/*
 * Local APIC virtualization
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2007 Novell
 * Copyright (C) 2007 Intel
 * Copyright 2009 Red Hat, Inc. and/or its affiliates.
 *
 * Authors:
 *   Dor Laor <dor.laor@qumranet.com>
 *   Gregory Haskins <ghaskins@novell.com>
 *   Yaozu (Eddie) Dong <eddie.dong@intel.com>
 *
 * Based on Xen 3.1 code, Copyright (c) 2004, Intel Corporation.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 */

#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/smp.h>
#include <linux/hrtimer.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/math64.h>
#include <linux/slab.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/page.h>
#include <asm/current.h>
#include <asm/apicdef.h>
#include <linux/atomic.h>
#include <linux/jump_label.h>
#include "kvm_cache_regs.h"
#include "irq.h"
#include "trace.h"
#include "x86.h"
#include "cpuid.h"

#ifndef CONFIG_X86_64
#define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
#else
#define mod_64(x, y) ((x) % (y))
#endif

#define PRId64 "d"
#define PRIx64 "llx"
#define PRIu64 "u"
#define PRIo64 "o"

#define APIC_BUS_CYCLE_NS 1

/* #define apic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg) */
#define apic_debug(fmt, arg...)

#define APIC_LVT_NUM                    6
/* 14 is the version for Xeon and Pentium 8.4.8*/
#define APIC_VERSION                    (0x14UL | ((APIC_LVT_NUM - 1) << 16))
#define LAPIC_MMIO_LENGTH               (1 << 12)
/* followed define is not in apicdef.h */
#define APIC_SHORT_MASK                 0xc0000
#define APIC_DEST_NOSHORT               0x0
#define APIC_DEST_MASK                  0x800
#define MAX_APIC_VECTOR                 256
#define APIC_VECTORS_PER_REG            32

#define VEC_POS(v) ((v) & (32 - 1))
#define REG_POS(v) (((v) >> 5) << 4)

static unsigned int min_timer_period_us = 500;
module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);

static inline void apic_set_reg(struct kvm_lapic *apic, int reg_off, u32 val)
{
        *((u32 *) (apic->regs + reg_off)) = val;
}

static inline int apic_test_and_set_vector(int vec, void *bitmap)
{
        return test_and_set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

static inline int apic_test_and_clear_vector(int vec, void *bitmap)
{
        return test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

static inline int apic_test_vector(int vec, void *bitmap)
{
        return test_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

static inline void apic_set_vector(int vec, void *bitmap)
{
        set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

static inline void apic_clear_vector(int vec, void *bitmap)
{
        clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

static inline int __apic_test_and_set_vector(int vec, void *bitmap)
{
        return __test_and_set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

static inline int __apic_test_and_clear_vector(int vec, void *bitmap)
{
        return __test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
}

struct static_key_deferred apic_hw_disabled __read_mostly;
struct static_key_deferred apic_sw_disabled __read_mostly;

static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val)
{
        if ((kvm_apic_get_reg(apic, APIC_SPIV) ^ val) & APIC_SPIV_APIC_ENABLED) {
                if (val & APIC_SPIV_APIC_ENABLED)
                        static_key_slow_dec_deferred(&apic_sw_disabled);
                else
                        static_key_slow_inc(&apic_sw_disabled.key);
        }
        apic_set_reg(apic, APIC_SPIV, val);
}

static inline int apic_enabled(struct kvm_lapic *apic)
{
        return kvm_apic_sw_enabled(apic) &&     kvm_apic_hw_enabled(apic);
}

#define LVT_MASK        \
        (APIC_LVT_MASKED | APIC_SEND_PENDING | APIC_VECTOR_MASK)

#define LINT_MASK       \
        (LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
         APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)

static inline int apic_x2apic_mode(struct kvm_lapic *apic)
{
        return apic->vcpu->arch.apic_base & X2APIC_ENABLE;
}

static inline int kvm_apic_id(struct kvm_lapic *apic)
{
        return (kvm_apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
}

static inline u16 apic_cluster_id(struct kvm_apic_map *map, u32 ldr)
{
        u16 cid;
        ldr >>= 32 - map->ldr_bits;
        cid = (ldr >> map->cid_shift) & map->cid_mask;

        BUG_ON(cid >= ARRAY_SIZE(map->logical_map));

        return cid;
}

static inline u16 apic_logical_id(struct kvm_apic_map *map, u32 ldr)
{
        ldr >>= (32 - map->ldr_bits);
        return ldr & map->lid_mask;
}

static void recalculate_apic_map(struct kvm *kvm)
{
        struct kvm_apic_map *new, *old = NULL;
        struct kvm_vcpu *vcpu;
        int i;

        new = kzalloc(sizeof(struct kvm_apic_map), GFP_KERNEL);

        mutex_lock(&kvm->arch.apic_map_lock);

        if (!new)
                goto out;

        new->ldr_bits = 8;
        /* flat mode is default */
        new->cid_shift = 8;
        new->cid_mask = 0;
        new->lid_mask = 0xff;

        kvm_for_each_vcpu(i, vcpu, kvm) {
                struct kvm_lapic *apic = vcpu->arch.apic;
                u16 cid, lid;
                u32 ldr;

                if (!kvm_apic_present(vcpu))
                        continue;

                /*
                 * All APICs have to be configured in the same mode by an OS.
                 * We take advatage of this while building logical id loockup
                 * table. After reset APICs are in xapic/flat mode, so if we
                 * find apic with different setting we assume this is the mode
                 * OS wants all apics to be in; build lookup table accordingly.
                 */
                if (apic_x2apic_mode(apic)) {
                        new->ldr_bits = 32;
                        new->cid_shift = 16;
                        new->cid_mask = new->lid_mask = 0xffff;
                } else if (kvm_apic_sw_enabled(apic) &&
                                !new->cid_mask /* flat mode */ &&
                                kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_CLUSTER) {
                        new->cid_shift = 4;
                        new->cid_mask = 0xf;
                        new->lid_mask = 0xf;
                }

                new->phys_map[kvm_apic_id(apic)] = apic;

                ldr = kvm_apic_get_reg(apic, APIC_LDR);
                cid = apic_cluster_id(new, ldr);
                lid = apic_logical_id(new, ldr);

                if (lid)
                        new->logical_map[cid][ffs(lid) - 1] = apic;
        }
out:
        old = rcu_dereference_protected(kvm->arch.apic_map,
                        lockdep_is_held(&kvm->arch.apic_map_lock));
        rcu_assign_pointer(kvm->arch.apic_map, new);
        mutex_unlock(&kvm->arch.apic_map_lock);

        if (old)
                kfree_rcu(old, rcu);
}

static inline void kvm_apic_set_id(struct kvm_lapic *apic, u8 id)
{
        apic_set_reg(apic, APIC_ID, id << 24);
        recalculate_apic_map(apic->vcpu->kvm);
}

