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 struct QEMUClock {
  48     QEMUTimerList *main_loop_timerlist;
  49     QLIST_HEAD(, QEMUTimerList) timerlists;
  50
  51     NotifierList reset_notifiers;
  52     int64_t last;
  53
  54     QEMUClockType type;
  55     bool enabled;
  56 };
  57
  58 QEMUTimerListGroup main_loop_tlg;
  59 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     QEMUTimer *active_timers;
  71     QLIST_ENTRY(QEMUTimerList) list;
  72     QEMUTimerListNotifyCB *notify_cb;
  73     void *notify_opaque;
  74 };
  75
  76 static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
  77 {
  78     return timer_head && (timer_head->expire_time <= current_time);
  79 }
  80
  81 static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock,
  82                                                QEMUTimerListNotifyCB *cb,
  83                                                void *opaque)
  84 {
  85     QEMUTimerList *timer_list;
  86
  87     /* Assert if we do not have a clock. If you see this
  88      * assertion in means that the clocks have not been
  89      * initialised before a timerlist is needed. This
  90      * normally happens if an AioContext is used before
  91      * init_clocks() is called within main().
  92      */
  93     assert(clock);
  94
  95     timer_list = g_malloc0(sizeof(QEMUTimerList));
  96     timer_list->clock = clock;
  97     timer_list->notify_cb = cb;
  98     timer_list->notify_opaque = opaque;
  99     QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
 100     return timer_list;
 101 }
 102
 103 QEMUTimerList *timerlist_new(QEMUClockType type,
 104                              QEMUTimerListNotifyCB *cb, void *opaque)
 105 {
 106     return timerlist_new_from_clock(qemu_clock_ptr(type), cb, opaque);
 107 }
 108
 109 void timerlist_free(QEMUTimerList *timer_list)
 110 {
 111     assert(!timerlist_has_timers(timer_list));
 112     if (timer_list->clock) {
 113         QLIST_REMOVE(timer_list, list);
 114         if (timer_list->clock->main_loop_timerlist == timer_list) {
 115             timer_list->clock->main_loop_timerlist = NULL;
 116         }
 117     }
 118     g_free(timer_list);
 119 }
 120
 121 static QEMUClock *qemu_clock_new(QEMUClockType type)
 122 {
 123     QEMUClock *clock;
 124
 125     clock = g_malloc0(sizeof(QEMUClock));
 126     clock->type = type;
 127     clock->enabled = true;
 128     clock->last = INT64_MIN;
 129     QLIST_INIT(&clock->timerlists);
 130     notifier_list_init(&clock->reset_notifiers);
 131     clock->main_loop_timerlist = timerlist_new_from_clock(clock, NULL, NULL);
 132     return clock;
 133 }
 134
 135 bool qemu_clock_use_for_deadline(QEMUClock *clock)
 136 {
 137     return !(use_icount && (clock->type == QEMU_CLOCK_VIRTUAL));
 138 }
 139
 140 void qemu_clock_notify(QEMUClock *clock)
 141 {
 142     QEMUTimerList *timer_list;
 143     QLIST_FOREACH(timer_list, &clock->timerlists, list) {
 144         timerlist_notify(timer_list);
 145     }
 146 }
 147
 148 void qemu_clock_enable(QEMUClock *clock, bool enabled)
 149 {
 150     bool old = clock->enabled;
 151     clock->enabled = enabled;
 152     if (enabled && !old) {
 153         qemu_clock_notify(clock);
 154     }
 155 }
 156
 157 bool timerlist_has_timers(QEMUTimerList *timer_list)
 158 {
 159     return !!timer_list->active_timers;
 160 }
 161
 162 bool qemu_clock_has_timers(QEMUClock *clock)
 163 {
 164     return timerlist_has_timers(clock->main_loop_timerlist);
 165 }
 166
 167 bool timerlist_expired(QEMUTimerList *timer_list)
 168 {
 169     return (timer_list->active_timers &&
 170             timer_list->active_timers->expire_time <
 171             qemu_get_clock_ns(timer_list->clock));
 172 }
 173
 174 bool qemu_clock_expired(QEMUClock *clock)
 175 {
 176     return timerlist_expired(clock->main_loop_timerlist);
 177 }
 178
 179 int64_t timerlist_deadline(QEMUTimerList *timer_list)
 180 {
 181     /* To avoid problems with overflow limit this to 2^32.  */
 182     int64_t delta = INT32_MAX;
 183
 184     if (timer_list->clock->enabled && timer_list->active_timers) {
 185         delta = timer_list->active_timers->expire_time -
 186             qemu_get_clock_ns(timer_list->clock);
 187     }
 188     if (delta < 0) {
 189         delta = 0;
 190     }
 191     return delta;
 192 }
 193
 194 int64_t qemu_clock_deadline(QEMUClock *clock)
 195 {
 196     return timerlist_deadline(clock->main_loop_timerlist);
 197 }
 198
 199 /*
 200  * As above, but return -1 for no deadline, and do not cap to 2^32
 201  * as we know the result is always positive.
