Archipelago » qemu

/*

 *  APIC support

 *

 *  Copyright (c) 2004-2005 Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>

 */

#include "hw.h"

#include "pc.h"

#include "apic.h"

#include "pci.h"

#include "msix.h"

#include "qemu-timer.h"

#include "host-utils.h"

#include "kvm.h"

//#define DEBUG_APIC

//#define DEBUG_COALESCING

#ifdef DEBUG_APIC

#define DPRINTF(fmt, ...)                                       \

    do { printf("apic: " fmt , ## __VA_ARGS__); } while (0)

#else

#define DPRINTF(fmt, ...)

#endif

#ifdef DEBUG_COALESCING

#define DPRINTF_C(fmt, ...)                                     \

    do { printf("apic: " fmt , ## __VA_ARGS__); } while (0)

#else

#define DPRINTF_C(fmt, ...)

#endif

/* APIC Local Vector Table */

#define APIC_LVT_TIMER   0

#define APIC_LVT_THERMAL 1

#define APIC_LVT_PERFORM 2

#define APIC_LVT_LINT0   3

#define APIC_LVT_LINT1   4

#define APIC_LVT_ERROR   5

#define APIC_LVT_NB      6

/* APIC delivery modes */

#define APIC_DM_FIXED        0

#define APIC_DM_LOWPRI        1

#define APIC_DM_SMI        2

#define APIC_DM_NMI        4

#define APIC_DM_INIT        5

#define APIC_DM_SIPI        6

#define APIC_DM_EXTINT        7

/* APIC destination mode */

#define APIC_DESTMODE_FLAT        0xf

#define APIC_DESTMODE_CLUSTER        1

#define APIC_TRIGGER_EDGE  0

#define APIC_TRIGGER_LEVEL 1

#define        APIC_LVT_TIMER_PERIODIC                (1<<17)

#define        APIC_LVT_MASKED                        (1<<16)

#define        APIC_LVT_LEVEL_TRIGGER                (1<<15)

#define        APIC_LVT_REMOTE_IRR                (1<<14)

#define        APIC_INPUT_POLARITY                (1<<13)

#define        APIC_SEND_PENDING                (1<<12)

#define ESR_ILLEGAL_ADDRESS (1 << 7)

#define APIC_SV_ENABLE (1 << 8)

#define MAX_APICS 255

#define MAX_APIC_WORDS 8

/* Intel APIC constants: from include/asm/msidef.h */

#define MSI_DATA_VECTOR_SHIFT                0

#define MSI_DATA_VECTOR_MASK                0x000000ff

#define MSI_DATA_DELIVERY_MODE_SHIFT        8

#define MSI_DATA_TRIGGER_SHIFT                15

#define MSI_DATA_LEVEL_SHIFT                14

#define MSI_ADDR_DEST_MODE_SHIFT        2

#define MSI_ADDR_DEST_ID_SHIFT                12

#define        MSI_ADDR_DEST_ID_MASK                0x00ffff0

#define MSI_ADDR_BASE                   0xfee00000

#define MSI_ADDR_SIZE                   0x100000

typedef struct APICState {

    CPUState *cpu_env;

    uint32_t apicbase;

    uint8_t id;

    uint8_t arb_id;

    uint8_t tpr;

    uint32_t spurious_vec;

    uint8_t log_dest;

    uint8_t dest_mode;

    uint32_t isr[8];  /* in service register */

    uint32_t tmr[8];  /* trigger mode register */

    uint32_t irr[8]; /* interrupt request register */

    uint32_t lvt[APIC_LVT_NB];

    uint32_t esr; /* error register */

    uint32_t icr[2];

    uint32_t divide_conf;

    int count_shift;

    uint32_t initial_count;

    int64_t initial_count_load_time, next_time;

    uint32_t idx;

    QEMUTimer *timer;

    int sipi_vector;

    int wait_for_sipi;

