// SPDX-License-Identifier: GPL-2.0-only
/*
 * KVM Microsoft Hyper-V emulation
 *
 * derived from arch/x86/kvm/x86.c
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2008 Qumranet, Inc.
 * Copyright IBM Corporation, 2008
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 * Copyright (C) 2015 Andrey Smetanin <asmetanin@virtuozzo.com>
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Amit Shah    <amit.shah@qumranet.com>
 *   Ben-Ami Yassour <benami@il.ibm.com>
 *   Andrey Smetanin <asmetanin@virtuozzo.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "x86.h"
#include "lapic.h"
#include "ioapic.h"
#include "cpuid.h"
#include "hyperv.h"
#include "mmu.h"
#include "xen.h"

#include <linux/cpu.h>
#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <linux/sched/cputime.h>
#include <linux/spinlock.h>
#include <linux/eventfd.h>

#include <asm/apicdef.h>
#include <asm/mshyperv.h>
#include <trace/events/kvm.h>

#include "trace.h"
#include "irq.h"
#include "fpu.h"

#define KVM_HV_MAX_SPARSE_VCPU_SET_BITS DIV_ROUND_UP(KVM_MAX_VCPUS, HV_VCPUS_PER_SPARSE_BANK)

/*
 * As per Hyper-V TLFS, extended hypercalls start from 0x8001
 * (HvExtCallQueryCapabilities). Response of this hypercalls is a 64 bit value
 * where each bit tells which extended hypercall is available besides
 * HvExtCallQueryCapabilities.
 *
 * 0x8001 - First extended hypercall, HvExtCallQueryCapabilities, no bit
 * assigned.
 *
 * 0x8002 - Bit 0
 * 0x8003 - Bit 1
 * ..
 * 0x8041 - Bit 63
 *
 * Therefore, HV_EXT_CALL_MAX = 0x8001 + 64
 */
#define HV_EXT_CALL_MAX (HV_EXT_CALL_QUERY_CAPABILITIES + 64)

static void stimer_mark_pending(struct kvm_vcpu_hv_stimer *stimer,
                                bool vcpu_kick);

static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
{
        return atomic64_read(&synic->sint[sint]);
}

static inline int synic_get_sint_vector(u64 sint_value)
{
        if (sint_value & HV_SYNIC_SINT_MASKED)
                return -1;
        return sint_value & HV_SYNIC_SINT_VECTOR_MASK;
}

static bool synic_has_vector_connected(struct kvm_vcpu_hv_synic *synic,
                                      int vector)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
                if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
                        return true;
        }
        return false;
}

static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic,
                                     int vector)
{
        int i;
        u64 sint_value;

        for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
                sint_value = synic_read_sint(synic, i);
                if (synic_get_sint_vector(sint_value) == vector &&
                    sint_value & HV_SYNIC_SINT_AUTO_EOI)
                        return true;
        }
        return false;
}

static void synic_update_vector(struct kvm_vcpu_hv_synic *synic,
                                int vector)
{
        struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);
        struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);
        bool auto_eoi_old, auto_eoi_new;

        if (vector < HV_SYNIC_FIRST_VALID_VECTOR)
                return;

        if (synic_has_vector_connected(synic, vector))
                __set_bit(vector, synic->vec_bitmap);
        else
                __clear_bit(vector, synic->vec_bitmap);

        auto_eoi_old = !bitmap_empty(synic->auto_eoi_bitmap, 256);

        if (synic_has_vector_auto_eoi(synic, vector))
                __set_bit(vector, synic->auto_eoi_bitmap);
        else
                __clear_bit(vector, synic->auto_eoi_bitmap);

        auto_eoi_new = !bitmap_empty(synic->auto_eoi_bitmap, 256);

        if (auto_eoi_old == auto_eoi_new)
                return;

        if (!enable_apicv)
                return;

        down_write(&vcpu->kvm->arch.apicv_update_lock);

        if (auto_eoi_new)
                hv->synic_auto_eoi_used++;
        else
                hv->synic_auto_eoi_used--;

        /*
         * Inhibit APICv if any vCPU is using SynIC's AutoEOI, which relies on
         * the hypervisor to manually inject IRQs.
         */
        __kvm_set_or_clear_apicv_inhibit(vcpu->kvm,
                                         APICV_INHIBIT_REASON_HYPERV,
                                         !!hv->synic_auto_eoi_used);

        up_write(&vcpu->kvm->arch.apicv_update_lock);
}

static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
                          u64 data, bool host)
{
        int vector, old_vector;
        bool masked;

        vector = data & HV_SYNIC_SINT_VECTOR_MASK;
        masked = data & HV_SYNIC_SINT_MASKED;

        /*
         * Valid vectors are 16-255, however, nested Hyper-V attempts to write
         * default '0x10000' value on boot and this should not #GP. We need to
         * allow zero-initing the register from host as well.
         */
        if (vector < HV_SYNIC_FIRST_VALID_VECTOR && !host && !masked)
                return 1;
        /*
         * Guest may configure multiple SINTs to use the same vector, so
         * we maintain a bitmap of vectors handled by synic, and a
         * bitmap of vectors with auto-eoi behavior.  The bitmaps are
         * updated here, and atomically queried on fast paths.
         */
        old_vector = synic_read_sint(synic, sint) & HV_SYNIC_SINT_VECTOR_MASK;

        atomic64_set(&synic->sint[sint], data);

        synic_update_vector(synic, old_vector);

        synic_update_vector(synic, vector);

        /* Load SynIC vectors into EOI exit bitmap */
        kvm_make_request(KVM_REQ_SCAN_IOAPIC, hv_synic_to_vcpu(synic));
        return 0;
}

static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm, u32 vpidx)
{
        struct kvm_vcpu *vcpu = NULL;
        unsigned long i;

        if (vpidx >= KVM_MAX_VCPUS)
                return NULL;

        vcpu = kvm_get_vcpu(kvm, vpidx);
        if (vcpu && kvm_hv_get_vpindex(vcpu) == vpidx)
                return vcpu;
        kvm_for_each_vcpu(i, vcpu, kvm)
                if (kvm_hv_get_vpindex(vcpu) == vpidx)
                        return vcpu;
        return NULL;
}

static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vpidx)
{
        struct kvm_vcpu *vcpu;
        struct kvm_vcpu_hv_synic *synic;

        vcpu = get_vcpu_by_vpidx(kvm, vpidx);
        if (!vcpu || !to_hv_vcpu(vcpu))
                return NULL;
        synic = to_hv_synic(vcpu);
        return (synic->active) ? synic : NULL;
}

static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint)
{
        struct kvm *kvm = vcpu->kvm;
        struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu);
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        struct kvm_vcpu_hv_stimer *stimer;
        int gsi, idx;

        trace_kvm_hv_notify_acked_sint(vcpu->vcpu_id, sint);

        /* Try to deliver pending Hyper-V SynIC timers messages */
        for (idx = 0; idx < ARRAY_SIZE(hv_vcpu->stimer); idx++) {
                stimer = &hv_vcpu->stimer[idx];
                if (stimer->msg_pending && stimer->config.enable &&
                    !stimer->config.direct_mode &&
                    stimer->config.sintx == sint)
                        stimer_mark_pending(stimer, false);
        }

        idx = srcu_read_lock(&kvm->irq_srcu);
        gsi = atomic_read(&synic->sint_to_gsi[sint]);
        if (gsi != -1)
                kvm_notify_acked_gsi(kvm, gsi);
        srcu_read_unlock(&kvm->irq_srcu, idx);
}

static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)
{
        struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNIC;
        hv_vcpu->exit.u.synic.msr = msr;
        hv_vcpu->exit.u.synic.control = synic->control;
        hv_vcpu->exit.u.synic.evt_page = synic->evt_page;
        hv_vcpu->exit.u.synic.msg_page = synic->msg_page;

        kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
}

static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
                         u32 msr, u64 data, bool host)
{
        struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);
        int ret;

        if (!synic->active && (!host || data))
                return 1;

        trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host);

        ret = 0;
        switch (msr) {
        case HV_X64_MSR_SCONTROL:
                synic->control = data;
                if (!host)
                        synic_exit(synic, msr);
                break;
        case HV_X64_MSR_SVERSION:
                if (!host) {
                        ret = 1;
                        break;
                }
                synic->version = data;
                break;
        case HV_X64_MSR_SIEFP:
                if ((data & HV_SYNIC_SIEFP_ENABLE) && !host &&
                    !synic->dont_zero_synic_pages)
                        if (kvm_clear_guest(vcpu->kvm,
                                            data & PAGE_MASK, PAGE_SIZE)) {
                                ret = 1;
                                break;
                        }
                synic->evt_page = data;
                if (!host)
                        synic_exit(synic, msr);
                break;
        case HV_X64_MSR_SIMP:
                if ((data & HV_SYNIC_SIMP_ENABLE) && !host &&
                    !synic->dont_zero_synic_pages)
                        if (kvm_clear_guest(vcpu->kvm,
                                            data & PAGE_MASK, PAGE_SIZE)) {
                                ret = 1;
                                break;
                        }
                synic->msg_page = data;
                if (!host)
                        synic_exit(synic, msr);
                break;
        case HV_X64_MSR_EOM: {
                int i;

                if (!synic->active)
                        break;

                for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
                        kvm_hv_notify_acked_sint(vcpu, i);
                break;
        }
        case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
                ret = synic_set_sint(synic, msr - HV_X64_MSR_SINT0, data, host);
                break;
        default:
                ret = 1;
                break;
        }
        return ret;
}

static bool kvm_hv_is_syndbg_enabled(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        return hv_vcpu->cpuid_cache.syndbg_cap_eax &
                HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
}

static int kvm_hv_syndbg_complete_userspace(struct kvm_vcpu *vcpu)
{
        struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);

        if (vcpu->run->hyperv.u.syndbg.msr == HV_X64_MSR_SYNDBG_CONTROL)
                hv->hv_syndbg.control.status =
                        vcpu->run->hyperv.u.syndbg.status;
        return 1;
}

static void syndbg_exit(struct kvm_vcpu *vcpu, u32 msr)
{
        struct kvm_hv_syndbg *syndbg = to_hv_syndbg(vcpu);
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNDBG;
        hv_vcpu->exit.u.syndbg.msr = msr;
        hv_vcpu->exit.u.syndbg.control = syndbg->control.control;
        hv_vcpu->exit.u.syndbg.send_page = syndbg->control.send_page;
        hv_vcpu->exit.u.syndbg.recv_page = syndbg->control.recv_page;
        hv_vcpu->exit.u.syndbg.pending_page = syndbg->control.pending_page;
        vcpu->arch.complete_userspace_io =
                        kvm_hv_syndbg_complete_userspace;

        kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
}

static int syndbg_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
{
        struct kvm_hv_syndbg *syndbg = to_hv_syndbg(vcpu);

        if (!kvm_hv_is_syndbg_enabled(vcpu) && !host)
                return 1;

        trace_kvm_hv_syndbg_set_msr(vcpu->vcpu_id,
                                    to_hv_vcpu(vcpu)->vp_index, msr, data);
        switch (msr) {
        case HV_X64_MSR_SYNDBG_CONTROL:
                syndbg->control.control = data;
                if (!host)
                        syndbg_exit(vcpu, msr);
                break;
        case HV_X64_MSR_SYNDBG_STATUS:
                syndbg->control.status = data;
                break;
        case HV_X64_MSR_SYNDBG_SEND_BUFFER:
                syndbg->control.send_page = data;
                break;
        case HV_X64_MSR_SYNDBG_RECV_BUFFER:
                syndbg->control.recv_page = data;
                break;
        case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
                syndbg->control.pending_page = data;
                if (!host)
                        syndbg_exit(vcpu, msr);
                break;
        case HV_X64_MSR_SYNDBG_OPTIONS:
                syndbg->options = data;
                break;
        default:
                break;
        }

        return 0;
}

static int syndbg_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
{
        struct kvm_hv_syndbg *syndbg = to_hv_syndbg(vcpu);

        if (!kvm_hv_is_syndbg_enabled(vcpu) && !host)
                return 1;