 202  */
 203
 204 int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
 205 {
 206     int64_t delta;
 207
 208     if (!timer_list->clock->enabled || !timer_list->active_timers) {
 209         return -1;
 210     }
 211
 212     delta = timer_list->active_timers->expire_time -
 213         qemu_get_clock_ns(timer_list->clock);
 214
 215     if (delta <= 0) {
 216         return 0;
 217     }
 218
 219     return delta;
 220 }
 221
 222 int64_t qemu_clock_deadline_ns(QEMUClock *clock)
 223 {
 224     return timerlist_deadline_ns(clock->main_loop_timerlist);
 225 }
 226
 227 /* Calculate the soonest deadline across all timerlists attached
 228  * to the clock. This is used for the icount timeout so we
 229  * ignore whether or not the clock should be used in deadline
 230  * calculations.
 231  */
 232 int64_t qemu_clock_deadline_ns_all(QEMUClock *clock)
 233 {
 234     int64_t deadline = -1;
 235     QEMUTimerList *timer_list;
 236     QLIST_FOREACH(timer_list, &clock->timerlists, list) {
 237         deadline = qemu_soonest_timeout(deadline,
 238                                         timerlist_deadline_ns(timer_list));
 239     }
 240     return deadline;
 241 }
 242
 243 QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list)
 244 {
 245     return timer_list->clock;
 246 }
 247
 248 QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock)
 249 {
 250     return clock->main_loop_timerlist;
 251 }
 252
 253 void timerlist_notify(QEMUTimerList *timer_list)
 254 {
 255     if (timer_list->notify_cb) {
 256         timer_list->notify_cb(timer_list->notify_opaque);
 257     } else {
 258         qemu_notify_event();
 259     }
 260 }
 261
 262 /* Transition function to convert a nanosecond timeout to ms
 263  * This is used where a system does not support ppoll
 264  */
 265 int qemu_timeout_ns_to_ms(int64_t ns)
 266 {
 267     int64_t ms;
 268     if (ns < 0) {
 269         return -1;
 270     }
 271
 272     if (!ns) {
 273         return 0;
 274     }
 275
 276     /* Always round up, because it's better to wait too long than to wait too
 277      * little and effectively busy-wait
 278      */
 279     ms = (ns + SCALE_MS - 1) / SCALE_MS;
 280
 281     /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
 282     if (ms > (int64_t) INT32_MAX) {
 283         ms = INT32_MAX;
 284     }
 285
 286     return (int) ms;
 287 }
 288
 289
 290 /* qemu implementation of g_poll which uses a nanosecond timeout but is
 291  * otherwise identical to g_poll
 292  */
 293 int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
 294 {
 295 #ifdef CONFIG_PPOLL
 296     if (timeout < 0) {
 297         return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
 298     } else {
 299         struct timespec ts;
 300         ts.tv_sec = timeout / 1000000000LL;
 301         ts.tv_nsec = timeout % 1000000000LL;
 302         return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
 303     }
 304 #else
 305     return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
 306 #endif
 307 }
 308
 309
 310 void timer_init(QEMUTimer *ts,
 311                 QEMUTimerList *timer_list, int scale,
 312                 QEMUTimerCB *cb, void *opaque)
 313 {
 314     ts->timer_list = timer_list;
 315     ts->cb = cb;
 316     ts->opaque = opaque;
 317     ts->scale = scale;
 318 }
 319
 320 QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
 321                           QEMUTimerCB *cb, void *opaque)
 322 {
 323     return timer_new_tl(clock->main_loop_timerlist,
 324                      scale, cb, opaque);
 325 }
 326
 327 void qemu_free_timer(QEMUTimer *ts)
 328 {
 329     g_free(ts);
 330 }
 331
 332 /* stop a timer, but do not dealloc it */
 333 void qemu_del_timer(QEMUTimer *ts)
 334 {
 335     QEMUTimer **pt, *t;
 336
 337     /* NOTE: this code must be signal safe because
 338        timer_expired() can be called from a signal. */
 339     pt = &ts->timer_list->active_timers;
 340     for(;;) {
 341         t = *pt;
 342         if (!t)
 343             break;
 344         if (t == ts) {
 345             *pt = t->next;
 346             break;
 347         }
 348         pt = &t->next;
 349     }
 350 }
 351
 352 /* modify the current timer so that it will be fired when current_time
 353    >= expire_time. The corresponding callback will be called. */
 354 void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
 355 {
 356     QEMUTimer **pt, *t;
 357
 358     qemu_del_timer(ts);
 359
 360     /* add the timer in the sorted list */
 361     /* NOTE: this code must be signal safe because
 362        timer_expired() can be called from a signal. */
 363     pt = &ts->timer_list->active_timers;
 364     for(;;) {
 365         t = *pt;
 366         if (!timer_expired_ns(t, expire_time)) {
 367             break;
 368         }
 369         pt = &t->next;
 370     }
 371     ts->expire_time = expire_time;
 372     ts->next = *pt;
 373     *pt = ts;
 374
 375     /* Rearm if necessary  */
