drm/panthor: Don't add write fences to the shared BOs

[drm/drm-misc.git] / arch / x86 / kvm / vmx / pmu_intel.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * KVM PMU support for Intel CPUs
 *
 * Copyright 2011 Red Hat, Inc. and/or its affiliates.
 *
 * Authors:
 *   Avi Kivity   <avi@redhat.com>
 *   Gleb Natapov <gleb@redhat.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/kvm_host.h>
#include <linux/perf_event.h>
#include <asm/perf_event.h>
#include "x86.h"
#include "cpuid.h"
#include "lapic.h"
#include "nested.h"
#include "pmu.h"

/*
 * Perf's "BASE" is wildly misleading, architectural PMUs use bits 31:16 of ECX
 * to encode the "type" of counter to read, i.e. this is not a "base".  And to
 * further confuse things, non-architectural PMUs use bit 31 as a flag for
 * "fast" reads, whereas the "type" is an explicit value.
 */
#define INTEL_RDPMC_GP          0
#define INTEL_RDPMC_FIXED       INTEL_PMC_FIXED_RDPMC_BASE

#define INTEL_RDPMC_TYPE_MASK   GENMASK(31, 16)
#define INTEL_RDPMC_INDEX_MASK  GENMASK(15, 0)

#define MSR_PMC_FULL_WIDTH_BIT      (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)

static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
{
        struct kvm_pmc *pmc;
        u64 old_fixed_ctr_ctrl = pmu->fixed_ctr_ctrl;
        int i;

        pmu->fixed_ctr_ctrl = data;
        for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
                u8 new_ctrl = fixed_ctrl_field(data, i);
                u8 old_ctrl = fixed_ctrl_field(old_fixed_ctr_ctrl, i);

                if (old_ctrl == new_ctrl)
                        continue;

                pmc = get_fixed_pmc(pmu, MSR_CORE_PERF_FIXED_CTR0 + i);

                __set_bit(KVM_FIXED_PMC_BASE_IDX + i, pmu->pmc_in_use);
                kvm_pmu_request_counter_reprogram(pmc);
        }
}

static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu,
                                            unsigned int idx, u64 *mask)
{
        unsigned int type = idx & INTEL_RDPMC_TYPE_MASK;
        struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
        struct kvm_pmc *counters;
        unsigned int num_counters;
        u64 bitmask;

        /*
         * The encoding of ECX for RDPMC is different for architectural versus
         * non-architecturals PMUs (PMUs with version '0').  For architectural
         * PMUs, bits 31:16 specify the PMC type and bits 15:0 specify the PMC
         * index.  For non-architectural PMUs, bit 31 is a "fast" flag, and
         * bits 30:0 specify the PMC index.
         *
         * Yell and reject attempts to read PMCs for a non-architectural PMU,
         * as KVM doesn't support such PMUs.
         */
        if (WARN_ON_ONCE(!pmu->version))
                return NULL;

        /*
         * General Purpose (GP) PMCs are supported on all PMUs, and fixed PMCs
         * are supported on all architectural PMUs, i.e. on all virtual PMUs
         * supported by KVM.  Note, KVM only emulates fixed PMCs for PMU v2+,
         * but the type itself is still valid, i.e. let RDPMC fail due to
         * accessing a non-existent counter.  Reject attempts to read all other
         * types, which are unknown/unsupported.
         */
        switch (type) {
        case INTEL_RDPMC_FIXED:
                counters = pmu->fixed_counters;
                num_counters = pmu->nr_arch_fixed_counters;
                bitmask = pmu->counter_bitmask[KVM_PMC_FIXED];
                break;
        case INTEL_RDPMC_GP:
                counters = pmu->gp_counters;
                num_counters = pmu->nr_arch_gp_counters;
                bitmask = pmu->counter_bitmask[KVM_PMC_GP];
                break;
        default:
                return NULL;
        }

        idx &= INTEL_RDPMC_INDEX_MASK;
        if (idx >= num_counters)
                return NULL;

        *mask &= bitmask;
        return &counters[array_index_nospec(idx, num_counters)];
}

static inline u64 vcpu_get_perf_capabilities(struct kvm_vcpu *vcpu)
{
        if (!guest_cpuid_has(vcpu, X86_FEATURE_PDCM))
                return 0;

