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, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include "vl.h"

//#define DEBUG_APIC

//#define DEBUG_IOAPIC

/* 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 IOAPIC_NUM_PINS                        0x18

#define ESR_ILLEGAL_ADDRESS (1 << 7)

#define APIC_SV_ENABLE (1 << 8)

#define MAX_APICS 255

#define MAX_APIC_WORDS 8

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;

    QEMUTimer *timer;

} APICState;

struct IOAPICState {

    uint8_t id;

    uint8_t ioregsel;

    uint32_t irr;

    uint64_t ioredtbl[IOAPIC_NUM_PINS];

};

static int apic_io_memory;

static APICState *local_apics[MAX_APICS + 1];

static int last_apic_id = 0;

static void apic_init_ipi(APICState *s);

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

static void apic_update_irq(APICState *s);

/* Find first bit starting from msb. Return 0 if value = 0 */

static int fls_bit(uint32_t value)

{

    unsigned int ret = 0;

#if defined(HOST_I386)

    __asm__ __volatile__ ("bsr %1, %0\n" : "+r" (ret) : "rm" (value));

    return ret;

#else

    if (value > 0xffff)

        value >>= 16, ret = 16;

    if (value > 0xff)

        value >>= 8, ret += 8;

    if (value > 0xf)

        value >>= 4, ret += 4;

    if (value > 0x3)

        value >>= 2, ret += 2;

    return ret + (value >> 1);

#endif

}

/* Find first bit starting from lsb. Return 0 if value = 0 */

static int ffs_bit(uint32_t value)

{

    unsigned int ret = 0;

#if defined(HOST_I386)

    __asm__ __volatile__ ("bsf %1, %0\n" : "+r" (ret) : "rm" (value));

    return ret;

#else

    if (!value)

        return 0;

    if (!(value & 0xffff))

        value >>= 16, ret = 16;

    if (!(value & 0xff))

        value >>= 8, ret += 8;

    if (!(value & 0xf))

        value >>= 4, ret += 4;

    if (!(value & 0x3))

        value >>= 2, ret += 2;

    if (!(value & 0x1))

        ret++;

    return ret;

#endif

}

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;

}

#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:

        case APIC_DM_NMI:

            break;

        case APIC_DM_INIT:

            /* normal INIT IPI sent to processors */

            foreach_apic(apic_iter, deliver_bitmask, 

                         apic_init_ipi(apic_iter) );

            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 cpu_set_apic_base(CPUState *env, uint64_t val)

{

    APICState *s = env->apic_state;

#ifdef DEBUG_APIC

    printf("cpu_set_apic_base: %016llx\n", val);

#endif

    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;

#ifdef DEBUG_APIC

    printf("cpu_get_apic_base: %016llx\n", (uint64_t)s->apicbase);

#endif

    return s->apicbase;

}

void cpu_set_apic_tpr(CPUX86State *env, uint8_t val)

{

    APICState *s = env->apic_state;

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

    apic_update_irq(s);

}

uint8_t cpu_get_apic_tpr(CPUX86State *env)

{

    APICState *s = env->apic_state;

    return s->tpr >> 4;

}

/* 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);

}

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

{

    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 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 {

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

            set_bit(deliver_bitmask, dest);

        }

    } 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);

                    }

                }

            }

        }

    }

}

static void apic_init_ipi(APICState *s)

{

    int i;

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

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

    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));

    memset(s->lvt, 0, sizeof(s->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;

}

/* send a SIPI message to the CPU to start it */

static void apic_startup(APICState *s, int vector_num)

{

    CPUState *env = s->cpu_env;

    if (!(env->hflags & HF_HALTED_MASK))

        return;

    env->eip = 0;

    cpu_x86_load_seg_cache(env, R_CS, vector_num << 8, vector_num << 12, 

                           0xffff, 0);

    env->hflags &= ~HF_HALTED_MASK;

}

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->id);

        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->id);

        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;

    reset_bit(s->irr, intno);

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

        return s->spurious_vec & 0xff;

    set_bit(s->isr, intno);

    apic_update_irq(s);

    return intno;

}

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) {

            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;

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

        apic_set_irq(s, s->lvt[APIC_LVT_TIMER] & 0xff, APIC_TRIGGER_EDGE);

    }

    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 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;

    }

#ifdef DEBUG_APIC

    printf("APIC read: %08x = %08x\n", (uint32_t)addr, val);

#endif

    return val;

}

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

{

    CPUState *env;

    APICState *s;

    int index;

    env = cpu_single_env;

    if (!env)

        return;

    s = env->apic_state;

#ifdef DEBUG_APIC

    printf("APIC write: %08x = %08x\n", (uint32_t)addr, val);

#endif

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

    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;

    }

}

static void apic_save(QEMUFile *f, void *opaque)

{

    APICState *s = opaque;

    int i;

    qemu_put_be32s(f, &s->apicbase);

    qemu_put_8s(f, &s->id);

    qemu_put_8s(f, &s->arb_id);

    qemu_put_8s(f, &s->tpr);

    qemu_put_be32s(f, &s->spurious_vec);

    qemu_put_8s(f, &s->log_dest);

    qemu_put_8s(f, &s->dest_mode);

    for (i = 0; i < 8; i++) {

        qemu_put_be32s(f, &s->isr[i]);

        qemu_put_be32s(f, &s->tmr[i]);

        qemu_put_be32s(f, &s->irr[i]);