static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id)
{
        apic_set_reg(apic, APIC_LDR, id);
        recalculate_apic_map(apic->vcpu->kvm);
}

static inline int apic_lvt_enabled(struct kvm_lapic *apic, int lvt_type)
{
        return !(kvm_apic_get_reg(apic, lvt_type) & APIC_LVT_MASKED);
}

static inline int apic_lvt_vector(struct kvm_lapic *apic, int lvt_type)
{
        return kvm_apic_get_reg(apic, lvt_type) & APIC_VECTOR_MASK;
}

static inline int apic_lvtt_oneshot(struct kvm_lapic *apic)
{
        return ((kvm_apic_get_reg(apic, APIC_LVTT) &
                apic->lapic_timer.timer_mode_mask) == APIC_LVT_TIMER_ONESHOT);
}

static inline int apic_lvtt_period(struct kvm_lapic *apic)
{
        return ((kvm_apic_get_reg(apic, APIC_LVTT) &
                apic->lapic_timer.timer_mode_mask) == APIC_LVT_TIMER_PERIODIC);
}

static inline int apic_lvtt_tscdeadline(struct kvm_lapic *apic)
{
        return ((kvm_apic_get_reg(apic, APIC_LVTT) &
                apic->lapic_timer.timer_mode_mask) ==
                        APIC_LVT_TIMER_TSCDEADLINE);
}

static inline int apic_lvt_nmi_mode(u32 lvt_val)
{
        return (lvt_val & (APIC_MODE_MASK | APIC_LVT_MASKED)) == APIC_DM_NMI;
}

void kvm_apic_set_version(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;
        struct kvm_cpuid_entry2 *feat;
        u32 v = APIC_VERSION;

        if (!kvm_vcpu_has_lapic(vcpu))
                return;

        feat = kvm_find_cpuid_entry(apic->vcpu, 0x1, 0);
        if (feat && (feat->ecx & (1 << (X86_FEATURE_X2APIC & 31))))
                v |= APIC_LVR_DIRECTED_EOI;
        apic_set_reg(apic, APIC_LVR, v);
}

static const unsigned int apic_lvt_mask[APIC_LVT_NUM] = {
        LVT_MASK ,      /* part LVTT mask, timer mode mask added at runtime */
        LVT_MASK | APIC_MODE_MASK,      /* LVTTHMR */
        LVT_MASK | APIC_MODE_MASK,      /* LVTPC */
        LINT_MASK, LINT_MASK,   /* LVT0-1 */
        LVT_MASK                /* LVTERR */
};

static int find_highest_vector(void *bitmap)
{
        int vec;
        u32 *reg;

        for (vec = MAX_APIC_VECTOR - APIC_VECTORS_PER_REG;
             vec >= 0; vec -= APIC_VECTORS_PER_REG) {
                reg = bitmap + REG_POS(vec);
                if (*reg)
                        return fls(*reg) - 1 + vec;
        }

        return -1;
}

static u8 count_vectors(void *bitmap)
{
        int vec;
        u32 *reg;
        u8 count = 0;

        for (vec = 0; vec < MAX_APIC_VECTOR; vec += APIC_VECTORS_PER_REG) {
                reg = bitmap + REG_POS(vec);
                count += hweight32(*reg);
        }

        return count;
}

static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
{
        apic->irr_pending = true;
        return apic_test_and_set_vector(vec, apic->regs + APIC_IRR);
}

static inline int apic_search_irr(struct kvm_lapic *apic)
{
        return find_highest_vector(apic->regs + APIC_IRR);
}

static inline int apic_find_highest_irr(struct kvm_lapic *apic)
{
        int result;

        if (!apic->irr_pending)
                return -1;

        result = apic_search_irr(apic);
        ASSERT(result == -1 || result >= 16);

        return result;
}

static inline void apic_clear_irr(int vec, struct kvm_lapic *apic)
{
        apic->irr_pending = false;
        apic_clear_vector(vec, apic->regs + APIC_IRR);
        if (apic_search_irr(apic) != -1)
                apic->irr_pending = true;
}

static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
{
        if (!__apic_test_and_set_vector(vec, apic->regs + APIC_ISR))
                ++apic->isr_count;
        BUG_ON(apic->isr_count > MAX_APIC_VECTOR);
        /*
         * ISR (in service register) bit is set when injecting an interrupt.
         * The highest vector is injected. Thus the latest bit set matches
         * the highest bit in ISR.
         */
        apic->highest_isr_cache = vec;
}

static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
{
        if (__apic_test_and_clear_vector(vec, apic->regs + APIC_ISR))
                --apic->isr_count;
        BUG_ON(apic->isr_count < 0);
        apic->highest_isr_cache = -1;
}

int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
{
        int highest_irr;

        /* This may race with setting of irr in __apic_accept_irq() and
         * value returned may be wrong, but kvm_vcpu_kick() in __apic_accept_irq
         * will cause vmexit immediately and the value will be recalculated
         * on the next vmentry.
         */
        if (!kvm_vcpu_has_lapic(vcpu))
                return 0;
        highest_irr = apic_find_highest_irr(vcpu->arch.apic);

        return highest_irr;
}

static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
                             int vector, int level, int trig_mode);

int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        return __apic_accept_irq(apic, irq->delivery_mode, irq->vector,
                        irq->level, irq->trig_mode);
}

static int pv_eoi_put_user(struct kvm_vcpu *vcpu, u8 val)
{

        return kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data, &val,
                                      sizeof(val));
}

static int pv_eoi_get_user(struct kvm_vcpu *vcpu, u8 *val)
{

        return kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data, val,
                                      sizeof(*val));
}

static inline bool pv_eoi_enabled(struct kvm_vcpu *vcpu)
{
        return vcpu->arch.pv_eoi.msr_val & KVM_MSR_ENABLED;
}

static bool pv_eoi_get_pending(struct kvm_vcpu *vcpu)
{
        u8 val;
        if (pv_eoi_get_user(vcpu, &val) < 0)
                apic_debug("Can't read EOI MSR value: 0x%llx\n",
                           (unsigned long long)vcpi->arch.pv_eoi.msr_val);
        return val & 0x1;
}

static void pv_eoi_set_pending(struct kvm_vcpu *vcpu)
{
        if (pv_eoi_put_user(vcpu, KVM_PV_EOI_ENABLED) < 0) {
                apic_debug("Can't set EOI MSR value: 0x%llx\n",
                           (unsigned long long)vcpi->arch.pv_eoi.msr_val);
                return;
        }
        __set_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
}

static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu)
{
        if (pv_eoi_put_user(vcpu, KVM_PV_EOI_DISABLED) < 0) {
                apic_debug("Can't clear EOI MSR value: 0x%llx\n",
                           (unsigned long long)vcpi->arch.pv_eoi.msr_val);
                return;
        }
        __clear_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
}

