Archipelago » qemu

/*

 * QEMU System Emulator

 *

 * Copyright (c) 2003-2008 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 "sysemu.h"

#include "monitor/monitor.h"

#include "ui/console.h"

#include "hw/hw.h"

#include "qemu/timer.h"

#ifdef CONFIG_POSIX

#include <pthread.h>

#endif

#ifdef _WIN32

#include <mmsystem.h>

#endif

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

/* timers */

#define QEMU_CLOCK_REALTIME 0

#define QEMU_CLOCK_VIRTUAL  1

#define QEMU_CLOCK_HOST     2

struct QEMUClock {

    QEMUTimer *active_timers;

    NotifierList reset_notifiers;

    int64_t last;

    int type;

    bool enabled;

};

struct QEMUTimer {

    int64_t expire_time;        /* in nanoseconds */

    QEMUClock *clock;

    QEMUTimerCB *cb;

    void *opaque;

    QEMUTimer *next;

    int scale;

};

struct qemu_alarm_timer {

    char const *name;

    int (*start)(struct qemu_alarm_timer *t);

    void (*stop)(struct qemu_alarm_timer *t);

    void (*rearm)(struct qemu_alarm_timer *t, int64_t nearest_delta_ns);

#if defined(__linux__)

    timer_t timer;

    int fd;

#elif defined(_WIN32)

    HANDLE timer;

#endif

    bool expired;

    bool pending;

};

static struct qemu_alarm_timer *alarm_timer;

static bool qemu_timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)

{

    return timer_head && (timer_head->expire_time <= current_time);

}

static int64_t qemu_next_alarm_deadline(void)

{

    int64_t delta = INT64_MAX;

    int64_t rtdelta;

    if (!use_icount && vm_clock->enabled && vm_clock->active_timers) {

        delta = vm_clock->active_timers->expire_time -

                     qemu_get_clock_ns(vm_clock);

    }

    if (host_clock->enabled && host_clock->active_timers) {

        int64_t hdelta = host_clock->active_timers->expire_time -

                 qemu_get_clock_ns(host_clock);

        if (hdelta < delta) {

            delta = hdelta;

        }

    }

    if (rt_clock->enabled && rt_clock->active_timers) {

        rtdelta = (rt_clock->active_timers->expire_time -

                 qemu_get_clock_ns(rt_clock));

        if (rtdelta < delta) {

            delta = rtdelta;

        }

    }

    return delta;

}

static void qemu_rearm_alarm_timer(struct qemu_alarm_timer *t)

{

    int64_t nearest_delta_ns = qemu_next_alarm_deadline();

    if (nearest_delta_ns < INT64_MAX) {

        t->rearm(t, nearest_delta_ns);

    }

}

/* TODO: MIN_TIMER_REARM_NS should be optimized */

#define MIN_TIMER_REARM_NS 250000

#ifdef _WIN32

static int mm_start_timer(struct qemu_alarm_timer *t);

static void mm_stop_timer(struct qemu_alarm_timer *t);

static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);

static int win32_start_timer(struct qemu_alarm_timer *t);

static void win32_stop_timer(struct qemu_alarm_timer *t);

static void win32_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);

#else

static int unix_start_timer(struct qemu_alarm_timer *t);

static void unix_stop_timer(struct qemu_alarm_timer *t);

static void unix_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);

#ifdef __linux__

static int dynticks_start_timer(struct qemu_alarm_timer *t);

static void dynticks_stop_timer(struct qemu_alarm_timer *t);

static void dynticks_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);

#endif /* __linux__ */

#endif /* _WIN32 */

static struct qemu_alarm_timer alarm_timers[] = {

#ifndef _WIN32

#ifdef __linux__

    {"dynticks", dynticks_start_timer,

     dynticks_stop_timer, dynticks_rearm_timer},

#endif

    {"unix", unix_start_timer, unix_stop_timer, unix_rearm_timer},

#else

    {"mmtimer", mm_start_timer, mm_stop_timer, mm_rearm_timer},

    {"dynticks", win32_start_timer, win32_stop_timer, win32_rearm_timer},

#endif

    {NULL, }

};

static void show_available_alarms(void)