        switch (msr) {
        case HV_X64_MSR_SYNDBG_CONTROL:
                *pdata = syndbg->control.control;
                break;
        case HV_X64_MSR_SYNDBG_STATUS:
                *pdata = syndbg->control.status;
                break;
        case HV_X64_MSR_SYNDBG_SEND_BUFFER:
                *pdata = syndbg->control.send_page;
                break;
        case HV_X64_MSR_SYNDBG_RECV_BUFFER:
                *pdata = syndbg->control.recv_page;
                break;
        case HV_X64_MSR_SYNDBG_PENDING_BUFFER:
                *pdata = syndbg->control.pending_page;
                break;
        case HV_X64_MSR_SYNDBG_OPTIONS:
                *pdata = syndbg->options;
                break;
        default:
                break;
        }

        trace_kvm_hv_syndbg_get_msr(vcpu->vcpu_id, kvm_hv_get_vpindex(vcpu), msr, *pdata);

        return 0;
}

static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata,
                         bool host)
{
        int ret;

        if (!synic->active && !host)
                return 1;

        ret = 0;
        switch (msr) {
        case HV_X64_MSR_SCONTROL:
                *pdata = synic->control;
                break;
        case HV_X64_MSR_SVERSION:
                *pdata = synic->version;
                break;
        case HV_X64_MSR_SIEFP:
                *pdata = synic->evt_page;
                break;
        case HV_X64_MSR_SIMP:
                *pdata = synic->msg_page;
                break;
        case HV_X64_MSR_EOM:
                *pdata = 0;
                break;
        case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
                *pdata = atomic64_read(&synic->sint[msr - HV_X64_MSR_SINT0]);
                break;
        default:
                ret = 1;
                break;
        }
        return ret;
}

static int synic_set_irq(struct kvm_vcpu_hv_synic *synic, u32 sint)
{
        struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);
        struct kvm_lapic_irq irq;
        int ret, vector;

        if (KVM_BUG_ON(!lapic_in_kernel(vcpu), vcpu->kvm))
                return -EINVAL;

        if (sint >= ARRAY_SIZE(synic->sint))
                return -EINVAL;

        vector = synic_get_sint_vector(synic_read_sint(synic, sint));
        if (vector < 0)
                return -ENOENT;

        memset(&irq, 0, sizeof(irq));
        irq.shorthand = APIC_DEST_SELF;
        irq.dest_mode = APIC_DEST_PHYSICAL;
        irq.delivery_mode = APIC_DM_FIXED;
        irq.vector = vector;
        irq.level = 1;

        ret = kvm_irq_delivery_to_apic(vcpu->kvm, vcpu->arch.apic, &irq);
        trace_kvm_hv_synic_set_irq(vcpu->vcpu_id, sint, irq.vector, ret);
        return ret;
}

int kvm_hv_synic_set_irq(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
                         int irq_source_id, int level, bool line_status)
{
        struct kvm_vcpu_hv_synic *synic;

        if (!level)
                return -1;

        synic = synic_get(kvm, e->hv_sint.vcpu);
        if (!synic)
                return -EINVAL;

        return synic_set_irq(synic, e->hv_sint.sint);
}

void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector)
{
        struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu);
        int i;

        trace_kvm_hv_synic_send_eoi(vcpu->vcpu_id, vector);

        for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
                if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
                        kvm_hv_notify_acked_sint(vcpu, i);
}

static int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vpidx, u32 sint, int gsi)
{
        struct kvm_vcpu_hv_synic *synic;

        synic = synic_get(kvm, vpidx);
        if (!synic)
                return -EINVAL;

        if (sint >= ARRAY_SIZE(synic->sint_to_gsi))
                return -EINVAL;

        atomic_set(&synic->sint_to_gsi[sint], gsi);
        return 0;
}

void kvm_hv_irq_routing_update(struct kvm *kvm)
{
        struct kvm_irq_routing_table *irq_rt;
        struct kvm_kernel_irq_routing_entry *e;
        u32 gsi;

        irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
                                        lockdep_is_held(&kvm->irq_lock));

        for (gsi = 0; gsi < irq_rt->nr_rt_entries; gsi++) {
                hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
                        if (e->type == KVM_IRQ_ROUTING_HV_SINT)
                                kvm_hv_set_sint_gsi(kvm, e->hv_sint.vcpu,
                                                    e->hv_sint.sint, gsi);
                }
        }
}

static void synic_init(struct kvm_vcpu_hv_synic *synic)
{
        int i;

        memset(synic, 0, sizeof(*synic));
        synic->version = HV_SYNIC_VERSION_1;
        for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
                atomic64_set(&synic->sint[i], HV_SYNIC_SINT_MASKED);
                atomic_set(&synic->sint_to_gsi[i], -1);
        }
}

static u64 get_time_ref_counter(struct kvm *kvm)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        struct kvm_vcpu *vcpu;
        u64 tsc;

        /*
         * Fall back to get_kvmclock_ns() when TSC page hasn't been set up,
         * is broken, disabled or being updated.
         */
        if (hv->hv_tsc_page_status != HV_TSC_PAGE_SET)
                return div_u64(get_kvmclock_ns(kvm), 100);

        vcpu = kvm_get_vcpu(kvm, 0);
        tsc = kvm_read_l1_tsc(vcpu, rdtsc());
        return mul_u64_u64_shr(tsc, hv->tsc_ref.tsc_scale, 64)
                + hv->tsc_ref.tsc_offset;
}

static void stimer_mark_pending(struct kvm_vcpu_hv_stimer *stimer,
                                bool vcpu_kick)
{
        struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);

        set_bit(stimer->index,
                to_hv_vcpu(vcpu)->stimer_pending_bitmap);
        kvm_make_request(KVM_REQ_HV_STIMER, vcpu);
        if (vcpu_kick)
                kvm_vcpu_kick(vcpu);
}

static void stimer_cleanup(struct kvm_vcpu_hv_stimer *stimer)
{
        struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);

        trace_kvm_hv_stimer_cleanup(hv_stimer_to_vcpu(stimer)->vcpu_id,
                                    stimer->index);

        hrtimer_cancel(&stimer->timer);
        clear_bit(stimer->index,
                  to_hv_vcpu(vcpu)->stimer_pending_bitmap);
        stimer->msg_pending = false;
        stimer->exp_time = 0;
}

static enum hrtimer_restart stimer_timer_callback(struct hrtimer *timer)
{
        struct kvm_vcpu_hv_stimer *stimer;

        stimer = container_of(timer, struct kvm_vcpu_hv_stimer, timer);
        trace_kvm_hv_stimer_callback(hv_stimer_to_vcpu(stimer)->vcpu_id,
                                     stimer->index);
        stimer_mark_pending(stimer, true);

        return HRTIMER_NORESTART;
}

/*
 * stimer_start() assumptions:
 * a) stimer->count is not equal to 0
 * b) stimer->config has HV_STIMER_ENABLE flag
 */
static int stimer_start(struct kvm_vcpu_hv_stimer *stimer)
{
        u64 time_now;
        ktime_t ktime_now;

        time_now = get_time_ref_counter(hv_stimer_to_vcpu(stimer)->kvm);
        ktime_now = ktime_get();

        if (stimer->config.periodic) {
                if (stimer->exp_time) {
                        if (time_now >= stimer->exp_time) {
                                u64 remainder;

                                div64_u64_rem(time_now - stimer->exp_time,
                                              stimer->count, &remainder);
                                stimer->exp_time =
                                        time_now + (stimer->count - remainder);
                        }
                } else
                        stimer->exp_time = time_now + stimer->count;

                trace_kvm_hv_stimer_start_periodic(
                                        hv_stimer_to_vcpu(stimer)->vcpu_id,
                                        stimer->index,
                                        time_now, stimer->exp_time);

                hrtimer_start(&stimer->timer,
                              ktime_add_ns(ktime_now,
                                           100 * (stimer->exp_time - time_now)),
                              HRTIMER_MODE_ABS);
                return 0;
        }
        stimer->exp_time = stimer->count;
        if (time_now >= stimer->count) {
                /*
                 * Expire timer according to Hypervisor Top-Level Functional
                 * specification v4(15.3.1):
                 * "If a one shot is enabled and the specified count is in
                 * the past, it will expire immediately."
                 */
                stimer_mark_pending(stimer, false);
                return 0;
        }

        trace_kvm_hv_stimer_start_one_shot(hv_stimer_to_vcpu(stimer)->vcpu_id,
                                           stimer->index,
                                           time_now, stimer->count);

        hrtimer_start(&stimer->timer,
                      ktime_add_ns(ktime_now, 100 * (stimer->count - time_now)),
                      HRTIMER_MODE_ABS);
        return 0;
}

static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config,
                             bool host)
{
        union hv_stimer_config new_config = {.as_uint64 = config},
                old_config = {.as_uint64 = stimer->config.as_uint64};
        struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu);

        if (!synic->active && (!host || config))
                return 1;

        if (unlikely(!host && hv_vcpu->enforce_cpuid && new_config.direct_mode &&
                     !(hv_vcpu->cpuid_cache.features_edx &
                       HV_STIMER_DIRECT_MODE_AVAILABLE)))
                return 1;

        trace_kvm_hv_stimer_set_config(hv_stimer_to_vcpu(stimer)->vcpu_id,
                                       stimer->index, config, host);

        stimer_cleanup(stimer);
        if (old_config.enable &&
            !new_config.direct_mode && new_config.sintx == 0)
                new_config.enable = 0;
        stimer->config.as_uint64 = new_config.as_uint64;

        if (stimer->config.enable)
                stimer_mark_pending(stimer, false);

        return 0;
}

static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count,
                            bool host)
{
        struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);
        struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu);

        if (!synic->active && (!host || count))
                return 1;

        trace_kvm_hv_stimer_set_count(hv_stimer_to_vcpu(stimer)->vcpu_id,
                                      stimer->index, count, host);

        stimer_cleanup(stimer);
        stimer->count = count;
        if (!host) {
                if (stimer->count == 0)
                        stimer->config.enable = 0;
                else if (stimer->config.auto_enable)
                        stimer->config.enable = 1;
        }

        if (stimer->config.enable)
                stimer_mark_pending(stimer, false);

        return 0;
}

static int stimer_get_config(struct kvm_vcpu_hv_stimer *stimer, u64 *pconfig)
{
        *pconfig = stimer->config.as_uint64;
        return 0;
}

static int stimer_get_count(struct kvm_vcpu_hv_stimer *stimer, u64 *pcount)
{
        *pcount = stimer->count;
        return 0;
}

static int synic_deliver_msg(struct kvm_vcpu_hv_synic *synic, u32 sint,
                             struct hv_message *src_msg, bool no_retry)
{
        struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);
        int msg_off = offsetof(struct hv_message_page, sint_message[sint]);
        gfn_t msg_page_gfn;
        struct hv_message_header hv_hdr;
        int r;

        if (!(synic->msg_page & HV_SYNIC_SIMP_ENABLE))
                return -ENOENT;

        msg_page_gfn = synic->msg_page >> PAGE_SHIFT;

        /*
         * Strictly following the spec-mandated ordering would assume setting
         * .msg_pending before checking .message_type.  However, this function
         * is only called in vcpu context so the entire update is atomic from
         * guest POV and thus the exact order here doesn't matter.
         */
        r = kvm_vcpu_read_guest_page(vcpu, msg_page_gfn, &hv_hdr.message_type,
                                     msg_off + offsetof(struct hv_message,
                                                        header.message_type),
                                     sizeof(hv_hdr.message_type));
        if (r < 0)
                return r;

        if (hv_hdr.message_type != HVMSG_NONE) {
                if (no_retry)
                        return 0;

                hv_hdr.message_flags.msg_pending = 1;
                r = kvm_vcpu_write_guest_page(vcpu, msg_page_gfn,
                                              &hv_hdr.message_flags,
                                              msg_off +
                                              offsetof(struct hv_message,
                                                       header.message_flags),
                                              sizeof(hv_hdr.message_flags));
                if (r < 0)
                        return r;
                return -EAGAIN;
        }

        r = kvm_vcpu_write_guest_page(vcpu, msg_page_gfn, src_msg, msg_off,
                                      sizeof(src_msg->header) +
                                      src_msg->header.payload_size);
        if (r < 0)
                return r;

        r = synic_set_irq(synic, sint);
        if (r < 0)
                return r;
        if (r == 0)
                return -EFAULT;
        return 0;
}

static int stimer_send_msg(struct kvm_vcpu_hv_stimer *stimer)
{
        struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);
        struct hv_message *msg = &stimer->msg;
        struct hv_timer_message_payload *payload =
                        (struct hv_timer_message_payload *)&msg->u.payload;

