util/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 "qemu/osdep.h"
  26 #include "qemu/main-loop.h"
  27 #include "qemu/timer.h"
  28 #include "sysemu/replay.h"
  29 #include "sysemu/sysemu.h"
  30 #include "sysemu/cpus.h"
  31
  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, true);
 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, QEMUTimerListNotifyCB *notify_cb)
 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 = (type == QEMU_CLOCK_VIRTUAL ? false : 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, notify_cb, 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 !!atomic_read(&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     if (!atomic_read(&timer_list->active_timers)) {
 192         return false;
 193     }
 194
 195     qemu_mutex_lock(&timer_list->active_timers_lock);
 196     if (!timer_list->active_timers) {
 197         qemu_mutex_unlock(&timer_list->active_timers_lock);
 198         return false;
 199     }
 200     expire_time = timer_list->active_timers->expire_time;
 201     qemu_mutex_unlock(&timer_list->active_timers_lock);
 202
 203     return expire_time <= qemu_clock_get_ns(timer_list->clock->type);
 204 }
 205
 206 bool qemu_clock_expired(QEMUClockType type)
 207 {
 208     return timerlist_expired(
 209         main_loop_tlg.tl[type]);
 210 }
 211
 212 /*
 213  * As above, but return -1 for no deadline, and do not cap to 2^32
 214  * as we know the result is always positive.
 215  */
 216
 217 int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
 218 {
 219     int64_t delta;
 220     int64_t expire_time;
 221
 222     if (!atomic_read(&timer_list->active_timers)) {
 223         return -1;
 224     }
 225
 226     if (!timer_list->clock->enabled) {
 227         return -1;
 228     }
 229
 230     /* The active timers list may be modified before the caller uses our return
 231      * value but ->notify_cb() is called when the deadline changes.  Therefore
 232      * the caller should notice the change and there is no race condition.
 233      */
 234     qemu_mutex_lock(&timer_list->active_timers_lock);
 235     if (!timer_list->active_timers) {
 236         qemu_mutex_unlock(&timer_list->active_timers_lock);
 237         return -1;
 238     }
 239     expire_time = timer_list->active_timers->expire_time;
 240     qemu_mutex_unlock(&timer_list->active_timers_lock);
 241
 242     delta = expire_time - qemu_clock_get_ns(timer_list->clock->type);
 243
 244     if (delta <= 0) {
 245         return 0;
 246     }
 247
 248     return delta;
 249 }
 250
 251 /* Calculate the soonest deadline across all timerlists attached
 252  * to the clock. This is used for the icount timeout so we
 253  * ignore whether or not the clock should be used in deadline
 254  * calculations.
 255  */
 256 int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
 257 {
 258     int64_t deadline = -1;
 259     QEMUTimerList *timer_list;
 260     QEMUClock *clock = qemu_clock_ptr(type);
 261     QLIST_FOREACH(timer_list, &clock->timerlists, list) {
 262         deadline = qemu_soonest_timeout(deadline,
 263                                         timerlist_deadline_ns(timer_list));
 264     }
 265     return deadline;
 266 }
 267
 268 QEMUClockType timerlist_get_clock(QEMUTimerList *timer_list)
 269 {
 270     return timer_list->clock->type;
 271 }
 272
 273 QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClockType type)
 274 {
 275     return main_loop_tlg.tl[type];
 276 }
 277
 278 void timerlist_notify(QEMUTimerList *timer_list)
 279 {
 280     if (timer_list->notify_cb) {
 281         timer_list->notify_cb(timer_list->notify_opaque, timer_list->clock->type);
 282     } else {
 283         qemu_notify_event();
 284     }
 285 }
 286
 287 /* Transition function to convert a nanosecond timeout to ms
 288  * This is used where a system does not support ppoll
 289  */
 290 int qemu_timeout_ns_to_ms(int64_t ns)
 291 {
 292     int64_t ms;
 293     if (ns < 0) {
 294         return -1;
 295     }
 296
 297     if (!ns) {
 298         return 0;
 299     }
 300
 301     /* Always round up, because it's better to wait too long than to wait too
 302      * little and effectively busy-wait
 303      */
 304     ms = DIV_ROUND_UP(ns, SCALE_MS);
 305
 306     /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
 307     if (ms > (int64_t) INT32_MAX) {
 308         ms = INT32_MAX;
 309     }
 310
 311     return (int) ms;
 312 }
 313
 314
 315 /* qemu implementation of g_poll which uses a nanosecond timeout but is
 316  * otherwise identical to g_poll
 317  */
 318 int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
 319 {
 320 #ifdef CONFIG_PPOLL
 321     if (timeout < 0) {
 322         return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
 323     } else {
 324         struct timespec ts;
 325         int64_t tvsec = timeout / 1000000000LL;
 326         /* Avoid possibly overflowing and specifying a negative number of
 327          * seconds, which would turn a very long timeout into a busy-wait.
