vl.c

/*
 * QEMU System Emulator
 * 
 * Copyright (c) 2003-2007 Fabrice Bellard
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "vl.h"

#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <sys/time.h>
#include <zlib.h>

#ifndef _WIN32
#include <sys/times.h>
#include <sys/wait.h>
#include <termios.h>
#include <sys/poll.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <dirent.h>
#include <netdb.h>
#ifdef _BSD
#include <sys/stat.h>
#ifndef __APPLE__
#include <libutil.h>
#endif
#else
#ifndef __sun__
#include <linux/if.h>
#include <linux/if_tun.h>
#include <pty.h>
#include <malloc.h>
#include <linux/rtc.h>
#include <linux/ppdev.h>
#else
#include <sys/stat.h>
#include <sys/ethernet.h>
#include <sys/sockio.h>
#include <arpa/inet.h>
#include <netinet/arp.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h> // must come after ip.h
#include <netinet/udp.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include <syslog.h>
#include <stropts.h>
#endif
#endif
#endif

#if defined(CONFIG_SLIRP)
#include "libslirp.h"
#endif

#ifdef _WIN32
#include <malloc.h>
#include <sys/timeb.h>
#include <windows.h>
#define getopt_long_only getopt_long
#define memalign(align, size) malloc(size)
#endif

#include "qemu_socket.h"

#ifdef CONFIG_SDL
#ifdef __APPLE__
#include <SDL/SDL.h>
#endif
#endif /* CONFIG_SDL */

#ifdef CONFIG_COCOA
#undef main
#define main qemu_main
#endif /* CONFIG_COCOA */

#include "disas.h"

#include "exec-all.h"

#define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup"
#ifdef __sun__
#define SMBD_COMMAND "/usr/sfw/sbin/smbd"
#else
#define SMBD_COMMAND "/usr/sbin/smbd"
#endif

//#define DEBUG_UNUSED_IOPORT
//#define DEBUG_IOPORT

#define PHYS_RAM_MAX_SIZE (2047 * 1024 * 1024)

#ifdef TARGET_PPC
#define DEFAULT_RAM_SIZE 144
#else
#define DEFAULT_RAM_SIZE 128
#endif
/* in ms */
#define GUI_REFRESH_INTERVAL 30

/* Max number of USB devices that can be specified on the commandline.  */
#define MAX_USB_CMDLINE 8

/* XXX: use a two level table to limit memory usage */
#define MAX_IOPORTS 65536

const char *bios_dir = CONFIG_QEMU_SHAREDIR;
char phys_ram_file[1024];
void *ioport_opaque[MAX_IOPORTS];
IOPortReadFunc *ioport_read_table[3][MAX_IOPORTS];
IOPortWriteFunc *ioport_write_table[3][MAX_IOPORTS];
/* Note: bs_table[MAX_DISKS] is a dummy block driver if none available
   to store the VM snapshots */
BlockDriverState *bs_table[MAX_DISKS + 1], *fd_table[MAX_FD];
/* point to the block driver where the snapshots are managed */
BlockDriverState *bs_snapshots;
int vga_ram_size;
static DisplayState display_state;
int nographic;
const char* keyboard_layout = NULL;
int64_t ticks_per_sec;
int boot_device = 'c';
int ram_size;
int pit_min_timer_count = 0;
int nb_nics;
NICInfo nd_table[MAX_NICS];
QEMUTimer *gui_timer;
int vm_running;
int rtc_utc = 1;
int cirrus_vga_enabled = 1;
#ifdef TARGET_SPARC
int graphic_width = 1024;
int graphic_height = 768;
#else
int graphic_width = 800;
int graphic_height = 600;
#endif
int graphic_depth = 15;
int full_screen = 0;
int no_quit = 0;
CharDriverState *serial_hds[MAX_SERIAL_PORTS];
CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];
#ifdef TARGET_I386
int win2k_install_hack = 0;
#endif
int usb_enabled = 0;
static VLANState *first_vlan;
int smp_cpus = 1;
const char *vnc_display;
#if defined(TARGET_SPARC)
#define MAX_CPUS 16
#elif defined(TARGET_I386)
#define MAX_CPUS 255
#else
#define MAX_CPUS 1
#endif
int acpi_enabled = 1;
int fd_bootchk = 1;
int no_reboot = 0;
int daemonize = 0;
const char *option_rom[MAX_OPTION_ROMS];
int nb_option_roms;
int semihosting_enabled = 0;
int autostart = 1;