{

    int i;

    printf("Available alarm timers, in order of precedence:\n");

    for (i = 0; alarm_timers[i].name; i++)

        printf("%s\n", alarm_timers[i].name);

}

void configure_alarms(char const *opt)

{

    int i;

    int cur = 0;

    int count = ARRAY_SIZE(alarm_timers) - 1;

    char *arg;

    char *name;

    struct qemu_alarm_timer tmp;

    if (is_help_option(opt)) {

        show_available_alarms();

        exit(0);

    }

    arg = g_strdup(opt);

    /* Reorder the array */

    name = strtok(arg, ",");

    while (name) {

        for (i = 0; i < count && alarm_timers[i].name; i++) {

            if (!strcmp(alarm_timers[i].name, name))

                break;

        }

        if (i == count) {

            fprintf(stderr, "Unknown clock %s\n", name);

            goto next;

        }

        if (i < cur)

            /* Ignore */

            goto next;

        /* Swap */

        tmp = alarm_timers[i];

        alarm_timers[i] = alarm_timers[cur];

        alarm_timers[cur] = tmp;

        cur++;

next:

        name = strtok(NULL, ",");

    }

    g_free(arg);

    if (cur) {

        /* Disable remaining timers */

        for (i = cur; i < count; i++)

            alarm_timers[i].name = NULL;

    } else {

        show_available_alarms();

        exit(1);

    }

}

QEMUClock *rt_clock;

QEMUClock *vm_clock;

QEMUClock *host_clock;

static QEMUClock *qemu_new_clock(int type)

{

    QEMUClock *clock;

    clock = g_malloc0(sizeof(QEMUClock));

    clock->type = type;

    clock->enabled = true;

    clock->last = INT64_MIN;

    notifier_list_init(&clock->reset_notifiers);

    return clock;

}

void qemu_clock_enable(QEMUClock *clock, bool enabled)

{

    bool old = clock->enabled;

    clock->enabled = enabled;

    if (enabled && !old) {

        qemu_rearm_alarm_timer(alarm_timer);

    }

}

int64_t qemu_clock_has_timers(QEMUClock *clock)

{

    return !!clock->active_timers;

}

int64_t qemu_clock_expired(QEMUClock *clock)

{

    return (clock->active_timers &&

            clock->active_timers->expire_time < qemu_get_clock_ns(clock));

}

int64_t qemu_clock_deadline(QEMUClock *clock)

{

    /* To avoid problems with overflow limit this to 2^32.  */

    int64_t delta = INT32_MAX;

    if (clock->active_timers) {

        delta = clock->active_timers->expire_time - qemu_get_clock_ns(clock);

    }

    if (delta < 0) {

        delta = 0;

    }

    return delta;

}

QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,

                          QEMUTimerCB *cb, void *opaque)

{

    QEMUTimer *ts;

    ts = g_malloc0(sizeof(QEMUTimer));

    ts->clock = clock;

    ts->cb = cb;

    ts->opaque = opaque;

    ts->scale = scale;

    return ts;

}

void qemu_free_timer(QEMUTimer *ts)

{

    g_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 = &ts->clock->active_timers;

    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_ns(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 = &ts->clock->active_timers;

    for(;;) {

        t = *pt;

        if (!qemu_timer_expired_ns(t, expire_time)) {

            break;

        }

        pt = &t->next;

    }

    ts->expire_time = expire_time;

    ts->next = *pt;

    *pt = ts;

    /* Rearm if necessary  */

    if (pt == &ts->clock->active_timers) {

        if (!alarm_timer->pending) {

            qemu_rearm_alarm_timer(alarm_timer);

        }

        /* Interrupt execution to force deadline recalculation.  */

        qemu_clock_warp(ts->clock);

        if (use_icount) {

            qemu_notify_event();

        }

    }

}

void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)

{

    qemu_mod_timer_ns(ts, expire_time * ts->scale);

}

bool qemu_timer_pending(QEMUTimer *ts)

{

    QEMUTimer *t;

    for (t = ts->clock->active_timers; t != NULL; t = t->next) {

        if (t == ts) {

            return true;

