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 _WIN32
  37 #include <mmsystem.h>
  38 #endif
  39
  40 #ifdef CONFIG_PPOLL
  41 #include <poll.h>
  42 #endif
  43
  44 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
  45 #include <sys/prctl.h>
  46 #endif
  47
  48 /***********************************************************/
  49 /* timers */
  50
  51 struct QEMUClock {
  52     QEMUTimerList *main_loop_timerlist;
  53     QLIST_HEAD(, QEMUTimerList) timerlists;
  54
  55     NotifierList reset_notifiers;
  56     int64_t last;
  57
  58     QEMUClockType type;
  59     bool enabled;
  60 };
  61
  62 QEMUTimerListGroup main_loop_tlg;
  63 QEMUClock *qemu_clocks[QEMU_CLOCK_MAX];
  64
  65 /* A QEMUTimerList is a list of timers attached to a clock. More
  66  * than one QEMUTimerList can be attached to each clock, for instance
  67  * used by different AioContexts / threads. Each clock also has
  68  * a list of the QEMUTimerLists associated with it, in order that
  69  * reenabling the clock can call all the notifiers.
  70  */
  71
  72 struct QEMUTimerList {
  73     QEMUClock *clock;
  74     QEMUTimer *active_timers;
  75     QLIST_ENTRY(QEMUTimerList) list;
  76     QEMUTimerListNotifyCB *notify_cb;
  77     void *notify_opaque;
  78 };
  79
  80 struct qemu_alarm_timer {
  81     char const *name;
  82     int (*start)(struct qemu_alarm_timer *t);
  83     void (*stop)(struct qemu_alarm_timer *t);
  84     void (*rearm)(struct qemu_alarm_timer *t, int64_t nearest_delta_ns);
  85 #if defined(__linux__)
  86     timer_t timer;
  87     int fd;
  88 #elif defined(_WIN32)
  89     HANDLE timer;
  90 #endif
  91     bool expired;
  92     bool pending;
  93 };
  94
  95 static struct qemu_alarm_timer *alarm_timer;
  96
  97 static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
  98 {
  99     return timer_head && (timer_head->expire_time <= current_time);
 100 }
 101
 102 static int64_t qemu_next_alarm_deadline(void)
 103 {
 104     int64_t delta = INT64_MAX;
 105     int64_t rtdelta;
 106     int64_t hdelta;
 107
 108     if (!use_icount && vm_clock->enabled &&
 109         vm_clock->main_loop_timerlist->active_timers) {
 110         delta = vm_clock->main_loop_timerlist->active_timers->expire_time -
 111             qemu_get_clock_ns(vm_clock);
 112     }
 113     if (host_clock->enabled &&
 114         host_clock->main_loop_timerlist->active_timers) {
 115         hdelta = host_clock->main_loop_timerlist->active_timers->expire_time -
 116             qemu_get_clock_ns(host_clock);
 117         if (hdelta < delta) {
 118             delta = hdelta;
 119         }
 120     }
 121     if (rt_clock->enabled &&
 122         rt_clock->main_loop_timerlist->active_timers) {
 123         rtdelta = (rt_clock->main_loop_timerlist->active_timers->expire_time -
 124                    qemu_get_clock_ns(rt_clock));
 125         if (rtdelta < delta) {
 126             delta = rtdelta;
 127         }
 128     }
 129
 130     return delta;
 131 }
 132
 133 static void qemu_rearm_alarm_timer(struct qemu_alarm_timer *t)
 134 {
 135     int64_t nearest_delta_ns = qemu_next_alarm_deadline();
 136     if (nearest_delta_ns < INT64_MAX) {
 137         t->rearm(t, nearest_delta_ns);
 138     }
 139 }
 140
 141 /* TODO: MIN_TIMER_REARM_NS should be optimized */
 142 #define MIN_TIMER_REARM_NS 250000
 143
 144 #ifdef _WIN32
 145
 146 static int mm_start_timer(struct qemu_alarm_timer *t);
 147 static void mm_stop_timer(struct qemu_alarm_timer *t);