        /*
         * To avoid piling up periodic ticks, don't retry message
         * delivery for them (within "lazy" lost ticks policy).
         */
        bool no_retry = stimer->config.periodic;

        payload->expiration_time = stimer->exp_time;
        payload->delivery_time = get_time_ref_counter(vcpu->kvm);
        return synic_deliver_msg(to_hv_synic(vcpu),
                                 stimer->config.sintx, msg,
                                 no_retry);
}

static int stimer_notify_direct(struct kvm_vcpu_hv_stimer *stimer)
{
        struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);
        struct kvm_lapic_irq irq = {
                .delivery_mode = APIC_DM_FIXED,
                .vector = stimer->config.apic_vector
        };

        if (lapic_in_kernel(vcpu))
                return !kvm_apic_set_irq(vcpu, &irq, NULL);
        return 0;
}

static void stimer_expiration(struct kvm_vcpu_hv_stimer *stimer)
{
        int r, direct = stimer->config.direct_mode;

        stimer->msg_pending = true;
        if (!direct)
                r = stimer_send_msg(stimer);
        else
                r = stimer_notify_direct(stimer);
        trace_kvm_hv_stimer_expiration(hv_stimer_to_vcpu(stimer)->vcpu_id,
                                       stimer->index, direct, r);
        if (!r) {
                stimer->msg_pending = false;
                if (!(stimer->config.periodic))
                        stimer->config.enable = 0;
        }
}

void kvm_hv_process_stimers(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        struct kvm_vcpu_hv_stimer *stimer;
        u64 time_now, exp_time;
        int i;

        if (!hv_vcpu)
                return;

        for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
                if (test_and_clear_bit(i, hv_vcpu->stimer_pending_bitmap)) {
                        stimer = &hv_vcpu->stimer[i];
                        if (stimer->config.enable) {
                                exp_time = stimer->exp_time;

                                if (exp_time) {
                                        time_now =
                                                get_time_ref_counter(vcpu->kvm);
                                        if (time_now >= exp_time)
                                                stimer_expiration(stimer);
                                }

                                if ((stimer->config.enable) &&
                                    stimer->count) {
                                        if (!stimer->msg_pending)
                                                stimer_start(stimer);
                                } else
                                        stimer_cleanup(stimer);
                        }
                }
}

void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        int i;

        if (!hv_vcpu)
                return;

        for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
                stimer_cleanup(&hv_vcpu->stimer[i]);

        kfree(hv_vcpu);
        vcpu->arch.hyperv = NULL;
}

bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        if (!hv_vcpu)
                return false;

        if (!(hv_vcpu->hv_vapic & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE))
                return false;
        return vcpu->arch.pv_eoi.msr_val & KVM_MSR_ENABLED;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_hv_assist_page_enabled);

int kvm_hv_get_assist_page(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        if (!hv_vcpu || !kvm_hv_assist_page_enabled(vcpu))
                return -EFAULT;

        return kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data,
                                     &hv_vcpu->vp_assist_page, sizeof(struct hv_vp_assist_page));
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_hv_get_assist_page);

static void stimer_prepare_msg(struct kvm_vcpu_hv_stimer *stimer)
{
        struct hv_message *msg = &stimer->msg;
        struct hv_timer_message_payload *payload =
                        (struct hv_timer_message_payload *)&msg->u.payload;

        memset(&msg->header, 0, sizeof(msg->header));
        msg->header.message_type = HVMSG_TIMER_EXPIRED;
        msg->header.payload_size = sizeof(*payload);

        payload->timer_index = stimer->index;
        payload->expiration_time = 0;
        payload->delivery_time = 0;
}

static void stimer_init(struct kvm_vcpu_hv_stimer *stimer, int timer_index)
{
        memset(stimer, 0, sizeof(*stimer));
        stimer->index = timer_index;
        hrtimer_setup(&stimer->timer, stimer_timer_callback, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
        stimer_prepare_msg(stimer);
}

int kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        int i;

        if (hv_vcpu)
                return 0;

        hv_vcpu = kzalloc_obj(struct kvm_vcpu_hv, GFP_KERNEL_ACCOUNT);
        if (!hv_vcpu)
                return -ENOMEM;

        vcpu->arch.hyperv = hv_vcpu;
        hv_vcpu->vcpu = vcpu;

        synic_init(&hv_vcpu->synic);

        bitmap_zero(hv_vcpu->stimer_pending_bitmap, HV_SYNIC_STIMER_COUNT);
        for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
                stimer_init(&hv_vcpu->stimer[i], i);

        hv_vcpu->vp_index = vcpu->vcpu_idx;

        for (i = 0; i < HV_NR_TLB_FLUSH_FIFOS; i++) {
                INIT_KFIFO(hv_vcpu->tlb_flush_fifo[i].entries);
                spin_lock_init(&hv_vcpu->tlb_flush_fifo[i].write_lock);
        }

        return 0;
}

int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages)
{
        struct kvm_vcpu_hv_synic *synic;
        int r;

        r = kvm_hv_vcpu_init(vcpu);
        if (r)
                return r;

        synic = to_hv_synic(vcpu);

        synic->active = true;
        synic->dont_zero_synic_pages = dont_zero_synic_pages;
        synic->control = HV_SYNIC_CONTROL_ENABLE;
        return 0;
}

static bool kvm_hv_msr_partition_wide(u32 msr)
{
        bool r = false;

        switch (msr) {
        case HV_X64_MSR_GUEST_OS_ID:
        case HV_X64_MSR_HYPERCALL:
        case HV_X64_MSR_REFERENCE_TSC:
        case HV_X64_MSR_TIME_REF_COUNT:
        case HV_X64_MSR_CRASH_CTL:
        case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
        case HV_X64_MSR_RESET:
        case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
        case HV_X64_MSR_TSC_EMULATION_CONTROL:
        case HV_X64_MSR_TSC_EMULATION_STATUS:
        case HV_X64_MSR_TSC_INVARIANT_CONTROL:
        case HV_X64_MSR_SYNDBG_OPTIONS:
        case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
                r = true;
                break;
        }

        return r;
}

static int kvm_hv_msr_get_crash_data(struct kvm *kvm, u32 index, u64 *pdata)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        size_t size = ARRAY_SIZE(hv->hv_crash_param);

        if (WARN_ON_ONCE(index >= size))
                return -EINVAL;

        *pdata = hv->hv_crash_param[array_index_nospec(index, size)];
        return 0;
}

static int kvm_hv_msr_get_crash_ctl(struct kvm *kvm, u64 *pdata)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);

        *pdata = hv->hv_crash_ctl;
        return 0;
}

static int kvm_hv_msr_set_crash_ctl(struct kvm *kvm, u64 data)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);

        hv->hv_crash_ctl = data & HV_CRASH_CTL_CRASH_NOTIFY;

        return 0;
}

static int kvm_hv_msr_set_crash_data(struct kvm *kvm, u32 index, u64 data)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        size_t size = ARRAY_SIZE(hv->hv_crash_param);

        if (WARN_ON_ONCE(index >= size))
                return -EINVAL;

        hv->hv_crash_param[array_index_nospec(index, size)] = data;
        return 0;
}

/*
 * The kvmclock and Hyper-V TSC page use similar formulas, and converting
 * between them is possible:
 *
 * kvmclock formula:
 *    nsec = (ticks - tsc_timestamp) * tsc_to_system_mul * 2^(tsc_shift-32)
 *           + system_time
 *
 * Hyper-V formula:
 *    nsec/100 = ticks * scale / 2^64 + offset
 *
 * When tsc_timestamp = system_time = 0, offset is zero in the Hyper-V formula.
 * By dividing the kvmclock formula by 100 and equating what's left we get:
 *    ticks * scale / 2^64 = ticks * tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *            scale / 2^64 =         tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *            scale        =         tsc_to_system_mul * 2^(32+tsc_shift) / 100
 *
 * Now expand the kvmclock formula and divide by 100:
 *    nsec = ticks * tsc_to_system_mul * 2^(tsc_shift-32)
 *           - tsc_timestamp * tsc_to_system_mul * 2^(tsc_shift-32)
 *           + system_time
 *    nsec/100 = ticks * tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *               - tsc_timestamp * tsc_to_system_mul * 2^(tsc_shift-32) / 100
 *               + system_time / 100
 *
 * Replace tsc_to_system_mul * 2^(tsc_shift-32) / 100 by scale / 2^64:
 *    nsec/100 = ticks * scale / 2^64
 *               - tsc_timestamp * scale / 2^64
 *               + system_time / 100
 *
 * Equate with the Hyper-V formula so that ticks * scale / 2^64 cancels out:
 *    offset = system_time / 100 - tsc_timestamp * scale / 2^64
 *
 * These two equivalencies are implemented in this function.
 */
static bool compute_tsc_page_parameters(struct pvclock_vcpu_time_info *hv_clock,
                                        struct ms_hyperv_tsc_page *tsc_ref)
{
        u64 max_mul;

        if (!(hv_clock->flags & PVCLOCK_TSC_STABLE_BIT))
                return false;

        /*
         * check if scale would overflow, if so we use the time ref counter
         *    tsc_to_system_mul * 2^(tsc_shift+32) / 100 >= 2^64
         *    tsc_to_system_mul / 100 >= 2^(32-tsc_shift)
         *    tsc_to_system_mul >= 100 * 2^(32-tsc_shift)
         */
        max_mul = 100ull << (32 - hv_clock->tsc_shift);
        if (hv_clock->tsc_to_system_mul >= max_mul)
                return false;

        /*
         * Otherwise compute the scale and offset according to the formulas
         * derived above.
         */
        tsc_ref->tsc_scale =
                mul_u64_u32_div(1ULL << (32 + hv_clock->tsc_shift),
                                hv_clock->tsc_to_system_mul,
                                100);

        tsc_ref->tsc_offset = hv_clock->system_time;
        do_div(tsc_ref->tsc_offset, 100);
        tsc_ref->tsc_offset -=
                mul_u64_u64_shr(hv_clock->tsc_timestamp, tsc_ref->tsc_scale, 64);
        return true;
}

/*
 * Don't touch TSC page values if the guest has opted for TSC emulation after
 * migration. KVM doesn't fully support reenlightenment notifications and TSC
 * access emulation and Hyper-V is known to expect the values in TSC page to
 * stay constant before TSC access emulation is disabled from guest side
 * (HV_X64_MSR_TSC_EMULATION_STATUS). KVM userspace is expected to preserve TSC
 * frequency and guest visible TSC value across migration (and prevent it when
 * TSC scaling is unsupported).
 */
static inline bool tsc_page_update_unsafe(struct kvm_hv *hv)
{
        return (hv->hv_tsc_page_status != HV_TSC_PAGE_GUEST_CHANGED) &&
                hv->hv_tsc_emulation_control;
}

void kvm_hv_setup_tsc_page(struct kvm *kvm,
                           struct pvclock_vcpu_time_info *hv_clock)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        u32 tsc_seq;
        u64 gfn;

        BUILD_BUG_ON(sizeof(tsc_seq) != sizeof(hv->tsc_ref.tsc_sequence));
        BUILD_BUG_ON(offsetof(struct ms_hyperv_tsc_page, tsc_sequence) != 0);

        guard(mutex)(&hv->hv_lock);

        if (hv->hv_tsc_page_status == HV_TSC_PAGE_BROKEN ||
            hv->hv_tsc_page_status == HV_TSC_PAGE_SET ||
            hv->hv_tsc_page_status == HV_TSC_PAGE_UNSET)
                return;

        if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
                return;

        gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
        /*
         * Because the TSC parameters only vary when there is a
         * change in the master clock, do not bother with caching.
         */
        if (unlikely(kvm_read_guest(kvm, gfn_to_gpa(gfn),
                                    &tsc_seq, sizeof(tsc_seq))))
                goto out_err;

        if (tsc_seq && tsc_page_update_unsafe(hv)) {
                if (kvm_read_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref)))
                        goto out_err;

                hv->hv_tsc_page_status = HV_TSC_PAGE_SET;
                return;
        }

        /*
         * While we're computing and writing the parameters, force the
         * guest to use the time reference count MSR.
         */
        hv->tsc_ref.tsc_sequence = 0;
        if (kvm_write_guest(kvm, gfn_to_gpa(gfn),
                            &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)))
                goto out_err;

        if (!compute_tsc_page_parameters(hv_clock, &hv->tsc_ref))
                goto out_err;