 328          */
 329         if (tvsec > (int64_t)INT32_MAX) {
 330             tvsec = INT32_MAX;
 331         }
 332         ts.tv_sec = tvsec;
 333         ts.tv_nsec = timeout % 1000000000LL;
 334         return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
 335     }
 336 #else
 337     return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
 338 #endif
 339 }
 340
 341
 342 void timer_init_full(QEMUTimer *ts,
 343                      QEMUTimerListGroup *timer_list_group, QEMUClockType type,
 344                      int scale, int attributes,
 345                      QEMUTimerCB *cb, void *opaque)
 346 {
 347     if (!timer_list_group) {
 348         timer_list_group = &main_loop_tlg;
 349     }
 350     ts->timer_list = timer_list_group->tl[type];
 351     ts->cb = cb;
 352     ts->opaque = opaque;
 353     ts->scale = scale;
 354     ts->attributes = attributes;
 355     ts->expire_time = -1;
 356 }
 357
 358 void timer_deinit(QEMUTimer *ts)
 359 {
 360     assert(ts->expire_time == -1);
 361     ts->timer_list = NULL;
 362 }
 363
 364 static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts)
 365 {
 366     QEMUTimer **pt, *t;
 367
 368     ts->expire_time = -1;
 369     pt = &timer_list->active_timers;
 370     for(;;) {
 371         t = *pt;
 372         if (!t)
 373             break;
 374         if (t == ts) {
 375             atomic_set(pt, t->next);
 376             break;
 377         }
 378         pt = &t->next;
 379     }
 380 }
 381
 382 static bool timer_mod_ns_locked(QEMUTimerList *timer_list,
 383                                 QEMUTimer *ts, int64_t expire_time)
 384 {
 385     QEMUTimer **pt, *t;
 386
 387     /* add the timer in the sorted list */
 388     pt = &timer_list->active_timers;
 389     for (;;) {
 390         t = *pt;
 391         if (!timer_expired_ns(t, expire_time)) {
 392             break;
 393         }
 394         pt = &t->next;
 395     }
 396     ts->expire_time = MAX(expire_time, 0);
 397     ts->next = *pt;
 398     atomic_set(pt, ts);
 399
 400     return pt == &timer_list->active_timers;
 401 }
 402
 403 static void timerlist_rearm(QEMUTimerList *timer_list)
 404 {
 405     /* Interrupt execution to force deadline recalculation.  */
 406     if (timer_list->clock->type == QEMU_CLOCK_VIRTUAL) {
 407         qemu_start_warp_timer();
 408     }
 409     timerlist_notify(timer_list);
 410 }
 411
 412 /* stop a timer, but do not dealloc it */
 413 void timer_del(QEMUTimer *ts)
 414 {
 415     QEMUTimerList *timer_list = ts->timer_list;
 416
 417     if (timer_list) {
 418         qemu_mutex_lock(&timer_list->active_timers_lock);
 419         timer_del_locked(timer_list, ts);
 420         qemu_mutex_unlock(&timer_list->active_timers_lock);
 421     }
 422 }
 423
 424 /* modify the current timer so that it will be fired when current_time
 425    >= expire_time. The corresponding callback will be called. */
 426 void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
 427 {
 428     QEMUTimerList *timer_list = ts->timer_list;
 429     bool rearm;
 430
 431     qemu_mutex_lock(&timer_list->active_timers_lock);
 432     timer_del_locked(timer_list, ts);
 433     rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
 434     qemu_mutex_unlock(&timer_list->active_timers_lock);
 435
 436     if (rearm) {
 437         timerlist_rearm(timer_list);
 438     }
 439 }
 440
 441 /* modify the current timer so that it will be fired when current_time
 442    >= expire_time or the current deadline, whichever comes earlier.