} APICState;

static int apic_io_memory;

static APICState *local_apics[MAX_APICS + 1];

static int last_apic_idx = 0;

static int apic_irq_delivered;

static void apic_set_irq(APICState *s, int vector_num, int trigger_mode);

static void apic_update_irq(APICState *s);

static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,

                                      uint8_t dest, uint8_t dest_mode);

/* Find first bit starting from msb */

static int fls_bit(uint32_t value)

{

    return 31 - clz32(value);

}

/* Find first bit starting from lsb */

static int ffs_bit(uint32_t value)

{

    return ctz32(value);

}

static inline void set_bit(uint32_t *tab, int index)

{

    int i, mask;

    i = index >> 5;

    mask = 1 << (index & 0x1f);

    tab[i] |= mask;

}

static inline void reset_bit(uint32_t *tab, int index)

{

    int i, mask;

    i = index >> 5;

    mask = 1 << (index & 0x1f);

    tab[i] &= ~mask;

}

static inline int get_bit(uint32_t *tab, int index)

{

    int i, mask;

    i = index >> 5;

    mask = 1 << (index & 0x1f);

    return !!(tab[i] & mask);

}

static void apic_local_deliver(CPUState *env, int vector)

{

    APICState *s = env->apic_state;

    uint32_t lvt = s->lvt[vector];

    int trigger_mode;

    DPRINTF("%s: vector %d delivery mode %d\n", __func__, vector,

            (lvt >> 8) & 7);

    if (lvt & APIC_LVT_MASKED)

        return;

    switch ((lvt >> 8) & 7) {

    case APIC_DM_SMI:

        cpu_interrupt(env, CPU_INTERRUPT_SMI);

        break;

    case APIC_DM_NMI:

        cpu_interrupt(env, CPU_INTERRUPT_NMI);

        break;

    case APIC_DM_EXTINT:

        cpu_interrupt(env, CPU_INTERRUPT_HARD);

        break;

    case APIC_DM_FIXED:

        trigger_mode = APIC_TRIGGER_EDGE;

        if ((vector == APIC_LVT_LINT0 || vector == APIC_LVT_LINT1) &&

            (lvt & APIC_LVT_LEVEL_TRIGGER))

            trigger_mode = APIC_TRIGGER_LEVEL;

        apic_set_irq(s, lvt & 0xff, trigger_mode);

    }

}

void apic_deliver_pic_intr(CPUState *env, int level)

{

    if (level)

        apic_local_deliver(env, APIC_LVT_LINT0);

    else {

        APICState *s = env->apic_state;

        uint32_t lvt = s->lvt[APIC_LVT_LINT0];

        switch ((lvt >> 8) & 7) {

        case APIC_DM_FIXED:

            if (!(lvt & APIC_LVT_LEVEL_TRIGGER))

                break;

            reset_bit(s->irr, lvt & 0xff);

            /* fall through */

        case APIC_DM_EXTINT:

            cpu_reset_interrupt(env, CPU_INTERRUPT_HARD);

            break;

        }

    }

}

#define foreach_apic(apic, deliver_bitmask, code) \

{\

    int __i, __j, __mask;\

    for(__i = 0; __i < MAX_APIC_WORDS; __i++) {\

        __mask = deliver_bitmask[__i];\

        if (__mask) {\

            for(__j = 0; __j < 32; __j++) {\

                if (__mask & (1 << __j)) {\

                    apic = local_apics[__i * 32 + __j];\

                    if (apic) {\

                        code;\

                    }\

                }\

            }\

        }\

    }\

}

static void apic_bus_deliver(const uint32_t *deliver_bitmask,

                             uint8_t delivery_mode,

                             uint8_t vector_num, uint8_t polarity,

                             uint8_t trigger_mode)

{

    APICState *apic_iter;

    switch (delivery_mode) {

        case APIC_DM_LOWPRI:

