Merge remote-tracking branch 'remotes/sstabellini/xen-2014-11-14' into staging
[qemu.git] / qemu-timer.c
1 /*
2 * QEMU System Emulator
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "sysemu/sysemu.h"
26 #include "monitor/monitor.h"
27 #include "ui/console.h"
28
29 #include "hw/hw.h"
30
31 #include "qemu/timer.h"
32 #ifdef CONFIG_POSIX
33 #include <pthread.h>
34 #endif
35
36 #ifdef CONFIG_PPOLL
37 #include <poll.h>
38 #endif
39
40 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
41 #include <sys/prctl.h>
42 #endif
43
44 /***********************************************************/
45 /* timers */
46
47 typedef struct QEMUClock {
48 /* We rely on BQL to protect the timerlists */
49 QLIST_HEAD(, QEMUTimerList) timerlists;
50
51 NotifierList reset_notifiers;
52 int64_t last;
53
54 QEMUClockType type;
55 bool enabled;
56 } QEMUClock;
57
58 QEMUTimerListGroup main_loop_tlg;
59 static QEMUClock qemu_clocks[QEMU_CLOCK_MAX];
60
61 /* A QEMUTimerList is a list of timers attached to a clock. More
62 * than one QEMUTimerList can be attached to each clock, for instance
63 * used by different AioContexts / threads. Each clock also has
64 * a list of the QEMUTimerLists associated with it, in order that
65 * reenabling the clock can call all the notifiers.
66 */
67
68 struct QEMUTimerList {
69 QEMUClock *clock;
70 QemuMutex active_timers_lock;
71 QEMUTimer *active_timers;
72 QLIST_ENTRY(QEMUTimerList) list;
73 QEMUTimerListNotifyCB *notify_cb;
74 void *notify_opaque;
75
76 /* lightweight method to mark the end of timerlist's running */
77 QemuEvent timers_done_ev;
78 };
79
80 /**
81 * qemu_clock_ptr:
82 * @type: type of clock
83 *
84 * Translate a clock type into a pointer to QEMUClock object.
85 *
86 * Returns: a pointer to the QEMUClock object
87 */
88 static inline QEMUClock *qemu_clock_ptr(QEMUClockType type)
89 {
90 return &qemu_clocks[type];
91 }
92
93 static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
94 {
95 return timer_head && (timer_head->expire_time <= current_time);
96 }
97
98 QEMUTimerList *timerlist_new(QEMUClockType type,
99 QEMUTimerListNotifyCB *cb,
100 void *opaque)
101 {
102 QEMUTimerList *timer_list;
103 QEMUClock *clock = qemu_clock_ptr(type);
104
105 timer_list = g_malloc0(sizeof(QEMUTimerList));
106 qemu_event_init(&timer_list->timers_done_ev, false);
107 timer_list->clock = clock;
108 timer_list->notify_cb = cb;
109 timer_list->notify_opaque = opaque;
110 qemu_mutex_init(&timer_list->active_timers_lock);
111 QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
112 return timer_list;
113 }
114
115 void timerlist_free(QEMUTimerList *timer_list)
116 {
117 assert(!timerlist_has_timers(timer_list));
118 if (timer_list->clock) {
119 QLIST_REMOVE(timer_list, list);
120 }
121 qemu_mutex_destroy(&timer_list->active_timers_lock);
122 g_free(timer_list);
123 }
124
125 static void qemu_clock_init(QEMUClockType type)
126 {
127 QEMUClock *clock = qemu_clock_ptr(type);
128
129 /* Assert that the clock of type TYPE has not been initialized yet. */
130 assert(main_loop_tlg.tl[type] == NULL);
131
132 clock->type = type;
133 clock->enabled = true;
134 clock->last = INT64_MIN;
135 QLIST_INIT(&clock->timerlists);
136 notifier_list_init(&clock->reset_notifiers);
137 main_loop_tlg.tl[type] = timerlist_new(type, NULL, NULL);
138 }
139
140 bool qemu_clock_use_for_deadline(QEMUClockType type)
141 {
142 return !(use_icount && (type == QEMU_CLOCK_VIRTUAL));
143 }
144
145 void qemu_clock_notify(QEMUClockType type)
146 {
147 QEMUTimerList *timer_list;
148 QEMUClock *clock = qemu_clock_ptr(type);
149 QLIST_FOREACH(timer_list, &clock->timerlists, list) {
150 timerlist_notify(timer_list);
151 }
152 }
153
154 /* Disabling the clock will wait for related timerlists to stop
155 * executing qemu_run_timers. Thus, this functions should not
156 * be used from the callback of a timer that is based on @clock.