/***********************************************************/
/* x86 ISA bus support */

target_phys_addr_t isa_mem_base = 0;
PicState2 *isa_pic;

uint32_t default_ioport_readb(void *opaque, uint32_t address)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "inb: port=0x%04x\n", address);
#endif
    return 0xff;
}

void default_ioport_writeb(void *opaque, uint32_t address, uint32_t data)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "outb: port=0x%04x data=0x%02x\n", address, data);
#endif
}

/* default is to make two byte accesses */
uint32_t default_ioport_readw(void *opaque, uint32_t address)
{
    uint32_t data;
    data = ioport_read_table[0][address](ioport_opaque[address], address);
    address = (address + 1) & (MAX_IOPORTS - 1);
    data |= ioport_read_table[0][address](ioport_opaque[address], address) << 8;
    return data;
}

void default_ioport_writew(void *opaque, uint32_t address, uint32_t data)
{
    ioport_write_table[0][address](ioport_opaque[address], address, data & 0xff);
    address = (address + 1) & (MAX_IOPORTS - 1);
    ioport_write_table[0][address](ioport_opaque[address], address, (data >> 8) & 0xff);
}

uint32_t default_ioport_readl(void *opaque, uint32_t address)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "inl: port=0x%04x\n", address);
#endif
    return 0xffffffff;
}

void default_ioport_writel(void *opaque, uint32_t address, uint32_t data)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "outl: port=0x%04x data=0x%02x\n", address, data);
#endif
}

void init_ioports(void)
{
    int i;

    for(i = 0; i < MAX_IOPORTS; i++) {
        ioport_read_table[0][i] = default_ioport_readb;
        ioport_write_table[0][i] = default_ioport_writeb;
        ioport_read_table[1][i] = default_ioport_readw;
        ioport_write_table[1][i] = default_ioport_writew;
        ioport_read_table[2][i] = default_ioport_readl;
        ioport_write_table[2][i] = default_ioport_writel;
    }
}

/* size is the word size in byte */
int register_ioport_read(int start, int length, int size, 
                         IOPortReadFunc *func, void *opaque)
{
    int i, bsize;

    if (size == 1) {
        bsize = 0;
    } else if (size == 2) {
        bsize = 1;
    } else if (size == 4) {
        bsize = 2;
    } else {
        hw_error("register_ioport_read: invalid size");
        return -1;
    }
    for(i = start; i < start + length; i += size) {
        ioport_read_table[bsize][i] = func;
        if (ioport_opaque[i] != NULL && ioport_opaque[i] != opaque)
            hw_error("register_ioport_read: invalid opaque");
        ioport_opaque[i] = opaque;
    }
    return 0;
}

/* size is the word size in byte */
int register_ioport_write(int start, int length, int size, 
                          IOPortWriteFunc *func, void *opaque)
{
    int i, bsize;

    if (size == 1) {
        bsize = 0;
    } else if (size == 2) {
        bsize = 1;
    } else if (size == 4) {
        bsize = 2;
    } else {
        hw_error("register_ioport_write: invalid size");
        return -1;
    }
    for(i = start; i < start + length; i += size) {
        ioport_write_table[bsize][i] = func;
        if (ioport_opaque[i] != NULL && ioport_opaque[i] != opaque)
            hw_error("register_ioport_write: invalid opaque");
        ioport_opaque[i] = opaque;
    }
    return 0;
}

void isa_unassign_ioport(int start, int length)
{
    int i;

    for(i = start; i < start + length; i++) {
        ioport_read_table[0][i] = default_ioport_readb;
        ioport_read_table[1][i] = default_ioport_readw;
        ioport_read_table[2][i] = default_ioport_readl;

        ioport_write_table[0][i] = default_ioport_writeb;
        ioport_write_table[1][i] = default_ioport_writew;
        ioport_write_table[2][i] = default_ioport_writel;
    }
}

