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 /*
 180  * As above, but return -1 for no deadline, and do not cap to 2^32
 181  * as we know the result is always positive.
 182  */
 183
 184 int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
 185 {
 186     int64_t delta;
 187
 188     if (!timer_list->clock->enabled || !timer_list->active_timers) {
 189         return -1;
 190     }
 191
 192     delta = timer_list->active_timers->expire_time -
 193         qemu_get_clock_ns(timer_list->clock);
 194
 195     if (delta <= 0) {
 196         return 0;
 197     }
 198
 199     return delta;
 200 }
 201
 202 int64_t qemu_clock_deadline_ns(QEMUClock *clock)
 203 {
 204     return timerlist_deadline_ns(clock->main_loop_timerlist);
 205 }
 206
 207 /* Calculate the soonest deadline across all timerlists attached
 208  * to the clock. This is used for the icount timeout so we
 209  * ignore whether or not the clock should be used in deadline
 210  * calculations.
 211  */
 212 int64_t qemu_clock_deadline_ns_all(QEMUClock *clock)
 213 {
 214     int64_t deadline = -1;
 215     QEMUTimerList *timer_list;
 216     QLIST_FOREACH(timer_list, &clock->timerlists, list) {
 217         deadline = qemu_soonest_timeout(deadline,
 218                                         timerlist_deadline_ns(timer_list));
 219     }
 220     return deadline;
 221 }
 222
 223 QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list)
 224 {
 225     return timer_list->clock;
 226 }
 227
 228 QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock)
 229 {
 230     return clock->main_loop_timerlist;
 231 }
 232
 233 void timerlist_notify(QEMUTimerList *timer_list)
 234 {
 235     if (timer_list->notify_cb) {
 236         timer_list->notify_cb(timer_list->notify_opaque);
 237     } else {
 238         qemu_notify_event();
 239     }
 240 }
 241
 242 /* Transition function to convert a nanosecond timeout to ms
 243  * This is used where a system does not support ppoll
 244  */
 245 int qemu_timeout_ns_to_ms(int64_t ns)
 246 {
 247     int64_t ms;
 248     if (ns < 0) {
 249         return -1;
 250     }
 251
 252     if (!ns) {
 253         return 0;
 254     }
 255
 256     /* Always round up, because it's better to wait too long than to wait too
 257      * little and effectively busy-wait
 258      */
 259     ms = (ns + SCALE_MS - 1) / SCALE_MS;
 260
 261     /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
 262     if (ms > (int64_t) INT32_MAX) {
 263         ms = INT32_MAX;
 264     }
 265
 266     return (int) ms;
 267 }
 268
 269
 270 /* qemu implementation of g_poll which uses a nanosecond timeout but is
 271  * otherwise identical to g_poll
 272  */
 273 int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
 274 {
 275 #ifdef CONFIG_PPOLL
 276     if (timeout < 0) {
 277         return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
 278     } else {
 279         struct timespec ts;
 280         ts.tv_sec = timeout / 1000000000LL;
 281         ts.tv_nsec = timeout % 1000000000LL;
 282         return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
 283     }
 284 #else
 285     return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
 286 #endif
 287 }
 288
 289
 290 void timer_init(QEMUTimer *ts,
 291                 QEMUTimerList *timer_list, int scale,
 292                 QEMUTimerCB *cb, void *opaque)
 293 {
 294     ts->timer_list = timer_list;
 295     ts->cb = cb;
 296     ts->opaque = opaque;
 297     ts->scale = scale;
 298 }
 299
 300 QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
 301                           QEMUTimerCB *cb, void *opaque)
 302 {
 303     return timer_new_tl(clock->main_loop_timerlist,
 304                      scale, cb, opaque);
 305 }
 306
 307 void qemu_free_timer(QEMUTimer *ts)
 308 {
 309     g_free(ts);
 310 }
 311
 312 /* stop a timer, but do not dealloc it */
 313 void qemu_del_timer(QEMUTimer *ts)
 314 {
 315     QEMUTimer **pt, *t;
 316
 317     /* NOTE: this code must be signal safe because
 318        timer_expired() can be called from a signal. */
 319     pt = &ts->timer_list->active_timers;
 320     for(;;) {
 321         t = *pt;
 322         if (!t)
 323             break;
 324         if (t == ts) {
 325             *pt = t->next;
 326             break;
 327         }
 328         pt = &t->next;
 329     }
 330 }
 331
 332 /* modify the current timer so that it will be fired when current_time
 333    >= expire_time. The corresponding callback will be called. */
 334 void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
 335 {
 336     QEMUTimer **pt, *t;
 337
 338     qemu_del_timer(ts);
 339
 340     /* add the timer in the sorted list */
 341     /* NOTE: this code must be signal safe because
 342        timer_expired() can be called from a signal. */
 343     pt = &ts->timer_list->active_timers;
 344     for(;;) {
 345         t = *pt;
 346         if (!timer_expired_ns(t, expire_time)) {
 347             break;
 348         }
 349         pt = &t->next;
 350     }
 351     ts->expire_time = expire_time;