        /* Ensure sequence is zero before writing the rest of the struct.  */
        smp_wmb();
        if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref)))
                goto out_err;

        /*
         * Now switch to the TSC page mechanism by writing the sequence.
         */
        tsc_seq++;
        if (tsc_seq == 0xFFFFFFFF || tsc_seq == 0)
                tsc_seq = 1;

        /* Write the struct entirely before the non-zero sequence.  */
        smp_wmb();

        hv->tsc_ref.tsc_sequence = tsc_seq;
        if (kvm_write_guest(kvm, gfn_to_gpa(gfn),
                            &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)))
                goto out_err;

        hv->hv_tsc_page_status = HV_TSC_PAGE_SET;
        return;

out_err:
        hv->hv_tsc_page_status = HV_TSC_PAGE_BROKEN;
}

void kvm_hv_request_tsc_page_update(struct kvm *kvm)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);

        mutex_lock(&hv->hv_lock);

        if (hv->hv_tsc_page_status == HV_TSC_PAGE_SET &&
            !tsc_page_update_unsafe(hv))
                hv->hv_tsc_page_status = HV_TSC_PAGE_HOST_CHANGED;

        mutex_unlock(&hv->hv_lock);
}

static bool hv_check_msr_access(struct kvm_vcpu_hv *hv_vcpu, u32 msr)
{
        if (!hv_vcpu->enforce_cpuid)
                return true;

        switch (msr) {
        case HV_X64_MSR_GUEST_OS_ID:
        case HV_X64_MSR_HYPERCALL:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_HYPERCALL_AVAILABLE;
        case HV_X64_MSR_VP_RUNTIME:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_VP_RUNTIME_AVAILABLE;
        case HV_X64_MSR_TIME_REF_COUNT:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_TIME_REF_COUNT_AVAILABLE;
        case HV_X64_MSR_VP_INDEX:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_VP_INDEX_AVAILABLE;
        case HV_X64_MSR_RESET:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_RESET_AVAILABLE;
        case HV_X64_MSR_REFERENCE_TSC:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_REFERENCE_TSC_AVAILABLE;
        case HV_X64_MSR_SCONTROL:
        case HV_X64_MSR_SVERSION:
        case HV_X64_MSR_SIEFP:
        case HV_X64_MSR_SIMP:
        case HV_X64_MSR_EOM:
        case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_SYNIC_AVAILABLE;
        case HV_X64_MSR_STIMER0_CONFIG:
        case HV_X64_MSR_STIMER1_CONFIG:
        case HV_X64_MSR_STIMER2_CONFIG:
        case HV_X64_MSR_STIMER3_CONFIG:
        case HV_X64_MSR_STIMER0_COUNT:
        case HV_X64_MSR_STIMER1_COUNT:
        case HV_X64_MSR_STIMER2_COUNT:
        case HV_X64_MSR_STIMER3_COUNT:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_SYNTIMER_AVAILABLE;
        case HV_X64_MSR_EOI:
        case HV_X64_MSR_ICR:
        case HV_X64_MSR_TPR:
        case HV_X64_MSR_VP_ASSIST_PAGE:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_MSR_APIC_ACCESS_AVAILABLE;
        case HV_X64_MSR_TSC_FREQUENCY:
        case HV_X64_MSR_APIC_FREQUENCY:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_ACCESS_FREQUENCY_MSRS;
        case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
        case HV_X64_MSR_TSC_EMULATION_CONTROL:
        case HV_X64_MSR_TSC_EMULATION_STATUS:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_ACCESS_REENLIGHTENMENT;
        case HV_X64_MSR_TSC_INVARIANT_CONTROL:
                return hv_vcpu->cpuid_cache.features_eax &
                        HV_ACCESS_TSC_INVARIANT;
        case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
        case HV_X64_MSR_CRASH_CTL:
                return hv_vcpu->cpuid_cache.features_edx &
                        HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
        case HV_X64_MSR_SYNDBG_OPTIONS:
        case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
                return hv_vcpu->cpuid_cache.features_edx &
                        HV_FEATURE_DEBUG_MSRS_AVAILABLE;
        default:
                break;
        }

        return false;
}

#define KVM_HV_WIN2016_GUEST_ID 0x1040a00003839
#define KVM_HV_WIN2016_GUEST_ID_MASK (~GENMASK_ULL(23, 16)) /* mask out the service version */

/*
 * Hyper-V enabled Windows Server 2016 SMP VMs fail to boot in !XSAVES && XSAVEC
 * configuration.
 * Such configuration can result from, for example, AMD Erratum 1386 workaround.
 *
 * Print a notice so users aren't left wondering what's suddenly gone wrong.
 */
static void __kvm_hv_xsaves_xsavec_maybe_warn(struct kvm_vcpu *vcpu)
{
        struct kvm *kvm = vcpu->kvm;
        struct kvm_hv *hv = to_kvm_hv(kvm);

        /* Check again under the hv_lock.  */
        if (hv->xsaves_xsavec_checked)
                return;

        if ((hv->hv_guest_os_id & KVM_HV_WIN2016_GUEST_ID_MASK) !=
            KVM_HV_WIN2016_GUEST_ID)
                return;

        hv->xsaves_xsavec_checked = true;

        /* UP configurations aren't affected */
        if (atomic_read(&kvm->online_vcpus) < 2)
                return;

        if (guest_cpuid_has(vcpu, X86_FEATURE_XSAVES) ||
            !guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVEC))
                return;

        pr_notice_ratelimited("Booting SMP Windows KVM VM with !XSAVES && XSAVEC. "
                              "If it fails to boot try disabling XSAVEC in the VM config.\n");
}

void kvm_hv_xsaves_xsavec_maybe_warn(struct kvm_vcpu *vcpu)
{
        struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);

        if (!vcpu->arch.hyperv_enabled ||
            hv->xsaves_xsavec_checked)
                return;

        mutex_lock(&hv->hv_lock);
        __kvm_hv_xsaves_xsavec_maybe_warn(vcpu);
        mutex_unlock(&hv->hv_lock);
}

static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
                             bool host)
{
        struct kvm *kvm = vcpu->kvm;
        struct kvm_hv *hv = to_kvm_hv(kvm);

        if (unlikely(!host && !hv_check_msr_access(to_hv_vcpu(vcpu), msr)))
                return 1;

        switch (msr) {
        case HV_X64_MSR_GUEST_OS_ID:
                hv->hv_guest_os_id = data;
                /* setting guest os id to zero disables hypercall page */
                if (!hv->hv_guest_os_id)
                        hv->hv_hypercall &= ~HV_X64_MSR_HYPERCALL_ENABLE;
                break;
        case HV_X64_MSR_HYPERCALL: {
                u8 instructions[9];
                int i = 0;
                u64 addr;

                /* if guest os id is not set hypercall should remain disabled */
                if (!hv->hv_guest_os_id)
                        break;
                if (!(data & HV_X64_MSR_HYPERCALL_ENABLE)) {
                        hv->hv_hypercall = data;
                        break;
                }

                /*
                 * If Xen and Hyper-V hypercalls are both enabled, disambiguate
                 * the same way Xen itself does, by setting the bit 31 of EAX
                 * which is RsvdZ in the 32-bit Hyper-V hypercall ABI and just
                 * going to be clobbered on 64-bit.
                 */
                if (kvm_xen_hypercall_enabled(kvm)) {
                        /* orl $0x80000000, %eax */
                        instructions[i++] = 0x0d;
                        instructions[i++] = 0x00;
                        instructions[i++] = 0x00;
                        instructions[i++] = 0x00;
                        instructions[i++] = 0x80;
                }

                /* vmcall/vmmcall */
                kvm_x86_call(patch_hypercall)(vcpu, instructions + i);
                i += 3;

                /* ret */
                ((unsigned char *)instructions)[i++] = 0xc3;

                addr = data & HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_MASK;
                if (kvm_vcpu_write_guest(vcpu, addr, instructions, i))
                        return 1;
                hv->hv_hypercall = data;
                break;
        }
        case HV_X64_MSR_REFERENCE_TSC:
                hv->hv_tsc_page = data;
                if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) {
                        if (!host)
                                hv->hv_tsc_page_status = HV_TSC_PAGE_GUEST_CHANGED;
                        else
                                hv->hv_tsc_page_status = HV_TSC_PAGE_HOST_CHANGED;
                        kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
                } else {
                        hv->hv_tsc_page_status = HV_TSC_PAGE_UNSET;
                }
                break;
        case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
                return kvm_hv_msr_set_crash_data(kvm,
                                                 msr - HV_X64_MSR_CRASH_P0,
                                                 data);
        case HV_X64_MSR_CRASH_CTL:
                if (host)
                        return kvm_hv_msr_set_crash_ctl(kvm, data);

                if (data & HV_CRASH_CTL_CRASH_NOTIFY) {
                        vcpu_debug(vcpu, "hv crash (0x%llx 0x%llx 0x%llx 0x%llx 0x%llx)\n",
                                   hv->hv_crash_param[0],
                                   hv->hv_crash_param[1],
                                   hv->hv_crash_param[2],
                                   hv->hv_crash_param[3],
                                   hv->hv_crash_param[4]);

                        /* Send notification about crash to user space */
                        kvm_make_request(KVM_REQ_HV_CRASH, vcpu);
                }
                break;
        case HV_X64_MSR_RESET:
                if (data == 1) {
                        vcpu_debug(vcpu, "hyper-v reset requested\n");
                        kvm_make_request(KVM_REQ_HV_RESET, vcpu);
                }
                break;
        case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
                hv->hv_reenlightenment_control = data;
                break;
        case HV_X64_MSR_TSC_EMULATION_CONTROL:
                hv->hv_tsc_emulation_control = data;
                break;
        case HV_X64_MSR_TSC_EMULATION_STATUS:
                if (data && !host)
                        return 1;

                hv->hv_tsc_emulation_status = data;
                break;
        case HV_X64_MSR_TIME_REF_COUNT:
                /* read-only, but still ignore it if host-initiated */
                if (!host)
                        return 1;
                break;
        case HV_X64_MSR_TSC_INVARIANT_CONTROL:
                /* Only bit 0 is supported */
                if (data & ~HV_EXPOSE_INVARIANT_TSC)
                        return 1;

                /* The feature can't be disabled from the guest */
                if (!host && hv->hv_invtsc_control && !data)
                        return 1;

                hv->hv_invtsc_control = data;
                break;
        case HV_X64_MSR_SYNDBG_OPTIONS:
        case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
                return syndbg_set_msr(vcpu, msr, data, host);
        default:
                kvm_pr_unimpl_wrmsr(vcpu, msr, data);
                return 1;
        }
        return 0;
}

/* Calculate cpu time spent by current task in 100ns units */
static u64 current_task_runtime_100ns(void)
{
        u64 utime, stime;

        task_cputime_adjusted(current, &utime, &stime);

        return div_u64(utime + stime, 100);
}

static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        if (unlikely(!host && !hv_check_msr_access(hv_vcpu, msr)))
                return 1;

        switch (msr) {
        case HV_X64_MSR_VP_INDEX: {
                struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);
                u32 new_vp_index = (u32)data;

                if (!host || new_vp_index >= KVM_MAX_VCPUS)
                        return 1;

                if (new_vp_index == hv_vcpu->vp_index)
                        return 0;

                /*
                 * The VP index is initialized to vcpu_index by
                 * kvm_hv_vcpu_postcreate so they initially match.  Now the
                 * VP index is changing, adjust num_mismatched_vp_indexes if
                 * it now matches or no longer matches vcpu_idx.
                 */
                if (hv_vcpu->vp_index == vcpu->vcpu_idx)
                        atomic_inc(&hv->num_mismatched_vp_indexes);
                else if (new_vp_index == vcpu->vcpu_idx)
                        atomic_dec(&hv->num_mismatched_vp_indexes);

                hv_vcpu->vp_index = new_vp_index;
                break;
        }
        case HV_X64_MSR_VP_ASSIST_PAGE: {
                u64 gfn;
                unsigned long addr;

                if (!(data & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE)) {
                        hv_vcpu->hv_vapic = data;
                        if (kvm_lapic_set_pv_eoi(vcpu, 0, 0))
                                return 1;
                        break;
                }
                gfn = data >> HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT;
                addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
                if (kvm_is_error_hva(addr))
                        return 1;