            /* XXX: search for focus processor, arbitration */

            {

                int i, d;

                d = -1;

                for(i = 0; i < MAX_APIC_WORDS; i++) {

                    if (deliver_bitmask[i]) {

                        d = i * 32 + ffs_bit(deliver_bitmask[i]);

                        break;

                    }

                }

                if (d >= 0) {

                    apic_iter = local_apics[d];

                    if (apic_iter) {

                        apic_set_irq(apic_iter, vector_num, trigger_mode);

                    }

                }

            }

            return;

        case APIC_DM_FIXED:

            break;

        case APIC_DM_SMI:

            foreach_apic(apic_iter, deliver_bitmask,

                cpu_interrupt(apic_iter->cpu_env, CPU_INTERRUPT_SMI) );

            return;

        case APIC_DM_NMI:

            foreach_apic(apic_iter, deliver_bitmask,

                cpu_interrupt(apic_iter->cpu_env, CPU_INTERRUPT_NMI) );

            return;

        case APIC_DM_INIT:

            /* normal INIT IPI sent to processors */

            foreach_apic(apic_iter, deliver_bitmask,

                         cpu_interrupt(apic_iter->cpu_env, CPU_INTERRUPT_INIT) );

            return;

        case APIC_DM_EXTINT:

            /* handled in I/O APIC code */

            break;

        default:

            return;

    }

    foreach_apic(apic_iter, deliver_bitmask,

                 apic_set_irq(apic_iter, vector_num, trigger_mode) );

}

void apic_deliver_irq(uint8_t dest, uint8_t dest_mode,

                      uint8_t delivery_mode, uint8_t vector_num,

                      uint8_t polarity, uint8_t trigger_mode)

{

    uint32_t deliver_bitmask[MAX_APIC_WORDS];

    DPRINTF("%s: dest %d dest_mode %d delivery_mode %d vector %d"

            " polarity %d trigger_mode %d\n", __func__, dest, dest_mode,

            delivery_mode, vector_num, polarity, trigger_mode);

    apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode);

    apic_bus_deliver(deliver_bitmask, delivery_mode, vector_num, polarity,

                     trigger_mode);

}

void cpu_set_apic_base(CPUState *env, uint64_t val)

{

    APICState *s = env->apic_state;

    DPRINTF("cpu_set_apic_base: %016" PRIx64 "\n", val);

    if (!s)

        return;

    s->apicbase = (val & 0xfffff000) |

        (s->apicbase & (MSR_IA32_APICBASE_BSP | MSR_IA32_APICBASE_ENABLE));

    /* if disabled, cannot be enabled again */

    if (!(val & MSR_IA32_APICBASE_ENABLE)) {

        s->apicbase &= ~MSR_IA32_APICBASE_ENABLE;

        env->cpuid_features &= ~CPUID_APIC;

        s->spurious_vec &= ~APIC_SV_ENABLE;

    }

}

uint64_t cpu_get_apic_base(CPUState *env)

{

    APICState *s = env->apic_state;

    DPRINTF("cpu_get_apic_base: %016" PRIx64 "\n",

            s ? (uint64_t)s->apicbase: 0);

    return s ? s->apicbase : 0;

}

void cpu_set_apic_tpr(CPUX86State *env, uint8_t val)

{

    APICState *s = env->apic_state;

    if (!s)

        return;

    s->tpr = (val & 0x0f) << 4;

    apic_update_irq(s);

}

uint8_t cpu_get_apic_tpr(CPUX86State *env)

{

    APICState *s = env->apic_state;

    return s ? s->tpr >> 4 : 0;

}

/* return -1 if no bit is set */

static int get_highest_priority_int(uint32_t *tab)

{

    int i;

    for(i = 7; i >= 0; i--) {

        if (tab[i] != 0) {

            return i * 32 + fls_bit(tab[i]);

        }

    }

    return -1;

}

static int apic_get_ppr(APICState *s)

