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     QLIST_HEAD(, QEMUTimerList) timerlists;
  49
  50     NotifierList reset_notifiers;
  51     int64_t last;
  52
  53     QEMUClockType type;
  54     bool enabled;
  55 } QEMUClock;
  56
  57 QEMUTimerListGroup main_loop_tlg;
  58 QEMUClock qemu_clocks[QEMU_CLOCK_MAX];
  59
  60 /* A QEMUTimerList is a list of timers attached to a clock. More
  61  * than one QEMUTimerList can be attached to each clock, for instance
  62  * used by different AioContexts / threads. Each clock also has
  63  * a list of the QEMUTimerLists associated with it, in order that
  64  * reenabling the clock can call all the notifiers.
  65  */
  66
  67 struct QEMUTimerList {
  68     QEMUClock *clock;
  69     QEMUTimer *active_timers;
  70     QLIST_ENTRY(QEMUTimerList) list;
  71     QEMUTimerListNotifyCB *notify_cb;
  72     void *notify_opaque;
  73 };
  74
  75 /**
  76  * qemu_clock_ptr:
  77  * @type: type of clock
  78  *
  79  * Translate a clock type into a pointer to QEMUClock object.
  80  *
  81  * Returns: a pointer to the QEMUClock object
  82  */
  83 static inline QEMUClock *qemu_clock_ptr(QEMUClockType type)
  84 {
  85     return &qemu_clocks[type];
  86 }
  87
  88 static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
  89 {
  90     return timer_head && (timer_head->expire_time <= current_time);
  91 }
  92
  93 QEMUTimerList *timerlist_new(QEMUClockType type,
  94                              QEMUTimerListNotifyCB *cb,
  95                              void *opaque)
  96 {
  97     QEMUTimerList *timer_list;
  98     QEMUClock *clock = qemu_clock_ptr(type);
  99
 100     timer_list = g_malloc0(sizeof(QEMUTimerList));
 101     timer_list->clock = clock;
 102     timer_list->notify_cb = cb;
 103     timer_list->notify_opaque = opaque;
 104     QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
 105     return timer_list;
 106 }
 107
 108 void timerlist_free(QEMUTimerList *timer_list)
 109 {
 110     assert(!timerlist_has_timers(timer_list));
 111     if (timer_list->clock) {
 112         QLIST_REMOVE(timer_list, list);
 113     }
 114     g_free(timer_list);
 115 }
 116
 117 static void qemu_clock_init(QEMUClockType type)
 118 {
 119     QEMUClock *clock = qemu_clock_ptr(type);
 120
 121     clock->type = type;
 122     clock->enabled = true;
 123     clock->last = INT64_MIN;
 124     QLIST_INIT(&clock->timerlists);
 125     notifier_list_init(&clock->reset_notifiers);
 126     main_loop_tlg.tl[type] = timerlist_new(type, NULL, NULL);
 127 }
 128
 129 bool qemu_clock_use_for_deadline(QEMUClockType type)
 130 {
 131     return !(use_icount && (type == QEMU_CLOCK_VIRTUAL));
 132 }
 133
 134 void qemu_clock_notify(QEMUClockType type)
 135 {
 136     QEMUTimerList *timer_list;
 137     QEMUClock *clock = qemu_clock_ptr(type);
 138     QLIST_FOREACH(timer_list, &clock->timerlists, list) {
 139         timerlist_notify(timer_list);
 140     }
 141 }
 142
 143 void qemu_clock_enable(QEMUClockType type, bool enabled)
 144 {
 145     QEMUClock *clock = qemu_clock_ptr(type);
 146     bool old = clock->enabled;
 147     clock->enabled = enabled;
 148     if (enabled && !old) {
 149         qemu_clock_notify(type);
 150     }
 151 }
 152
 153 bool timerlist_has_timers(QEMUTimerList *timer_list)
 154 {
 155     return !!timer_list->active_timers;
 156 }
 157
 158 bool qemu_clock_has_timers(QEMUClockType type)
 159 {
 160     return timerlist_has_timers(
 161         main_loop_tlg.tl[type]);
 162 }
 163
 164 bool timerlist_expired(QEMUTimerList *timer_list)
 165 {
 166     return (timer_list->active_timers &&
 167             timer_list->active_timers->expire_time <
 168             qemu_clock_get_ns(timer_list->clock->type));
 169 }
 170
 171 bool qemu_clock_expired(QEMUClockType type)
 172 {
 173     return timerlist_expired(
 174         main_loop_tlg.tl[type]);
 175 }
 176
 177 /*
 178  * As above, but return -1 for no deadline, and do not cap to 2^32
 179  * as we know the result is always positive.