157 * Doing so would cause a deadlock.
158 *
159 * Caller should hold BQL.
160 */
161 void qemu_clock_enable(QEMUClockType type, bool enabled)
162 {
163 QEMUClock *clock = qemu_clock_ptr(type);
164 QEMUTimerList *tl;
165 bool old = clock->enabled;
166 clock->enabled = enabled;
167 if (enabled && !old) {
168 qemu_clock_notify(type);
169 } else if (!enabled && old) {
170 QLIST_FOREACH(tl, &clock->timerlists, list) {
171 qemu_event_wait(&tl->timers_done_ev);
172 }
173 }
174 }
175
176 bool timerlist_has_timers(QEMUTimerList *timer_list)
177 {
178 return !!timer_list->active_timers;
179 }
180
181 bool qemu_clock_has_timers(QEMUClockType type)
182 {
183 return timerlist_has_timers(
184 main_loop_tlg.tl[type]);
185 }
186
187 bool timerlist_expired(QEMUTimerList *timer_list)
188 {
189 int64_t expire_time;
190
191 qemu_mutex_lock(&timer_list->active_timers_lock);
192 if (!timer_list->active_timers) {
193 qemu_mutex_unlock(&timer_list->active_timers_lock);
194 return false;
195 }
196 expire_time = timer_list->active_timers->expire_time;
197 qemu_mutex_unlock(&timer_list->active_timers_lock);
198
199 return expire_time < qemu_clock_get_ns(timer_list->clock->type);
200 }
201
202 bool qemu_clock_expired(QEMUClockType type)
203 {
204 return timerlist_expired(
205 main_loop_tlg.tl[type]);
206 }
207
208 /*
209 * As above, but return -1 for no deadline, and do not cap to 2^32
210 * as we know the result is always positive.
211 */
212
213 int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
214 {
215 int64_t delta;
216 int64_t expire_time;
217
218 if (!timer_list->clock->enabled) {
219 return -1;
220 }
221
222 /* The active timers list may be modified before the caller uses our return
223 * value but ->notify_cb() is called when the deadline changes. Therefore
224 * the caller should notice the change and there is no race condition.
225 */
226 qemu_mutex_lock(&timer_list->active_timers_lock);
227 if (!timer_list->active_timers) {
228 qemu_mutex_unlock(&timer_list->active_timers_lock);
229 return -1;
230 }
231 expire_time = timer_list->active_timers->expire_time;
232 qemu_mutex_unlock(&timer_list->active_timers_lock);
233
234 delta = expire_time - qemu_clock_get_ns(timer_list->clock->type);
235
236 if (delta <= 0) {
237 return 0;
238 }
239
240 return delta;
241 }
242
243 /* Calculate the soonest deadline across all timerlists attached
244 * to the clock. This is used for the icount timeout so we
245 * ignore whether or not the clock should be used in deadline
246 * calculations.
247 */
248 int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
249 {
250 int64_t deadline = -1;
251 QEMUTimerList *timer_list;
252 QEMUClock *clock = qemu_clock_ptr(type);
253 QLIST_FOREACH(timer_list, &clock->timerlists, list) {
254 deadline = qemu_soonest_timeout(deadline,
255 timerlist_deadline_ns(timer_list));
256 }
257 return deadline;
258 }
259
260 QEMUClockType timerlist_get_clock(QEMUTimerList *timer_list)
261 {
262 return timer_list->clock->type;
263 }
264
265 QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClockType type)
266 {
267 return main_loop_tlg.tl[type];
268 }
269
270 void timerlist_notify(QEMUTimerList *timer_list)
271 {
272 if (timer_list->notify_cb) {
273 timer_list->notify_cb(timer_list->notify_opaque);
274 } else {
275 qemu_notify_event();
276 }
277 }
278
279 /* Transition function to convert a nanosecond timeout to ms