 148 static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);
 149
 150 static int win32_start_timer(struct qemu_alarm_timer *t);
 151 static void win32_stop_timer(struct qemu_alarm_timer *t);
 152 static void win32_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);
 153
 154 #else
 155
 156 static int unix_start_timer(struct qemu_alarm_timer *t);
 157 static void unix_stop_timer(struct qemu_alarm_timer *t);
 158 static void unix_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);
 159
 160 #ifdef __linux__
 161
 162 static int dynticks_start_timer(struct qemu_alarm_timer *t);
 163 static void dynticks_stop_timer(struct qemu_alarm_timer *t);
 164 static void dynticks_rearm_timer(struct qemu_alarm_timer *t, int64_t delta);
 165
 166 #endif /* __linux__ */
 167
 168 #endif /* _WIN32 */
 169
 170 static struct qemu_alarm_timer alarm_timers[] = {
 171 #ifndef _WIN32
 172 #ifdef __linux__
 173     {"dynticks", dynticks_start_timer,
 174      dynticks_stop_timer, dynticks_rearm_timer},
 175 #endif
 176     {"unix", unix_start_timer, unix_stop_timer, unix_rearm_timer},
 177 #else
 178     {"mmtimer", mm_start_timer, mm_stop_timer, mm_rearm_timer},
 179     {"dynticks", win32_start_timer, win32_stop_timer, win32_rearm_timer},
 180 #endif
 181     {NULL, }
 182 };
 183
 184 static void show_available_alarms(void)
 185 {
 186     int i;
 187
 188     printf("Available alarm timers, in order of precedence:\n");
 189     for (i = 0; alarm_timers[i].name; i++)
 190         printf("%s\n", alarm_timers[i].name);
 191 }
 192
 193 void configure_alarms(char const *opt)
 194 {
 195     int i;
 196     int cur = 0;
 197     int count = ARRAY_SIZE(alarm_timers) - 1;
 198     char *arg;
 199     char *name;
 200     struct qemu_alarm_timer tmp;
 201
 202     if (is_help_option(opt)) {
 203         show_available_alarms();
 204         exit(0);
 205     }
 206
 207     arg = g_strdup(opt);
 208
 209     /* Reorder the array */
 210     name = strtok(arg, ",");
 211     while (name) {
 212         for (i = 0; i < count && alarm_timers[i].name; i++) {
 213             if (!strcmp(alarm_timers[i].name, name))
 214                 break;
 215         }
 216
 217         if (i == count) {
 218             fprintf(stderr, "Unknown clock %s\n", name);
 219             goto next;
 220         }
 221
 222         if (i < cur)
 223             /* Ignore */
 224             goto next;
 225
 226         /* Swap */
 227         tmp = alarm_timers[i];
 228         alarm_timers[i] = alarm_timers[cur];
 229         alarm_timers[cur] = tmp;
 230
 231         cur++;
 232 next:
 233         name = strtok(NULL, ",");
 234     }
 235
 236     g_free(arg);
 237
 238     if (cur) {
 239         /* Disable remaining timers */
 240         for (i = cur; i < count; i++)
 241             alarm_timers[i].name = NULL;
 242     } else {
 243         show_available_alarms();
 244         exit(1);
 245     }
 246 }
 247
 248 static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock,
 249                                                QEMUTimerListNotifyCB *cb,
 250                                                void *opaque)
 251 {
 252     QEMUTimerList *timer_list;
 253
 254     /* Assert if we do not have a clock. If you see this
 255      * assertion in means that the clocks have not been
 256      * initialised before a timerlist is needed. This
 257      * normally happens if an AioContext is used before
 258      * init_clocks() is called within main().
