aboutsummaryrefslogtreecommitdiff
path: root/qemu-timer.c
blob: eb22e9218bc06f885b922acf543056358663e281 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
/*
 * 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 "qemu/osdep.h"
#include "qemu/main-loop.h"
#include "qemu/timer.h"
#include "sysemu/replay.h"
#include "sysemu/sysemu.h"

#ifdef CONFIG_POSIX
#include <pthread.h>
#endif

#ifdef CONFIG_PPOLL
#include <poll.h>
#endif

#ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
#include <sys/prctl.h>
#endif

/***********************************************************/
/* timers */

typedef struct QEMUClock {
    /* We rely on BQL to protect the timerlists */
    QLIST_HEAD(, QEMUTimerList) timerlists;

    NotifierList reset_notifiers;
    int64_t last;

    QEMUClockType type;
    bool enabled;
} QEMUClock;

QEMUTimerListGroup main_loop_tlg;
static QEMUClock qemu_clocks[QEMU_CLOCK_MAX];

/* A QEMUTimerList is a list of timers attached to a clock. More
 * than one QEMUTimerList can be attached to each clock, for instance
 * used by different AioContexts / threads. Each clock also has
 * a list of the QEMUTimerLists associated with it, in order that
 * reenabling the clock can call all the notifiers.
 */

struct QEMUTimerList {
    QEMUClock *clock;
    QemuMutex active_timers_lock;
    QEMUTimer *active_timers;
    QLIST_ENTRY(QEMUTimerList) list;
    QEMUTimerListNotifyCB *notify_cb;
    void *notify_opaque;

    /* lightweight method to mark the end of timerlist's running */
    QemuEvent timers_done_ev;
};

/**
 * qemu_clock_ptr:
 * @type: type of clock
 *
 * Translate a clock type into a pointer to QEMUClock object.
 *
 * Returns: a pointer to the QEMUClock object
 */
static inline QEMUClock *qemu_clock_ptr(QEMUClockType type)
{
    return &qemu_clocks[type];
}

static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
{
    return timer_head && (timer_head->expire_time <= current_time);
}

QEMUTimerList *timerlist_new(QEMUClockType type,
                             QEMUTimerListNotifyCB *cb,
                             void *opaque)
{
    QEMUTimerList *timer_list;
    QEMUClock *clock = qemu_clock_ptr(type);

    timer_list = g_malloc0(sizeof(QEMUTimerList));
    qemu_event_init(&timer_list->timers_done_ev, true);
    timer_list->clock = clock;
    timer_list->notify_cb = cb;
    timer_list->notify_opaque = opaque;
    qemu_mutex_init(&timer_list->active_timers_lock);
    QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
    return timer_list;
}

void timerlist_free(QEMUTimerList *timer_list)
{
    assert(!timerlist_has_timers(timer_list));
    if (timer_list->clock) {
        QLIST_REMOVE(timer_list, list);
    }
    qemu_mutex_destroy(&timer_list->active_timers_lock);
    g_free(timer_list);
}

static void qemu_clock_init(QEMUClockType type)
{
    QEMUClock *clock = qemu_clock_ptr(type);

    /* Assert that the clock of type TYPE has not been initialized yet. */
    assert(main_loop_tlg.tl[type] == NULL);

    clock->type = type;
    clock->enabled = true;
    clock->last = INT64_MIN;
    QLIST_INIT(&clock->timerlists);
    notifier_list_init(&clock->reset_notifiers);
    main_loop_tlg.tl[type] = timerlist_new(type, NULL, NULL);
}

bool qemu_clock_use_for_deadline(QEMUClockType type)
{
    return !(use_icount && (type == QEMU_CLOCK_VIRTUAL));
}

void qemu_clock_notify(QEMUClockType type)
{
    QEMUTimerList *timer_list;
    QEMUClock *clock = qemu_clock_ptr(type);
    QLIST_FOREACH(timer_list, &clock->timerlists, list) {
        timerlist_notify(timer_list);
    }
}