                /*
                 * Clear apic_assist portion of struct hv_vp_assist_page
                 * only, there can be valuable data in the rest which needs
                 * to be preserved e.g. on migration.
                 */
                if (put_user(0, (u32 __user *)addr))
                        return 1;
                hv_vcpu->hv_vapic = data;
                kvm_vcpu_mark_page_dirty(vcpu, gfn);
                if (kvm_lapic_set_pv_eoi(vcpu,
                                            gfn_to_gpa(gfn) | KVM_MSR_ENABLED,
                                            sizeof(struct hv_vp_assist_page)))
                        return 1;
                break;
        }
        case HV_X64_MSR_EOI:
                return kvm_hv_vapic_msr_write(vcpu, APIC_EOI, data);
        case HV_X64_MSR_ICR:
                return kvm_hv_vapic_msr_write(vcpu, APIC_ICR, data);
        case HV_X64_MSR_TPR:
                return kvm_hv_vapic_msr_write(vcpu, APIC_TASKPRI, data);
        case HV_X64_MSR_VP_RUNTIME:
                if (!host)
                        return 1;
                hv_vcpu->runtime_offset = data - current_task_runtime_100ns();
                break;
        case HV_X64_MSR_SCONTROL:
        case HV_X64_MSR_SVERSION:
        case HV_X64_MSR_SIEFP:
        case HV_X64_MSR_SIMP:
        case HV_X64_MSR_EOM:
        case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
                return synic_set_msr(to_hv_synic(vcpu), msr, data, host);
        case HV_X64_MSR_STIMER0_CONFIG:
        case HV_X64_MSR_STIMER1_CONFIG:
        case HV_X64_MSR_STIMER2_CONFIG:
        case HV_X64_MSR_STIMER3_CONFIG: {
                int timer_index = (msr - HV_X64_MSR_STIMER0_CONFIG)/2;

                return stimer_set_config(to_hv_stimer(vcpu, timer_index),
                                         data, host);
        }
        case HV_X64_MSR_STIMER0_COUNT:
        case HV_X64_MSR_STIMER1_COUNT:
        case HV_X64_MSR_STIMER2_COUNT:
        case HV_X64_MSR_STIMER3_COUNT: {
                int timer_index = (msr - HV_X64_MSR_STIMER0_COUNT)/2;

                return stimer_set_count(to_hv_stimer(vcpu, timer_index),
                                        data, host);
        }
        case HV_X64_MSR_TSC_FREQUENCY:
        case HV_X64_MSR_APIC_FREQUENCY:
                /* read-only, but still ignore it if host-initiated */
                if (!host)
                        return 1;
                break;
        default:
                kvm_pr_unimpl_wrmsr(vcpu, msr, data);
                return 1;
        }

        return 0;
}

static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
                             bool host)
{
        u64 data = 0;
        struct kvm *kvm = vcpu->kvm;
        struct kvm_hv *hv = to_kvm_hv(kvm);

        if (unlikely(!host && !hv_check_msr_access(to_hv_vcpu(vcpu), msr)))
                return 1;

        switch (msr) {
        case HV_X64_MSR_GUEST_OS_ID:
                data = hv->hv_guest_os_id;
                break;
        case HV_X64_MSR_HYPERCALL:
                data = hv->hv_hypercall;
                break;
        case HV_X64_MSR_TIME_REF_COUNT:
                data = get_time_ref_counter(kvm);
                break;
        case HV_X64_MSR_REFERENCE_TSC:
                data = hv->hv_tsc_page;
                break;
        case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
                return kvm_hv_msr_get_crash_data(kvm,
                                                 msr - HV_X64_MSR_CRASH_P0,
                                                 pdata);
        case HV_X64_MSR_CRASH_CTL:
                return kvm_hv_msr_get_crash_ctl(kvm, pdata);
        case HV_X64_MSR_RESET:
                data = 0;
                break;
        case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
                data = hv->hv_reenlightenment_control;
                break;
        case HV_X64_MSR_TSC_EMULATION_CONTROL:
                data = hv->hv_tsc_emulation_control;
                break;
        case HV_X64_MSR_TSC_EMULATION_STATUS:
                data = hv->hv_tsc_emulation_status;
                break;
        case HV_X64_MSR_TSC_INVARIANT_CONTROL:
                data = hv->hv_invtsc_control;
                break;
        case HV_X64_MSR_SYNDBG_OPTIONS:
        case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
                return syndbg_get_msr(vcpu, msr, pdata, host);
        default:
                kvm_pr_unimpl_rdmsr(vcpu, msr);
                return 1;
        }

        *pdata = data;
        return 0;
}

static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
                          bool host)
{
        u64 data = 0;
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

        if (unlikely(!host && !hv_check_msr_access(hv_vcpu, msr)))
                return 1;

        switch (msr) {
        case HV_X64_MSR_VP_INDEX:
                data = hv_vcpu->vp_index;
                break;
        case HV_X64_MSR_EOI:
                return kvm_hv_vapic_msr_read(vcpu, APIC_EOI, pdata);
        case HV_X64_MSR_ICR:
                return kvm_hv_vapic_msr_read(vcpu, APIC_ICR, pdata);
        case HV_X64_MSR_TPR:
                return kvm_hv_vapic_msr_read(vcpu, APIC_TASKPRI, pdata);
        case HV_X64_MSR_VP_ASSIST_PAGE:
                data = hv_vcpu->hv_vapic;
                break;
        case HV_X64_MSR_VP_RUNTIME:
                data = current_task_runtime_100ns() + hv_vcpu->runtime_offset;
                break;
        case HV_X64_MSR_SCONTROL:
        case HV_X64_MSR_SVERSION:
        case HV_X64_MSR_SIEFP:
        case HV_X64_MSR_SIMP:
        case HV_X64_MSR_EOM:
        case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
                return synic_get_msr(to_hv_synic(vcpu), msr, pdata, host);
        case HV_X64_MSR_STIMER0_CONFIG:
        case HV_X64_MSR_STIMER1_CONFIG:
        case HV_X64_MSR_STIMER2_CONFIG:
        case HV_X64_MSR_STIMER3_CONFIG: {
                int timer_index = (msr - HV_X64_MSR_STIMER0_CONFIG)/2;

                return stimer_get_config(to_hv_stimer(vcpu, timer_index),
                                         pdata);
        }
        case HV_X64_MSR_STIMER0_COUNT:
        case HV_X64_MSR_STIMER1_COUNT:
        case HV_X64_MSR_STIMER2_COUNT:
        case HV_X64_MSR_STIMER3_COUNT: {
                int timer_index = (msr - HV_X64_MSR_STIMER0_COUNT)/2;

                return stimer_get_count(to_hv_stimer(vcpu, timer_index),
                                        pdata);
        }
        case HV_X64_MSR_TSC_FREQUENCY:
                data = (u64)vcpu->arch.virtual_tsc_khz * 1000;
                break;
        case HV_X64_MSR_APIC_FREQUENCY:
                data = div64_u64(1000000000ULL,
                                 vcpu->kvm->arch.apic_bus_cycle_ns);
                break;
        default:
                kvm_pr_unimpl_rdmsr(vcpu, msr);
                return 1;
        }
        *pdata = data;
        return 0;
}

int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
{
        struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);

        if (!host && !vcpu->arch.hyperv_enabled)
                return 1;

        if (kvm_hv_vcpu_init(vcpu))
                return 1;

        if (kvm_hv_msr_partition_wide(msr)) {
                int r;

                mutex_lock(&hv->hv_lock);
                r = kvm_hv_set_msr_pw(vcpu, msr, data, host);
                mutex_unlock(&hv->hv_lock);
                return r;
        } else
                return kvm_hv_set_msr(vcpu, msr, data, host);
}

int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
{
        struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);

        if (!host && !vcpu->arch.hyperv_enabled)
                return 1;

        if (kvm_hv_vcpu_init(vcpu))
                return 1;

        if (kvm_hv_msr_partition_wide(msr)) {
                int r;

                mutex_lock(&hv->hv_lock);
                r = kvm_hv_get_msr_pw(vcpu, msr, pdata, host);
                mutex_unlock(&hv->hv_lock);
                return r;
        } else
                return kvm_hv_get_msr(vcpu, msr, pdata, host);
}

static void sparse_set_to_vcpu_mask(struct kvm *kvm, u64 *sparse_banks,
                                    u64 valid_bank_mask, unsigned long *vcpu_mask)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        bool has_mismatch = atomic_read(&hv->num_mismatched_vp_indexes);
        u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS];
        struct kvm_vcpu *vcpu;
        int bank, sbank = 0;
        unsigned long i;
        u64 *bitmap;

        BUILD_BUG_ON(sizeof(vp_bitmap) >
                     sizeof(*vcpu_mask) * BITS_TO_LONGS(KVM_MAX_VCPUS));

        /*
         * If vp_index == vcpu_idx for all vCPUs, fill vcpu_mask directly, else
         * fill a temporary buffer and manually test each vCPU's VP index.
         */
        if (likely(!has_mismatch))
                bitmap = (u64 *)vcpu_mask;
        else
                bitmap = vp_bitmap;

        /*
         * Each set of 64 VPs is packed into sparse_banks, with valid_bank_mask
         * having a '1' for each bank that exists in sparse_banks.  Sets must
         * be in ascending order, i.e. bank0..bankN.
         */
        memset(bitmap, 0, sizeof(vp_bitmap));
        for_each_set_bit(bank, (unsigned long *)&valid_bank_mask,
                         KVM_HV_MAX_SPARSE_VCPU_SET_BITS)
                bitmap[bank] = sparse_banks[sbank++];

        if (likely(!has_mismatch))
                return;

        bitmap_zero(vcpu_mask, KVM_MAX_VCPUS);
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (test_bit(kvm_hv_get_vpindex(vcpu), (unsigned long *)vp_bitmap))
                        __set_bit(i, vcpu_mask);
        }
}

static bool hv_is_vp_in_sparse_set(u32 vp_id, u64 valid_bank_mask, u64 sparse_banks[])
{
        int valid_bit_nr = vp_id / HV_VCPUS_PER_SPARSE_BANK;
        unsigned long sbank;

        if (!test_bit(valid_bit_nr, (unsigned long *)&valid_bank_mask))
                return false;

        /*
         * The index into the sparse bank is the number of preceding bits in
         * the valid mask.  Optimize for VMs with <64 vCPUs by skipping the
         * fancy math if there can't possibly be preceding bits.
         */
        if (valid_bit_nr)
                sbank = hweight64(valid_bank_mask & GENMASK_ULL(valid_bit_nr - 1, 0));
        else
                sbank = 0;

        return test_bit(vp_id % HV_VCPUS_PER_SPARSE_BANK,
                        (unsigned long *)&sparse_banks[sbank]);
}

struct kvm_hv_hcall {
        /* Hypercall input data */
        u64 param;
        u64 ingpa;
        u64 outgpa;
        u16 code;
        u16 var_cnt;
        u16 rep_cnt;
        u16 rep_idx;
        bool fast;
        bool rep;
        sse128_t xmm[HV_HYPERCALL_MAX_XMM_REGISTERS];

        /*
         * Current read offset when KVM reads hypercall input data gradually,
         * either offset in bytes from 'ingpa' for regular hypercalls or the
         * number of already consumed 'XMM halves' for 'fast' hypercalls.
         */
        union {
                gpa_t data_offset;
                int consumed_xmm_halves;
        };
};


static int kvm_hv_get_hc_data(struct kvm *kvm, struct kvm_hv_hcall *hc,
                              u16 orig_cnt, u16 cnt_cap, u64 *data)
{
        /*
         * Preserve the original count when ignoring entries via a "cap", KVM
         * still needs to validate the guest input (though the non-XMM path
         * punts on the checks).
         */
        u16 cnt = min(orig_cnt, cnt_cap);
        int i, j;

        if (hc->fast) {
                /*
                 * Each XMM holds two sparse banks, but do not count halves that
                 * have already been consumed for hypercall parameters.
                 */
                if (orig_cnt > 2 * HV_HYPERCALL_MAX_XMM_REGISTERS - hc->consumed_xmm_halves)
                        return HV_STATUS_INVALID_HYPERCALL_INPUT;

                for (i = 0; i < cnt; i++) {
                        j = i + hc->consumed_xmm_halves;
                        if (j % 2)
                                data[i] = sse128_hi(hc->xmm[j / 2]);
                        else
                                data[i] = sse128_lo(hc->xmm[j / 2]);
                }
                return 0;
        }

        return kvm_read_guest(kvm, hc->ingpa + hc->data_offset, data,
                              cnt * sizeof(*data));
}

static u64 kvm_get_sparse_vp_set(struct kvm *kvm, struct kvm_hv_hcall *hc,
                                 u64 *sparse_banks)
{
        if (hc->var_cnt > HV_MAX_SPARSE_VCPU_BANKS)
                return -EINVAL;