280 * This is used where a system does not support ppoll
281 */
282 int qemu_timeout_ns_to_ms(int64_t ns)
283 {
284 int64_t ms;
285 if (ns < 0) {
286 return -1;
287 }
288
289 if (!ns) {
290 return 0;
291 }
292
293 /* Always round up, because it's better to wait too long than to wait too
294 * little and effectively busy-wait
295 */
296 ms = (ns + SCALE_MS - 1) / SCALE_MS;
297
298 /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
299 if (ms > (int64_t) INT32_MAX) {
300 ms = INT32_MAX;
301 }
302
303 return (int) ms;
304 }
305
306
307 /* qemu implementation of g_poll which uses a nanosecond timeout but is
308 * otherwise identical to g_poll
309 */
310 int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
311 {
312 #ifdef CONFIG_PPOLL
313 if (timeout < 0) {
314 return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
315 } else {
316 struct timespec ts;
317 ts.tv_sec = timeout / 1000000000LL;
318 ts.tv_nsec = timeout % 1000000000LL;
319 return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
320 }
321 #else
322 return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
323 #endif
324 }
325
326
327 void timer_init(QEMUTimer *ts,
328 QEMUTimerList *timer_list, int scale,
329 QEMUTimerCB *cb, void *opaque)
330 {
331 ts->timer_list = timer_list;
332 ts->cb = cb;
333 ts->opaque = opaque;
334 ts->scale = scale;
335 ts->expire_time = -1;
336 }
337
338 void timer_free(QEMUTimer *ts)
339 {
340 g_free(ts);
341 }
342
343 static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts)
344 {
345 QEMUTimer **pt, *t;
346
347 ts->expire_time = -1;
348 pt = &timer_list->active_timers;
349 for(;;) {
350 t = *pt;
351 if (!t)
352 break;
353 if (t == ts) {
354 *pt = t->next;
355 break;
356 }
357 pt = &t->next;
358 }
359 }
360
361 static bool timer_mod_ns_locked(QEMUTimerList *timer_list,
362 QEMUTimer *ts, int64_t expire_time)
363 {
364 QEMUTimer **pt, *t;
365
366 /* add the timer in the sorted list */
367 pt = &timer_list->active_timers;
368 for (;;) {
369 t = *pt;
370 if (!timer_expired_ns(t, expire_time)) {
371 break;
372 }
373 pt = &t->next;
374 }
375 ts->expire_time = MAX(expire_time, 0);
376 ts->next = *pt;
377 *pt = ts;
378
379 return pt == &timer_list->active_timers;
380 }
381
382 static void timerlist_rearm(QEMUTimerList *timer_list)
383 {
384 /* Interrupt execution to force deadline recalculation. */
385 qemu_clock_warp(timer_list->clock->type);
386 timerlist_notify(timer_list);
387 }
388
389 /* stop a timer, but do not dealloc it */
390 void timer_del(QEMUTimer *ts)
391 {
392 QEMUTimerList *timer_list = ts->timer_list;
393
394 qemu_mutex_lock(&timer_list->active_timers_lock);
395 timer_del_locked(timer_list, ts);
396 qemu_mutex_unlock(&timer_list->active_timers_lock);
397 }
398
399 /* modify the current timer so that it will be fired when current_time
400 >= expire_time. The corresponding callback will be called. */
401 void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
402 {
403 QEMUTimerList *timer_list = ts->timer_list;
404 bool rearm;
405
406 qemu_mutex_lock(&timer_list->active_timers_lock);
407 timer_del_locked(timer_list, ts);
408 rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
409 qemu_mutex_unlock(&timer_list->active_timers_lock);
410
411 if (rearm) {
412 timerlist_rearm(timer_list);
413 }
414 }
415
416 /* modify the current timer so that it will be fired when current_time
417 >= expire_time or the current deadline, whichever comes earlier.