        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)
{
        if (!fw_writes_is_enabled(pmu_to_vcpu(pmu)))
                return NULL;

        return get_gp_pmc(pmu, msr, MSR_IA32_PMC0);
}

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);
        u64 perf_capabilities;
        int ret;

        switch (msr) {
        case MSR_CORE_PERF_FIXED_CTR_CTRL:
                return kvm_pmu_has_perf_global_ctrl(pmu);
        case MSR_IA32_PEBS_ENABLE:
                ret = vcpu_get_perf_capabilities(vcpu) & PERF_CAP_PEBS_FORMAT;
                break;
        case MSR_IA32_DS_AREA:
                ret = guest_cpuid_has(vcpu, X86_FEATURE_DS);
                break;
        case MSR_PEBS_DATA_CFG:
                perf_capabilities = vcpu_get_perf_capabilities(vcpu);
                ret = (perf_capabilities & PERF_CAP_PEBS_BASELINE) &&
                        ((perf_capabilities & PERF_CAP_PEBS_FORMAT) > 3);
                break;
        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) ||
                        intel_pmu_is_valid_lbr_msr(vcpu, msr);
                break;
        }

        return ret;
}

static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
{
        struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
        struct kvm_pmc *pmc;

        pmc = get_fixed_pmc(pmu, msr);
        pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0);
        pmc = pmc ? pmc : get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0);

        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);
        struct kvm_pmc *pmc;
        u32 msr = msr_info->index;

        switch (msr) {
        case MSR_CORE_PERF_FIXED_CTR_CTRL:
                msr_info->data = pmu->fixed_ctr_ctrl;
                break;
        case MSR_IA32_PEBS_ENABLE:
                msr_info->data = pmu->pebs_enable;
                break;
        case MSR_IA32_DS_AREA:
                msr_info->data = pmu->ds_area;
                break;
        case MSR_PEBS_DATA_CFG:
                msr_info->data = pmu->pebs_data_cfg;
                break;
        default:
                if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
                    (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
                        u64 val = pmc_read_counter(pmc);
                        msr_info->data =
                                val & pmu->counter_bitmask[KVM_PMC_GP];
                        break;
                } else if ((pmc = get_fixed_pmc(pmu, msr))) {
                        u64 val = pmc_read_counter(pmc);
                        msr_info->data =
                                val & pmu->counter_bitmask[KVM_PMC_FIXED];
                        break;
                } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
                        msr_info->data = pmc->eventsel;
                        break;
                } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, true)) {
                        break;
                }
                return 1;
        }

        return 0;
}

static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
        struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
        struct kvm_pmc *pmc;
        u32 msr = msr_info->index;
        u64 data = msr_info->data;
        u64 reserved_bits, diff;

        switch (msr) {
        case MSR_CORE_PERF_FIXED_CTR_CTRL:
                if (data & pmu->fixed_ctr_ctrl_rsvd)
                        return 1;

                if (pmu->fixed_ctr_ctrl != data)
                        reprogram_fixed_counters(pmu, data);
                break;
        case MSR_IA32_PEBS_ENABLE:
                if (data & pmu->pebs_enable_rsvd)
                        return 1;

                if (pmu->pebs_enable != data) {
                        diff = pmu->pebs_enable ^ data;
                        pmu->pebs_enable = data;
                        reprogram_counters(pmu, diff);
                }
                break;
        case MSR_IA32_DS_AREA:
                if (is_noncanonical_address(data, vcpu))
                        return 1;

                pmu->ds_area = data;
                break;
        case MSR_PEBS_DATA_CFG:
                if (data & pmu->pebs_data_cfg_rsvd)
                        return 1;

                pmu->pebs_data_cfg = data;
                break;
        default:
                if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
                    (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
                        if ((msr & MSR_PMC_FULL_WIDTH_BIT) &&
                            (data & ~pmu->counter_bitmask[KVM_PMC_GP]))
                                return 1;

                        if (!msr_info->host_initiated &&
                            !(msr & MSR_PMC_FULL_WIDTH_BIT))
                                data = (s64)(s32)data;
                        pmc_write_counter(pmc, data);
                        break;
                } else if ((pmc = get_fixed_pmc(pmu, msr))) {
                        pmc_write_counter(pmc, data);
                        break;
                } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
                        reserved_bits = pmu->reserved_bits;
                        if ((pmc->idx == 2) &&
                            (pmu->raw_event_mask & HSW_IN_TX_CHECKPOINTED))
                                reserved_bits ^= HSW_IN_TX_CHECKPOINTED;
                        if (data & reserved_bits)
                                return 1;