static inline int apic_find_highest_isr(struct kvm_lapic *apic)
{
        int result;
        if (!apic->isr_count)
                return -1;
        if (likely(apic->highest_isr_cache != -1))
                return apic->highest_isr_cache;

        result = find_highest_vector(apic->regs + APIC_ISR);
        ASSERT(result == -1 || result >= 16);

        return result;
}

static void apic_update_ppr(struct kvm_lapic *apic)
{
        u32 tpr, isrv, ppr, old_ppr;
        int isr;

        old_ppr = kvm_apic_get_reg(apic, APIC_PROCPRI);
        tpr = kvm_apic_get_reg(apic, APIC_TASKPRI);
        isr = apic_find_highest_isr(apic);
        isrv = (isr != -1) ? isr : 0;

        if ((tpr & 0xf0) >= (isrv & 0xf0))
                ppr = tpr & 0xff;
        else
                ppr = isrv & 0xf0;

        apic_debug("vlapic %p, ppr 0x%x, isr 0x%x, isrv 0x%x",
                   apic, ppr, isr, isrv);

        if (old_ppr != ppr) {
                apic_set_reg(apic, APIC_PROCPRI, ppr);
                if (ppr < old_ppr)
                        kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
        }
}

static void apic_set_tpr(struct kvm_lapic *apic, u32 tpr)
{
        apic_set_reg(apic, APIC_TASKPRI, tpr);
        apic_update_ppr(apic);
}

int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest)
{
        return dest == 0xff || kvm_apic_id(apic) == dest;
}

int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
{
        int result = 0;
        u32 logical_id;

        if (apic_x2apic_mode(apic)) {
                logical_id = kvm_apic_get_reg(apic, APIC_LDR);
                return logical_id & mda;
        }

        logical_id = GET_APIC_LOGICAL_ID(kvm_apic_get_reg(apic, APIC_LDR));

        switch (kvm_apic_get_reg(apic, APIC_DFR)) {
        case APIC_DFR_FLAT:
                if (logical_id & mda)
                        result = 1;
                break;
        case APIC_DFR_CLUSTER:
                if (((logical_id >> 4) == (mda >> 0x4))
                    && (logical_id & mda & 0xf))
                        result = 1;
                break;
        default:
                apic_debug("Bad DFR vcpu %d: %08x\n",
                           apic->vcpu->vcpu_id, kvm_apic_get_reg(apic, APIC_DFR));
                break;
        }

        return result;
}

int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
                           int short_hand, int dest, int dest_mode)
{
        int result = 0;
        struct kvm_lapic *target = vcpu->arch.apic;

        apic_debug("target %p, source %p, dest 0x%x, "
                   "dest_mode 0x%x, short_hand 0x%x\n",
                   target, source, dest, dest_mode, short_hand);

        ASSERT(target);
        switch (short_hand) {
        case APIC_DEST_NOSHORT:
                if (dest_mode == 0)
                        /* Physical mode. */
                        result = kvm_apic_match_physical_addr(target, dest);
                else
                        /* Logical mode. */
                        result = kvm_apic_match_logical_addr(target, dest);
                break;
        case APIC_DEST_SELF:
                result = (target == source);
                break;
        case APIC_DEST_ALLINC:
                result = 1;
                break;
        case APIC_DEST_ALLBUT:
                result = (target != source);
                break;
        default:
                apic_debug("kvm: apic: Bad dest shorthand value %x\n",
                           short_hand);
                break;
        }

        return result;
}

bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
                struct kvm_lapic_irq *irq, int *r)
{
        struct kvm_apic_map *map;
        unsigned long bitmap = 1;
        struct kvm_lapic **dst;
        int i;
        bool ret = false;

        *r = -1;

        if (irq->shorthand == APIC_DEST_SELF) {
                *r = kvm_apic_set_irq(src->vcpu, irq);
                return true;
        }

        if (irq->shorthand)
                return false;

        rcu_read_lock();
        map = rcu_dereference(kvm->arch.apic_map);

        if (!map)
                goto out;

        if (irq->dest_mode == 0) { /* physical mode */
                if (irq->delivery_mode == APIC_DM_LOWEST ||
                                irq->dest_id == 0xff)
                        goto out;
                dst = &map->phys_map[irq->dest_id & 0xff];
        } else {
                u32 mda = irq->dest_id << (32 - map->ldr_bits);

                dst = map->logical_map[apic_cluster_id(map, mda)];

                bitmap = apic_logical_id(map, mda);

                if (irq->delivery_mode == APIC_DM_LOWEST) {
                        int l = -1;
                        for_each_set_bit(i, &bitmap, 16) {
                                if (!dst[i])
                                        continue;
                                if (l < 0)
                                        l = i;
                                else if (kvm_apic_compare_prio(dst[i]->vcpu, dst[l]->vcpu) < 0)
                                        l = i;
                        }

                        bitmap = (l >= 0) ? 1 << l : 0;
                }
        }

        for_each_set_bit(i, &bitmap, 16) {
                if (!dst[i])
                        continue;
                if (*r < 0)
                        *r = 0;
                *r += kvm_apic_set_irq(dst[i]->vcpu, irq);
        }

        ret = true;
out:
        rcu_read_unlock();
        return ret;
}

/*
 * Add a pending IRQ into lapic.
 * Return 1 if successfully added and 0 if discarded.
 */
static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
                             int vector, int level, int trig_mode)
{
        int result = 0;
        struct kvm_vcpu *vcpu = apic->vcpu;

        switch (delivery_mode) {
        case APIC_DM_LOWEST:
                vcpu->arch.apic_arb_prio++;
        case APIC_DM_FIXED:
                /* FIXME add logic for vcpu on reset */
                if (unlikely(!apic_enabled(apic)))
                        break;

                if (trig_mode) {
                        apic_debug("level trig mode for vector %d", vector);
                        apic_set_vector(vector, apic->regs + APIC_TMR);
                } else
                        apic_clear_vector(vector, apic->regs + APIC_TMR);

                result = !apic_test_and_set_irr(vector, apic);
                trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
                                          trig_mode, vector, !result);
                if (!result) {
                        if (trig_mode)
                                apic_debug("level trig mode repeatedly for "
                                                "vector %d", vector);
                        break;
                }

                kvm_make_request(KVM_REQ_EVENT, vcpu);
                kvm_vcpu_kick(vcpu);
                break;

        case APIC_DM_REMRD:
                apic_debug("Ignoring delivery mode 3\n");
                break;

        case APIC_DM_SMI:
                apic_debug("Ignoring guest SMI\n");
                break;

        case APIC_DM_NMI:
                result = 1;
                kvm_inject_nmi(vcpu);
                kvm_vcpu_kick(vcpu);
                break;

        case APIC_DM_INIT:
                if (!trig_mode || level) {
                        result = 1;
                        vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
                        kvm_make_request(KVM_REQ_EVENT, vcpu);
                        kvm_vcpu_kick(vcpu);
                } else {
                        apic_debug("Ignoring de-assert INIT to vcpu %d\n",
                                   vcpu->vcpu_id);
                }
                break;