418 The corresponding callback will be called. */
419 void timer_mod_anticipate_ns(QEMUTimer *ts, int64_t expire_time)
420 {
421 QEMUTimerList *timer_list = ts->timer_list;
422 bool rearm;
423
424 qemu_mutex_lock(&timer_list->active_timers_lock);
425 if (ts->expire_time == -1 || ts->expire_time > expire_time) {
426 if (ts->expire_time != -1) {
427 timer_del_locked(timer_list, ts);
428 }
429 rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
430 } else {
431 rearm = false;
432 }
433 qemu_mutex_unlock(&timer_list->active_timers_lock);
434
435 if (rearm) {
436 timerlist_rearm(timer_list);
437 }
438 }
439
440 void timer_mod(QEMUTimer *ts, int64_t expire_time)
441 {
442 timer_mod_ns(ts, expire_time * ts->scale);
443 }
444
445 void timer_mod_anticipate(QEMUTimer *ts, int64_t expire_time)
446 {
447 timer_mod_anticipate_ns(ts, expire_time * ts->scale);
448 }
449
450 bool timer_pending(QEMUTimer *ts)
451 {
452 return ts->expire_time >= 0;
453 }
454
455 bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
456 {
457 return timer_expired_ns(timer_head, current_time * timer_head->scale);
458 }
459
460 bool timerlist_run_timers(QEMUTimerList *timer_list)
461 {
462 QEMUTimer *ts;
463 int64_t current_time;
464 bool progress = false;
465 QEMUTimerCB *cb;
466 void *opaque;
467
468 qemu_event_reset(&timer_list->timers_done_ev);
469 if (!timer_list->clock->enabled) {
470 goto out;
471 }
472
473 current_time = qemu_clock_get_ns(timer_list->clock->type);
474 for(;;) {
475 qemu_mutex_lock(&timer_list->active_timers_lock);
476 ts = timer_list->active_timers;
477 if (!timer_expired_ns(ts, current_time)) {
478 qemu_mutex_unlock(&timer_list->active_timers_lock);
479 break;
480 }
481
482 /* remove timer from the list before calling the callback */
483 timer_list->active_timers = ts->next;
484 ts->next = NULL;
485 ts->expire_time = -1;
486 cb = ts->cb;
487 opaque = ts->opaque;
488 qemu_mutex_unlock(&timer_list->active_timers_lock);
489
490 /* run the callback (the timer list can be modified) */
491 cb(opaque);
492 progress = true;
493 }
494
495 out:
496 qemu_event_set(&timer_list->timers_done_ev);
497 return progress;
498 }
499
500 bool qemu_clock_run_timers(QEMUClockType type)
501 {
502 return timerlist_run_timers(main_loop_tlg.tl[type]);
503 }
504
505 void timerlistgroup_init(QEMUTimerListGroup *tlg,
506 QEMUTimerListNotifyCB *cb, void *opaque)
507 {
508 QEMUClockType type;
509 for (type = 0; type < QEMU_CLOCK_MAX; type++) {
510 tlg->tl[type] = timerlist_new(type, cb, opaque);
511 }
512 }
513
514 void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
515 {
516 QEMUClockType type;
517 for (type = 0; type < QEMU_CLOCK_MAX; type++) {
518 timerlist_free(tlg->tl[type]);
519 }
520 }
521
522 bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
523 {
524 QEMUClockType type;
525 bool progress = false;
526 for (type = 0; type < QEMU_CLOCK_MAX; type++) {
527 progress |= timerlist_run_timers(tlg->tl[type]);
528 }
529 return progress;
530 }
531
532 int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
533 {
534 int64_t deadline = -1;
535 QEMUClockType type;
536 for (type = 0; type < QEMU_CLOCK_MAX; type++) {
537 if (qemu_clock_use_for_deadline(tlg->tl[type]->clock->type)) {
538 deadline = qemu_soonest_timeout(deadline,
539 timerlist_deadline_ns(
540 tlg->tl[type]));
541 }
542 }
543 return deadline;
544 }
545
546 int64_t qemu_clock_get_ns(QEMUClockType type)
547 {
548 int64_t now, last;
549 QEMUClock *clock = qemu_clock_ptr(type);
550
551 switch (type) {
552 case QEMU_CLOCK_REALTIME:
553 return get_clock();
554 default:
555 case QEMU_CLOCK_VIRTUAL:
556 if (use_icount) {
557 return cpu_get_icount();
558 } else {
559 return cpu_get_clock();
560 }
561 case QEMU_CLOCK_HOST:
562 now = get_clock_realtime();
563 last = clock->last;
564 clock->last = now;
565 if (now < last) {
566 notifier_list_notify(&clock->reset_notifiers, &now);
567 }
568 return now;
569 }
570 }
571
572 void qemu_clock_register_reset_notifier(QEMUClockType type,
573 Notifier *notifier)
574 {
575 QEMUClock *clock = qemu_clock_ptr(type);
576 notifier_list_add(&clock->reset_notifiers, notifier);
577 }
578
579 void qemu_clock_unregister_reset_notifier(QEMUClockType type,
580 Notifier *notifier)
581 {
582 notifier_remove(notifier);
583 }
584
585 void init_clocks(void)
586 {
587 QEMUClockType type;
588 for (type = 0; type < QEMU_CLOCK_MAX; type++) {
589 qemu_clock_init(type);
590 }
591
592 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
593 prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
594 #endif
595 }
596
597 uint64_t timer_expire_time_ns(QEMUTimer *ts)
598 {
599 return timer_pending(ts) ? ts->expire_time : -1;
600 }
601
602 bool qemu_clock_run_all_timers(void)
603 {
604 bool progress = false;
605 QEMUClockType type;
606
607 for (type = 0; type < QEMU_CLOCK_MAX; type++) {
608 progress |= qemu_clock_run_timers(type);
609 }
610
611 return progress;
612 }