[4] = { 0x2e, 0x41, PERF_COUNT_HW_CACHE_MISSES },
[5] = { 0xc4, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
[6] = { 0xc5, 0x00, PERF_COUNT_HW_BRANCH_MISSES },
- [7] = { 0x00, 0x30, PERF_COUNT_HW_REF_CPU_CYCLES },
+ [7] = { 0x00, 0x03, PERF_COUNT_HW_REF_CPU_CYCLES },
};
/* mapping between fixed pmc index and intel_arch_events array */
return &counters[array_index_nospec(idx, num_counters)];
}
-static inline bool fw_writes_is_enabled(struct kvm_vcpu *vcpu)
+static inline u64 vcpu_get_perf_capabilities(struct kvm_vcpu *vcpu)
{
if (!guest_cpuid_has(vcpu, X86_FEATURE_PDCM))
- return false;
+ return 0;
- return vcpu->arch.perf_capabilities & PMU_CAP_FW_WRITES;
+ return vcpu->arch.perf_capabilities;
+}
+
+static inline bool fw_writes_is_enabled(struct kvm_vcpu *vcpu)
+{
+ return (vcpu_get_perf_capabilities(vcpu) & PMU_CAP_FW_WRITES) != 0;
}
static inline struct kvm_pmc *get_fw_gp_pmc(struct kvm_pmu *pmu, u32 msr)
return get_gp_pmc(pmu, msr, MSR_IA32_PMC0);
}
+bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu)
+{
+ /*
+ * As a first step, a guest could only enable LBR feature if its
+ * cpu model is the same as the host because the LBR registers
+ * would be pass-through to the guest and they're model specific.
+ */
+ return boot_cpu_data.x86_model == guest_cpuid_model(vcpu);
+}
+
+bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
+{
+ struct x86_pmu_lbr *lbr = vcpu_to_lbr_records(vcpu);
+
+ return lbr->nr && (vcpu_get_perf_capabilities(vcpu) & PMU_CAP_LBR_FMT);
+}
+
+static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index)
+{
+ struct x86_pmu_lbr *records = vcpu_to_lbr_records(vcpu);
+ bool ret = false;
+
+ if (!intel_pmu_lbr_is_enabled(vcpu))
+ return ret;
+
+ ret = (index == MSR_LBR_SELECT) || (index == MSR_LBR_TOS) ||
+ (index >= records->from && index < records->from + records->nr) ||
+ (index >= records->to && index < records->to + records->nr);
+
+ if (!ret && records->info)
+ ret = (index >= records->info && index < records->info + records->nr);
+
+ return ret;
+}
+
static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
default:
ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) ||
get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) ||
- get_fixed_pmc(pmu, msr) || get_fw_gp_pmc(pmu, msr);
+ get_fixed_pmc(pmu, msr) || get_fw_gp_pmc(pmu, msr) ||
+ intel_pmu_is_valid_lbr_msr(vcpu, msr);
break;
}
return pmc;
}
+static inline void intel_pmu_release_guest_lbr_event(struct kvm_vcpu *vcpu)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+
+ if (lbr_desc->event) {
+ perf_event_release_kernel(lbr_desc->event);
+ lbr_desc->event = NULL;
+ vcpu_to_pmu(vcpu)->event_count--;
+ }
+}
+
+int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+ struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+ struct perf_event *event;
+
+ /*
+ * The perf_event_attr is constructed in the minimum efficient way:
+ * - set 'pinned = true' to make it task pinned so that if another
+ * cpu pinned event reclaims LBR, the event->oncpu will be set to -1;
+ * - set '.exclude_host = true' to record guest branches behavior;
+ *
+ * - set '.config = INTEL_FIXED_VLBR_EVENT' to indicates host perf
+ * schedule the event without a real HW counter but a fake one;
+ * check is_guest_lbr_event() and __intel_get_event_constraints();
+ *
+ * - set 'sample_type = PERF_SAMPLE_BRANCH_STACK' and
+ * 'branch_sample_type = PERF_SAMPLE_BRANCH_CALL_STACK |
+ * PERF_SAMPLE_BRANCH_USER' to configure it as a LBR callstack
+ * event, which helps KVM to save/restore guest LBR records
+ * during host context switches and reduces quite a lot overhead,
+ * check branch_user_callstack() and intel_pmu_lbr_sched_task();
+ */
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_RAW,
+ .size = sizeof(attr),
+ .config = INTEL_FIXED_VLBR_EVENT,
+ .sample_type = PERF_SAMPLE_BRANCH_STACK,
+ .pinned = true,
+ .exclude_host = true,
+ .branch_sample_type = PERF_SAMPLE_BRANCH_CALL_STACK |
+ PERF_SAMPLE_BRANCH_USER,
+ };
+
+ if (unlikely(lbr_desc->event)) {
+ __set_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use);
+ return 0;
+ }
+
+ event = perf_event_create_kernel_counter(&attr, -1,
+ current, NULL, NULL);
+ if (IS_ERR(event)) {
+ pr_debug_ratelimited("%s: failed %ld\n",
+ __func__, PTR_ERR(event));
+ return PTR_ERR(event);
+ }
+ lbr_desc->event = event;
+ pmu->event_count++;
+ __set_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use);
+ return 0;
+}
+
+/*
+ * It's safe to access LBR msrs from guest when they have not
+ * been passthrough since the host would help restore or reset
+ * the LBR msrs records when the guest LBR event is scheduled in.