        case APIC_DM_STARTUP:
                apic_debug("SIPI to vcpu %d vector 0x%02x\n",
                           vcpu->vcpu_id, vector);
                if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
                        result = 1;
                        vcpu->arch.sipi_vector = vector;
                        vcpu->arch.mp_state = KVM_MP_STATE_SIPI_RECEIVED;
                        kvm_make_request(KVM_REQ_EVENT, vcpu);
                        kvm_vcpu_kick(vcpu);
                }
                break;

        case APIC_DM_EXTINT:
                /*
                 * Should only be called by kvm_apic_local_deliver() with LVT0,
                 * before NMI watchdog was enabled. Already handled by
                 * kvm_apic_accept_pic_intr().
                 */
                break;

        default:
                printk(KERN_ERR "TODO: unsupported delivery mode %x\n",
                       delivery_mode);
                break;
        }
        return result;
}

int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2)
{
        return vcpu1->arch.apic_arb_prio - vcpu2->arch.apic_arb_prio;
}

static int apic_set_eoi(struct kvm_lapic *apic)
{
        int vector = apic_find_highest_isr(apic);

        trace_kvm_eoi(apic, vector);

        /*
         * Not every write EOI will has corresponding ISR,
         * one example is when Kernel check timer on setup_IO_APIC
         */
        if (vector == -1)
                return vector;

        apic_clear_isr(vector, apic);
        apic_update_ppr(apic);

        if (!(kvm_apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_DIRECTED_EOI) &&
            kvm_ioapic_handles_vector(apic->vcpu->kvm, vector)) {
                int trigger_mode;
                if (apic_test_vector(vector, apic->regs + APIC_TMR))
                        trigger_mode = IOAPIC_LEVEL_TRIG;
                else
                        trigger_mode = IOAPIC_EDGE_TRIG;
                kvm_ioapic_update_eoi(apic->vcpu->kvm, vector, trigger_mode);
        }
        kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
        return vector;
}

static void apic_send_ipi(struct kvm_lapic *apic)
{
        u32 icr_low = kvm_apic_get_reg(apic, APIC_ICR);
        u32 icr_high = kvm_apic_get_reg(apic, APIC_ICR2);
        struct kvm_lapic_irq irq;

        irq.vector = icr_low & APIC_VECTOR_MASK;
        irq.delivery_mode = icr_low & APIC_MODE_MASK;
        irq.dest_mode = icr_low & APIC_DEST_MASK;
        irq.level = icr_low & APIC_INT_ASSERT;
        irq.trig_mode = icr_low & APIC_INT_LEVELTRIG;
        irq.shorthand = icr_low & APIC_SHORT_MASK;
        if (apic_x2apic_mode(apic))
                irq.dest_id = icr_high;
        else
                irq.dest_id = GET_APIC_DEST_FIELD(icr_high);

        trace_kvm_apic_ipi(icr_low, irq.dest_id);

        apic_debug("icr_high 0x%x, icr_low 0x%x, "
                   "short_hand 0x%x, dest 0x%x, trig_mode 0x%x, level 0x%x, "
                   "dest_mode 0x%x, delivery_mode 0x%x, vector 0x%x\n",
                   icr_high, icr_low, irq.shorthand, irq.dest_id,
                   irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode,
                   irq.vector);

        kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);
}

static u32 apic_get_tmcct(struct kvm_lapic *apic)
{
        ktime_t remaining;
        s64 ns;
        u32 tmcct;

        ASSERT(apic != NULL);

        /* if initial count is 0, current count should also be 0 */
        if (kvm_apic_get_reg(apic, APIC_TMICT) == 0)
                return 0;

        remaining = hrtimer_get_remaining(&apic->lapic_timer.timer);
        if (ktime_to_ns(remaining) < 0)
                remaining = ktime_set(0, 0);

        ns = mod_64(ktime_to_ns(remaining), apic->lapic_timer.period);
        tmcct = div64_u64(ns,
                         (APIC_BUS_CYCLE_NS * apic->divide_count));

        return tmcct;
}

static void __report_tpr_access(struct kvm_lapic *apic, bool write)
{
        struct kvm_vcpu *vcpu = apic->vcpu;
        struct kvm_run *run = vcpu->run;

        kvm_make_request(KVM_REQ_REPORT_TPR_ACCESS, vcpu);
        run->tpr_access.rip = kvm_rip_read(vcpu);
        run->tpr_access.is_write = write;
}

static inline void report_tpr_access(struct kvm_lapic *apic, bool write)
{
        if (apic->vcpu->arch.tpr_access_reporting)
                __report_tpr_access(apic, write);
}

static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
{
        u32 val = 0;

        if (offset >= LAPIC_MMIO_LENGTH)
                return 0;

        switch (offset) {
        case APIC_ID:
                if (apic_x2apic_mode(apic))
                        val = kvm_apic_id(apic);
                else
                        val = kvm_apic_id(apic) << 24;
                break;
        case APIC_ARBPRI:
                apic_debug("Access APIC ARBPRI register which is for P6\n");
                break;

        case APIC_TMCCT:        /* Timer CCR */
                if (apic_lvtt_tscdeadline(apic))
                        return 0;

                val = apic_get_tmcct(apic);
                break;
        case APIC_PROCPRI:
                apic_update_ppr(apic);
                val = kvm_apic_get_reg(apic, offset);
                break;
        case APIC_TASKPRI:
                report_tpr_access(apic, false);
                /* fall thru */
        default:
                val = kvm_apic_get_reg(apic, offset);
                break;
        }

        return val;
}

static inline struct kvm_lapic *to_lapic(struct kvm_io_device *dev)
{
        return container_of(dev, struct kvm_lapic, dev);
}

static int apic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
                void *data)
{
        unsigned char alignment = offset & 0xf;
        u32 result;
        /* this bitmask has a bit cleared for each reserved register */
        static const u64 rmask = 0x43ff01ffffffe70cULL;

        if ((alignment + len) > 4) {
                apic_debug("KVM_APIC_READ: alignment error %x %d\n",
                           offset, len);
                return 1;
        }

        if (offset > 0x3f0 || !(rmask & (1ULL << (offset >> 4)))) {
                apic_debug("KVM_APIC_READ: read reserved register %x\n",
                           offset);
                return 1;
        }

        result = __apic_read(apic, offset & ~0xf);

        trace_kvm_apic_read(offset, result);

        switch (len) {
        case 1:
        case 2:
        case 4:
                memcpy(data, (char *)&result + alignment, len);
                break;
        default:
                printk(KERN_ERR "Local APIC read with len = %x, "
                       "should be 1,2, or 4 instead\n", len);
                break;
        }
        return 0;
}