/***********************************************************/

void cpu_outb(CPUState *env, int addr, int val)
{
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "outb: %04x %02x\n", addr, val);
#endif    
    ioport_write_table[0][addr](ioport_opaque[addr], addr, val);
#ifdef USE_KQEMU
    if (env)
        env->last_io_time = cpu_get_time_fast();
#endif
}

void cpu_outw(CPUState *env, int addr, int val)
{
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "outw: %04x %04x\n", addr, val);
#endif    
    ioport_write_table[1][addr](ioport_opaque[addr], addr, val);
#ifdef USE_KQEMU
    if (env)
        env->last_io_time = cpu_get_time_fast();
#endif
}

void cpu_outl(CPUState *env, int addr, int val)
{
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "outl: %04x %08x\n", addr, val);
#endif
    ioport_write_table[2][addr](ioport_opaque[addr], addr, val);
#ifdef USE_KQEMU
    if (env)
        env->last_io_time = cpu_get_time_fast();
#endif
}

int cpu_inb(CPUState *env, int addr)
{
    int val;
    val = ioport_read_table[0][addr](ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "inb : %04x %02x\n", addr, val);
#endif
#ifdef USE_KQEMU
    if (env)
        env->last_io_time = cpu_get_time_fast();
#endif
    return val;
}

int cpu_inw(CPUState *env, int addr)
{
    int val;
    val = ioport_read_table[1][addr](ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "inw : %04x %04x\n", addr, val);
#endif
#ifdef USE_KQEMU
    if (env)
        env->last_io_time = cpu_get_time_fast();
#endif
    return val;
}

int cpu_inl(CPUState *env, int addr)
{
    int val;
    val = ioport_read_table[2][addr](ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "inl : %04x %08x\n", addr, val);
#endif
#ifdef USE_KQEMU
    if (env)
        env->last_io_time = cpu_get_time_fast();
#endif
    return val;
}

/***********************************************************/
void hw_error(const char *fmt, ...)
{
    va_list ap;
    CPUState *env;

    va_start(ap, fmt);
    fprintf(stderr, "qemu: hardware error: ");
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    for(env = first_cpu; env != NULL; env = env->next_cpu) {
        fprintf(stderr, "CPU #%d:\n", env->cpu_index);
#ifdef TARGET_I386
        cpu_dump_state(env, stderr, fprintf, X86_DUMP_FPU);
#else
        cpu_dump_state(env, stderr, fprintf, 0);
#endif
    }
    va_end(ap);
    abort();
}

/***********************************************************/
/* keyboard/mouse */

static QEMUPutKBDEvent *qemu_put_kbd_event;
static void *qemu_put_kbd_event_opaque;
static QEMUPutMouseEntry *qemu_put_mouse_event_head;
static QEMUPutMouseEntry *qemu_put_mouse_event_current;

void qemu_add_kbd_event_handler(QEMUPutKBDEvent *func, void *opaque)
{
    qemu_put_kbd_event_opaque = opaque;
    qemu_put_kbd_event = func;
}

QEMUPutMouseEntry *qemu_add_mouse_event_handler(QEMUPutMouseEvent *func,
                                                void *opaque, int absolute,
                                                const char *name)
{
    QEMUPutMouseEntry *s, *cursor;

    s = qemu_mallocz(sizeof(QEMUPutMouseEntry));
    if (!s)
        return NULL;

    s->qemu_put_mouse_event = func;
    s->qemu_put_mouse_event_opaque = opaque;
    s->qemu_put_mouse_event_absolute = absolute;
    s->qemu_put_mouse_event_name = qemu_strdup(name);
    s->next = NULL;

    if (!qemu_put_mouse_event_head) {
        qemu_put_mouse_event_head = qemu_put_mouse_event_current = s;
        return s;
    }

    cursor = qemu_put_mouse_event_head;
    while (cursor->next != NULL)
        cursor = cursor->next;

    cursor->next = s;
    qemu_put_mouse_event_current = s;

    return s;
}

void qemu_remove_mouse_event_handler(QEMUPutMouseEntry *entry)
{
    QEMUPutMouseEntry *prev = NULL, *cursor;

    if (!qemu_put_mouse_event_head || entry == NULL)
        return;

    cursor = qemu_put_mouse_event_head;
    while (cursor != NULL && cursor != entry) {
        prev = cursor;
        cursor = cursor->next;
    }

    if (cursor == NULL) // does not exist or list empty
        return;
    else if (prev == NULL) { // entry is head
        qemu_put_mouse_event_head = cursor->next;
        if (qemu_put_mouse_event_current == entry)
            qemu_put_mouse_event_current = cursor->next;
        qemu_free(entry->qemu_put_mouse_event_name);
        qemu_free(entry);
        return;
    }