 259      */
 260     assert(clock);
 261
 262     timer_list = g_malloc0(sizeof(QEMUTimerList));
 263     timer_list->clock = clock;
 264     timer_list->notify_cb = cb;
 265     timer_list->notify_opaque = opaque;
 266     QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
 267     return timer_list;
 268 }
 269
 270 QEMUTimerList *timerlist_new(QEMUClockType type,
 271                              QEMUTimerListNotifyCB *cb, void *opaque)
 272 {
 273     return timerlist_new_from_clock(qemu_clock_ptr(type), cb, opaque);
 274 }
 275
 276 void timerlist_free(QEMUTimerList *timer_list)
 277 {
 278     assert(!timerlist_has_timers(timer_list));
 279     if (timer_list->clock) {
 280         QLIST_REMOVE(timer_list, list);
 281         if (timer_list->clock->main_loop_timerlist == timer_list) {
 282             timer_list->clock->main_loop_timerlist = NULL;
 283         }
 284     }
 285     g_free(timer_list);
 286 }
 287
 288 static QEMUClock *qemu_clock_new(QEMUClockType type)
 289 {
 290     QEMUClock *clock;
 291
 292     clock = g_malloc0(sizeof(QEMUClock));
 293     clock->type = type;
 294     clock->enabled = true;
 295     clock->last = INT64_MIN;
 296     QLIST_INIT(&clock->timerlists);
 297     notifier_list_init(&clock->reset_notifiers);
 298     clock->main_loop_timerlist = timerlist_new_from_clock(clock, NULL, NULL);
 299     return clock;
 300 }
 301
 302 bool qemu_clock_use_for_deadline(QEMUClock *clock)
 303 {
 304     return !(use_icount && (clock->type == QEMU_CLOCK_VIRTUAL));
 305 }
 306
 307 void qemu_clock_enable(QEMUClock *clock, bool enabled)
 308 {
 309     bool old = clock->enabled;
 310     clock->enabled = enabled;
 311     if (enabled && !old) {
 312         qemu_rearm_alarm_timer(alarm_timer);
 313     }
 314 }
 315
 316 bool timerlist_has_timers(QEMUTimerList *timer_list)
 317 {
 318     return !!timer_list->active_timers;
 319 }
 320
 321 bool qemu_clock_has_timers(QEMUClock *clock)
 322 {
 323     return timerlist_has_timers(clock->main_loop_timerlist);
 324 }
 325
 326 bool timerlist_expired(QEMUTimerList *timer_list)
 327 {
 328     return (timer_list->active_timers &&
 329             timer_list->active_timers->expire_time <
 330             qemu_get_clock_ns(timer_list->clock));
 331 }
 332
 333 bool qemu_clock_expired(QEMUClock *clock)
 334 {
 335     return timerlist_expired(clock->main_loop_timerlist);
 336 }
 337
 338 int64_t timerlist_deadline(QEMUTimerList *timer_list)
 339 {
 340     /* To avoid problems with overflow limit this to 2^32.  */
 341     int64_t delta = INT32_MAX;
 342
 343     if (timer_list->clock->enabled && timer_list->active_timers) {
 344         delta = timer_list->active_timers->expire_time -
 345             qemu_get_clock_ns(timer_list->clock);
 346     }
 347     if (delta < 0) {
 348         delta = 0;
 349     }
 350     return delta;
 351 }
 352
 353 int64_t qemu_clock_deadline(QEMUClock *clock)
 354 {
 355     return timerlist_deadline(clock->main_loop_timerlist);
 356 }
 357
 358 /*
 359  * As above, but return -1 for no deadline, and do not cap to 2^32
 360  * as we know the result is always positive.