        }

    }

    return false;

}

bool qemu_timer_expired(QEMUTimer *timer_head, int64_t current_time)

{

    return qemu_timer_expired_ns(timer_head, current_time * timer_head->scale);

}

void qemu_run_timers(QEMUClock *clock)

{

    QEMUTimer *ts;

    int64_t current_time;

    if (!clock->enabled)

        return;

    current_time = qemu_get_clock_ns(clock);

    for(;;) {

        ts = clock->active_timers;

        if (!qemu_timer_expired_ns(ts, current_time)) {

            break;

        }

        /* remove timer from the list before calling the callback */

        clock->active_timers = ts->next;

        ts->next = NULL;

        /* run the callback (the timer list can be modified) */

        ts->cb(ts->opaque);

    }

}

int64_t qemu_get_clock_ns(QEMUClock *clock)

{

    int64_t now, last;

    switch(clock->type) {

    case QEMU_CLOCK_REALTIME:

        return get_clock();

    default:

    case QEMU_CLOCK_VIRTUAL:

        if (use_icount) {

            return cpu_get_icount();

        } else {

            return cpu_get_clock();

        }

    case QEMU_CLOCK_HOST:

        now = get_clock_realtime();

        last = clock->last;

        clock->last = now;

        if (now < last) {

            notifier_list_notify(&clock->reset_notifiers, &now);

        }

        return now;

    }

}

void qemu_register_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)

{

    notifier_list_add(&clock->reset_notifiers, notifier);

}

void qemu_unregister_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)

{

    notifier_remove(notifier);

}

void init_clocks(void)

{

    if (!rt_clock) {

        rt_clock = qemu_new_clock(QEMU_CLOCK_REALTIME);

        vm_clock = qemu_new_clock(QEMU_CLOCK_VIRTUAL);

        host_clock = qemu_new_clock(QEMU_CLOCK_HOST);

    }

}

uint64_t qemu_timer_expire_time_ns(QEMUTimer *ts)

{

    return qemu_timer_pending(ts) ? ts->expire_time : -1;

}

void qemu_run_all_timers(void)

{

    alarm_timer->pending = false;

    /* vm time timers */

    qemu_run_timers(vm_clock);

    qemu_run_timers(rt_clock);

    qemu_run_timers(host_clock);

    /* rearm timer, if not periodic */

    if (alarm_timer->expired) {

        alarm_timer->expired = false;

        qemu_rearm_alarm_timer(alarm_timer);

    }

}

#ifdef _WIN32

static void CALLBACK host_alarm_handler(PVOID lpParam, BOOLEAN unused)

#else

static void host_alarm_handler(int host_signum)

#endif

{

    struct qemu_alarm_timer *t = alarm_timer;

    if (!t)

        return;

    t->expired = true;

    t->pending = true;

    qemu_notify_event();

}

#if defined(__linux__)

#include "qemu/compatfd.h"

static int dynticks_start_timer(struct qemu_alarm_timer *t)

{

    struct sigevent ev;

    timer_t host_timer;

    struct sigaction act;

    sigfillset(&act.sa_mask);

    act.sa_flags = 0;

    act.sa_handler = host_alarm_handler;

    sigaction(SIGALRM, &act, NULL);

    /* 

     * Initialize ev struct to 0 to avoid valgrind complaining

     * about uninitialized data in timer_create call

     */

    memset(&ev, 0, sizeof(ev));

    ev.sigev_value.sival_int = 0;

    ev.sigev_notify = SIGEV_SIGNAL;

#ifdef CONFIG_SIGEV_THREAD_ID

    if (qemu_signalfd_available()) {

        ev.sigev_notify = SIGEV_THREAD_ID;

        ev._sigev_un._tid = qemu_get_thread_id();

    }

#endif /* CONFIG_SIGEV_THREAD_ID */

    ev.sigev_signo = SIGALRM;

    if (timer_create(CLOCK_REALTIME, &ev, &host_timer)) {

        perror("timer_create");

        return -1;

    }

    t->timer = host_timer;

    return 0;