    prev->next = entry->next;

    if (qemu_put_mouse_event_current == entry)
        qemu_put_mouse_event_current = prev;

    qemu_free(entry->qemu_put_mouse_event_name);
    qemu_free(entry);
}

void kbd_put_keycode(int keycode)
{
    if (qemu_put_kbd_event) {
        qemu_put_kbd_event(qemu_put_kbd_event_opaque, keycode);
    }
}

void kbd_mouse_event(int dx, int dy, int dz, int buttons_state)
{
    QEMUPutMouseEvent *mouse_event;
    void *mouse_event_opaque;

    if (!qemu_put_mouse_event_current) {
        return;
    }

    mouse_event =
        qemu_put_mouse_event_current->qemu_put_mouse_event;
    mouse_event_opaque =
        qemu_put_mouse_event_current->qemu_put_mouse_event_opaque;

    if (mouse_event) {
        mouse_event(mouse_event_opaque, dx, dy, dz, buttons_state);
    }
}

int kbd_mouse_is_absolute(void)
{
    if (!qemu_put_mouse_event_current)
        return 0;

    return qemu_put_mouse_event_current->qemu_put_mouse_event_absolute;
}

void do_info_mice(void)
{
    QEMUPutMouseEntry *cursor;
    int index = 0;

    if (!qemu_put_mouse_event_head) {
        term_printf("No mouse devices connected\n");
        return;
    }

    term_printf("Mouse devices available:\n");
    cursor = qemu_put_mouse_event_head;
    while (cursor != NULL) {
        term_printf("%c Mouse #%d: %s\n",
                    (cursor == qemu_put_mouse_event_current ? '*' : ' '),
                    index, cursor->qemu_put_mouse_event_name);
        index++;
        cursor = cursor->next;
    }
}

void do_mouse_set(int index)
{
    QEMUPutMouseEntry *cursor;
    int i = 0;

    if (!qemu_put_mouse_event_head) {
        term_printf("No mouse devices connected\n");
        return;
    }

    cursor = qemu_put_mouse_event_head;
    while (cursor != NULL && index != i) {
        i++;
        cursor = cursor->next;
    }

    if (cursor != NULL)
        qemu_put_mouse_event_current = cursor;
    else
        term_printf("Mouse at given index not found\n");
}

/* compute with 96 bit intermediate result: (a*b)/c */
uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
{
    union {
        uint64_t ll;
        struct {
#ifdef WORDS_BIGENDIAN
            uint32_t high, low;
#else
            uint32_t low, high;
#endif            
        } l;
    } u, res;
    uint64_t rl, rh;

    u.ll = a;
    rl = (uint64_t)u.l.low * (uint64_t)b;
    rh = (uint64_t)u.l.high * (uint64_t)b;
    rh += (rl >> 32);
    res.l.high = rh / c;
    res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
    return res.ll;
}

/***********************************************************/
/* real time host monotonic timer */

#define QEMU_TIMER_BASE 1000000000LL

#ifdef WIN32

static int64_t clock_freq;

static void init_get_clock(void)
{
    LARGE_INTEGER freq;
    int ret;
    ret = QueryPerformanceFrequency(&freq);
    if (ret == 0) {
        fprintf(stderr, "Could not calibrate ticks\n");
        exit(1);
    }
    clock_freq = freq.QuadPart;
}

static int64_t get_clock(void)
{
    LARGE_INTEGER ti;
    QueryPerformanceCounter(&ti);
    return muldiv64(ti.QuadPart, QEMU_TIMER_BASE, clock_freq);
}

#else

static int use_rt_clock;

static void init_get_clock(void)
{
    use_rt_clock = 0;
#if defined(__linux__)
    {
        struct timespec ts;
        if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
            use_rt_clock = 1;
        }
    }
#endif
}

static int64_t get_clock(void)
{
#if defined(__linux__)
    if (use_rt_clock) {
        struct timespec ts;
        clock_gettime(CLOCK_MONOTONIC, &ts);
        return ts.tv_sec * 1000000000LL + ts.tv_nsec;
    } else 
#endif
    {
        /* XXX: using gettimeofday leads to problems if the date
           changes, so it should be avoided. */
        struct timeval tv;
        gettimeofday(&tv, NULL);
        return tv.tv_sec * 1000000000LL + (tv.tv_usec * 1000);
    }
}

