vl.c

qemu虚拟机代码

#elif defined(__ia64)

int64_t cpu_get_real_ticks(void)
{
	int64_t val;
	asm volatile ("mov %0 = ar.itc" : "=r"(val) :: "memory");
	return val;
}

#elif defined(__s390__)

int64_t cpu_get_real_ticks(void)
{
    int64_t val;
    asm volatile("stck 0(%1)" : "=m" (val) : "a" (&val) : "cc");
    return val;
}

#else
#error unsupported CPU
#endif

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

static inline 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;
    }
}

/* enable cpu_get_ticks() */
void cpu_enable_ticks(void)
{
    if (!cpu_ticks_enabled) {
        cpu_ticks_offset -= cpu_get_real_ticks();
        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_ticks_enabled = 0;
    }
}

#ifdef _WIN32
void cpu_calibrate_ticks(void)
{
    LARGE_INTEGER freq;
    int ret;

    ret = QueryPerformanceFrequency(&freq);
    if (ret == 0) {
        fprintf(stderr, "Could not calibrate ticks\n");
        exit(1);
    }
    ticks_per_sec = freq.QuadPart;
}

#else
static int64_t get_clock(void)
{
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return tv.tv_sec * 1000000LL + tv.tv_usec;
}

void cpu_calibrate_ticks(void)
{
    int64_t usec, ticks;

    usec = get_clock();
    ticks = cpu_get_real_ticks();
    usleep(50 * 1000);
    usec = get_clock() - usec;
    ticks = cpu_get_real_ticks() - ticks;
    ticks_per_sec = (ticks * 1000000LL + (usec >> 1)) / usec;
}
#endif /* !_WIN32 */

/* 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;
}

#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:
#ifdef _WIN32
        return GetTickCount();
#else
        {
            struct tms tp;

            /* Note that using gettimeofday() is not a good solution
               for timers because its value change when the date is
               modified. */
            if (timer_freq == 100) {
                return times(&tp) * 10;
            } else {
                return ((int64_t)times(&tp) * 1000) / timer_freq;
            }
        }
#endif
    default:
    case QEMU_TIMER_VIRTUAL:
        return cpu_get_ticks();
    }
}

/* 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);
}

static int timer_load(QEMUFile *f, void *opaque, int version_id)
{
    if (version_id != 1)
        return -EINVAL;
    if (cpu_ticks_enabled) {
        return -EINVAL;
    }
    qemu_get_be64s(f, &cpu_ticks_offset);
    qemu_get_be64s(f, &ticks_per_sec);
    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=%lld us max=%lld us avg=%lld 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_timers(void)
{
    rt_clock = qemu_new_clock(QEMU_TIMER_REALTIME);
    vm_clock = qemu_new_clock(QEMU_TIMER_VIRTUAL);

#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);
        }
        ResetEvent(host_alarm);
    }
    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 = 0;
            itv.it_value.tv_usec = 0;
            setitimer(ITIMER_REAL, &itv, NULL);

            /* use the RTC */
            sigaction(SIGIO, &act, NULL);
            fcntl(rtc_fd, F_SETFL, O_ASYNC);
            fcntl(rtc_fd, F_SETOWN, getpid());
        } else 
#endif /* defined(__linux__) */
        {
        use_itimer:
            pit_min_timer_count = ((uint64_t)itv.it_interval.tv_usec * 
                                   PIT_FREQ) / 1000000;
        }
    }
#endif
}

void quit_timers(void)
{
#ifdef _WIN32
    timeKillEvent(timerID);
    timeEndPeriod(period);
    if (host_alarm) {
        CloseHandle(host_alarm);
        host_alarm = NULL;
    }
#endif
}

/***********************************************************/
/* character device */

int qemu_chr_write(CharDriverState *s, const uint8_t *buf, int len)
{
    return s->chr_write(s, buf, len);
}

int qemu_chr_ioctl(CharDriverState *s, int cmd, void *arg)
{
    if (!s->chr_ioctl)
        return -ENOTSUP;
    return s->chr_ioctl(s, cmd, arg);
}

void qemu_chr_printf(CharDriverState *s, const char *fmt, ...)
{
    char buf[4096];
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(buf, sizeof(buf), fmt, ap);