 361  */
 362
 363 int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
 364 {
 365     int64_t delta;
 366
 367     if (!timer_list->clock->enabled || !timer_list->active_timers) {
 368         return -1;
 369     }
 370
 371     delta = timer_list->active_timers->expire_time -
 372         qemu_get_clock_ns(timer_list->clock);
 373
 374     if (delta <= 0) {
 375         return 0;
 376     }
 377
 378     return delta;
 379 }
 380
 381 int64_t qemu_clock_deadline_ns(QEMUClock *clock)
 382 {
 383     return timerlist_deadline_ns(clock->main_loop_timerlist);
 384 }
 385
 386 QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list)
 387 {
 388     return timer_list->clock;
 389 }
 390
 391 QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock)
 392 {
 393     return clock->main_loop_timerlist;
 394 }
 395
 396 void timerlist_notify(QEMUTimerList *timer_list)
 397 {
 398     if (timer_list->notify_cb) {
 399         timer_list->notify_cb(timer_list->notify_opaque);
 400     } else {
 401         qemu_notify_event();
 402     }
 403 }
 404
 405 /* Transition function to convert a nanosecond timeout to ms
 406  * This is used where a system does not support ppoll
 407  */
 408 int qemu_timeout_ns_to_ms(int64_t ns)
 409 {
 410     int64_t ms;
 411     if (ns < 0) {
 412         return -1;
 413     }
 414
 415     if (!ns) {
 416         return 0;
 417     }
 418
 419     /* Always round up, because it's better to wait too long than to wait too
 420      * little and effectively busy-wait
 421      */
 422     ms = (ns + SCALE_MS - 1) / SCALE_MS;
 423
 424     /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
 425     if (ms > (int64_t) INT32_MAX) {
 426         ms = INT32_MAX;
 427     }
 428
 429     return (int) ms;
 430 }
 431
 432
 433 /* qemu implementation of g_poll which uses a nanosecond timeout but is
 434  * otherwise identical to g_poll
 435  */
 436 int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
 437 {
 438 #ifdef CONFIG_PPOLL
 439     if (timeout < 0) {
 440         return ppoll((struct pollfd *)fds, nfds, NULL, NULL);
 441     } else {
 442         struct timespec ts;
 443         ts.tv_sec = timeout / 1000000000LL;
 444         ts.tv_nsec = timeout % 1000000000LL;
 445         return ppoll((struct pollfd *)fds, nfds, &ts, NULL);
 446     }
 447 #else
 448     return g_poll(fds, nfds, qemu_timeout_ns_to_ms(timeout));
 449 #endif
 450 }
 451
 452
 453 void timer_init(QEMUTimer *ts,
 454                 QEMUTimerList *timer_list, int scale,
 455                 QEMUTimerCB *cb, void *opaque)
 456 {
 457     ts->timer_list = timer_list;
 458     ts->cb = cb;
 459     ts->opaque = opaque;
 460     ts->scale = scale;
 461 }
 462
 463 QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
 464                           QEMUTimerCB *cb, void *opaque)
 465 {
 466     return timer_new_tl(clock->main_loop_timerlist,
 467                      scale, cb, opaque);
 468 }
 469
 470 void qemu_free_timer(QEMUTimer *ts)
 471 {
 472     g_free(ts);
 473 }
 474
 475 /* stop a timer, but do not dealloc it */
 476 void qemu_del_timer(QEMUTimer *ts)
 477 {
 478     QEMUTimer **pt, *t;
 479
 480     /* NOTE: this code must be signal safe because
 481        timer_expired() can be called from a signal. */
 482     pt = &ts->timer_list->active_timers;
 483     for(;;) {
 484         t = *pt;
 485         if (!t)
 486             break;
 487         if (t == ts) {
 488             *pt = t->next;
 489             break;
 490         }
 491         pt = &t->next;
 492     }
 493 }
 494
 495 /* modify the current timer so that it will be fired when current_time
 496    >= expire_time. The corresponding callback will be called. */
 497 void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
 498 {
 499     QEMUTimer **pt, *t;
 500
 501     qemu_del_timer(ts);
 502
 503     /* add the timer in the sorted list */
 504     /* NOTE: this code must be signal safe because
 505        timer_expired() can be called from a signal. */