static int apic_mmio_in_range(struct kvm_lapic *apic, gpa_t addr)
{
        return kvm_apic_hw_enabled(apic) &&
            addr >= apic->base_address &&
            addr < apic->base_address + LAPIC_MMIO_LENGTH;
}

static int apic_mmio_read(struct kvm_io_device *this,
                           gpa_t address, int len, void *data)
{
        struct kvm_lapic *apic = to_lapic(this);
        u32 offset = address - apic->base_address;

        if (!apic_mmio_in_range(apic, address))
                return -EOPNOTSUPP;

        apic_reg_read(apic, offset, len, data);

        return 0;
}

static void update_divide_count(struct kvm_lapic *apic)
{
        u32 tmp1, tmp2, tdcr;

        tdcr = kvm_apic_get_reg(apic, APIC_TDCR);
        tmp1 = tdcr & 0xf;
        tmp2 = ((tmp1 & 0x3) | ((tmp1 & 0x8) >> 1)) + 1;
        apic->divide_count = 0x1 << (tmp2 & 0x7);

        apic_debug("timer divide count is 0x%x\n",
                                   apic->divide_count);
}

static void start_apic_timer(struct kvm_lapic *apic)
{
        ktime_t now;
        atomic_set(&apic->lapic_timer.pending, 0);

        if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
                /* lapic timer in oneshot or periodic mode */
                now = apic->lapic_timer.timer.base->get_time();
                apic->lapic_timer.period = (u64)kvm_apic_get_reg(apic, APIC_TMICT)
                            * APIC_BUS_CYCLE_NS * apic->divide_count;

                if (!apic->lapic_timer.period)
                        return;
                /*
                 * Do not allow the guest to program periodic timers with small
                 * interval, since the hrtimers are not throttled by the host
                 * scheduler.
                 */
                if (apic_lvtt_period(apic)) {
                        s64 min_period = min_timer_period_us * 1000LL;

                        if (apic->lapic_timer.period < min_period) {
                                pr_info_ratelimited(
                                    "kvm: vcpu %i: requested %lld ns "
                                    "lapic timer period limited to %lld ns\n",
                                    apic->vcpu->vcpu_id,
                                    apic->lapic_timer.period, min_period);
                                apic->lapic_timer.period = min_period;
                        }
                }

                hrtimer_start(&apic->lapic_timer.timer,
                              ktime_add_ns(now, apic->lapic_timer.period),
                              HRTIMER_MODE_ABS);

                apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
                           PRIx64 ", "
                           "timer initial count 0x%x, period %lldns, "
                           "expire @ 0x%016" PRIx64 ".\n", __func__,
                           APIC_BUS_CYCLE_NS, ktime_to_ns(now),
                           kvm_apic_get_reg(apic, APIC_TMICT),
                           apic->lapic_timer.period,
                           ktime_to_ns(ktime_add_ns(now,
                                        apic->lapic_timer.period)));
        } else if (apic_lvtt_tscdeadline(apic)) {

                /* lapic timer in tsc deadline mode */
                u64 guest_tsc, tscdeadline = apic->lapic_timer.tscdeadline;
                u64 ns = 0;
                struct kvm_vcpu *vcpu = apic->vcpu;
                unsigned long this_tsc_khz = vcpu->arch.virtual_tsc_khz;
                unsigned long flags;

                if (unlikely(!tscdeadline || !this_tsc_khz))
                        return;

                local_irq_save(flags);

                now = apic->lapic_timer.timer.base->get_time();
                guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu);
                if (likely(tscdeadline > guest_tsc)) {
                        ns = (tscdeadline - guest_tsc) * 1000000ULL;
                        do_div(ns, this_tsc_khz);
                }
                hrtimer_start(&apic->lapic_timer.timer,
                        ktime_add_ns(now, ns), HRTIMER_MODE_ABS);

                local_irq_restore(flags);
        }
}

static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
{
        int nmi_wd_enabled = apic_lvt_nmi_mode(kvm_apic_get_reg(apic, APIC_LVT0));

        if (apic_lvt_nmi_mode(lvt0_val)) {
                if (!nmi_wd_enabled) {
                        apic_debug("Receive NMI setting on APIC_LVT0 "
                                   "for cpu %d\n", apic->vcpu->vcpu_id);
                        apic->vcpu->kvm->arch.vapics_in_nmi_mode++;
                }
        } else if (nmi_wd_enabled)
                apic->vcpu->kvm->arch.vapics_in_nmi_mode--;
}

static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
{
        int ret = 0;

        trace_kvm_apic_write(reg, val);

        switch (reg) {
        case APIC_ID:           /* Local APIC ID */
                if (!apic_x2apic_mode(apic))
                        kvm_apic_set_id(apic, val >> 24);
                else
                        ret = 1;
                break;

        case APIC_TASKPRI:
                report_tpr_access(apic, true);
                apic_set_tpr(apic, val & 0xff);
                break;

        case APIC_EOI:
                apic_set_eoi(apic);
                break;

        case APIC_LDR:
                if (!apic_x2apic_mode(apic))
                        kvm_apic_set_ldr(apic, val & APIC_LDR_MASK);
                else
                        ret = 1;
                break;

        case APIC_DFR:
                if (!apic_x2apic_mode(apic)) {
                        apic_set_reg(apic, APIC_DFR, val | 0x0FFFFFFF);
                        recalculate_apic_map(apic->vcpu->kvm);
                } else
                        ret = 1;
                break;

        case APIC_SPIV: {
                u32 mask = 0x3ff;
                if (kvm_apic_get_reg(apic, APIC_LVR) & APIC_LVR_DIRECTED_EOI)
                        mask |= APIC_SPIV_DIRECTED_EOI;
                apic_set_spiv(apic, val & mask);
                if (!(val & APIC_SPIV_APIC_ENABLED)) {
                        int i;
                        u32 lvt_val;

                        for (i = 0; i < APIC_LVT_NUM; i++) {
                                lvt_val = kvm_apic_get_reg(apic,
                                                       APIC_LVTT + 0x10 * i);
                                apic_set_reg(apic, APIC_LVTT + 0x10 * i,
                                             lvt_val | APIC_LVT_MASKED);
                        }
                        atomic_set(&apic->lapic_timer.pending, 0);