}

static void dynticks_stop_timer(struct qemu_alarm_timer *t)

{

    timer_t host_timer = t->timer;

    timer_delete(host_timer);

}

static void dynticks_rearm_timer(struct qemu_alarm_timer *t,

                                 int64_t nearest_delta_ns)

{

    timer_t host_timer = t->timer;

    struct itimerspec timeout;

    int64_t current_ns;

    if (nearest_delta_ns < MIN_TIMER_REARM_NS)

        nearest_delta_ns = MIN_TIMER_REARM_NS;

    /* check whether a timer is already running */

    if (timer_gettime(host_timer, &timeout)) {

        perror("gettime");

        fprintf(stderr, "Internal timer error: aborting\n");

        exit(1);

    }

    current_ns = timeout.it_value.tv_sec * 1000000000LL + timeout.it_value.tv_nsec;

    if (current_ns && current_ns <= nearest_delta_ns)

        return;

    timeout.it_interval.tv_sec = 0;

    timeout.it_interval.tv_nsec = 0; /* 0 for one-shot timer */

    timeout.it_value.tv_sec =  nearest_delta_ns / 1000000000;

    timeout.it_value.tv_nsec = nearest_delta_ns % 1000000000;

    if (timer_settime(host_timer, 0 /* RELATIVE */, &timeout, NULL)) {

        perror("settime");

        fprintf(stderr, "Internal timer error: aborting\n");

        exit(1);

    }

}

#endif /* defined(__linux__) */

#if !defined(_WIN32)

static int unix_start_timer(struct qemu_alarm_timer *t)

{

    struct sigaction act;

    /* timer signal */

    sigfillset(&act.sa_mask);

    act.sa_flags = 0;

    act.sa_handler = host_alarm_handler;

    sigaction(SIGALRM, &act, NULL);

    return 0;

}

static void unix_rearm_timer(struct qemu_alarm_timer *t,

                             int64_t nearest_delta_ns)

{

    struct itimerval itv;

    int err;

    if (nearest_delta_ns < MIN_TIMER_REARM_NS)

        nearest_delta_ns = MIN_TIMER_REARM_NS;

    itv.it_interval.tv_sec = 0;

    itv.it_interval.tv_usec = 0; /* 0 for one-shot timer */

    itv.it_value.tv_sec =  nearest_delta_ns / 1000000000;

    itv.it_value.tv_usec = (nearest_delta_ns % 1000000000) / 1000;

    err = setitimer(ITIMER_REAL, &itv, NULL);

    if (err) {

        perror("setitimer");

        fprintf(stderr, "Internal timer error: aborting\n");

        exit(1);

    }

}

static void unix_stop_timer(struct qemu_alarm_timer *t)

{

    struct itimerval itv;

    memset(&itv, 0, sizeof(itv));

    setitimer(ITIMER_REAL, &itv, NULL);

}

#endif /* !defined(_WIN32) */

#ifdef _WIN32

static MMRESULT mm_timer;

static TIMECAPS mm_tc;

static void CALLBACK mm_alarm_handler(UINT uTimerID, UINT uMsg,

                                      DWORD_PTR dwUser, DWORD_PTR dw1,

                                      DWORD_PTR dw2)

{

    struct qemu_alarm_timer *t = alarm_timer;

    if (!t) {

        return;

    }

    t->expired = true;

    t->pending = true;

    qemu_notify_event();

}

static int mm_start_timer(struct qemu_alarm_timer *t)

{

    timeGetDevCaps(&mm_tc, sizeof(mm_tc));

    timeBeginPeriod(mm_tc.wPeriodMin);

    mm_timer = timeSetEvent(mm_tc.wPeriodMin,   /* interval (ms) */

                            mm_tc.wPeriodMin,   /* resolution */

                            mm_alarm_handler,   /* function */

                            (DWORD_PTR)t,       /* parameter */

                            TIME_ONESHOT | TIME_CALLBACK_FUNCTION);

    if (!mm_timer) {

        fprintf(stderr, "Failed to initialize win32 alarm timer\n");

        timeEndPeriod(mm_tc.wPeriodMin);

        return -1;

    }

    return 0;