    }

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

        qemu_put_be32s(f, &s->lvt[i]);

    }

    qemu_put_be32s(f, &s->esr);

    qemu_put_be32s(f, &s->icr[0]);

    qemu_put_be32s(f, &s->icr[1]);

    qemu_put_be32s(f, &s->divide_conf);

    qemu_put_be32s(f, &s->count_shift);

    qemu_put_be32s(f, &s->initial_count);

    qemu_put_be64s(f, &s->initial_count_load_time);

    qemu_put_be64s(f, &s->next_time);

}

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

{

    APICState *s = opaque;

    int i;

    if (version_id != 1)

        return -EINVAL;

    /* XXX: what if the base changes? (registered memory regions) */

    qemu_get_be32s(f, &s->apicbase);

    qemu_get_8s(f, &s->id);

    qemu_get_8s(f, &s->arb_id);

    qemu_get_8s(f, &s->tpr);

    qemu_get_be32s(f, &s->spurious_vec);

    qemu_get_8s(f, &s->log_dest);

    qemu_get_8s(f, &s->dest_mode);

    for (i = 0; i < 8; i++) {

        qemu_get_be32s(f, &s->isr[i]);

        qemu_get_be32s(f, &s->tmr[i]);

        qemu_get_be32s(f, &s->irr[i]);

    }

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

        qemu_get_be32s(f, &s->lvt[i]);

    }

    qemu_get_be32s(f, &s->esr);

    qemu_get_be32s(f, &s->icr[0]);

    qemu_get_be32s(f, &s->icr[1]);

    qemu_get_be32s(f, &s->divide_conf);

    qemu_get_be32s(f, &s->count_shift);

    qemu_get_be32s(f, &s->initial_count);

    qemu_get_be64s(f, &s->initial_count_load_time);

    qemu_get_be64s(f, &s->next_time);

    return 0;

}

static void apic_reset(void *opaque)

{

    APICState *s = opaque;

    apic_init_ipi(s);

}

static CPUReadMemoryFunc *apic_mem_read[3] = {

    apic_mem_readb,

    apic_mem_readw,

    apic_mem_readl,

};

static CPUWriteMemoryFunc *apic_mem_write[3] = {

    apic_mem_writeb,

    apic_mem_writew,

    apic_mem_writel,

};

int apic_init(CPUState *env)

{

    APICState *s;

    if (last_apic_id >= MAX_APICS)

        return -1;

    s = qemu_mallocz(sizeof(APICState));

    if (!s)

        return -1;

    env->apic_state = s;

    apic_init_ipi(s);

    s->id = last_apic_id++;

    s->cpu_env = env;

    s->apicbase = 0xfee00000 | 

        (s->id ? 0 : MSR_IA32_APICBASE_BSP) | MSR_IA32_APICBASE_ENABLE;

    /* XXX: mapping more APICs at the same memory location */

    if (apic_io_memory == 0) {

        /* NOTE: the APIC is directly connected to the CPU - it is not

           on the global memory bus. */

        apic_io_memory = cpu_register_io_memory(0, apic_mem_read, 

                                                apic_mem_write, NULL);

        cpu_register_physical_memory(s->apicbase & ~0xfff, 0x1000,

                                     apic_io_memory);

    }

    s->timer = qemu_new_timer(vm_clock, apic_timer, s);

    register_savevm("apic", 0, 1, apic_save, apic_load, s);

    qemu_register_reset(apic_reset, s);

    local_apics[s->id] = s;

    return 0;

}

static void ioapic_service(IOAPICState *s)

{

    uint8_t i;

    uint8_t trig_mode;

    uint8_t vector;

    uint8_t delivery_mode;

    uint32_t mask;

    uint64_t entry;

    uint8_t dest;

    uint8_t dest_mode;

    uint8_t polarity;

    uint32_t deliver_bitmask[MAX_APIC_WORDS];

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

        mask = 1 << i;

        if (s->irr & mask) {

            entry = s->ioredtbl[i];

            if (!(entry & APIC_LVT_MASKED)) {

                trig_mode = ((entry >> 15) & 1);

                dest = entry >> 56;

                dest_mode = (entry >> 11) & 1;

                delivery_mode = (entry >> 8) & 7;

                polarity = (entry >> 13) & 1;

                if (trig_mode == APIC_TRIGGER_EDGE)

                    s->irr &= ~mask;

                if (delivery_mode == APIC_DM_EXTINT)

                    vector = pic_read_irq(isa_pic);

                else

                    vector = entry & 0xff;

                apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode);

                apic_bus_deliver(deliver_bitmask, delivery_mode, 

                                 vector, polarity, trig_mode);

            }

        }

    }

}

void ioapic_set_irq(void *opaque, int vector, int level)

{

    IOAPICState *s = opaque;

    if (vector >= 0 && vector < IOAPIC_NUM_PINS) {

        uint32_t mask = 1 << vector;

        uint64_t entry = s->ioredtbl[vector];

        if ((entry >> 15) & 1) {

            /* level triggered */

            if (level) {

                s->irr |= mask;

                ioapic_service(s);

            } else {

                s->irr &= ~mask;