                }
                break;
        }
        case APIC_ICR:
                /* No delay here, so we always clear the pending bit */
                apic_set_reg(apic, APIC_ICR, val & ~(1 << 12));
                apic_send_ipi(apic);
                break;

        case APIC_ICR2:
                if (!apic_x2apic_mode(apic))
                        val &= 0xff000000;
                apic_set_reg(apic, APIC_ICR2, val);
                break;

        case APIC_LVT0:
                apic_manage_nmi_watchdog(apic, val);
        case APIC_LVTTHMR:
        case APIC_LVTPC:
        case APIC_LVT1:
        case APIC_LVTERR:
                /* TODO: Check vector */
                if (!kvm_apic_sw_enabled(apic))
                        val |= APIC_LVT_MASKED;

                val &= apic_lvt_mask[(reg - APIC_LVTT) >> 4];
                apic_set_reg(apic, reg, val);

                break;

        case APIC_LVTT:
                if ((kvm_apic_get_reg(apic, APIC_LVTT) &
                    apic->lapic_timer.timer_mode_mask) !=
                   (val & apic->lapic_timer.timer_mode_mask))
                        hrtimer_cancel(&apic->lapic_timer.timer);

                if (!kvm_apic_sw_enabled(apic))
                        val |= APIC_LVT_MASKED;
                val &= (apic_lvt_mask[0] | apic->lapic_timer.timer_mode_mask);
                apic_set_reg(apic, APIC_LVTT, val);
                break;

        case APIC_TMICT:
                if (apic_lvtt_tscdeadline(apic))
                        break;

                hrtimer_cancel(&apic->lapic_timer.timer);
                apic_set_reg(apic, APIC_TMICT, val);
                start_apic_timer(apic);
                break;

        case APIC_TDCR:
                if (val & 4)
                        apic_debug("KVM_WRITE:TDCR %x\n", val);
                apic_set_reg(apic, APIC_TDCR, val);
                update_divide_count(apic);
                break;

        case APIC_ESR:
                if (apic_x2apic_mode(apic) && val != 0) {
                        apic_debug("KVM_WRITE:ESR not zero %x\n", val);
                        ret = 1;
                }
                break;

        case APIC_SELF_IPI:
                if (apic_x2apic_mode(apic)) {
                        apic_reg_write(apic, APIC_ICR, 0x40000 | (val & 0xff));
                } else
                        ret = 1;
                break;
        default:
                ret = 1;
                break;
        }
        if (ret)
                apic_debug("Local APIC Write to read-only register %x\n", reg);
        return ret;
}

static int apic_mmio_write(struct kvm_io_device *this,
                            gpa_t address, int len, const void *data)
{
        struct kvm_lapic *apic = to_lapic(this);
        unsigned int offset = address - apic->base_address;
        u32 val;

        if (!apic_mmio_in_range(apic, address))
                return -EOPNOTSUPP;

        /*
         * APIC register must be aligned on 128-bits boundary.
         * 32/64/128 bits registers must be accessed thru 32 bits.
         * Refer SDM 8.4.1
         */
        if (len != 4 || (offset & 0xf)) {
                /* Don't shout loud, $infamous_os would cause only noise. */
                apic_debug("apic write: bad size=%d %lx\n", len, (long)address);
                return 0;
        }

        val = *(u32*)data;

        /* too common printing */
        if (offset != APIC_EOI)
                apic_debug("%s: offset 0x%x with length 0x%x, and value is "
                           "0x%x\n", __func__, offset, len, val);

        apic_reg_write(apic, offset & 0xff0, val);

        return 0;
}

void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu)
{
        if (kvm_vcpu_has_lapic(vcpu))
                apic_reg_write(vcpu->arch.apic, APIC_EOI, 0);
}
EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi);

void kvm_free_lapic(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

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

        hrtimer_cancel(&apic->lapic_timer.timer);

        if (!(vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE))
                static_key_slow_dec_deferred(&apic_hw_disabled);

        if (!(kvm_apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED))
                static_key_slow_dec_deferred(&apic_sw_disabled);

        if (apic->regs)
                free_page((unsigned long)apic->regs);

        kfree(apic);
}

/*
 *----------------------------------------------------------------------
 * LAPIC interface
 *----------------------------------------------------------------------
 */

u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (!kvm_vcpu_has_lapic(vcpu) || apic_lvtt_oneshot(apic) ||
                        apic_lvtt_period(apic))
                return 0;

        return apic->lapic_timer.tscdeadline;
}

void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (!kvm_vcpu_has_lapic(vcpu) || apic_lvtt_oneshot(apic) ||
                        apic_lvtt_period(apic))
                return;

        hrtimer_cancel(&apic->lapic_timer.timer);
        apic->lapic_timer.tscdeadline = data;
        start_apic_timer(apic);
}

void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (!kvm_vcpu_has_lapic(vcpu))
                return;

        apic_set_tpr(apic, ((cr8 & 0x0f) << 4)
                     | (kvm_apic_get_reg(apic, APIC_TASKPRI) & 4));
}

u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu)
{
        u64 tpr;

        if (!kvm_vcpu_has_lapic(vcpu))
                return 0;

        tpr = (u64) kvm_apic_get_reg(vcpu->arch.apic, APIC_TASKPRI);

        return (tpr & 0xf0) >> 4;
}

void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (!apic) {
                value |= MSR_IA32_APICBASE_BSP;
                vcpu->arch.apic_base = value;
                return;
        }

        /* update jump label if enable bit changes */
        if ((vcpu->arch.apic_base ^ value) & MSR_IA32_APICBASE_ENABLE) {
                if (value & MSR_IA32_APICBASE_ENABLE)
                        static_key_slow_dec_deferred(&apic_hw_disabled);
                else
                        static_key_slow_inc(&apic_hw_disabled.key);
                recalculate_apic_map(vcpu->kvm);
        }

        if (!kvm_vcpu_is_bsp(apic->vcpu))
                value &= ~MSR_IA32_APICBASE_BSP;

        vcpu->arch.apic_base = value;
        if (apic_x2apic_mode(apic)) {
                u32 id = kvm_apic_id(apic);
                u32 ldr = ((id >> 4) << 16) | (1 << (id & 0xf));
                kvm_apic_set_ldr(apic, ldr);
        }
        apic->base_address = apic->vcpu->arch.apic_base &
                             MSR_IA32_APICBASE_BASE;

        /* with FSB delivery interrupt, we can restart APIC functionality */
        apic_debug("apic base msr is 0x%016" PRIx64 ", and base address is "
                   "0x%lx.\n", apic->vcpu->arch.apic_base, apic->base_address);

}

void kvm_lapic_reset(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic;
        int i;

        apic_debug("%s\n", __func__);

        ASSERT(vcpu);
        apic = vcpu->arch.apic;
        ASSERT(apic != NULL);

