !(eventsel & ARCH_PERFMON_EVENTSEL_USR),
192 !(eventsel & ARCH_PERFMON_EVENTSEL_OS),
193 eventsel & ARCH_PERFMON_EVENTSEL_INT,
194 (eventsel & HSW_IN_TX),
195 (eventsel & HSW_IN_TX_CHECKPOINTED));
197 EXPORT_SYMBOL_GPL(reprogram_gp_counter);
199 void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
201 unsigned en_field = ctrl & 0x3;
202 bool pmi = ctrl & 0x8;
203 struct kvm_pmu_event_filter *filter;
204 struct kvm *kvm = pmc->vcpu->kvm;
206 pmc_stop_counter(pmc);
208 if (!en_field || !pmc_is_enabled(pmc))
211 filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
213 if (filter->action == KVM_PMU_EVENT_DENY &&
214 test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
216 if (filter->action == KVM_PMU_EVENT_ALLOW &&
217 !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
221 pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
222 kvm_x86_ops->pmu_ops->find_fixed_event(idx),
223 !(en_field & 0x2), /* exclude user */
224 !(en_field & 0x1), /* exclude kernel */
227 EXPORT_SYMBOL_GPL(reprogram_fixed_counter);
229 void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx)
231 struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->pmc_idx_to_pmc(pmu, pmc_idx);
237 reprogram_gp_counter(pmc, pmc->eventsel);
239 int idx = pmc_idx - INTEL_PMC_IDX_FIXED;
240 u8 ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl, idx);
242 reprogram_fixed_counter(pmc, ctrl, idx);
245 EXPORT_SYMBOL_GPL(reprogram_counter);
247 void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
249 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
253 bitmask = pmu->reprogram_pmi;
255 for_each_set_bit(bit, (unsigned long *)&bitmask, X86_PMC_IDX_MAX) {
256 struct kvm_pmc *pmc = kvm_x86_ops->pmu_ops->pmc_idx_to_pmc(pmu, bit);
258 if (unlikely(!pmc || !pmc->perf_event)) {
259 clear_bit(bit, (unsigned long *)&pmu->reprogram_pmi);
263 reprogram_counter(pmu, bit);
267 /* check if idx is a valid index to access PMU */
268 int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
270 return kvm_x86_ops->pmu_ops->is_valid_msr_idx(vcpu, idx);
273 bool is_vmware_backdoor_pmc(u32 pmc_idx)
276 case VMWARE_BACKDOOR_PMC_HOST_TSC:
277 case VMWARE_BACKDOOR_PMC_REAL_TIME:
278 case VMWARE_BACKDOOR_PMC_APPARENT_TIME:
284 static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
289 case VMWARE_BACKDOOR_PMC_HOST_TSC:
292 case VMWARE_BACKDOOR_PMC_REAL_TIME:
293 ctr_val = ktime_get_boottime_ns();
295 case VMWARE_BACKDOOR_PMC_APPARENT_TIME:
296 ctr_val = ktime_get_boottime_ns() +
297 vcpu->kvm->arch.kvmclock_offset;
307 int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
309 bool fast_mode = idx & (1u << 31);
310 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
312 u64 mask = fast_mode ? ~0u : ~0ull;
317 if (is_vmware_backdoor_pmc(idx))
318 return kvm_pmu_rdpmc_vmware(vcpu, idx, data);
320 pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx, &mask);
324 *data = pmc_read_counter(pmc) & mask;
328 void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
330 if (lapic_in_kernel(vcpu))
331 kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
334 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
336 return kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr);
339 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
341 return kvm_x86_ops->pmu_ops->get_msr(vcpu, msr, data);
344 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
346 return kvm_x86_ops->pmu_ops->set_msr(vcpu, msr_info);
349 /* refresh PMU settings. This function generally is called when underlying
350 * settings are changed (such as changes of PMU CPUID by guest VMs), which
351 * should rarely happen.
353 void kvm_pmu_refresh(struct kvm_vcpu *vcpu)
355 kvm_x86_ops->pmu_ops->refresh(vcpu);
358 void kvm_pmu_reset(struct kvm_vcpu *vcpu)
360 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
362 irq_work_sync(&pmu->irq_work);
363 kvm_x86_ops->pmu_ops->reset(vcpu);
366 void kvm_pmu_init(struct kvm_vcpu *vcpu)
368 struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
370 memset(pmu, 0, sizeof(*pmu));
371 kvm_x86_ops->pmu_ops->init(vcpu);
372 init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn);
373 kvm_pmu_refresh(vcpu);
376 void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
381 int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
383 struct kvm_pmu_event_filter tmp, *filter;
387 if (copy_from_user(&tmp, argp, sizeof(tmp)))
390 if (tmp.action != KVM_PMU_EVENT_ALLOW &&
391 tmp.action != KVM_PMU_EVENT_DENY)
397 if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS)
400 size = struct_size(filter, events, tmp.nevents);
401 filter = kmalloc(size, GFP_KERNEL_ACCOUNT);
406 if (copy_from_user(filter, argp, size))
409 /* Ensure nevents can't be changed between the user copies. */
412 mutex_lock(&kvm->lock);
413 rcu_swap_protected(kvm->arch.pmu_event_filter, filter,
414 mutex_is_locked(&kvm->lock));
415 mutex_unlock(&kvm->lock);
417 synchronize_srcu_expedited(&kvm->srcu);