/* Disabling the clock will wait for related timerlists to stop
 * executing qemu_run_timers.  Thus, this functions should not
 * be used from the callback of a timer that is based on @clock.
 * Doing so would cause a deadlock.
 *
 * Caller should hold BQL.
 */
void qemu_clock_enable(QEMUClockType type, bool enabled)
{
    QEMUClock *clock = qemu_clock_ptr(type);
    QEMUTimerList *tl;
    bool old = clock->enabled;
    clock->enabled = enabled;
    if (enabled && !old) {
        qemu_clock_notify(type);
    } else if (!enabled && old) {
        QLIST_FOREACH(tl, &clock->timerlists, list) {
            qemu_event_wait(&tl->timers_done_ev);
        }
    }
}

bool timerlist_has_timers(QEMUTimerList *timer_list)
{
    return !!timer_list->active_timers;
}

bool qemu_clock_has_timers(QEMUClockType type)
{
    return timerlist_has_timers(
        main_loop_tlg.tl[type]);
}

bool timerlist_expired(QEMUTimerList *timer_list)
{
    int64_t expire_time;

    qemu_mutex_lock(&timer_list->active_timers_lock);
    if (!timer_list->active_timers) {
        qemu_mutex_unlock(&timer_list->active_timers_lock);
        return false;
    }
    expire_time = timer_list->active_timers->expire_time;
    qemu_mutex_unlock(&timer_list->active_timers_lock);

    return expire_time < qemu_clock_get_ns(timer_list->clock->type);
}

bool qemu_clock_expired(QEMUClockType type)
{
    return timerlist_expired(
        main_loop_tlg.tl[type]);
}

/*
 * As above, but return -1 for no deadline, and do not cap to 2^32
 * as we know the result is always positive.
 */

int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
{
    int64_t delta;
    int64_t expire_time;

    if (!timer_list->clock->enabled) {
        return -1;
    }

    /* The active timers list may be modified before the caller uses our return
     * value but ->notify_cb() is called when the deadline changes.  Therefore
     * the caller should notice the change and there is no race condition.
     */
    qemu_mutex_lock(&timer_list->active_timers_lock);
    if (!timer_list->active_timers) {
        qemu_mutex_unlock(&timer_list->active_timers_lock);
        return -1;
    }
    expire_time = timer_list->active_timers->expire_time;
    qemu_mutex_unlock(&timer_list->active_timers_lock);

    delta = expire_time - qemu_clock_get_ns(timer_list->clock->type);

    if (delta <= 0) {
        return 0;
    }

    return delta;
}

/* Calculate the soonest deadline across all timerlists attached
 * to the clock. This is used for the icount timeout so we
 * ignore whether or not the clock should be used in deadline
 * calculations.
 */
int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
{
    int64_t deadline = -1;
    QEMUTimerList *timer_list;
    QEMUClock *clock = qemu_clock_ptr(type);
    QLIST_FOREACH(timer_list, &clock->timerlists, list) {
        deadline = qemu_soonest_timeout(deadline,
                                        timerlist_deadline_ns(timer_list));
    }
    return deadline;
}

QEMUClockType timerlist_get_clock(QEMUTimerList *timer_list)
{
    return timer_list->clock->type;
}

QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClockType type)
{
    return main_loop_tlg.tl[type];
}

void timerlist_notify(QEMUTimerList *timer_list)
{
    if (timer_list->notify_cb) {
        timer_list->notify_cb(timer_list->notify_opaque);
    } else {
        qemu_notify_event();
    }
}

/* Transition function to convert a nanosecond timeout to ms
 * This is used where a system does not support ppoll
 */
int qemu_timeout_ns_to_ms(int64_t ns)
{
    int64_t ms;
    if (ns < 0) {
        return -1;
    }

    if (!ns) {
        return 0;
    }

    /* Always round up, because it's better to wait too long than to wait too
     * little and effectively busy-wait
     */
    ms = DIV_ROUND_UP(ns, SCALE_MS);

    /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
    if (ms > (int64_t) INT32_MAX) {
        ms = INT32_MAX;
    }

    return (int) ms;
}


/* qemu implementation of g_poll which uses a nanosecond timeout but is
 * otherwise identical to g_poll
 */
int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
{
#ifdef CONFIG_PPOLL
    if (timeout < 0) {
        return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
    } else {
        struct timespec ts;
        int64_t tvsec = timeout / 1000000000LL;
        /* Avoid possibly overflowing and specifying a negative number of
         * seconds, which would turn a very long timeout into a busy-wait.
         */
        if (tvsec > (int64_t)INT32_MAX) {
            tvsec = INT32_MAX;
        }
        ts.tv_sec = tvsec;
        ts.tv_nsec = timeout % 1000000000LL;
        return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
    }
#else
    return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
#endif
}