+ */
+static bool intel_pmu_handle_lbr_msrs_access(struct kvm_vcpu *vcpu,
+ struct msr_data *msr_info, bool read)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+ u32 index = msr_info->index;
+
+ if (!intel_pmu_is_valid_lbr_msr(vcpu, index))
+ return false;
+
+ if (!lbr_desc->event && intel_pmu_create_guest_lbr_event(vcpu) < 0)
+ goto dummy;
+
+ /*
+ * Disable irq to ensure the LBR feature doesn't get reclaimed by the
+ * host at the time the value is read from the msr, and this avoids the
+ * host LBR value to be leaked to the guest. If LBR has been reclaimed,
+ * return 0 on guest reads.
+ */
+ local_irq_disable();
+ if (lbr_desc->event->state == PERF_EVENT_STATE_ACTIVE) {
+ if (read)
+ rdmsrl(index, msr_info->data);
+ else
+ wrmsrl(index, msr_info->data);
+ __set_bit(INTEL_PMC_IDX_FIXED_VLBR, vcpu_to_pmu(vcpu)->pmc_in_use);
+ local_irq_enable();
+ return true;
+ }
+ clear_bit(INTEL_PMC_IDX_FIXED_VLBR, vcpu_to_pmu(vcpu)->pmc_in_use);
+ local_irq_enable();
+
+dummy:
+ if (read)
+ msr_info->data = 0;
+ return true;
+}
+
static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
} else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
msr_info->data = pmc->eventsel;
return 0;
- }
+ } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, true))
+ return 0;
}
return 1;
reprogram_gp_counter(pmc, data);
return 0;
}
- }
+ } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false))
+ return 0;
}
return 1;
static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+
struct x86_pmu_capability x86_pmu;
struct kvm_cpuid_entry2 *entry;
union cpuid10_eax eax;
pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
pmu->version = 0;
pmu->reserved_bits = 0xffffffff00200000ull;
- vcpu->arch.perf_capabilities = 0;
entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
if (!entry)
return;
perf_get_x86_pmu_capability(&x86_pmu);
- if (guest_cpuid_has(vcpu, X86_FEATURE_PDCM))
- vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
x86_pmu.num_counters_gp);
+ eax.split.bit_width = min_t(int, eax.split.bit_width, x86_pmu.bit_width_gp);
pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1;
+ eax.split.mask_length = min_t(int, eax.split.mask_length, x86_pmu.events_mask_len);
pmu->available_event_types = ~entry->ebx &
((1ull << eax.split.mask_length) - 1);
pmu->nr_arch_fixed_counters =
min_t(int, edx.split.num_counters_fixed,
x86_pmu.num_counters_fixed);
+ edx.split.bit_width_fixed = min_t(int,
+ edx.split.bit_width_fixed, x86_pmu.bit_width_fixed);
pmu->counter_bitmask[KVM_PMC_FIXED] =
((u64)1 << edx.split.bit_width_fixed) - 1;
}
INTEL_PMC_MAX_GENERIC, pmu->nr_arch_fixed_counters);
nested_vmx_pmu_entry_exit_ctls_update(vcpu);
+
+ if (intel_pmu_lbr_is_compatible(vcpu))
+ x86_perf_get_lbr(&lbr_desc->records);
+ else
+ lbr_desc->records.nr = 0;
+
+ if (lbr_desc->records.nr)
+ bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1);
}
static void intel_pmu_init(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) {
pmu->gp_counters[i].type = KVM_PMC_GP;
pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
pmu->fixed_counters[i].current_config = 0;
}
+
+ vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
+ lbr_desc->records.nr = 0;
+ lbr_desc->event = NULL;
+ lbr_desc->msr_passthrough = false;
}
static void intel_pmu_reset(struct kvm_vcpu *vcpu)
pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status =
pmu->global_ovf_ctrl = 0;
+
+ intel_pmu_release_guest_lbr_event(vcpu);
+}
+
+/*
+ * Emulate LBR_On_PMI behavior for 1 < pmu.version < 4.