}

static void mm_stop_timer(struct qemu_alarm_timer *t)

{

    timeKillEvent(mm_timer);

    timeEndPeriod(mm_tc.wPeriodMin);

}

static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta)

{

    int64_t nearest_delta_ms = delta / 1000000;

    if (nearest_delta_ms < mm_tc.wPeriodMin) {

        nearest_delta_ms = mm_tc.wPeriodMin;

    } else if (nearest_delta_ms > mm_tc.wPeriodMax) {

        nearest_delta_ms = mm_tc.wPeriodMax;

    }

    timeKillEvent(mm_timer);

    mm_timer = timeSetEvent((UINT)nearest_delta_ms,

                            mm_tc.wPeriodMin,

                            mm_alarm_handler,

                            (DWORD_PTR)t,

                            TIME_ONESHOT | TIME_CALLBACK_FUNCTION);

    if (!mm_timer) {

        fprintf(stderr, "Failed to re-arm win32 alarm timer\n");

        timeEndPeriod(mm_tc.wPeriodMin);

        exit(1);

    }

}

static int win32_start_timer(struct qemu_alarm_timer *t)

{

    HANDLE hTimer;

    BOOLEAN success;

    /* If you call ChangeTimerQueueTimer on a one-shot timer (its period

       is zero) that has already expired, the timer is not updated.  Since

       creating a new timer is relatively expensive, set a bogus one-hour

       interval in the dynticks case.  */

    success = CreateTimerQueueTimer(&hTimer,

                          NULL,

                          host_alarm_handler,

                          t,

                          1,

                          3600000,

                          WT_EXECUTEINTIMERTHREAD);

    if (!success) {

        fprintf(stderr, "Failed to initialize win32 alarm timer: %ld\n",

                GetLastError());

        return -1;

    }

    t->timer = hTimer;

    return 0;

}

static void win32_stop_timer(struct qemu_alarm_timer *t)

{

    HANDLE hTimer = t->timer;

    if (hTimer) {

        DeleteTimerQueueTimer(NULL, hTimer, NULL);

    }

}

static void win32_rearm_timer(struct qemu_alarm_timer *t,

                              int64_t nearest_delta_ns)

{

    HANDLE hTimer = t->timer;

    int64_t nearest_delta_ms;

    BOOLEAN success;

    nearest_delta_ms = nearest_delta_ns / 1000000;

    if (nearest_delta_ms < 1) {

        nearest_delta_ms = 1;

    }

    /* ULONG_MAX can be 32 bit */

    if (nearest_delta_ms > ULONG_MAX) {

        nearest_delta_ms = ULONG_MAX;

    }

    success = ChangeTimerQueueTimer(NULL,

                                    hTimer,

                                    (unsigned long) nearest_delta_ms,

                                    3600000);

    if (!success) {

        fprintf(stderr, "Failed to rearm win32 alarm timer: %ld\n",

                GetLastError());

        exit(-1);

    }

}

#endif /* _WIN32 */

static void quit_timers(void)

{

    struct qemu_alarm_timer *t = alarm_timer;

    alarm_timer = NULL;

    t->stop(t);

}

#ifdef CONFIG_POSIX

static void reinit_timers(void)

{

    struct qemu_alarm_timer *t = alarm_timer;

    t->stop(t);

    if (t->start(t)) {

        fprintf(stderr, "Internal timer error: aborting\n");

        exit(1);

    }

    qemu_rearm_alarm_timer(t);

}

#endif /* CONFIG_POSIX */

int init_timer_alarm(void)

{

    struct qemu_alarm_timer *t = NULL;

    int i, err = -1;

    if (alarm_timer) {

        return 0;

    }

    for (i = 0; alarm_timers[i].name; i++) {

        t = &alarm_timers[i];

        err = t->start(t);

        if (!err)

            break;

    }

    if (err) {

        err = -ENOENT;

        goto fail;

    }

    atexit(quit_timers);

#ifdef CONFIG_POSIX

    pthread_atfork(NULL, NULL, reinit_timers);

#endif

    alarm_timer = t;

    return 0;

fail:

    return err;

}