#endif

/***********************************************************/
/* guest cycle counter */

static int64_t cpu_ticks_prev;
static int64_t cpu_ticks_offset;
static int64_t cpu_clock_offset;
static int cpu_ticks_enabled;

/* return the host CPU cycle counter and handle stop/restart */
int64_t cpu_get_ticks(void)
{
    if (!cpu_ticks_enabled) {
        return cpu_ticks_offset;
    } else {
        int64_t ticks;
        ticks = cpu_get_real_ticks();
        if (cpu_ticks_prev > ticks) {
            /* Note: non increasing ticks may happen if the host uses
               software suspend */
            cpu_ticks_offset += cpu_ticks_prev - ticks;
        }
        cpu_ticks_prev = ticks;
        return ticks + cpu_ticks_offset;
    }
}

/* return the host CPU monotonic timer and handle stop/restart */
static int64_t cpu_get_clock(void)
{
    int64_t ti;
    if (!cpu_ticks_enabled) {
        return cpu_clock_offset;
    } else {
        ti = get_clock();
        return ti + cpu_clock_offset;
    }
}

/* enable cpu_get_ticks() */
void cpu_enable_ticks(void)
{
    if (!cpu_ticks_enabled) {
        cpu_ticks_offset -= cpu_get_real_ticks();
        cpu_clock_offset -= get_clock();
        cpu_ticks_enabled = 1;
    }
}

/* disable cpu_get_ticks() : the clock is stopped. You must not call
   cpu_get_ticks() after that.  */
void cpu_disable_ticks(void)
{
    if (cpu_ticks_enabled) {
        cpu_ticks_offset = cpu_get_ticks();
        cpu_clock_offset = cpu_get_clock();
        cpu_ticks_enabled = 0;
    }
}

/***********************************************************/
/* timers */
 
#define QEMU_TIMER_REALTIME 0
#define QEMU_TIMER_VIRTUAL  1

struct QEMUClock {
    int type;
    /* XXX: add frequency */
};

struct QEMUTimer {
    QEMUClock *clock;
    int64_t expire_time;
    QEMUTimerCB *cb;
    void *opaque;
    struct QEMUTimer *next;
};

QEMUClock *rt_clock;
QEMUClock *vm_clock;

static QEMUTimer *active_timers[2];
#ifdef _WIN32
static MMRESULT timerID;
static HANDLE host_alarm = NULL;
static unsigned int period = 1;
#else
/* frequency of the times() clock tick */
static int timer_freq;
#endif

QEMUClock *qemu_new_clock(int type)
{
    QEMUClock *clock;
    clock = qemu_mallocz(sizeof(QEMUClock));
    if (!clock)
        return NULL;
    clock->type = type;
    return clock;
}

QEMUTimer *qemu_new_timer(QEMUClock *clock, QEMUTimerCB *cb, void *opaque)
{
    QEMUTimer *ts;

    ts = qemu_mallocz(sizeof(QEMUTimer));
    ts->clock = clock;
    ts->cb = cb;
    ts->opaque = opaque;
    return ts;
}

void qemu_free_timer(QEMUTimer *ts)
{
    qemu_free(ts);
}

/* stop a timer, but do not dealloc it */
void qemu_del_timer(QEMUTimer *ts)
{
    QEMUTimer **pt, *t;

    /* NOTE: this code must be signal safe because
       qemu_timer_expired() can be called from a signal. */
    pt = &active_timers[ts->clock->type];
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t == ts) {
            *pt = t->next;
            break;
        }
        pt = &t->next;
    }
}

/* modify the current timer so that it will be fired when current_time
   >= expire_time. The corresponding callback will be called. */
void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimer **pt, *t;

    qemu_del_timer(ts);