        /* Cap var_cnt to ignore banks that cannot contain a legal VP index. */
        return kvm_hv_get_hc_data(kvm, hc, hc->var_cnt, KVM_HV_MAX_SPARSE_VCPU_SET_BITS,
                                  sparse_banks);
}

static int kvm_hv_get_tlb_flush_entries(struct kvm *kvm, struct kvm_hv_hcall *hc, u64 entries[])
{
        return kvm_hv_get_hc_data(kvm, hc, hc->rep_cnt, hc->rep_cnt, entries);
}

static void hv_tlb_flush_enqueue(struct kvm_vcpu *vcpu,
                                 struct kvm_vcpu_hv_tlb_flush_fifo *tlb_flush_fifo,
                                 u64 *entries, int count)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        u64 flush_all_entry = KVM_HV_TLB_FLUSHALL_ENTRY;

        if (!hv_vcpu)
                return;

        spin_lock(&tlb_flush_fifo->write_lock);

        /*
         * All entries should fit on the fifo leaving one free for 'flush all'
         * entry in case another request comes in. In case there's not enough
         * space, just put 'flush all' entry there.
         */
        if (count && entries && count < kfifo_avail(&tlb_flush_fifo->entries)) {
                WARN_ON(kfifo_in(&tlb_flush_fifo->entries, entries, count) != count);
                goto out_unlock;
        }

        /*
         * Note: full fifo always contains 'flush all' entry, no need to check the
         * return value.
         */
        kfifo_in(&tlb_flush_fifo->entries, &flush_all_entry, 1);

out_unlock:
        spin_unlock(&tlb_flush_fifo->write_lock);
}

int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv_tlb_flush_fifo *tlb_flush_fifo;
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        u64 entries[KVM_HV_TLB_FLUSH_FIFO_SIZE];
        int i, j, count;
        gva_t gva;

        if (!tdp_enabled || !hv_vcpu)
                return -EINVAL;

        tlb_flush_fifo = kvm_hv_get_tlb_flush_fifo(vcpu, is_guest_mode(vcpu));

        count = kfifo_out(&tlb_flush_fifo->entries, entries, KVM_HV_TLB_FLUSH_FIFO_SIZE);

        for (i = 0; i < count; i++) {
                if (entries[i] == KVM_HV_TLB_FLUSHALL_ENTRY)
                        goto out_flush_all;

                /*
                 * Lower 12 bits of 'address' encode the number of additional
                 * pages to flush.
                 */
                gva = entries[i] & PAGE_MASK;
                for (j = 0; j < (entries[i] & ~PAGE_MASK) + 1; j++) {
                        if (is_noncanonical_invlpg_address(gva + j * PAGE_SIZE, vcpu))
                                continue;

                        kvm_x86_call(flush_tlb_gva)(vcpu, gva + j * PAGE_SIZE);
                }

                ++vcpu->stat.tlb_flush;
        }
        return 0;

out_flush_all:
        kfifo_reset_out(&tlb_flush_fifo->entries);

        /* Fall back to full flush. */
        return -ENOSPC;
}

static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        unsigned long *vcpu_mask = hv_vcpu->vcpu_mask;
        u64 *sparse_banks = hv_vcpu->sparse_banks;
        struct kvm *kvm = vcpu->kvm;
        struct hv_tlb_flush_ex flush_ex;
        struct hv_tlb_flush flush;
        struct kvm_vcpu_hv_tlb_flush_fifo *tlb_flush_fifo;
        /*
         * Normally, there can be no more than 'KVM_HV_TLB_FLUSH_FIFO_SIZE'
         * entries on the TLB flush fifo. The last entry, however, needs to be
         * always left free for 'flush all' entry which gets placed when
         * there is not enough space to put all the requested entries.
         */
        u64 __tlb_flush_entries[KVM_HV_TLB_FLUSH_FIFO_SIZE - 1];
        u64 *tlb_flush_entries;
        u64 valid_bank_mask;
        struct kvm_vcpu *v;
        unsigned long i;
        bool all_cpus;

        /*
         * The Hyper-V TLFS doesn't allow more than HV_MAX_SPARSE_VCPU_BANKS
         * sparse banks. Fail the build if KVM's max allowed number of
         * vCPUs (>4096) exceeds this limit.
         */
        BUILD_BUG_ON(KVM_HV_MAX_SPARSE_VCPU_SET_BITS > HV_MAX_SPARSE_VCPU_BANKS);

        /*
         * 'Slow' hypercall's first parameter is the address in guest's memory
         * where hypercall parameters are placed. This is either a GPA or a
         * nested GPA when KVM is handling the call from L2 ('direct' TLB
         * flush).  Translate the address here so the memory can be uniformly
         * read with kvm_read_guest().
         */
        if (!hc->fast && is_guest_mode(vcpu)) {
                hc->ingpa = translate_nested_gpa(vcpu, hc->ingpa, 0, NULL);
                if (unlikely(hc->ingpa == INVALID_GPA))
                        return HV_STATUS_INVALID_HYPERCALL_INPUT;
        }

        if (hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST ||
            hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE) {
                if (hc->fast) {
                        flush.address_space = hc->ingpa;
                        flush.flags = hc->outgpa;
                        flush.processor_mask = sse128_lo(hc->xmm[0]);
                        hc->consumed_xmm_halves = 1;
                } else {
                        if (unlikely(kvm_read_guest(kvm, hc->ingpa,
                                                    &flush, sizeof(flush))))
                                return HV_STATUS_INVALID_HYPERCALL_INPUT;
                        hc->data_offset = sizeof(flush);
                }

                trace_kvm_hv_flush_tlb(flush.processor_mask,
                                       flush.address_space, flush.flags,
                                       is_guest_mode(vcpu));

                valid_bank_mask = BIT_ULL(0);
                sparse_banks[0] = flush.processor_mask;

                /*
                 * Work around possible WS2012 bug: it sends hypercalls
                 * with processor_mask = 0x0 and HV_FLUSH_ALL_PROCESSORS clear,
                 * while also expecting us to flush something and crashing if
                 * we don't. Let's treat processor_mask == 0 same as
                 * HV_FLUSH_ALL_PROCESSORS.
                 */
                all_cpus = (flush.flags & HV_FLUSH_ALL_PROCESSORS) ||
                        flush.processor_mask == 0;
        } else {
                if (hc->fast) {
                        flush_ex.address_space = hc->ingpa;
                        flush_ex.flags = hc->outgpa;
                        memcpy(&flush_ex.hv_vp_set,
                               &hc->xmm[0], sizeof(hc->xmm[0]));
                        hc->consumed_xmm_halves = 2;
                } else {
                        if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush_ex,
                                                    sizeof(flush_ex))))
                                return HV_STATUS_INVALID_HYPERCALL_INPUT;
                        hc->data_offset = sizeof(flush_ex);
                }

                trace_kvm_hv_flush_tlb_ex(flush_ex.hv_vp_set.valid_bank_mask,
                                          flush_ex.hv_vp_set.format,
                                          flush_ex.address_space,
                                          flush_ex.flags, is_guest_mode(vcpu));

                valid_bank_mask = flush_ex.hv_vp_set.valid_bank_mask;
                all_cpus = flush_ex.hv_vp_set.format !=
                        HV_GENERIC_SET_SPARSE_4K;

                if (hc->var_cnt != hweight64(valid_bank_mask))
                        return HV_STATUS_INVALID_HYPERCALL_INPUT;

                if (!all_cpus) {
                        if (!hc->var_cnt)
                                goto ret_success;

                        if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks))
                                return HV_STATUS_INVALID_HYPERCALL_INPUT;
                }

                /*
                 * Hyper-V TLFS doesn't explicitly forbid non-empty sparse vCPU
                 * banks (and, thus, non-zero 'var_cnt') for the 'all vCPUs'
                 * case (HV_GENERIC_SET_ALL).  Always adjust data_offset and
                 * consumed_xmm_halves to make sure TLB flush entries are read
                 * from the correct offset.
                 */
                if (hc->fast)
                        hc->consumed_xmm_halves += hc->var_cnt;
                else
                        hc->data_offset += hc->var_cnt * sizeof(sparse_banks[0]);
        }

        if (hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE ||
            hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX ||
            hc->rep_cnt > ARRAY_SIZE(__tlb_flush_entries)) {
                tlb_flush_entries = NULL;
        } else {
                if (kvm_hv_get_tlb_flush_entries(kvm, hc, __tlb_flush_entries))
                        return HV_STATUS_INVALID_HYPERCALL_INPUT;
                tlb_flush_entries = __tlb_flush_entries;
        }

        /*
         * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't
         * analyze it here, flush TLB regardless of the specified address space.
         */
        if (all_cpus && !is_guest_mode(vcpu)) {
                kvm_for_each_vcpu(i, v, kvm) {
                        tlb_flush_fifo = kvm_hv_get_tlb_flush_fifo(v, false);
                        hv_tlb_flush_enqueue(v, tlb_flush_fifo,
                                             tlb_flush_entries, hc->rep_cnt);
                }

                kvm_make_all_cpus_request(kvm, KVM_REQ_HV_TLB_FLUSH);
        } else if (!is_guest_mode(vcpu)) {
                sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask);

                for_each_set_bit(i, vcpu_mask, KVM_MAX_VCPUS) {
                        v = kvm_get_vcpu(kvm, i);
                        if (!v)
                                continue;
                        tlb_flush_fifo = kvm_hv_get_tlb_flush_fifo(v, false);
                        hv_tlb_flush_enqueue(v, tlb_flush_fifo,
                                             tlb_flush_entries, hc->rep_cnt);
                }

                kvm_make_vcpus_request_mask(kvm, KVM_REQ_HV_TLB_FLUSH, vcpu_mask);
        } else {
                struct kvm_vcpu_hv *hv_v;

                bitmap_zero(vcpu_mask, KVM_MAX_VCPUS);

                kvm_for_each_vcpu(i, v, kvm) {
                        hv_v = to_hv_vcpu(v);

                        /*
                         * The following check races with nested vCPUs entering/exiting
                         * and/or migrating between L1's vCPUs, however the only case when
                         * KVM *must* flush the TLB is when the target L2 vCPU keeps
                         * running on the same L1 vCPU from the moment of the request until
                         * kvm_hv_flush_tlb() returns. TLB is fully flushed in all other
                         * cases, e.g. when the target L2 vCPU migrates to a different L1
                         * vCPU or when the corresponding L1 vCPU temporary switches to a
                         * different L2 vCPU while the request is being processed.
                         */
                        if (!hv_v || hv_v->nested.vm_id != hv_vcpu->nested.vm_id)
                                continue;

                        if (!all_cpus &&
                            !hv_is_vp_in_sparse_set(hv_v->nested.vp_id, valid_bank_mask,
                                                    sparse_banks))
                                continue;

                        __set_bit(i, vcpu_mask);
                        tlb_flush_fifo = kvm_hv_get_tlb_flush_fifo(v, true);
                        hv_tlb_flush_enqueue(v, tlb_flush_fifo,
                                             tlb_flush_entries, hc->rep_cnt);
                }

                kvm_make_vcpus_request_mask(kvm, KVM_REQ_HV_TLB_FLUSH, vcpu_mask);
        }

ret_success:
        /* We always do full TLB flush, set 'Reps completed' = 'Rep Count' */
        return (u64)HV_STATUS_SUCCESS |
                ((u64)hc->rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET);
}

static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector,
                                    u64 *sparse_banks, u64 valid_bank_mask)
{
        struct kvm_lapic_irq irq = {
                .delivery_mode = APIC_DM_FIXED,
                .vector = vector
        };
        struct kvm_vcpu *vcpu;
        unsigned long i;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (sparse_banks &&
                    !hv_is_vp_in_sparse_set(kvm_hv_get_vpindex(vcpu),
                                            valid_bank_mask, sparse_banks))
                        continue;