{

    int tpr, isrv, ppr;

    tpr = (s->tpr >> 4);

    isrv = get_highest_priority_int(s->isr);

    if (isrv < 0)

        isrv = 0;

    isrv >>= 4;

    if (tpr >= isrv)

        ppr = s->tpr;

    else

        ppr = isrv << 4;

    return ppr;

}

static int apic_get_arb_pri(APICState *s)

{

    /* XXX: arbitration */

    return 0;

}

/* signal the CPU if an irq is pending */

static void apic_update_irq(APICState *s)

{

    int irrv, ppr;

    if (!(s->spurious_vec & APIC_SV_ENABLE))

        return;

    irrv = get_highest_priority_int(s->irr);

    if (irrv < 0)

        return;

    ppr = apic_get_ppr(s);

    if (ppr && (irrv & 0xf0) <= (ppr & 0xf0))

        return;

    cpu_interrupt(s->cpu_env, CPU_INTERRUPT_HARD);

}

void apic_reset_irq_delivered(void)

{

    DPRINTF_C("%s: old coalescing %d\n", __func__, apic_irq_delivered);

    apic_irq_delivered = 0;

}

int apic_get_irq_delivered(void)

{

    DPRINTF_C("%s: returning coalescing %d\n", __func__, apic_irq_delivered);

    return apic_irq_delivered;

}

static void apic_set_irq(APICState *s, int vector_num, int trigger_mode)

{

    apic_irq_delivered += !get_bit(s->irr, vector_num);

    DPRINTF_C("%s: coalescing %d\n", __func__, apic_irq_delivered);

    set_bit(s->irr, vector_num);

    if (trigger_mode)

        set_bit(s->tmr, vector_num);

    else

        reset_bit(s->tmr, vector_num);

    apic_update_irq(s);

}

static void apic_eoi(APICState *s)

{

    int isrv;

    isrv = get_highest_priority_int(s->isr);

    if (isrv < 0)

        return;

    reset_bit(s->isr, isrv);

    /* XXX: send the EOI packet to the APIC bus to allow the I/O APIC to

            set the remote IRR bit for level triggered interrupts. */

    apic_update_irq(s);

}

static int apic_find_dest(uint8_t dest)

{

    APICState *apic = local_apics[dest];

    int i;

    if (apic && apic->id == dest)

        return dest;  /* shortcut in case apic->id == apic->idx */

    for (i = 0; i < MAX_APICS; i++) {

        apic = local_apics[i];

        if (apic && apic->id == dest)

            return i;

    }

    return -1;

}

static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,

                                      uint8_t dest, uint8_t dest_mode)

{

    APICState *apic_iter;

    int i;

    if (dest_mode == 0) {

        if (dest == 0xff) {

            memset(deliver_bitmask, 0xff, MAX_APIC_WORDS * sizeof(uint32_t));

        } else {

            int idx = apic_find_dest(dest);

            memset(deliver_bitmask, 0x00, MAX_APIC_WORDS * sizeof(uint32_t));

            if (idx >= 0)

                set_bit(deliver_bitmask, idx);

        }

    } else {

        /* XXX: cluster mode */

        memset(deliver_bitmask, 0x00, MAX_APIC_WORDS * sizeof(uint32_t));

        for(i = 0; i < MAX_APICS; i++) {

            apic_iter = local_apics[i];

            if (apic_iter) {

                if (apic_iter->dest_mode == 0xf) {

                    if (dest & apic_iter->log_dest)

                        set_bit(deliver_bitmask, i);

                } else if (apic_iter->dest_mode == 0x0) {

                    if ((dest & 0xf0) == (apic_iter->log_dest & 0xf0) &&

                        (dest & apic_iter->log_dest & 0x0f)) {

                        set_bit(deliver_bitmask, i);

                    }

                }

            }

        }

    }

}

void apic_init_reset(CPUState *env)