void timer_init_tl(QEMUTimer *ts,
                   QEMUTimerList *timer_list, int scale,
                   QEMUTimerCB *cb, void *opaque)
{
    ts->timer_list = timer_list;
    ts->cb = cb;
    ts->opaque = opaque;
    ts->scale = scale;
    ts->expire_time = -1;
}

void timer_deinit(QEMUTimer *ts)
{
    assert(ts->expire_time == -1);
    ts->timer_list = NULL;
}

void timer_free(QEMUTimer *ts)
{
    g_free(ts);
}

static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts)
{
    QEMUTimer **pt, *t;

    ts->expire_time = -1;
    pt = &timer_list->active_timers;
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t == ts) {
            *pt = t->next;
            break;
        }
        pt = &t->next;
    }
}

static bool timer_mod_ns_locked(QEMUTimerList *timer_list,
                                QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimer **pt, *t;

    /* add the timer in the sorted list */
    pt = &timer_list->active_timers;
    for (;;) {
        t = *pt;
        if (!timer_expired_ns(t, expire_time)) {
            break;
        }
        pt = &t->next;
    }
    ts->expire_time = MAX(expire_time, 0);
    ts->next = *pt;
    *pt = ts;

    return pt == &timer_list->active_timers;
}

static void timerlist_rearm(QEMUTimerList *timer_list)
{
    /* Interrupt execution to force deadline recalculation.  */
    if (timer_list->clock->type == QEMU_CLOCK_VIRTUAL) {
        qemu_start_warp_timer();
    }
    timerlist_notify(timer_list);
}

/* stop a timer, but do not dealloc it */
void timer_del(QEMUTimer *ts)
{
    QEMUTimerList *timer_list = ts->timer_list;

    if (timer_list) {
        qemu_mutex_lock(&timer_list->active_timers_lock);
        timer_del_locked(timer_list, ts);
        qemu_mutex_unlock(&timer_list->active_timers_lock);
    }
}

/* modify the current timer so that it will be fired when current_time
   >= expire_time. The corresponding callback will be called. */
void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimerList *timer_list = ts->timer_list;
    bool rearm;

    qemu_mutex_lock(&timer_list->active_timers_lock);
    timer_del_locked(timer_list, ts);
    rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
    qemu_mutex_unlock(&timer_list->active_timers_lock);

    if (rearm) {
        timerlist_rearm(timer_list);
    }
}

/* modify the current timer so that it will be fired when current_time
   >= expire_time or the current deadline, whichever comes earlier.
   The corresponding callback will be called. */
void timer_mod_anticipate_ns(QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimerList *timer_list = ts->timer_list;
    bool rearm;

    qemu_mutex_lock(&timer_list->active_timers_lock);
    if (ts->expire_time == -1 || ts->expire_time > expire_time) {
        if (ts->expire_time != -1) {
            timer_del_locked(timer_list, ts);
        }
        rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
    } else {
        rearm = false;
    }
    qemu_mutex_unlock(&timer_list->active_timers_lock);

    if (rearm) {
        timerlist_rearm(timer_list);
    }
}

void timer_mod(QEMUTimer *ts, int64_t expire_time)
{
    timer_mod_ns(ts, expire_time * ts->scale);
}

void timer_mod_anticipate(QEMUTimer *ts, int64_t expire_time)
{
    timer_mod_anticipate_ns(ts, expire_time * ts->scale);
}

bool timer_pending(QEMUTimer *ts)
{
    return ts->expire_time >= 0;
}

bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
{
    return timer_expired_ns(timer_head, current_time * timer_head->scale);
}

bool timerlist_run_timers(QEMUTimerList *timer_list)
{
    QEMUTimer *ts;
    int64_t current_time;
    bool progress = false;
    QEMUTimerCB *cb;
    void *opaque;

    qemu_event_reset(&timer_list->timers_done_ev);
    if (!timer_list->clock->enabled || !timer_list->active_timers) {
        goto out;
    }