                        if (data != pmc->eventsel) {
                                pmc->eventsel = data;
                                kvm_pmu_request_counter_reprogram(pmc);
                        }
                        break;
                } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false)) {
                        break;
                }
                /* Not a known PMU MSR. */
                return 1;
        }

        return 0;
}

/*
 * Map fixed counter events to architectural general purpose event encodings.
 * Perf doesn't provide APIs to allow KVM to directly program a fixed counter,
 * and so KVM instead programs the architectural event to effectively request
 * the fixed counter.  Perf isn't guaranteed to use a fixed counter and may
 * instead program the encoding into a general purpose counter, e.g. if a
 * different perf_event is already utilizing the requested counter, but the end
 * result is the same (ignoring the fact that using a general purpose counter
 * will likely exacerbate counter contention).
 *
 * Forcibly inlined to allow asserting on @index at build time, and there should
 * never be more than one user.
 */
static __always_inline u64 intel_get_fixed_pmc_eventsel(unsigned int index)
{
        const enum perf_hw_id fixed_pmc_perf_ids[] = {
                [0] = PERF_COUNT_HW_INSTRUCTIONS,
                [1] = PERF_COUNT_HW_CPU_CYCLES,
                [2] = PERF_COUNT_HW_REF_CPU_CYCLES,
        };
        u64 eventsel;

        BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_perf_ids) != KVM_MAX_NR_INTEL_FIXED_COUTNERS);
        BUILD_BUG_ON(index >= KVM_MAX_NR_INTEL_FIXED_COUTNERS);

        /*
         * Yell if perf reports support for a fixed counter but perf doesn't
         * have a known encoding for the associated general purpose event.
         */
        eventsel = perf_get_hw_event_config(fixed_pmc_perf_ids[index]);
        WARN_ON_ONCE(!eventsel && index < kvm_pmu_cap.num_counters_fixed);
        return eventsel;
}

static void intel_pmu_enable_fixed_counter_bits(struct kvm_pmu *pmu, u64 bits)
{
        int i;

        for (i = 0; i < pmu->nr_arch_fixed_counters; i++)
                pmu->fixed_ctr_ctrl_rsvd &= ~intel_fixed_bits_by_idx(i, bits);
}

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 kvm_cpuid_entry2 *entry;
        union cpuid10_eax eax;
        union cpuid10_edx edx;
        u64 perf_capabilities;
        u64 counter_rsvd;

        memset(&lbr_desc->records, 0, sizeof(lbr_desc->records));

        /*
         * Setting passthrough of LBR MSRs is done only in the VM-Entry loop,
         * and PMU refresh is disallowed after the vCPU has run, i.e. this code
         * should never be reached while KVM is passing through MSRs.
         */
        if (KVM_BUG_ON(lbr_desc->msr_passthrough, vcpu->kvm))
                return;

        entry = kvm_find_cpuid_entry(vcpu, 0xa);
        if (!entry)
                return;

        eax.full = entry->eax;
        edx.full = entry->edx;

        pmu->version = eax.split.version_id;
        if (!pmu->version)
                return;

        pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
                                         kvm_pmu_cap.num_counters_gp);
        eax.split.bit_width = min_t(int, eax.split.bit_width,
                                    kvm_pmu_cap.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,
                                      kvm_pmu_cap.events_mask_len);
        pmu->available_event_types = ~entry->ebx &
                                        ((1ull << eax.split.mask_length) - 1);

        if (pmu->version == 1) {
                pmu->nr_arch_fixed_counters = 0;
        } else {
                pmu->nr_arch_fixed_counters = min_t(int, edx.split.num_counters_fixed,
                                                    kvm_pmu_cap.num_counters_fixed);
                edx.split.bit_width_fixed = min_t(int, edx.split.bit_width_fixed,
                                                  kvm_pmu_cap.bit_width_fixed);
                pmu->counter_bitmask[KVM_PMC_FIXED] =
                        ((u64)1 << edx.split.bit_width_fixed) - 1;
        }

        intel_pmu_enable_fixed_counter_bits(pmu, INTEL_FIXED_0_KERNEL |
                                                 INTEL_FIXED_0_USER |
                                                 INTEL_FIXED_0_ENABLE_PMI);

        counter_rsvd = ~(((1ull << pmu->nr_arch_gp_counters) - 1) |
                (((1ull << pmu->nr_arch_fixed_counters) - 1) << KVM_FIXED_PMC_BASE_IDX));
        pmu->global_ctrl_rsvd = counter_rsvd;