        /* Stop the timer in case it's a reset to an active apic */
        hrtimer_cancel(&apic->lapic_timer.timer);

        kvm_apic_set_id(apic, vcpu->vcpu_id);
        kvm_apic_set_version(apic->vcpu);

        for (i = 0; i < APIC_LVT_NUM; i++)
                apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED);
        apic_set_reg(apic, APIC_LVT0,
                     SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));

        apic_set_reg(apic, APIC_DFR, 0xffffffffU);
        apic_set_spiv(apic, 0xff);
        apic_set_reg(apic, APIC_TASKPRI, 0);
        kvm_apic_set_ldr(apic, 0);
        apic_set_reg(apic, APIC_ESR, 0);
        apic_set_reg(apic, APIC_ICR, 0);
        apic_set_reg(apic, APIC_ICR2, 0);
        apic_set_reg(apic, APIC_TDCR, 0);
        apic_set_reg(apic, APIC_TMICT, 0);
        for (i = 0; i < 8; i++) {
                apic_set_reg(apic, APIC_IRR + 0x10 * i, 0);
                apic_set_reg(apic, APIC_ISR + 0x10 * i, 0);
                apic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
        }
        apic->irr_pending = false;
        apic->isr_count = 0;
        apic->highest_isr_cache = -1;
        update_divide_count(apic);
        atomic_set(&apic->lapic_timer.pending, 0);
        if (kvm_vcpu_is_bsp(vcpu))
                kvm_lapic_set_base(vcpu,
                                vcpu->arch.apic_base | MSR_IA32_APICBASE_BSP);
        vcpu->arch.pv_eoi.msr_val = 0;
        apic_update_ppr(apic);

        vcpu->arch.apic_arb_prio = 0;
        vcpu->arch.apic_attention = 0;

        apic_debug(KERN_INFO "%s: vcpu=%p, id=%d, base_msr="
                   "0x%016" PRIx64 ", base_address=0x%0lx.\n", __func__,
                   vcpu, kvm_apic_id(apic),
                   vcpu->arch.apic_base, apic->base_address);
}

/*
 *----------------------------------------------------------------------
 * timer interface
 *----------------------------------------------------------------------
 */

static bool lapic_is_periodic(struct kvm_lapic *apic)
{
        return apic_lvtt_period(apic);
}

int apic_has_pending_timer(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (kvm_vcpu_has_lapic(vcpu) && apic_enabled(apic) &&
                        apic_lvt_enabled(apic, APIC_LVTT))
                return atomic_read(&apic->lapic_timer.pending);

        return 0;
}

int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type)
{
        u32 reg = kvm_apic_get_reg(apic, lvt_type);
        int vector, mode, trig_mode;

        if (kvm_apic_hw_enabled(apic) && !(reg & APIC_LVT_MASKED)) {
                vector = reg & APIC_VECTOR_MASK;
                mode = reg & APIC_MODE_MASK;
                trig_mode = reg & APIC_LVT_LEVEL_TRIGGER;
                return __apic_accept_irq(apic, mode, vector, 1, trig_mode);
        }
        return 0;
}

void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (apic)
                kvm_apic_local_deliver(apic, APIC_LVT0);
}

static const struct kvm_io_device_ops apic_mmio_ops = {
        .read     = apic_mmio_read,
        .write    = apic_mmio_write,
};

static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
{
        struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
        struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic, lapic_timer);
        struct kvm_vcpu *vcpu = apic->vcpu;
        wait_queue_head_t *q = &vcpu->wq;

        /*
         * There is a race window between reading and incrementing, but we do
         * not care about potentially losing timer events in the !reinject
         * case anyway. Note: KVM_REQ_PENDING_TIMER is implicitly checked
         * in vcpu_enter_guest.
         */
        if (!atomic_read(&ktimer->pending)) {
                atomic_inc(&ktimer->pending);
                /* FIXME: this code should not know anything about vcpus */
                kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
        }

        if (waitqueue_active(q))
                wake_up_interruptible(q);

        if (lapic_is_periodic(apic)) {
                hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
                return HRTIMER_RESTART;
        } else
                return HRTIMER_NORESTART;
}

int kvm_create_lapic(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic;

        ASSERT(vcpu != NULL);
        apic_debug("apic_init %d\n", vcpu->vcpu_id);

        apic = kzalloc(sizeof(*apic), GFP_KERNEL);
        if (!apic)
                goto nomem;

        vcpu->arch.apic = apic;

        apic->regs = (void *)get_zeroed_page(GFP_KERNEL);
        if (!apic->regs) {
                printk(KERN_ERR "malloc apic regs error for vcpu %x\n",
                       vcpu->vcpu_id);
                goto nomem_free_apic;
        }
        apic->vcpu = vcpu;

        hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
                     HRTIMER_MODE_ABS);
        apic->lapic_timer.timer.function = apic_timer_fn;

        /*
         * APIC is created enabled. This will prevent kvm_lapic_set_base from
         * thinking that APIC satet has changed.
         */
        vcpu->arch.apic_base = MSR_IA32_APICBASE_ENABLE;
        kvm_lapic_set_base(vcpu,
                        APIC_DEFAULT_PHYS_BASE | MSR_IA32_APICBASE_ENABLE);

        static_key_slow_inc(&apic_sw_disabled.key); /* sw disabled at reset */
        kvm_lapic_reset(vcpu);
        kvm_iodevice_init(&apic->dev, &apic_mmio_ops);

        return 0;
nomem_free_apic:
        kfree(apic);
nomem:
        return -ENOMEM;
}

int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;
        int highest_irr;

        if (!kvm_vcpu_has_lapic(vcpu) || !apic_enabled(apic))
                return -1;

        apic_update_ppr(apic);
        highest_irr = apic_find_highest_irr(apic);
        if ((highest_irr == -1) ||
            ((highest_irr & 0xF0) <= kvm_apic_get_reg(apic, APIC_PROCPRI)))
                return -1;
        return highest_irr;
}

int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
{
        u32 lvt0 = kvm_apic_get_reg(vcpu->arch.apic, APIC_LVT0);
        int r = 0;

        if (!kvm_apic_hw_enabled(vcpu->arch.apic))
                r = 1;
        if ((lvt0 & APIC_LVT_MASKED) == 0 &&
            GET_APIC_DELIVERY_MODE(lvt0) == APIC_MODE_EXTINT)
                r = 1;
        return r;
}

void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (!kvm_vcpu_has_lapic(vcpu))
                return;

        if (atomic_read(&apic->lapic_timer.pending) > 0) {
                if (kvm_apic_local_deliver(apic, APIC_LVTT))
                        atomic_dec(&apic->lapic_timer.pending);
        }
}

int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
{
        int vector = kvm_apic_has_interrupt(vcpu);
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (vector == -1)
                return -1;

        apic_set_isr(vector, apic);
        apic_update_ppr(apic);
        apic_clear_irr(vector, apic);
        return vector;
}

void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
                struct kvm_lapic_state *s)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        kvm_lapic_set_base(vcpu, vcpu->arch.apic_base);
        /* set SPIV separately to get count of SW disabled APICs right */
        apic_set_spiv(apic, *((u32 *)(s->regs + APIC_SPIV)));
        memcpy(vcpu->arch.apic->regs, s->regs, sizeof *s);
        /* call kvm_apic_set_id() to put apic into apic_map */
        kvm_apic_set_id(apic, kvm_apic_id(apic));
        kvm_apic_set_version(vcpu);

        apic_update_ppr(apic);
        hrtimer_cancel(&apic->lapic_timer.timer);
        update_divide_count(apic);
        start_apic_timer(apic);
        apic->irr_pending = true;
        apic->isr_count = count_vectors(apic->regs + APIC_ISR);
        apic->highest_isr_cache = -1;
        kvm_make_request(KVM_REQ_EVENT, vcpu);
}

void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
{
        struct hrtimer *timer;

        if (!kvm_vcpu_has_lapic(vcpu))
                return;

        timer = &vcpu->arch.apic->lapic_timer.timer;
        if (hrtimer_cancel(timer))
                hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}