    switch (timer_list->clock->type) {
    case QEMU_CLOCK_REALTIME:
        break;
    default:
    case QEMU_CLOCK_VIRTUAL:
        if (!replay_checkpoint(CHECKPOINT_CLOCK_VIRTUAL)) {
            goto out;
        }
        break;
    case QEMU_CLOCK_HOST:
        if (!replay_checkpoint(CHECKPOINT_CLOCK_HOST)) {
            goto out;
        }
        break;
    case QEMU_CLOCK_VIRTUAL_RT:
        if (!replay_checkpoint(CHECKPOINT_CLOCK_VIRTUAL_RT)) {
            goto out;
        }
        break;
    }

    current_time = qemu_clock_get_ns(timer_list->clock->type);
    for(;;) {
        qemu_mutex_lock(&timer_list->active_timers_lock);
        ts = timer_list->active_timers;
        if (!timer_expired_ns(ts, current_time)) {
            qemu_mutex_unlock(&timer_list->active_timers_lock);
            break;
        }

        /* remove timer from the list before calling the callback */
        timer_list->active_timers = ts->next;
        ts->next = NULL;
        ts->expire_time = -1;
        cb = ts->cb;
        opaque = ts->opaque;
        qemu_mutex_unlock(&timer_list->active_timers_lock);

        /* run the callback (the timer list can be modified) */
        cb(opaque);
        progress = true;
    }

out:
    qemu_event_set(&timer_list->timers_done_ev);
    return progress;
}

bool qemu_clock_run_timers(QEMUClockType type)
{
    return timerlist_run_timers(main_loop_tlg.tl[type]);
}

void timerlistgroup_init(QEMUTimerListGroup *tlg,
                         QEMUTimerListNotifyCB *cb, void *opaque)
{
    QEMUClockType type;
    for (type = 0; type < QEMU_CLOCK_MAX; type++) {
        tlg->tl[type] = timerlist_new(type, cb, opaque);
    }
}

void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
{
    QEMUClockType type;
    for (type = 0; type < QEMU_CLOCK_MAX; type++) {
        timerlist_free(tlg->tl[type]);
    }
}

bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
{
    QEMUClockType type;
    bool progress = false;
    for (type = 0; type < QEMU_CLOCK_MAX; type++) {
        progress |= timerlist_run_timers(tlg->tl[type]);
    }
    return progress;
}

int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
{
    int64_t deadline = -1;
    QEMUClockType type;
    bool play = replay_mode == REPLAY_MODE_PLAY;
    for (type = 0; type < QEMU_CLOCK_MAX; type++) {
        if (qemu_clock_use_for_deadline(type)) {
            if (!play || type == QEMU_CLOCK_REALTIME) {
                deadline = qemu_soonest_timeout(deadline,
                                                timerlist_deadline_ns(tlg->tl[type]));
            } else {
                /* Read clock from the replay file and
                   do not calculate the deadline, based on virtual clock. */
                qemu_clock_get_ns(type);
            }
        }
    }
    return deadline;
}

int64_t qemu_clock_get_ns(QEMUClockType type)
{
    int64_t now, last;
    QEMUClock *clock = qemu_clock_ptr(type);

    switch (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 = REPLAY_CLOCK(REPLAY_CLOCK_HOST, get_clock_realtime());
        last = clock->last;
        clock->last = now;
        if (now < last || now > (last + get_max_clock_jump())) {
            notifier_list_notify(&clock->reset_notifiers, &now);
        }
        return now;
    case QEMU_CLOCK_VIRTUAL_RT:
        return REPLAY_CLOCK(REPLAY_CLOCK_VIRTUAL_RT, cpu_get_clock());
    }
}

void qemu_clock_register_reset_notifier(QEMUClockType type,
                                        Notifier *notifier)
{
    QEMUClock *clock = qemu_clock_ptr(type);
    notifier_list_add(&clock->reset_notifiers, notifier);
}

void qemu_clock_unregister_reset_notifier(QEMUClockType type,
                                          Notifier *notifier)
{
    notifier_remove(notifier);
}

void init_clocks(void)
{
    QEMUClockType type;
    for (type = 0; type < QEMU_CLOCK_MAX; type++) {
        qemu_clock_init(type);
    }

#ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
    prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
#endif
}

uint64_t timer_expire_time_ns(QEMUTimer *ts)
{
    return timer_pending(ts) ? ts->expire_time : -1;
}

bool qemu_clock_run_all_timers(void)
{
    bool progress = false;
    QEMUClockType type;

    for (type = 0; type < QEMU_CLOCK_MAX; type++) {
        progress |= qemu_clock_run_timers(type);
    }

    return progress;
}