{

    APICState *s = env->apic_state;

    int i;

    if (!s)

        return;

    s->tpr = 0;

    s->spurious_vec = 0xff;

    s->log_dest = 0;

    s->dest_mode = 0xf;

    memset(s->isr, 0, sizeof(s->isr));

    memset(s->tmr, 0, sizeof(s->tmr));

    memset(s->irr, 0, sizeof(s->irr));

    for(i = 0; i < APIC_LVT_NB; i++)

        s->lvt[i] = 1 << 16; /* mask LVT */

    s->esr = 0;

    memset(s->icr, 0, sizeof(s->icr));

    s->divide_conf = 0;

    s->count_shift = 0;

    s->initial_count = 0;

    s->initial_count_load_time = 0;

    s->next_time = 0;

    s->wait_for_sipi = 1;

    env->halted = !(s->apicbase & MSR_IA32_APICBASE_BSP);

}

static void apic_startup(APICState *s, int vector_num)

{

    s->sipi_vector = vector_num;

    cpu_interrupt(s->cpu_env, CPU_INTERRUPT_SIPI);

}

void apic_sipi(CPUState *env)

{

    APICState *s = env->apic_state;

    cpu_reset_interrupt(env, CPU_INTERRUPT_SIPI);

    if (!s->wait_for_sipi)

        return;

    env->eip = 0;

    cpu_x86_load_seg_cache(env, R_CS, s->sipi_vector << 8, s->sipi_vector << 12,

                           env->segs[R_CS].limit, env->segs[R_CS].flags);

    env->halted = 0;

    s->wait_for_sipi = 0;

}

static void apic_deliver(APICState *s, uint8_t dest, uint8_t dest_mode,

                         uint8_t delivery_mode, uint8_t vector_num,

                         uint8_t polarity, uint8_t trigger_mode)

{

    uint32_t deliver_bitmask[MAX_APIC_WORDS];

    int dest_shorthand = (s->icr[0] >> 18) & 3;

    APICState *apic_iter;

    switch (dest_shorthand) {

    case 0:

        apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode);

        break;

    case 1:

        memset(deliver_bitmask, 0x00, sizeof(deliver_bitmask));

        set_bit(deliver_bitmask, s->idx);

        break;

    case 2:

        memset(deliver_bitmask, 0xff, sizeof(deliver_bitmask));

        break;

    case 3:

        memset(deliver_bitmask, 0xff, sizeof(deliver_bitmask));

        reset_bit(deliver_bitmask, s->idx);

        break;

    }

    switch (delivery_mode) {

        case APIC_DM_INIT:

            {

                int trig_mode = (s->icr[0] >> 15) & 1;

                int level = (s->icr[0] >> 14) & 1;

                if (level == 0 && trig_mode == 1) {

                    foreach_apic(apic_iter, deliver_bitmask,

                                 apic_iter->arb_id = apic_iter->id );

                    return;

                }

            }

            break;

        case APIC_DM_SIPI:

            foreach_apic(apic_iter, deliver_bitmask,

                         apic_startup(apic_iter, vector_num) );

            return;

    }

    apic_bus_deliver(deliver_bitmask, delivery_mode, vector_num, polarity,

                     trigger_mode);

}

int apic_get_interrupt(CPUState *env)

{

    APICState *s = env->apic_state;

    int intno;

    /* if the APIC is installed or enabled, we let the 8259 handle the

       IRQs */

    if (!s)

        return -1;

    if (!(s->spurious_vec & APIC_SV_ENABLE))

        return -1;

    /* XXX: spurious IRQ handling */

    intno = get_highest_priority_int(s->irr);

    if (intno < 0)

        return -1;

    if (s->tpr && intno <= s->tpr)

        return s->spurious_vec & 0xff;

    reset_bit(s->irr, intno);

    set_bit(s->isr, intno);

    apic_update_irq(s);

    return intno;