/*
 * apic_sync_pv_eoi_from_guest - called on vmexit or cancel interrupt
 *
 * Detect whether guest triggered PV EOI since the
 * last entry. If yes, set EOI on guests's behalf.
 * Clear PV EOI in guest memory in any case.
 */
static void apic_sync_pv_eoi_from_guest(struct kvm_vcpu *vcpu,
                                        struct kvm_lapic *apic)
{
        bool pending;
        int vector;
        /*
         * PV EOI state is derived from KVM_APIC_PV_EOI_PENDING in host
         * and KVM_PV_EOI_ENABLED in guest memory as follows:
         *
         * KVM_APIC_PV_EOI_PENDING is unset:
         *      -> host disabled PV EOI.
         * KVM_APIC_PV_EOI_PENDING is set, KVM_PV_EOI_ENABLED is set:
         *      -> host enabled PV EOI, guest did not execute EOI yet.
         * KVM_APIC_PV_EOI_PENDING is set, KVM_PV_EOI_ENABLED is unset:
         *      -> host enabled PV EOI, guest executed EOI.
         */
        BUG_ON(!pv_eoi_enabled(vcpu));
        pending = pv_eoi_get_pending(vcpu);
        /*
         * Clear pending bit in any case: it will be set again on vmentry.
         * While this might not be ideal from performance point of view,
         * this makes sure pv eoi is only enabled when we know it's safe.
         */
        pv_eoi_clr_pending(vcpu);
        if (pending)
                return;
        vector = apic_set_eoi(apic);
        trace_kvm_pv_eoi(apic, vector);
}

void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu)
{
        u32 data;
        void *vapic;

        if (test_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention))
                apic_sync_pv_eoi_from_guest(vcpu, vcpu->arch.apic);

        if (!test_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention))
                return;

        vapic = kmap_atomic(vcpu->arch.apic->vapic_page);
        data = *(u32 *)(vapic + offset_in_page(vcpu->arch.apic->vapic_addr));
        kunmap_atomic(vapic);

        apic_set_tpr(vcpu->arch.apic, data & 0xff);
}

/*
 * apic_sync_pv_eoi_to_guest - called before vmentry
 *
 * Detect whether it's safe to enable PV EOI and
 * if yes do so.
 */
static void apic_sync_pv_eoi_to_guest(struct kvm_vcpu *vcpu,
                                        struct kvm_lapic *apic)
{
        if (!pv_eoi_enabled(vcpu) ||
            /* IRR set or many bits in ISR: could be nested. */
            apic->irr_pending ||
            /* Cache not set: could be safe but we don't bother. */
            apic->highest_isr_cache == -1 ||
            /* Need EOI to update ioapic. */
            kvm_ioapic_handles_vector(vcpu->kvm, apic->highest_isr_cache)) {
                /*
                 * PV EOI was disabled by apic_sync_pv_eoi_from_guest
                 * so we need not do anything here.
                 */
                return;
        }

        pv_eoi_set_pending(apic->vcpu);
}

void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu)
{
        u32 data, tpr;
        int max_irr, max_isr;
        struct kvm_lapic *apic = vcpu->arch.apic;
        void *vapic;

        apic_sync_pv_eoi_to_guest(vcpu, apic);

        if (!test_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention))
                return;

        tpr = kvm_apic_get_reg(apic, APIC_TASKPRI) & 0xff;
        max_irr = apic_find_highest_irr(apic);
        if (max_irr < 0)
                max_irr = 0;
        max_isr = apic_find_highest_isr(apic);
        if (max_isr < 0)
                max_isr = 0;
        data = (tpr & 0xff) | ((max_isr & 0xf0) << 8) | (max_irr << 24);

        vapic = kmap_atomic(vcpu->arch.apic->vapic_page);
        *(u32 *)(vapic + offset_in_page(vcpu->arch.apic->vapic_addr)) = data;
        kunmap_atomic(vapic);
}

void kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr)
{
        vcpu->arch.apic->vapic_addr = vapic_addr;
        if (vapic_addr)
                __set_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention);
        else
                __clear_bit(KVM_APIC_CHECK_VAPIC, &vcpu->arch.apic_attention);
}

int kvm_x2apic_msr_write(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
        struct kvm_lapic *apic = vcpu->arch.apic;
        u32 reg = (msr - APIC_BASE_MSR) << 4;

        if (!irqchip_in_kernel(vcpu->kvm) || !apic_x2apic_mode(apic))
                return 1;

        /* if this is ICR write vector before command */
        if (msr == 0x830)
                apic_reg_write(apic, APIC_ICR2, (u32)(data >> 32));
        return apic_reg_write(apic, reg, (u32)data);
}

int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
{
        struct kvm_lapic *apic = vcpu->arch.apic;
        u32 reg = (msr - APIC_BASE_MSR) << 4, low, high = 0;

        if (!irqchip_in_kernel(vcpu->kvm) || !apic_x2apic_mode(apic))
                return 1;

        if (apic_reg_read(apic, reg, 4, &low))
                return 1;
        if (msr == 0x830)
                apic_reg_read(apic, APIC_ICR2, 4, &high);

        *data = (((u64)high) << 32) | low;

        return 0;
}

int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 reg, u64 data)
{
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (!kvm_vcpu_has_lapic(vcpu))
                return 1;

        /* if this is ICR write vector before command */
        if (reg == APIC_ICR)
                apic_reg_write(apic, APIC_ICR2, (u32)(data >> 32));
        return apic_reg_write(apic, reg, (u32)data);
}

int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
{
        struct kvm_lapic *apic = vcpu->arch.apic;
        u32 low, high = 0;

        if (!kvm_vcpu_has_lapic(vcpu))
                return 1;

        if (apic_reg_read(apic, reg, 4, &low))
                return 1;
        if (reg == APIC_ICR)
                apic_reg_read(apic, APIC_ICR2, 4, &high);

        *data = (((u64)high) << 32) | low;

        return 0;
}

int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data)
{
        u64 addr = data & ~KVM_MSR_ENABLED;
        if (!IS_ALIGNED(addr, 4))
                return 1;

        vcpu->arch.pv_eoi.msr_val = data;
        if (!pv_eoi_enabled(vcpu))
                return 0;
        return kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.pv_eoi.data,
                                         addr);
}

void kvm_lapic_init(void)
{
        /* do not patch jump label more than once per second */
        jump_label_rate_limit(&apic_hw_disabled, HZ);
        jump_label_rate_limit(&apic_sw_disabled, HZ);
}