 180  */
 181
 182 int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
 183 {
 184     int64_t delta;
 185
 186     if (!timer_list->clock->enabled || !timer_list->active_timers) {
 187         return -1;
 188     }
 189
 190     delta = timer_list->active_timers->expire_time -
 191         qemu_clock_get_ns(timer_list->clock->type);
 192
 193     if (delta <= 0) {
 194         return 0;
 195     }
 196
 197     return delta;
 198 }
 199
 200 /* Calculate the soonest deadline across all timerlists attached
 201  * to the clock. This is used for the icount timeout so we
 202  * ignore whether or not the clock should be used in deadline
 203  * calculations.
 204  */
 205 int64_t qemu_clock_deadline_ns_all(QEMUClockType type)
 206 {
 207     int64_t deadline = -1;
 208     QEMUTimerList *timer_list;
 209     QEMUClock *clock = qemu_clock_ptr(type);
 210     QLIST_FOREACH(timer_list, &clock->timerlists, list) {
 211         deadline = qemu_soonest_timeout(deadline,
 212                                         timerlist_deadline_ns(timer_list));
 213     }
 214     return deadline;
 215 }
 216
 217 QEMUClockType timerlist_get_clock(QEMUTimerList *timer_list)
 218 {
 219     return timer_list->clock->type;
 220 }
 221
 222 QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClockType type)
 223 {
 224     return main_loop_tlg.tl[type];
 225 }
 226
 227 void timerlist_notify(QEMUTimerList *timer_list)
 228 {
 229     if (timer_list->notify_cb) {
 230         timer_list->notify_cb(timer_list->notify_opaque);
 231     } else {
 232         qemu_notify_event();
 233     }
 234 }
 235
 236 /* Transition function to convert a nanosecond timeout to ms
 237  * This is used where a system does not support ppoll
 238  */
 239 int qemu_timeout_ns_to_ms(int64_t ns)
 240 {
 241     int64_t ms;
 242     if (ns < 0) {
 243         return -1;
 244     }
 245
 246     if (!ns) {
 247         return 0;
 248     }
 249
 250     /* Always round up, because it's better to wait too long than to wait too
 251      * little and effectively busy-wait
 252      */
 253     ms = (ns + SCALE_MS - 1) / SCALE_MS;
 254
 255     /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
 256     if (ms > (int64_t) INT32_MAX) {
 257         ms = INT32_MAX;
 258     }
 259
 260     return (int) ms;
 261 }
 262
 263
 264 /* qemu implementation of g_poll which uses a nanosecond timeout but is
 265  * otherwise identical to g_poll
 266  */
 267 int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
 268 {
 269 #ifdef CONFIG_PPOLL
 270     if (timeout < 0) {
 271         return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
 272     } else {
 273         struct timespec ts;
 274         ts.tv_sec = timeout / 1000000000LL;
 275         ts.tv_nsec = timeout % 1000000000LL;
 276         return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
 277     }
 278 #else
 279     return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
 280 #endif
 281 }
 282
 283
 284 void timer_init(QEMUTimer *ts,
 285                 QEMUTimerList *timer_list, int scale,
 286                 QEMUTimerCB *cb, void *opaque)
 287 {
 288     ts->timer_list = timer_list;
 289     ts->cb = cb;
 290     ts->opaque = opaque;
 291     ts->scale = scale;
 292 }
 293
 294 void timer_free(QEMUTimer *ts)
 295 {
 296     g_free(ts);
 297 }
 298
 299 /* stop a timer, but do not dealloc it */
 300 void timer_del(QEMUTimer *ts)
 301 {
 302     QEMUTimer **pt, *t;
 303
 304     /* NOTE: this code must be signal safe because
 305        timer_expired() can be called from a signal. */
 306     pt = &ts->timer_list->active_timers;
 307     for(;;) {
 308         t = *pt;
 309         if (!t)
 310             break;
 311         if (t == ts) {
 312             *pt = t->next;
 313             break;
 314         }
 315         pt = &t->next;
 316     }
 317 }
 318
 319 /* modify the current timer so that it will be fired when current_time
 320    >= expire_time. The corresponding callback will be called. */
 321 void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
 322 {
 323     QEMUTimer **pt, *t;
 324
 325     timer_del(ts);
 326
 327     /* add the timer in the sorted list */
 328     /* NOTE: this code must be signal safe because
 329        timer_expired() can be called from a signal. */
 330     pt = &ts->timer_list->active_timers;
 331     for(;;) {
 332         t = *pt;
 333         if (!timer_expired_ns(t, expire_time)) {
 334             break;
 335         }
 336         pt = &t->next;
 337     }
 338     ts->expire_time = expire_time;
 339     ts->next = *pt;
 340     *pt = ts;
 341
 342     /* Rearm if necessary  */
 343     if (pt == &ts->timer_list->active_timers) {
 344         /* Interrupt execution to force deadline recalculation.  */
 345         qemu_clock_warp(ts->timer_list->clock->type);