}

int apic_accept_pic_intr(CPUState *env)

{

    APICState *s = env->apic_state;

    uint32_t lvt0;

    if (!s)

        return -1;

    lvt0 = s->lvt[APIC_LVT_LINT0];

    if ((s->apicbase & MSR_IA32_APICBASE_ENABLE) == 0 ||

        (lvt0 & APIC_LVT_MASKED) == 0)

        return 1;

    return 0;

}

static uint32_t apic_get_current_count(APICState *s)

{

    int64_t d;

    uint32_t val;

    d = (qemu_get_clock(vm_clock) - s->initial_count_load_time) >>

        s->count_shift;

    if (s->lvt[APIC_LVT_TIMER] & APIC_LVT_TIMER_PERIODIC) {

        /* periodic */

        val = s->initial_count - (d % ((uint64_t)s->initial_count + 1));

    } else {

        if (d >= s->initial_count)

            val = 0;

        else

            val = s->initial_count - d;

    }

    return val;

}

static void apic_timer_update(APICState *s, int64_t current_time)

{

    int64_t next_time, d;

    if (!(s->lvt[APIC_LVT_TIMER] & APIC_LVT_MASKED)) {

        d = (current_time - s->initial_count_load_time) >>

            s->count_shift;

        if (s->lvt[APIC_LVT_TIMER] & APIC_LVT_TIMER_PERIODIC) {

            if (!s->initial_count)

                goto no_timer;

            d = ((d / ((uint64_t)s->initial_count + 1)) + 1) * ((uint64_t)s->initial_count + 1);

        } else {

            if (d >= s->initial_count)

                goto no_timer;

            d = (uint64_t)s->initial_count + 1;

        }

        next_time = s->initial_count_load_time + (d << s->count_shift);

        qemu_mod_timer(s->timer, next_time);

        s->next_time = next_time;

    } else {

    no_timer:

        qemu_del_timer(s->timer);

    }

}

static void apic_timer(void *opaque)

{

    APICState *s = opaque;

    apic_local_deliver(s->cpu_env, APIC_LVT_TIMER);

    apic_timer_update(s, s->next_time);

}

static uint32_t apic_mem_readb(void *opaque, target_phys_addr_t addr)

{

    return 0;

}

static uint32_t apic_mem_readw(void *opaque, target_phys_addr_t addr)

{

    return 0;

}

static void apic_mem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)

{

}

static void apic_mem_writew(void *opaque, target_phys_addr_t addr, uint32_t val)

{

}

static uint32_t apic_mem_readl(void *opaque, target_phys_addr_t addr)

{

    CPUState *env;

    APICState *s;

    uint32_t val;

    int index;

    env = cpu_single_env;

    if (!env)

        return 0;

    s = env->apic_state;

    index = (addr >> 4) & 0xff;

    switch(index) {

    case 0x02: /* id */

        val = s->id << 24;

        break;

    case 0x03: /* version */

        val = 0x11 | ((APIC_LVT_NB - 1) << 16); /* version 0x11 */

        break;

    case 0x08:

        val = s->tpr;

        break;

    case 0x09:

        val = apic_get_arb_pri(s);

        break;

    case 0x0a:

        /* ppr */

        val = apic_get_ppr(s);

        break;

    case 0x0b:

        val = 0;

        break;

    case 0x0d:

        val = s->log_dest << 24;

        break;

    case 0x0e:

        val = s->dest_mode << 28;

        break;

    case 0x0f:

        val = s->spurious_vec;

        break;

    case 0x10 ... 0x17:

        val = s->isr[index & 7];

        break;

    case 0x18 ... 0x1f:

        val = s->tmr[index & 7];

        break;

    case 0x20 ... 0x27:

        val = s->irr[index & 7];

        break;

    case 0x28:

        val = s->esr;

        break;

    case 0x30:

    case 0x31:

        val = s->icr[index & 1];

        break;

    case 0x32 ... 0x37:

        val = s->lvt[index - 0x32];

        break;

    case 0x38:

        val = s->initial_count;

        break;

    case 0x39:

        val = apic_get_current_count(s);

        break;

    case 0x3e:

        val = s->divide_conf;

        break;

    default:

        s->esr |= ESR_ILLEGAL_ADDRESS;

        val = 0;

        break;