    /* add the timer in the sorted list */
    /* NOTE: this code must be signal safe because
       qemu_timer_expired() can be called from a signal. */
    pt = &active_timers[ts->clock->type];
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t->expire_time > expire_time) 
            break;
        pt = &t->next;
    }
    ts->expire_time = expire_time;
    ts->next = *pt;
    *pt = ts;
}

int qemu_timer_pending(QEMUTimer *ts)
{
    QEMUTimer *t;
    for(t = active_timers[ts->clock->type]; t != NULL; t = t->next) {
        if (t == ts)
            return 1;
    }
    return 0;
}

static inline int qemu_timer_expired(QEMUTimer *timer_head, int64_t current_time)
{
    if (!timer_head)
        return 0;
    return (timer_head->expire_time <= current_time);
}

static void qemu_run_timers(QEMUTimer **ptimer_head, int64_t current_time)
{
    QEMUTimer *ts;
    
    for(;;) {
        ts = *ptimer_head;
        if (!ts || ts->expire_time > current_time)
            break;
        /* remove timer from the list before calling the callback */
        *ptimer_head = ts->next;
        ts->next = NULL;
        
        /* run the callback (the timer list can be modified) */
        ts->cb(ts->opaque);
    }
}

int64_t qemu_get_clock(QEMUClock *clock)
{
    switch(clock->type) {
    case QEMU_TIMER_REALTIME:
        return get_clock() / 1000000;
    default:
    case QEMU_TIMER_VIRTUAL:
        return cpu_get_clock();
    }
}

static void init_timers(void)
{
    init_get_clock();
    ticks_per_sec = QEMU_TIMER_BASE;
    rt_clock = qemu_new_clock(QEMU_TIMER_REALTIME);
    vm_clock = qemu_new_clock(QEMU_TIMER_VIRTUAL);
}

/* save a timer */
void qemu_put_timer(QEMUFile *f, QEMUTimer *ts)
{
    uint64_t expire_time;

    if (qemu_timer_pending(ts)) {
        expire_time = ts->expire_time;
    } else {
        expire_time = -1;
    }
    qemu_put_be64(f, expire_time);
}

void qemu_get_timer(QEMUFile *f, QEMUTimer *ts)
{
    uint64_t expire_time;

    expire_time = qemu_get_be64(f);
    if (expire_time != -1) {
        qemu_mod_timer(ts, expire_time);
    } else {
        qemu_del_timer(ts);
    }
}

static void timer_save(QEMUFile *f, void *opaque)
{
    if (cpu_ticks_enabled) {
        hw_error("cannot save state if virtual timers are running");
    }
    qemu_put_be64s(f, &cpu_ticks_offset);
    qemu_put_be64s(f, &ticks_per_sec);
    qemu_put_be64s(f, &cpu_clock_offset);
}

static int timer_load(QEMUFile *f, void *opaque, int version_id)
{
    if (version_id != 1 && version_id != 2)
        return -EINVAL;
    if (cpu_ticks_enabled) {
        return -EINVAL;
    }
    qemu_get_be64s(f, &cpu_ticks_offset);
    qemu_get_be64s(f, &ticks_per_sec);
    if (version_id == 2) {
        qemu_get_be64s(f, &cpu_clock_offset);
    }
    return 0;
}

#ifdef _WIN32
void CALLBACK host_alarm_handler(UINT uTimerID, UINT uMsg, 
                                 DWORD_PTR dwUser, DWORD_PTR dw1, DWORD_PTR dw2)
#else
static void host_alarm_handler(int host_signum)
#endif
{
#if 0
#define DISP_FREQ 1000
    {
        static int64_t delta_min = INT64_MAX;
        static int64_t delta_max, delta_cum, last_clock, delta, ti;
        static int count;
        ti = qemu_get_clock(vm_clock);
        if (last_clock != 0) {
            delta = ti - last_clock;
            if (delta < delta_min)
                delta_min = delta;
            if (delta > delta_max)
                delta_max = delta;
            delta_cum += delta;
            if (++count == DISP_FREQ) {
                printf("timer: min=%" PRId64 " us max=%" PRId64 " us avg=%" PRId64 " us avg_freq=%0.3f Hz\n",
                       muldiv64(delta_min, 1000000, ticks_per_sec),
                       muldiv64(delta_max, 1000000, ticks_per_sec),
                       muldiv64(delta_cum, 1000000 / DISP_FREQ, ticks_per_sec),
                       (double)ticks_per_sec / ((double)delta_cum / DISP_FREQ));
                count = 0;
                delta_min = INT64_MAX;
                delta_max = 0;
                delta_cum = 0;
            }
        }
        last_clock = ti;
    }
#endif
    if (qemu_timer_expired(active_timers[QEMU_TIMER_VIRTUAL],
                           qemu_get_clock(vm_clock)) ||
        qemu_timer_expired(active_timers[QEMU_TIMER_REALTIME],
                           qemu_get_clock(rt_clock))) {
#ifdef _WIN32
        SetEvent(host_alarm);
#endif
        CPUState *env = cpu_single_env;
        if (env) {
            /* stop the currently executing cpu because a timer occured */
            cpu_interrupt(env, CPU_INTERRUPT_EXIT);
#ifdef USE_KQEMU
            if (env->kqemu_enabled) {
                kqemu_cpu_interrupt(env);
            }
#endif
        }
    }
}