 346         timerlist_notify(ts->timer_list);
 347     }
 348 }
 349
 350 void timer_mod(QEMUTimer *ts, int64_t expire_time)
 351 {
 352     timer_mod_ns(ts, expire_time * ts->scale);
 353 }
 354
 355 bool timer_pending(QEMUTimer *ts)
 356 {
 357     QEMUTimer *t;
 358     for (t = ts->timer_list->active_timers; t != NULL; t = t->next) {
 359         if (t == ts) {
 360             return true;
 361         }
 362     }
 363     return false;
 364 }
 365
 366 bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
 367 {
 368     return timer_expired_ns(timer_head, current_time * timer_head->scale);
 369 }
 370
 371 bool timerlist_run_timers(QEMUTimerList *timer_list)
 372 {
 373     QEMUTimer *ts;
 374     int64_t current_time;
 375     bool progress = false;
 376
 377     if (!timer_list->clock->enabled) {
 378         return progress;
 379     }
 380
 381     current_time = qemu_clock_get_ns(timer_list->clock->type);
 382     for(;;) {
 383         ts = timer_list->active_timers;
 384         if (!timer_expired_ns(ts, current_time)) {
 385             break;
 386         }
 387         /* remove timer from the list before calling the callback */
 388         timer_list->active_timers = ts->next;
 389         ts->next = NULL;
 390
 391         /* run the callback (the timer list can be modified) */
 392         ts->cb(ts->opaque);
 393         progress = true;
 394     }
 395     return progress;
 396 }
 397
 398 bool qemu_clock_run_timers(QEMUClockType type)
 399 {
 400     return timerlist_run_timers(main_loop_tlg.tl[type]);
 401 }
 402
 403 void timerlistgroup_init(QEMUTimerListGroup *tlg,
 404                          QEMUTimerListNotifyCB *cb, void *opaque)
 405 {
 406     QEMUClockType type;
 407     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 408         tlg->tl[type] = timerlist_new(type, cb, opaque);
 409     }
 410 }
 411
 412 void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
 413 {
 414     QEMUClockType type;
 415     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 416         timerlist_free(tlg->tl[type]);
 417     }
 418 }
 419
 420 bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
 421 {
 422     QEMUClockType type;
 423     bool progress = false;
 424     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 425         progress |= timerlist_run_timers(tlg->tl[type]);
 426     }
 427     return progress;
 428 }
 429
 430 int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
 431 {
 432     int64_t deadline = -1;
 433     QEMUClockType type;
 434     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 435         if (qemu_clock_use_for_deadline(tlg->tl[type]->clock->type)) {
 436             deadline = qemu_soonest_timeout(deadline,
 437                                             timerlist_deadline_ns(
 438                                                 tlg->tl[type]));
 439         }
 440     }
 441     return deadline;
 442 }
 443
 444 int64_t qemu_clock_get_ns(QEMUClockType type)
 445 {
 446     int64_t now, last;
 447     QEMUClock *clock = qemu_clock_ptr(type);
 448
 449     switch (type) {
 450     case QEMU_CLOCK_REALTIME:
 451         return get_clock();
 452     default:
 453     case QEMU_CLOCK_VIRTUAL:
 454         if (use_icount) {
 455             return cpu_get_icount();
 456         } else {
 457             return cpu_get_clock();
 458         }
 459     case QEMU_CLOCK_HOST:
 460         now = get_clock_realtime();
 461         last = clock->last;
 462         clock->last = now;
 463         if (now < last) {
 464             notifier_list_notify(&clock->reset_notifiers, &now);
 465         }
 466         return now;
 467     }
 468 }
 469
 470 void qemu_clock_register_reset_notifier(QEMUClockType type,
 471                                         Notifier *notifier)
 472 {
 473     QEMUClock *clock = qemu_clock_ptr(type);
 474     notifier_list_add(&clock->reset_notifiers, notifier);
 475 }
 476
 477 void qemu_clock_unregister_reset_notifier(QEMUClockType type,
 478                                           Notifier *notifier)
 479 {
 480     notifier_remove(notifier);
 481 }
 482
 483 void init_clocks(void)
 484 {
 485     QEMUClockType type;
 486     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 487         qemu_clock_init(type);
 488     }
 489
 490 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
 491     prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
 492 #endif
 493 }
 494
 495 uint64_t timer_expire_time_ns(QEMUTimer *ts)
 496 {
 497     return timer_pending(ts) ? ts->expire_time : -1;
 498 }
 499
 500 bool qemu_clock_run_all_timers(void)
 501 {
 502     bool progress = false;
 503     QEMUClockType type;
 504
 505     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 506         progress |= qemu_clock_run_timers(type);
 507     }
 508
 509     return progress;
 510 }