    }

    DPRINTF("read: " TARGET_FMT_plx " = %08x\n", addr, val);

    return val;

}

static void apic_send_msi(target_phys_addr_t addr, uint32 data)

{

    uint8_t dest = (addr & MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;

    uint8_t vector = (data & MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;

    uint8_t dest_mode = (addr >> MSI_ADDR_DEST_MODE_SHIFT) & 0x1;

    uint8_t trigger_mode = (data >> MSI_DATA_TRIGGER_SHIFT) & 0x1;

    uint8_t delivery = (data >> MSI_DATA_DELIVERY_MODE_SHIFT) & 0x7;

    /* XXX: Ignore redirection hint. */

    apic_deliver_irq(dest, dest_mode, delivery, vector, 0, trigger_mode);

}

static void apic_mem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)

{

    CPUState *env;

    APICState *s;

    int index = (addr >> 4) & 0xff;

    if (addr > 0xfff || !index) {

        /* MSI and MMIO APIC are at the same memory location,

         * but actually not on the global bus: MSI is on PCI bus

         * APIC is connected directly to the CPU.

         * Mapping them on the global bus happens to work because

         * MSI registers are reserved in APIC MMIO and vice versa. */

        apic_send_msi(addr, val);

        return;

    }

    env = cpu_single_env;

    if (!env)

        return;

    s = env->apic_state;

    DPRINTF("write: " TARGET_FMT_plx " = %08x\n", addr, val);

    switch(index) {

    case 0x02:

        s->id = (val >> 24);

        break;

    case 0x03:

        break;

    case 0x08:

        s->tpr = val;

        apic_update_irq(s);

        break;

    case 0x09:

    case 0x0a:

        break;

    case 0x0b: /* EOI */

        apic_eoi(s);

        break;

    case 0x0d:

        s->log_dest = val >> 24;

        break;

    case 0x0e:

        s->dest_mode = val >> 28;

        break;

    case 0x0f:

        s->spurious_vec = val & 0x1ff;

        apic_update_irq(s);

        break;

    case 0x10 ... 0x17:

    case 0x18 ... 0x1f:

    case 0x20 ... 0x27:

    case 0x28:

        break;

    case 0x30:

        s->icr[0] = val;

        apic_deliver(s, (s->icr[1] >> 24) & 0xff, (s->icr[0] >> 11) & 1,

                     (s->icr[0] >> 8) & 7, (s->icr[0] & 0xff),

                     (s->icr[0] >> 14) & 1, (s->icr[0] >> 15) & 1);

        break;

    case 0x31:

        s->icr[1] = val;

        break;

    case 0x32 ... 0x37:

        {

            int n = index - 0x32;

            s->lvt[n] = val;

            if (n == APIC_LVT_TIMER)

                apic_timer_update(s, qemu_get_clock(vm_clock));

        }

        break;

    case 0x38:

        s->initial_count = val;

        s->initial_count_load_time = qemu_get_clock(vm_clock);

        apic_timer_update(s, s->initial_count_load_time);

        break;

    case 0x39:

        break;

    case 0x3e:

        {

            int v;

            s->divide_conf = val & 0xb;

            v = (s->divide_conf & 3) | ((s->divide_conf >> 1) & 4);

            s->count_shift = (v + 1) & 7;

        }

        break;

    default:

        s->esr |= ESR_ILLEGAL_ADDRESS;

        break;

    }

}

/* This function is only used for old state version 1 and 2 */

static int apic_load_old(QEMUFile *f, void *opaque, int version_id)