#ifndef _WIN32

#if defined(__linux__)

#define RTC_FREQ 1024

static int rtc_fd;

static int start_rtc_timer(void)
{
    rtc_fd = open("/dev/rtc", O_RDONLY);
    if (rtc_fd < 0)
        return -1;
    if (ioctl(rtc_fd, RTC_IRQP_SET, RTC_FREQ) < 0) {
        fprintf(stderr, "Could not configure '/dev/rtc' to have a 1024 Hz timer. This is not a fatal\n"
                "error, but for better emulation accuracy either use a 2.6 host Linux kernel or\n"
                "type 'echo 1024 > /proc/sys/dev/rtc/max-user-freq' as root.\n");
        goto fail;
    }
    if (ioctl(rtc_fd, RTC_PIE_ON, 0) < 0) {
    fail:
        close(rtc_fd);
        return -1;
    }
    pit_min_timer_count = PIT_FREQ / RTC_FREQ;
    return 0;
}

#else

static int start_rtc_timer(void)
{
    return -1;
}

#endif /* !defined(__linux__) */

#endif /* !defined(_WIN32) */

static void init_timer_alarm(void)
{
#ifdef _WIN32
    {
        int count=0;
        TIMECAPS tc;

        ZeroMemory(&tc, sizeof(TIMECAPS));
        timeGetDevCaps(&tc, sizeof(TIMECAPS));
        if (period < tc.wPeriodMin)
            period = tc.wPeriodMin;
        timeBeginPeriod(period);
        timerID = timeSetEvent(1,     // interval (ms)
                               period,     // resolution
                               host_alarm_handler, // function
                               (DWORD)&count,  // user parameter
                               TIME_PERIODIC | TIME_CALLBACK_FUNCTION);
 	if( !timerID ) {
            perror("failed timer alarm");
            exit(1);
 	}
        host_alarm = CreateEvent(NULL, FALSE, FALSE, NULL);
        if (!host_alarm) {
            perror("failed CreateEvent");
            exit(1);
        }
        qemu_add_wait_object(host_alarm, NULL, NULL);
    }
    pit_min_timer_count = ((uint64_t)10000 * PIT_FREQ) / 1000000;
#else
    {
        struct sigaction act;
        struct itimerval itv;
        
        /* get times() syscall frequency */
        timer_freq = sysconf(_SC_CLK_TCK);
        
        /* timer signal */
        sigfillset(&act.sa_mask);
       act.sa_flags = 0;
#if defined (TARGET_I386) && defined(USE_CODE_COPY)
        act.sa_flags |= SA_ONSTACK;
#endif
        act.sa_handler = host_alarm_handler;
        sigaction(SIGALRM, &act, NULL);

        itv.it_interval.tv_sec = 0;
        itv.it_interval.tv_usec = 999; /* for i386 kernel 2.6 to get 1 ms */
        itv.it_value.tv_sec = 0;
        itv.it_value.tv_usec = 10 * 1000;
        setitimer(ITIMER_REAL, &itv, NULL);
        /* we probe the tick duration of the kernel to inform the user if
           the emulated kernel requested a too high timer frequency */
        getitimer(ITIMER_REAL, &itv);

#if defined(__linux__)
        /* XXX: force /dev/rtc usage because even 2.6 kernels may not
           have timers with 1 ms resolution. The correct solution will
           be to use the POSIX real time timers available in recent
           2.6 kernels */
        if (itv.it_interval.tv_usec > 1000 || 1) {
            /* try to use /dev/rtc to have a faster timer */
            if (start_rtc_timer() < 0)
                goto use_itimer;
            /* disable itimer */
            itv.it_interval.tv_sec = 0;
            itv.it_interval.tv_usec = 0;
            itv.it_value.tv_sec =