 352     ts->next = *pt;
 353     *pt = ts;
 354
 355     /* Rearm if necessary  */
 356     if (pt == &ts->timer_list->active_timers) {
 357         /* Interrupt execution to force deadline recalculation.  */
 358         qemu_clock_warp(ts->timer_list->clock);
 359         timerlist_notify(ts->timer_list);
 360     }
 361 }
 362
 363 void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
 364 {
 365     qemu_mod_timer_ns(ts, expire_time * ts->scale);
 366 }
 367
 368 bool timer_pending(QEMUTimer *ts)
 369 {
 370     QEMUTimer *t;
 371     for (t = ts->timer_list->active_timers; t != NULL; t = t->next) {
 372         if (t == ts) {
 373             return true;
 374         }
 375     }
 376     return false;
 377 }
 378
 379 bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
 380 {
 381     return timer_expired_ns(timer_head, current_time * timer_head->scale);
 382 }
 383
 384 bool timerlist_run_timers(QEMUTimerList *timer_list)
 385 {
 386     QEMUTimer *ts;
 387     int64_t current_time;
 388     bool progress = false;
 389
 390     if (!timer_list->clock->enabled) {
 391         return progress;
 392     }
 393
 394     current_time = qemu_get_clock_ns(timer_list->clock);
 395     for(;;) {
 396         ts = timer_list->active_timers;
 397         if (!timer_expired_ns(ts, current_time)) {
 398             break;
 399         }
 400         /* remove timer from the list before calling the callback */
 401         timer_list->active_timers = ts->next;
 402         ts->next = NULL;
 403
 404         /* run the callback (the timer list can be modified) */
 405         ts->cb(ts->opaque);
 406         progress = true;
 407     }
 408     return progress;
 409 }
 410
 411 bool qemu_run_timers(QEMUClock *clock)
 412 {
 413     return timerlist_run_timers(clock->main_loop_timerlist);
 414 }
 415
 416 void timerlistgroup_init(QEMUTimerListGroup *tlg,
 417                          QEMUTimerListNotifyCB *cb, void *opaque)
 418 {
 419     QEMUClockType type;
 420     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 421         tlg->tl[type] = timerlist_new(type, cb, opaque);
 422     }
 423 }
 424
 425 void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
 426 {
 427     QEMUClockType type;
 428     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 429         timerlist_free(tlg->tl[type]);
 430     }
 431 }
 432
 433 bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
 434 {
 435     QEMUClockType type;
 436     bool progress = false;
 437     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 438         progress |= timerlist_run_timers(tlg->tl[type]);
 439     }
 440     return progress;
 441 }
 442
 443 int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
 444 {
 445     int64_t deadline = -1;
 446     QEMUClockType type;
 447     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 448         if (qemu_clock_use_for_deadline(tlg->tl[type]->clock)) {
 449             deadline = qemu_soonest_timeout(deadline,
 450                                             timerlist_deadline_ns(
 451                                                 tlg->tl[type]));
 452         }
 453     }
 454     return deadline;
 455 }
 456
 457 int64_t qemu_get_clock_ns(QEMUClock *clock)
 458 {
 459     int64_t now, last;
 460
 461     switch(clock->type) {
 462     case QEMU_CLOCK_REALTIME:
 463         return get_clock();
 464     default:
 465     case QEMU_CLOCK_VIRTUAL:
 466         if (use_icount) {
 467             return cpu_get_icount();
 468         } else {
 469             return cpu_get_clock();
 470         }
 471     case QEMU_CLOCK_HOST:
 472         now = get_clock_realtime();
 473         last = clock->last;
 474         clock->last = now;
 475         if (now < last) {
 476             notifier_list_notify(&clock->reset_notifiers, &now);
 477         }
 478         return now;
 479     }
 480 }
 481
 482 void qemu_register_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)
 483 {
 484     notifier_list_add(&clock->reset_notifiers, notifier);
 485 }
 486
 487 void qemu_unregister_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)
 488 {
 489     notifier_remove(notifier);
 490 }
 491
 492 void init_clocks(void)
 493 {
 494     QEMUClockType type;
 495     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 496         if (!qemu_clocks[type]) {
 497             qemu_clocks[type] = qemu_clock_new(type);
 498             main_loop_tlg.tl[type] = qemu_clocks[type]->main_loop_timerlist;
 499         }
 500     }
 501
 502 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
 503     prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
 504 #endif
 505 }
 506
 507 uint64_t timer_expire_time_ns(QEMUTimer *ts)
 508 {
 509     return timer_pending(ts) ? ts->expire_time : -1;
 510 }
 511
 512 bool qemu_run_all_timers(void)
 513 {
 514     bool progress = false;
 515     QEMUClockType type;
 516
 517     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 518         progress |= qemu_run_timers(qemu_clock_ptr(type));
 519     }
 520
 521     return progress;
 522 }