                /* We fail only when APIC is disabled */
                kvm_apic_set_irq(vcpu, &irq, NULL);
        }
}

static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        u64 *sparse_banks = hv_vcpu->sparse_banks;
        struct kvm *kvm = vcpu->kvm;
        struct hv_send_ipi_ex send_ipi_ex;
        struct hv_send_ipi send_ipi;
        u64 valid_bank_mask;
        u32 vector;
        bool all_cpus;

        if (!lapic_in_kernel(vcpu))
                return HV_STATUS_INVALID_HYPERCALL_INPUT;

        if (hc->code == HVCALL_SEND_IPI) {
                if (!hc->fast) {
                        if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi,
                                                    sizeof(send_ipi))))
                                return HV_STATUS_INVALID_HYPERCALL_INPUT;
                        sparse_banks[0] = send_ipi.cpu_mask;
                        vector = send_ipi.vector;
                } else {
                        /* 'reserved' part of hv_send_ipi should be 0 */
                        if (unlikely(hc->ingpa >> 32 != 0))
                                return HV_STATUS_INVALID_HYPERCALL_INPUT;
                        sparse_banks[0] = hc->outgpa;
                        vector = (u32)hc->ingpa;
                }
                all_cpus = false;
                valid_bank_mask = BIT_ULL(0);

                trace_kvm_hv_send_ipi(vector, sparse_banks[0]);
        } else {
                if (!hc->fast) {
                        if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi_ex,
                                                    sizeof(send_ipi_ex))))
                                return HV_STATUS_INVALID_HYPERCALL_INPUT;
                } else {
                        send_ipi_ex.vector = (u32)hc->ingpa;
                        send_ipi_ex.vp_set.format = hc->outgpa;
                        send_ipi_ex.vp_set.valid_bank_mask = sse128_lo(hc->xmm[0]);
                }

                trace_kvm_hv_send_ipi_ex(send_ipi_ex.vector,
                                         send_ipi_ex.vp_set.format,
                                         send_ipi_ex.vp_set.valid_bank_mask);

                vector = send_ipi_ex.vector;
                valid_bank_mask = send_ipi_ex.vp_set.valid_bank_mask;
                all_cpus = send_ipi_ex.vp_set.format == HV_GENERIC_SET_ALL;

                if (hc->var_cnt != hweight64(valid_bank_mask))
                        return HV_STATUS_INVALID_HYPERCALL_INPUT;

                if (all_cpus)
                        goto check_and_send_ipi;

                if (!hc->var_cnt)
                        goto ret_success;

                if (!hc->fast)
                        hc->data_offset = offsetof(struct hv_send_ipi_ex,
                                                   vp_set.bank_contents);
                else
                        hc->consumed_xmm_halves = 1;

                if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks))
                        return HV_STATUS_INVALID_HYPERCALL_INPUT;
        }

check_and_send_ipi:
        if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
                return HV_STATUS_INVALID_HYPERCALL_INPUT;

        if (all_cpus)
                kvm_hv_send_ipi_to_many(kvm, vector, NULL, 0);
        else
                kvm_hv_send_ipi_to_many(kvm, vector, sparse_banks, valid_bank_mask);

ret_success:
        return HV_STATUS_SUCCESS;
}

void kvm_hv_set_cpuid(struct kvm_vcpu *vcpu, bool hyperv_enabled)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        struct kvm_cpuid_entry2 *entry;

        vcpu->arch.hyperv_enabled = hyperv_enabled;

        if (!hv_vcpu) {
                /*
                 * KVM should have already allocated kvm_vcpu_hv if Hyper-V is
                 * enabled in CPUID.
                 */
                WARN_ON_ONCE(vcpu->arch.hyperv_enabled);
                return;
        }

        memset(&hv_vcpu->cpuid_cache, 0, sizeof(hv_vcpu->cpuid_cache));

        if (!vcpu->arch.hyperv_enabled)
                return;

        entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_FEATURES);
        if (entry) {
                hv_vcpu->cpuid_cache.features_eax = entry->eax;
                hv_vcpu->cpuid_cache.features_ebx = entry->ebx;
                hv_vcpu->cpuid_cache.features_edx = entry->edx;
        }

        entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_ENLIGHTMENT_INFO);
        if (entry) {
                hv_vcpu->cpuid_cache.enlightenments_eax = entry->eax;
                hv_vcpu->cpuid_cache.enlightenments_ebx = entry->ebx;
        }

        entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES);
        if (entry)
                hv_vcpu->cpuid_cache.syndbg_cap_eax = entry->eax;

        entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_NESTED_FEATURES);
        if (entry) {
                hv_vcpu->cpuid_cache.nested_eax = entry->eax;
                hv_vcpu->cpuid_cache.nested_ebx = entry->ebx;
        }
}

int kvm_hv_set_enforce_cpuid(struct kvm_vcpu *vcpu, bool enforce)
{
        struct kvm_vcpu_hv *hv_vcpu;
        int ret = 0;

        if (!to_hv_vcpu(vcpu)) {
                if (enforce) {
                        ret = kvm_hv_vcpu_init(vcpu);
                        if (ret)
                                return ret;
                } else {
                        return 0;
                }
        }

        hv_vcpu = to_hv_vcpu(vcpu);
        hv_vcpu->enforce_cpuid = enforce;

        return ret;
}

static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
{
        bool longmode;

        longmode = is_64_bit_hypercall(vcpu);
        if (longmode)
                kvm_rax_write(vcpu, result);
        else {
                kvm_rdx_write(vcpu, result >> 32);
                kvm_rax_write(vcpu, result & 0xffffffff);
        }
}

static int kvm_hv_hypercall_complete(struct kvm_vcpu *vcpu, u64 result)
{
        u32 tlb_lock_count = 0;
        int ret;

        if (hv_result_success(result) && is_guest_mode(vcpu) &&
            kvm_hv_is_tlb_flush_hcall(vcpu) &&
            kvm_read_guest(vcpu->kvm, to_hv_vcpu(vcpu)->nested.pa_page_gpa,
                           &tlb_lock_count, sizeof(tlb_lock_count)))
                result = HV_STATUS_INVALID_HYPERCALL_INPUT;

        trace_kvm_hv_hypercall_done(result);
        kvm_hv_hypercall_set_result(vcpu, result);
        ++vcpu->stat.hypercalls;

        ret = kvm_skip_emulated_instruction(vcpu);

        if (tlb_lock_count)
                kvm_x86_ops.nested_ops->hv_inject_synthetic_vmexit_post_tlb_flush(vcpu);

        return ret;
}

static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
{
        return kvm_hv_hypercall_complete(vcpu, vcpu->run->hyperv.u.hcall.result);
}

static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
{
        struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);
        struct eventfd_ctx *eventfd;

        if (unlikely(!hc->fast)) {
                int ret;
                gpa_t gpa = hc->ingpa;

                if ((gpa & (__alignof__(hc->ingpa) - 1)) ||
                    offset_in_page(gpa) + sizeof(hc->ingpa) > PAGE_SIZE)
                        return HV_STATUS_INVALID_ALIGNMENT;

                ret = kvm_vcpu_read_guest(vcpu, gpa,
                                          &hc->ingpa, sizeof(hc->ingpa));
                if (ret < 0)
                        return HV_STATUS_INVALID_ALIGNMENT;
        }

        /*
         * Per spec, bits 32-47 contain the extra "flag number".  However, we
         * have no use for it, and in all known usecases it is zero, so just
         * report lookup failure if it isn't.
         */
        if (hc->ingpa & 0xffff00000000ULL)
                return HV_STATUS_INVALID_PORT_ID;
        /* remaining bits are reserved-zero */
        if (hc->ingpa & ~KVM_HYPERV_CONN_ID_MASK)
                return HV_STATUS_INVALID_HYPERCALL_INPUT;

        /* the eventfd is protected by vcpu->kvm->srcu, but conn_to_evt isn't */
        rcu_read_lock();
        eventfd = idr_find(&hv->conn_to_evt, hc->ingpa);
        rcu_read_unlock();
        if (!eventfd)
                return HV_STATUS_INVALID_PORT_ID;

        eventfd_signal(eventfd);
        return HV_STATUS_SUCCESS;
}

static bool is_xmm_fast_hypercall(struct kvm_hv_hcall *hc)
{
        switch (hc->code) {
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
        case HVCALL_SEND_IPI_EX:
                return true;
        }

        return false;
}

static void kvm_hv_hypercall_read_xmm(struct kvm_hv_hcall *hc)
{
        int reg;

        kvm_fpu_get();
        for (reg = 0; reg < HV_HYPERCALL_MAX_XMM_REGISTERS; reg++)
                _kvm_read_sse_reg(reg, &hc->xmm[reg]);
        kvm_fpu_put();
}

static bool hv_check_hypercall_access(struct kvm_vcpu_hv *hv_vcpu, u16 code)
{
        if (!hv_vcpu->enforce_cpuid)
                return true;

        switch (code) {
        case HVCALL_NOTIFY_LONG_SPIN_WAIT:
                return hv_vcpu->cpuid_cache.enlightenments_ebx &&
                        hv_vcpu->cpuid_cache.enlightenments_ebx != U32_MAX;
        case HVCALL_POST_MESSAGE:
                return hv_vcpu->cpuid_cache.features_ebx & HV_POST_MESSAGES;
        case HVCALL_SIGNAL_EVENT:
                return hv_vcpu->cpuid_cache.features_ebx & HV_SIGNAL_EVENTS;
        case HVCALL_POST_DEBUG_DATA:
        case HVCALL_RETRIEVE_DEBUG_DATA:
        case HVCALL_RESET_DEBUG_SESSION:
                /*
                 * Return 'true' when SynDBG is disabled so the resulting code
                 * will be HV_STATUS_INVALID_HYPERCALL_CODE.
                 */
                return !kvm_hv_is_syndbg_enabled(hv_vcpu->vcpu) ||
                        hv_vcpu->cpuid_cache.features_ebx & HV_DEBUGGING;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
                if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
                      HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
                        return false;
                fallthrough;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
                return hv_vcpu->cpuid_cache.enlightenments_eax &
                        HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
        case HVCALL_SEND_IPI_EX:
                if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
                      HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
                        return false;
                fallthrough;
        case HVCALL_SEND_IPI:
                return hv_vcpu->cpuid_cache.enlightenments_eax &
                        HV_X64_CLUSTER_IPI_RECOMMENDED;
        case HV_EXT_CALL_QUERY_CAPABILITIES ... HV_EXT_CALL_MAX:
                return hv_vcpu->cpuid_cache.features_ebx &
                        HV_ENABLE_EXTENDED_HYPERCALLS;
        default:
                break;
        }

        return true;
}

int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
{
        struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
        struct kvm_hv_hcall hc;
        u64 ret = HV_STATUS_SUCCESS;

        /*
         * hypercall generates UD from non zero cpl and real mode
         * per HYPER-V spec
         */
        if (kvm_x86_call(get_cpl)(vcpu) != 0 || !is_protmode(vcpu)) {
                kvm_queue_exception(vcpu, UD_VECTOR);
                return 1;
        }