 443    The corresponding callback will be called. */
 444 void timer_mod_anticipate_ns(QEMUTimer *ts, int64_t expire_time)
 445 {
 446     QEMUTimerList *timer_list = ts->timer_list;
 447     bool rearm;
 448
 449     qemu_mutex_lock(&timer_list->active_timers_lock);
 450     if (ts->expire_time == -1 || ts->expire_time > expire_time) {
 451         if (ts->expire_time != -1) {
 452             timer_del_locked(timer_list, ts);
 453         }
 454         rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
 455     } else {
 456         rearm = false;
 457     }
 458     qemu_mutex_unlock(&timer_list->active_timers_lock);
 459
 460     if (rearm) {
 461         timerlist_rearm(timer_list);
 462     }
 463 }
 464
 465 void timer_mod(QEMUTimer *ts, int64_t expire_time)
 466 {
 467     timer_mod_ns(ts, expire_time * ts->scale);
 468 }
 469
 470 void timer_mod_anticipate(QEMUTimer *ts, int64_t expire_time)
 471 {
 472     timer_mod_anticipate_ns(ts, expire_time * ts->scale);
 473 }
 474
 475 bool timer_pending(QEMUTimer *ts)
 476 {
 477     return ts->expire_time >= 0;
 478 }
 479
 480 bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
 481 {
 482     return timer_expired_ns(timer_head, current_time * timer_head->scale);
 483 }
 484
 485 bool timerlist_run_timers(QEMUTimerList *timer_list)
 486 {
 487     QEMUTimer *ts;
 488     int64_t current_time;
 489     bool progress = false;
 490     QEMUTimerCB *cb;
 491     void *opaque;
 492     bool need_replay_checkpoint = false;
 493
 494     if (!atomic_read(&timer_list->active_timers)) {
 495         return false;
 496     }
 497
 498     qemu_event_reset(&timer_list->timers_done_ev);
 499     if (!timer_list->clock->enabled) {
 500         goto out;
 501     }
 502
 503     switch (timer_list->clock->type) {
 504     case QEMU_CLOCK_REALTIME:
 505         break;
 506     default:
 507     case QEMU_CLOCK_VIRTUAL:
 508         if (replay_mode != REPLAY_MODE_NONE) {
 509             /* Checkpoint for virtual clock is redundant in cases where
 510              * it's being triggered with only non-EXTERNAL timers, because
 511              * these timers don't change guest state directly.
 512              * Since it has conditional dependence on specific timers, it is
 513              * subject to race conditions and requires special handling.
 514              * See below.
 515              */
 516             need_replay_checkpoint = true;
 517         }
 518         break;
 519     case QEMU_CLOCK_HOST:
 520         if (!replay_checkpoint(CHECKPOINT_CLOCK_HOST)) {
 521             goto out;
 522         }
 523         break;
 524     case QEMU_CLOCK_VIRTUAL_RT:
 525         if (!replay_checkpoint(CHECKPOINT_CLOCK_VIRTUAL_RT)) {
 526             goto out;
 527         }
 528         break;
 529     }
 530
 531     /*
 532      * Extract expired timers from active timers list and and process them.
 533      *
 534      * In rr mode we need "filtered" checkpointing for virtual clock.  The
 535      * checkpoint must be recorded/replayed before processing any non-EXTERNAL timer,
 536      * and that must only be done once since the clock value stays the same. Because
 537      * non-EXTERNAL timers may appear in the timers list while it being processed,
 538      * the checkpoint can be issued at a time until no timers are left and we are
 539      * done".
 540      */
 541     current_time = qemu_clock_get_ns(timer_list->clock->type);
 542     qemu_mutex_lock(&timer_list->active_timers_lock);
 543     while ((ts = timer_list->active_timers)) {
 544         if (!timer_expired_ns(ts, current_time)) {
 545             /* No expired timers left.  The checkpoint can be skipped
 546              * if no timers fired or they were all external.
 547              */
 548             break;
 549         }
 550         if (need_replay_checkpoint
 551                 && !(ts->attributes & QEMU_TIMER_ATTR_EXTERNAL)) {
 552             /* once we got here, checkpoint clock only once */
 553             need_replay_checkpoint = false;
 554             qemu_mutex_unlock(&timer_list->active_timers_lock);
 555             if (!replay_checkpoint(CHECKPOINT_CLOCK_VIRTUAL)) {
 556                 goto out;
 557             }
 558             qemu_mutex_lock(&timer_list->active_timers_lock);
 559             /* The lock was released; start over again in case the list was
 560              * modified.