+ *
+ * If Freeze_LBR_On_PMI = 1, the LBR is frozen on PMI and
+ * the KVM emulates to clear the LBR bit (bit 0) in IA32_DEBUGCTL.
+ *
+ * Guest needs to re-enable LBR to resume branches recording.
+ */
+static void intel_pmu_legacy_freezing_lbrs_on_pmi(struct kvm_vcpu *vcpu)
+{
+ u64 data = vmcs_read64(GUEST_IA32_DEBUGCTL);
+
+ if (data & DEBUGCTLMSR_FREEZE_LBRS_ON_PMI) {
+ data &= ~DEBUGCTLMSR_LBR;
+ vmcs_write64(GUEST_IA32_DEBUGCTL, data);
+ }
+}
+
+static void intel_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
+{
+ u8 version = vcpu_to_pmu(vcpu)->version;
+
+ if (!intel_pmu_lbr_is_enabled(vcpu))
+ return;
+
+ if (version > 1 && version < 4)
+ intel_pmu_legacy_freezing_lbrs_on_pmi(vcpu);
+}
+
+static void vmx_update_intercept_for_lbr_msrs(struct kvm_vcpu *vcpu, bool set)
+{
+ struct x86_pmu_lbr *lbr = vcpu_to_lbr_records(vcpu);
+ int i;
+
+ for (i = 0; i < lbr->nr; i++) {
+ vmx_set_intercept_for_msr(vcpu, lbr->from + i, MSR_TYPE_RW, set);
+ vmx_set_intercept_for_msr(vcpu, lbr->to + i, MSR_TYPE_RW, set);
+ if (lbr->info)
+ vmx_set_intercept_for_msr(vcpu, lbr->info + i, MSR_TYPE_RW, set);
+ }
+
+ vmx_set_intercept_for_msr(vcpu, MSR_LBR_SELECT, MSR_TYPE_RW, set);
+ vmx_set_intercept_for_msr(vcpu, MSR_LBR_TOS, MSR_TYPE_RW, set);
+}
+
+static inline void vmx_disable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+
+ if (!lbr_desc->msr_passthrough)
+ return;
+
+ vmx_update_intercept_for_lbr_msrs(vcpu, true);
+ lbr_desc->msr_passthrough = false;
+}
+
+static inline void vmx_enable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+
+ if (lbr_desc->msr_passthrough)
+ return;
+
+ vmx_update_intercept_for_lbr_msrs(vcpu, false);
+ lbr_desc->msr_passthrough = true;
+}
+
+/*
+ * Higher priority host perf events (e.g. cpu pinned) could reclaim the
+ * pmu resources (e.g. LBR) that were assigned to the guest. This is
+ * usually done via ipi calls (more details in perf_install_in_context).
+ *
+ * Before entering the non-root mode (with irq disabled here), double
+ * confirm that the pmu features enabled to the guest are not reclaimed
+ * by higher priority host events. Otherwise, disallow vcpu's access to
+ * the reclaimed features.
+ */
+void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
+{
+ struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+
+ if (!lbr_desc->event) {
+ vmx_disable_lbr_msrs_passthrough(vcpu);
+ if (vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR)
+ goto warn;
+ if (test_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use))
+ goto warn;
+ return;
+ }
+
+ if (lbr_desc->event->state < PERF_EVENT_STATE_ACTIVE) {
+ vmx_disable_lbr_msrs_passthrough(vcpu);
+ __clear_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use);
+ goto warn;
+ } else
+ vmx_enable_lbr_msrs_passthrough(vcpu);
+
+ return;
+
+warn:
+ pr_warn_ratelimited("kvm: vcpu-%d: fail to passthrough LBR.\n",
+ vcpu->vcpu_id);
+}
+
+static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
+{
+ if (!(vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR))
+ intel_pmu_release_guest_lbr_event(vcpu);
}
struct kvm_pmu_ops intel_pmu_ops = {
.refresh = intel_pmu_refresh,
.init = intel_pmu_init,
.reset = intel_pmu_reset,
+ .deliver_pmi = intel_pmu_deliver_pmi,
+ .cleanup = intel_pmu_cleanup,
};
projects / mirror_ubuntu-jammy-kernel.git / blobdiff