#ifdef CONFIG_X86_64
        if (is_64_bit_hypercall(vcpu)) {
                hc.param = kvm_rcx_read(vcpu);
                hc.ingpa = kvm_rdx_read(vcpu);
                hc.outgpa = kvm_r8_read(vcpu);
        } else
#endif
        {
                hc.param = ((u64)kvm_rdx_read(vcpu) << 32) |
                            (kvm_rax_read(vcpu) & 0xffffffff);
                hc.ingpa = ((u64)kvm_rbx_read(vcpu) << 32) |
                            (kvm_rcx_read(vcpu) & 0xffffffff);
                hc.outgpa = ((u64)kvm_rdi_read(vcpu) << 32) |
                             (kvm_rsi_read(vcpu) & 0xffffffff);
        }

        hc.code = hc.param & 0xffff;
        hc.var_cnt = (hc.param & HV_HYPERCALL_VARHEAD_MASK) >> HV_HYPERCALL_VARHEAD_OFFSET;
        hc.fast = !!(hc.param & HV_HYPERCALL_FAST_BIT);
        hc.rep_cnt = (hc.param >> HV_HYPERCALL_REP_COMP_OFFSET) & 0xfff;
        hc.rep_idx = (hc.param >> HV_HYPERCALL_REP_START_OFFSET) & 0xfff;
        hc.rep = !!(hc.rep_cnt || hc.rep_idx);

        trace_kvm_hv_hypercall(hc.code, hc.fast, hc.var_cnt, hc.rep_cnt,
                               hc.rep_idx, hc.ingpa, hc.outgpa);

        if (unlikely(!hv_check_hypercall_access(hv_vcpu, hc.code))) {
                ret = HV_STATUS_ACCESS_DENIED;
                goto hypercall_complete;
        }

        if (unlikely(hc.param & HV_HYPERCALL_RSVD_MASK)) {
                ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                goto hypercall_complete;
        }

        if (hc.fast && is_xmm_fast_hypercall(&hc)) {
                if (unlikely(hv_vcpu->enforce_cpuid &&
                             !(hv_vcpu->cpuid_cache.features_edx &
                               HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE))) {
                        kvm_queue_exception(vcpu, UD_VECTOR);
                        return 1;
                }

                kvm_hv_hypercall_read_xmm(&hc);
        }

        switch (hc.code) {
        case HVCALL_NOTIFY_LONG_SPIN_WAIT:
                if (unlikely(hc.rep || hc.var_cnt)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                kvm_vcpu_on_spin(vcpu, true);
                break;
        case HVCALL_SIGNAL_EVENT:
                if (unlikely(hc.rep || hc.var_cnt)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                ret = kvm_hvcall_signal_event(vcpu, &hc);
                if (ret != HV_STATUS_INVALID_PORT_ID)
                        break;
                fallthrough;    /* maybe userspace knows this conn_id */
        case HVCALL_POST_MESSAGE:
                /* don't bother userspace if it has no way to handle it */
                if (unlikely(hc.rep || hc.var_cnt || !to_hv_synic(vcpu)->active)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                goto hypercall_userspace_exit;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
                if (unlikely(hc.var_cnt)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                fallthrough;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
                if (unlikely(!hc.rep_cnt || hc.rep_idx)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                ret = kvm_hv_flush_tlb(vcpu, &hc);
                break;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
                if (unlikely(hc.var_cnt)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                fallthrough;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
                if (unlikely(hc.rep)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                ret = kvm_hv_flush_tlb(vcpu, &hc);
                break;
        case HVCALL_SEND_IPI:
                if (unlikely(hc.var_cnt)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                fallthrough;
        case HVCALL_SEND_IPI_EX:
                if (unlikely(hc.rep)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
                        break;
                }
                ret = kvm_hv_send_ipi(vcpu, &hc);
                break;
        case HVCALL_POST_DEBUG_DATA:
        case HVCALL_RETRIEVE_DEBUG_DATA:
                if (unlikely(hc.fast)) {
                        ret = HV_STATUS_INVALID_PARAMETER;
                        break;
                }
                fallthrough;
        case HVCALL_RESET_DEBUG_SESSION: {
                struct kvm_hv_syndbg *syndbg = to_hv_syndbg(vcpu);

                if (!kvm_hv_is_syndbg_enabled(vcpu)) {
                        ret = HV_STATUS_INVALID_HYPERCALL_CODE;
                        break;
                }

                if (!(syndbg->options & HV_X64_SYNDBG_OPTION_USE_HCALLS)) {
                        ret = HV_STATUS_OPERATION_DENIED;
                        break;
                }
                goto hypercall_userspace_exit;
        }
        case HV_EXT_CALL_QUERY_CAPABILITIES ... HV_EXT_CALL_MAX:
                if (unlikely(hc.fast)) {
                        ret = HV_STATUS_INVALID_PARAMETER;
                        break;
                }
                goto hypercall_userspace_exit;
        default:
                ret = HV_STATUS_INVALID_HYPERCALL_CODE;
                break;
        }

hypercall_complete:
        return kvm_hv_hypercall_complete(vcpu, ret);

hypercall_userspace_exit:
        vcpu->run->exit_reason = KVM_EXIT_HYPERV;
        vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
        vcpu->run->hyperv.u.hcall.input = hc.param;
        vcpu->run->hyperv.u.hcall.params[0] = hc.ingpa;
        vcpu->run->hyperv.u.hcall.params[1] = hc.outgpa;
        vcpu->arch.complete_userspace_io = kvm_hv_hypercall_complete_userspace;
        return 0;
}

void kvm_hv_init_vm(struct kvm *kvm)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);

        mutex_init(&hv->hv_lock);
        idr_init(&hv->conn_to_evt);
}

void kvm_hv_destroy_vm(struct kvm *kvm)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        struct eventfd_ctx *eventfd;
        int i;

        idr_for_each_entry(&hv->conn_to_evt, eventfd, i)
                eventfd_ctx_put(eventfd);
        idr_destroy(&hv->conn_to_evt);
}

static int kvm_hv_eventfd_assign(struct kvm *kvm, u32 conn_id, int fd)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        struct eventfd_ctx *eventfd;
        int ret;

        eventfd = eventfd_ctx_fdget(fd);
        if (IS_ERR(eventfd))
                return PTR_ERR(eventfd);

        mutex_lock(&hv->hv_lock);
        ret = idr_alloc(&hv->conn_to_evt, eventfd, conn_id, conn_id + 1,
                        GFP_KERNEL_ACCOUNT);
        mutex_unlock(&hv->hv_lock);

        if (ret >= 0)
                return 0;

        if (ret == -ENOSPC)
                ret = -EEXIST;
        eventfd_ctx_put(eventfd);
        return ret;
}

static int kvm_hv_eventfd_deassign(struct kvm *kvm, u32 conn_id)
{
        struct kvm_hv *hv = to_kvm_hv(kvm);
        struct eventfd_ctx *eventfd;

        mutex_lock(&hv->hv_lock);
        eventfd = idr_remove(&hv->conn_to_evt, conn_id);
        mutex_unlock(&hv->hv_lock);

        if (!eventfd)
                return -ENOENT;

        synchronize_srcu(&kvm->srcu);
        eventfd_ctx_put(eventfd);
        return 0;
}

int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args)
{
        if ((args->flags & ~KVM_HYPERV_EVENTFD_DEASSIGN) ||
            (args->conn_id & ~KVM_HYPERV_CONN_ID_MASK))
                return -EINVAL;

        if (args->flags == KVM_HYPERV_EVENTFD_DEASSIGN)
                return kvm_hv_eventfd_deassign(kvm, args->conn_id);
        return kvm_hv_eventfd_assign(kvm, args->conn_id, args->fd);
}

int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
                     struct kvm_cpuid_entry2 __user *entries)
{
        uint16_t evmcs_ver = 0;
        struct kvm_cpuid_entry2 cpuid_entries[] = {
                { .function = HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS },
                { .function = HYPERV_CPUID_INTERFACE },
                { .function = HYPERV_CPUID_VERSION },
                { .function = HYPERV_CPUID_FEATURES },
                { .function = HYPERV_CPUID_ENLIGHTMENT_INFO },
                { .function = HYPERV_CPUID_IMPLEMENT_LIMITS },
                { .function = HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS },
                { .function = HYPERV_CPUID_SYNDBG_INTERFACE },
                { .function = HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES },
                { .function = HYPERV_CPUID_NESTED_FEATURES },
        };
        int i, nent = ARRAY_SIZE(cpuid_entries);

        if (kvm_x86_ops.nested_ops->get_evmcs_version)
                evmcs_ver = kvm_x86_ops.nested_ops->get_evmcs_version(vcpu);

        if (cpuid->nent < nent)
                return -E2BIG;

        if (cpuid->nent > nent)
                cpuid->nent = nent;

        for (i = 0; i < nent; i++) {
                struct kvm_cpuid_entry2 *ent = &cpuid_entries[i];
                u32 signature[3];

                switch (ent->function) {
                case HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS:
                        memcpy(signature, "Linux KVM Hv", 12);

                        ent->eax = HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES;
                        ent->ebx = signature[0];
                        ent->ecx = signature[1];
                        ent->edx = signature[2];
                        break;

                case HYPERV_CPUID_INTERFACE:
                        ent->eax = HYPERV_CPUID_SIGNATURE_EAX;
                        break;

                case HYPERV_CPUID_VERSION:
                        /*
                         * We implement some Hyper-V 2016 functions so let's use
                         * this version.
                         */
                        ent->eax = 0x00003839;
                        ent->ebx = 0x000A0000;
                        break;

                case HYPERV_CPUID_FEATURES:
                        ent->eax |= HV_MSR_VP_RUNTIME_AVAILABLE;
                        ent->eax |= HV_MSR_TIME_REF_COUNT_AVAILABLE;
                        ent->eax |= HV_MSR_SYNIC_AVAILABLE;
                        ent->eax |= HV_MSR_SYNTIMER_AVAILABLE;
                        ent->eax |= HV_MSR_APIC_ACCESS_AVAILABLE;
                        ent->eax |= HV_MSR_HYPERCALL_AVAILABLE;
                        ent->eax |= HV_MSR_VP_INDEX_AVAILABLE;
                        ent->eax |= HV_MSR_RESET_AVAILABLE;
                        ent->eax |= HV_MSR_REFERENCE_TSC_AVAILABLE;
                        ent->eax |= HV_ACCESS_FREQUENCY_MSRS;
                        ent->eax |= HV_ACCESS_REENLIGHTENMENT;
                        ent->eax |= HV_ACCESS_TSC_INVARIANT;

                        ent->ebx |= HV_POST_MESSAGES;
                        ent->ebx |= HV_SIGNAL_EVENTS;
                        ent->ebx |= HV_ENABLE_EXTENDED_HYPERCALLS;

                        ent->edx |= HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE;
                        ent->edx |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE;
                        ent->edx |= HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;

                        ent->ebx |= HV_DEBUGGING;
                        ent->edx |= HV_X64_GUEST_DEBUGGING_AVAILABLE;
                        ent->edx |= HV_FEATURE_DEBUG_MSRS_AVAILABLE;
                        ent->edx |= HV_FEATURE_EXT_GVA_RANGES_FLUSH;

                        /*
                         * Direct Synthetic timers only make sense with in-kernel
                         * LAPIC
                         */
                        if (!vcpu || lapic_in_kernel(vcpu))
                                ent->edx |= HV_STIMER_DIRECT_MODE_AVAILABLE;

                        break;

                case HYPERV_CPUID_ENLIGHTMENT_INFO:
                        ent->eax |= HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
                        ent->eax |= HV_X64_APIC_ACCESS_RECOMMENDED;
                        ent->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED;
                        if (!vcpu || lapic_in_kernel(vcpu))
                                ent->eax |= HV_X64_CLUSTER_IPI_RECOMMENDED;
                        ent->eax |= HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED;
                        if (evmcs_ver)
                                ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
                        if (!cpu_smt_possible())
                                ent->eax |= HV_X64_NO_NONARCH_CORESHARING;

                        ent->eax |= HV_DEPRECATING_AEOI_RECOMMENDED;
                        /*
                         * Default number of spinlock retry attempts, matches
                         * HyperV 2016.
                         */
                        ent->ebx = 0x00000FFF;

                        break;

                case HYPERV_CPUID_IMPLEMENT_LIMITS:
                        /* Maximum number of virtual processors */
                        ent->eax = KVM_MAX_VCPUS;
                        /*
                         * Maximum number of logical processors, matches
                         * HyperV 2016.
                         */
                        ent->ebx = 64;

                        break;

                case HYPERV_CPUID_NESTED_FEATURES:
                        ent->eax = evmcs_ver;
                        ent->eax |= HV_X64_NESTED_DIRECT_FLUSH;
                        ent->eax |= HV_X64_NESTED_MSR_BITMAP;
                        ent->ebx |= HV_X64_NESTED_EVMCS1_PERF_GLOBAL_CTRL;
                        break;

                case HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS:
                        memcpy(signature, "Linux KVM Hv", 12);

                        ent->eax = 0;
                        ent->ebx = signature[0];
                        ent->ecx = signature[1];
                        ent->edx = signature[2];
                        break;

                case HYPERV_CPUID_SYNDBG_INTERFACE:
                        memcpy(signature, "VS#1\0\0\0\0\0\0\0\0", 12);
                        ent->eax = signature[0];
                        break;

                case HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES:
                        ent->eax |= HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING;
                        break;

                default:
                        break;
                }
        }

        if (copy_to_user(entries, cpuid_entries,
                         nent * sizeof(struct kvm_cpuid_entry2)))
                return -EFAULT;

        return 0;
}