 561              */
 562             continue;
 563         }
 564
 565         /* remove timer from the list before calling the callback */
 566         timer_list->active_timers = ts->next;
 567         ts->next = NULL;
 568         ts->expire_time = -1;
 569         cb = ts->cb;
 570         opaque = ts->opaque;
 571
 572         /* run the callback (the timer list can be modified) */
 573         qemu_mutex_unlock(&timer_list->active_timers_lock);
 574         cb(opaque);
 575         qemu_mutex_lock(&timer_list->active_timers_lock);
 576
 577         progress = true;
 578     }
 579     qemu_mutex_unlock(&timer_list->active_timers_lock);
 580
 581 out:
 582     qemu_event_set(&timer_list->timers_done_ev);
 583     return progress;
 584 }
 585
 586 bool qemu_clock_run_timers(QEMUClockType type)
 587 {
 588     return timerlist_run_timers(main_loop_tlg.tl[type]);
 589 }
 590
 591 void timerlistgroup_init(QEMUTimerListGroup *tlg,
 592                          QEMUTimerListNotifyCB *cb, void *opaque)
 593 {
 594     QEMUClockType type;
 595     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 596         tlg->tl[type] = timerlist_new(type, cb, opaque);
 597     }
 598 }
 599
 600 void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
 601 {
 602     QEMUClockType type;
 603     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 604         timerlist_free(tlg->tl[type]);
 605     }
 606 }
 607
 608 bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
 609 {
 610     QEMUClockType type;
 611     bool progress = false;
 612     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 613         progress |= timerlist_run_timers(tlg->tl[type]);
 614     }
 615     return progress;
 616 }
 617
 618 int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
 619 {
 620     int64_t deadline = -1;
 621     QEMUClockType type;
 622     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 623         if (qemu_clock_use_for_deadline(type)) {
 624             deadline = qemu_soonest_timeout(deadline,
 625                                             timerlist_deadline_ns(tlg->tl[type]));
 626         }
 627     }
 628     return deadline;
 629 }
 630
 631 int64_t qemu_clock_get_ns(QEMUClockType type)
 632 {
 633     int64_t now, last;
 634     QEMUClock *clock = qemu_clock_ptr(type);
 635
 636     switch (type) {
 637     case QEMU_CLOCK_REALTIME:
 638         return get_clock();
 639     default:
 640     case QEMU_CLOCK_VIRTUAL:
 641         if (use_icount) {
 642             return cpu_get_icount();
 643         } else {
 644             return cpu_get_clock();
 645         }
 646     case QEMU_CLOCK_HOST:
 647         now = REPLAY_CLOCK(REPLAY_CLOCK_HOST, get_clock_realtime());
 648         last = clock->last;
 649         clock->last = now;
 650         if (now < last || now > (last + get_max_clock_jump())) {
 651             notifier_list_notify(&clock->reset_notifiers, &now);
 652         }
 653         return now;
 654     case QEMU_CLOCK_VIRTUAL_RT:
 655         return REPLAY_CLOCK(REPLAY_CLOCK_VIRTUAL_RT, cpu_get_clock());
 656     }
 657 }
 658
 659 uint64_t qemu_clock_get_last(QEMUClockType type)
 660 {
 661     QEMUClock *clock = qemu_clock_ptr(type);
 662     return clock->last;
 663 }
 664
 665 void qemu_clock_set_last(QEMUClockType type, uint64_t last)
 666 {
 667     QEMUClock *clock = qemu_clock_ptr(type);
 668     clock->last = last;
 669 }
 670
 671 void qemu_clock_register_reset_notifier(QEMUClockType type,
 672                                         Notifier *notifier)
 673 {
 674     QEMUClock *clock = qemu_clock_ptr(type);
 675     notifier_list_add(&clock->reset_notifiers, notifier);
 676 }
 677
 678 void qemu_clock_unregister_reset_notifier(QEMUClockType type,
 679                                           Notifier *notifier)
 680 {
 681     notifier_remove(notifier);
 682 }
 683
 684 void init_clocks(QEMUTimerListNotifyCB *notify_cb)
 685 {
 686     QEMUClockType type;
 687     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 688         qemu_clock_init(type, notify_cb);
 689     }
 690
 691 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
 692     prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
 693 #endif
 694 }
 695
 696 uint64_t timer_expire_time_ns(QEMUTimer *ts)
 697 {
 698     return timer_pending(ts) ? ts->expire_time : -1;
 699 }
 700
 701 bool qemu_clock_run_all_timers(void)
 702 {
 703     bool progress = false;
 704     QEMUClockType type;
 705
 706     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 707         if (qemu_clock_use_for_deadline(type)) {
 708             progress |= qemu_clock_run_timers(type);
 709         }
 710     }
 711
 712     return progress;
 713 }