 376     if (pt == &ts->timer_list->active_timers) {
 377         /* Interrupt execution to force deadline recalculation.  */
 378         qemu_clock_warp(ts->timer_list->clock);
 379         timerlist_notify(ts->timer_list);
 380     }
 381 }
 382
 383 void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
 384 {
 385     qemu_mod_timer_ns(ts, expire_time * ts->scale);
 386 }
 387
 388 bool timer_pending(QEMUTimer *ts)
 389 {
 390     QEMUTimer *t;
 391     for (t = ts->timer_list->active_timers; t != NULL; t = t->next) {
 392         if (t == ts) {
 393             return true;
 394         }
 395     }
 396     return false;
 397 }
 398
 399 bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
 400 {
 401     return timer_expired_ns(timer_head, current_time * timer_head->scale);
 402 }
 403
 404 bool timerlist_run_timers(QEMUTimerList *timer_list)
 405 {
 406     QEMUTimer *ts;
 407     int64_t current_time;
 408     bool progress = false;
 409
 410     if (!timer_list->clock->enabled) {
 411         return progress;
 412     }
 413
 414     current_time = qemu_get_clock_ns(timer_list->clock);
 415     for(;;) {
 416         ts = timer_list->active_timers;
 417         if (!timer_expired_ns(ts, current_time)) {
 418             break;
 419         }
 420         /* remove timer from the list before calling the callback */
 421         timer_list->active_timers = ts->next;
 422         ts->next = NULL;
 423
 424         /* run the callback (the timer list can be modified) */
 425         ts->cb(ts->opaque);
 426         progress = true;
 427     }
 428     return progress;
 429 }
 430
 431 bool qemu_run_timers(QEMUClock *clock)
 432 {
 433     return timerlist_run_timers(clock->main_loop_timerlist);
 434 }
 435
 436 void timerlistgroup_init(QEMUTimerListGroup *tlg,
 437                          QEMUTimerListNotifyCB *cb, void *opaque)
 438 {
 439     QEMUClockType type;
 440     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 441         tlg->tl[type] = timerlist_new(type, cb, opaque);
 442     }
 443 }
 444
 445 void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
 446 {
 447     QEMUClockType type;
 448     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 449         timerlist_free(tlg->tl[type]);
 450     }
 451 }
 452
 453 bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
 454 {
 455     QEMUClockType type;
 456     bool progress = false;
 457     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 458         progress |= timerlist_run_timers(tlg->tl[type]);
 459     }
 460     return progress;
 461 }
 462
 463 int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
 464 {
 465     int64_t deadline = -1;
 466     QEMUClockType type;
 467     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 468         if (qemu_clock_use_for_deadline(tlg->tl[type]->clock)) {
 469             deadline = qemu_soonest_timeout(deadline,
 470                                             timerlist_deadline_ns(
 471                                                 tlg->tl[type]));
 472         }
 473     }
 474     return deadline;
 475 }
 476
 477 int64_t qemu_get_clock_ns(QEMUClock *clock)
 478 {
 479     int64_t now, last;
 480
 481     switch(clock->type) {
 482     case QEMU_CLOCK_REALTIME:
 483         return get_clock();
 484     default:
 485     case QEMU_CLOCK_VIRTUAL:
 486         if (use_icount) {
 487             return cpu_get_icount();
 488         } else {
 489             return cpu_get_clock();
 490         }
 491     case QEMU_CLOCK_HOST:
 492         now = get_clock_realtime();
 493         last = clock->last;
 494         clock->last = now;
 495         if (now < last) {
 496             notifier_list_notify(&clock->reset_notifiers, &now);
 497         }
 498         return now;
 499     }
 500 }
 501
 502 void qemu_register_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)
 503 {
 504     notifier_list_add(&clock->reset_notifiers, notifier);
 505 }
 506
 507 void qemu_unregister_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)
 508 {
 509     notifier_remove(notifier);
 510 }
 511
 512 void init_clocks(void)
 513 {
 514     QEMUClockType type;
 515     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 516         if (!qemu_clocks[type]) {
 517             qemu_clocks[type] = qemu_clock_new(type);
 518             main_loop_tlg.tl[type] = qemu_clocks[type]->main_loop_timerlist;
 519         }
 520     }
 521
 522 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
 523     prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
 524 #endif
 525 }
 526
 527 uint64_t timer_expire_time_ns(QEMUTimer *ts)
 528 {
 529     return timer_pending(ts) ? ts->expire_time : -1;
 530 }
 531
 532 bool qemu_run_all_timers(void)
 533 {
 534     bool progress = false;
 535     QEMUClockType type;
 536
 537     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 538         progress |= qemu_run_timers(qemu_clock_ptr(type));
 539     }
 540
 541     return progress;
 542 }