        /*
         * GLOBAL_STATUS and GLOBAL_OVF_CONTROL (a.k.a. GLOBAL_STATUS_RESET)
         * share reserved bit definitions.  The kernel just happens to use
         * OVF_CTRL for the names.
         */
        pmu->global_status_rsvd = pmu->global_ctrl_rsvd
                        & ~(MSR_CORE_PERF_GLOBAL_OVF_CTRL_OVF_BUF |
                            MSR_CORE_PERF_GLOBAL_OVF_CTRL_COND_CHGD);
        if (vmx_pt_mode_is_host_guest())
                pmu->global_status_rsvd &=
                                ~MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI;

        entry = kvm_find_cpuid_entry_index(vcpu, 7, 0);
        if (entry &&
            (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
            (entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM))) {
                pmu->reserved_bits ^= HSW_IN_TX;
                pmu->raw_event_mask |= (HSW_IN_TX|HSW_IN_TX_CHECKPOINTED);
        }

        bitmap_set(pmu->all_valid_pmc_idx,
                0, pmu->nr_arch_gp_counters);
        bitmap_set(pmu->all_valid_pmc_idx,
                INTEL_PMC_MAX_GENERIC, pmu->nr_arch_fixed_counters);

        perf_capabilities = vcpu_get_perf_capabilities(vcpu);
        if (cpuid_model_is_consistent(vcpu) &&
            (perf_capabilities & PMU_CAP_LBR_FMT))
                memcpy(&lbr_desc->records, &vmx_lbr_caps, sizeof(vmx_lbr_caps));
        else
                lbr_desc->records.nr = 0;

        if (lbr_desc->records.nr)
                bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1);

        if (perf_capabilities & PERF_CAP_PEBS_FORMAT) {
                if (perf_capabilities & PERF_CAP_PEBS_BASELINE) {
                        pmu->pebs_enable_rsvd = counter_rsvd;
                        pmu->reserved_bits &= ~ICL_EVENTSEL_ADAPTIVE;
                        pmu->pebs_data_cfg_rsvd = ~0xff00000full;
                        intel_pmu_enable_fixed_counter_bits(pmu, ICL_FIXED_0_ADAPTIVE);
                } else {
                        pmu->pebs_enable_rsvd =
                                ~((1ull << pmu->nr_arch_gp_counters) - 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 < KVM_MAX_NR_INTEL_GP_COUNTERS; i++) {
                pmu->gp_counters[i].type = KVM_PMC_GP;
                pmu->gp_counters[i].vcpu = vcpu;
                pmu->gp_counters[i].idx = i;
                pmu->gp_counters[i].current_config = 0;
        }

        for (i = 0; i < KVM_MAX_NR_INTEL_FIXED_COUTNERS; i++) {
                pmu->fixed_counters[i].type = KVM_PMC_FIXED;
                pmu->fixed_counters[i].vcpu = vcpu;
                pmu->fixed_counters[i].idx = i + KVM_FIXED_PMC_BASE_IDX;
                pmu->fixed_counters[i].current_config = 0;
                pmu->fixed_counters[i].eventsel = intel_get_fixed_pmc_eventsel(i);
        }

        lbr_desc->records.nr = 0;
        lbr_desc->event = NULL;
        lbr_desc->msr_passthrough = false;
}

static void intel_pmu_reset(struct kvm_vcpu *vcpu)
{
        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("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);
}

void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
{
        struct kvm_pmc *pmc = NULL;
        int bit, hw_idx;

        kvm_for_each_pmc(pmu, pmc, bit, (unsigned long *)&pmu->global_ctrl) {
                if (!pmc_speculative_in_use(pmc) ||
                    !pmc_is_globally_enabled(pmc) || !pmc->perf_event)
                        continue;

                /*
                 * A negative index indicates the event isn't mapped to a
                 * physical counter in the host, e.g. due to contention.
                 */
                hw_idx = pmc->perf_event->hw.idx;
                if (hw_idx != pmc->idx && hw_idx > -1)
                        pmu->host_cross_mapped_mask |= BIT_ULL(hw_idx);
        }
}

struct kvm_pmu_ops intel_pmu_ops __initdata = {
        .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
        .msr_idx_to_pmc = intel_msr_idx_to_pmc,
        .is_valid_msr = intel_is_valid_msr,
        .get_msr = intel_pmu_get_msr,
        .set_msr = intel_pmu_set_msr,
        .refresh = intel_pmu_refresh,
        .init = intel_pmu_init,
        .reset = intel_pmu_reset,
        .deliver_pmi = intel_pmu_deliver_pmi,
        .cleanup = intel_pmu_cleanup,
        .EVENTSEL_EVENT = ARCH_PERFMON_EVENTSEL_EVENT,
        .MAX_NR_GP_COUNTERS = KVM_MAX_NR_INTEL_GP_COUNTERS,
        .MIN_NR_GP_COUNTERS = 1,
};