 506     pt = &ts->timer_list->active_timers;
 507     for(;;) {
 508         t = *pt;
 509         if (!timer_expired_ns(t, expire_time)) {
 510             break;
 511         }
 512         pt = &t->next;
 513     }
 514     ts->expire_time = expire_time;
 515     ts->next = *pt;
 516     *pt = ts;
 517
 518     /* Rearm if necessary  */
 519     if (pt == &ts->timer_list->active_timers) {
 520         if (!alarm_timer->pending) {
 521             qemu_rearm_alarm_timer(alarm_timer);
 522         }
 523         /* Interrupt execution to force deadline recalculation.  */
 524         qemu_clock_warp(ts->timer_list->clock);
 525         if (use_icount) {
 526             timerlist_notify(ts->timer_list);
 527         }
 528     }
 529 }
 530
 531 void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
 532 {
 533     qemu_mod_timer_ns(ts, expire_time * ts->scale);
 534 }
 535
 536 bool timer_pending(QEMUTimer *ts)
 537 {
 538     QEMUTimer *t;
 539     for (t = ts->timer_list->active_timers; t != NULL; t = t->next) {
 540         if (t == ts) {
 541             return true;
 542         }
 543     }
 544     return false;
 545 }
 546
 547 bool timer_expired(QEMUTimer *timer_head, int64_t current_time)
 548 {
 549     return timer_expired_ns(timer_head, current_time * timer_head->scale);
 550 }
 551
 552 bool timerlist_run_timers(QEMUTimerList *timer_list)
 553 {
 554     QEMUTimer *ts;
 555     int64_t current_time;
 556     bool progress = false;
 557
 558     if (!timer_list->clock->enabled) {
 559         return progress;
 560     }
 561
 562     current_time = qemu_get_clock_ns(timer_list->clock);
 563     for(;;) {
 564         ts = timer_list->active_timers;
 565         if (!timer_expired_ns(ts, current_time)) {
 566             break;
 567         }
 568         /* remove timer from the list before calling the callback */
 569         timer_list->active_timers = ts->next;
 570         ts->next = NULL;
 571
 572         /* run the callback (the timer list can be modified) */
 573         ts->cb(ts->opaque);
 574         progress = true;
 575     }
 576     return progress;
 577 }
 578
 579 bool qemu_run_timers(QEMUClock *clock)
 580 {
 581     return timerlist_run_timers(clock->main_loop_timerlist);
 582 }
 583
 584 void timerlistgroup_init(QEMUTimerListGroup *tlg,
 585                          QEMUTimerListNotifyCB *cb, void *opaque)
 586 {
 587     QEMUClockType type;
 588     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 589         tlg->tl[type] = timerlist_new(type, cb, opaque);
 590     }
 591 }
 592
 593 void timerlistgroup_deinit(QEMUTimerListGroup *tlg)
 594 {
 595     QEMUClockType type;
 596     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 597         timerlist_free(tlg->tl[type]);
 598     }
 599 }
 600
 601 bool timerlistgroup_run_timers(QEMUTimerListGroup *tlg)
 602 {
 603     QEMUClockType type;
 604     bool progress = false;
 605     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 606         progress |= timerlist_run_timers(tlg->tl[type]);
 607     }
 608     return progress;
 609 }
 610
 611 int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg)
 612 {
 613     int64_t deadline = -1;
 614     QEMUClockType type;
 615     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 616         if (qemu_clock_use_for_deadline(tlg->tl[type]->clock)) {
 617             deadline = qemu_soonest_timeout(deadline,
 618                                             timerlist_deadline_ns(
 619                                                 tlg->tl[type]));
 620         }
 621     }
 622     return deadline;
 623 }
 624
 625 int64_t qemu_get_clock_ns(QEMUClock *clock)
 626 {
 627     int64_t now, last;
 628
 629     switch(clock->type) {
 630     case QEMU_CLOCK_REALTIME:
 631         return get_clock();
 632     default:
 633     case QEMU_CLOCK_VIRTUAL:
 634         if (use_icount) {
 635             return cpu_get_icount();
 636         } else {
 637             return cpu_get_clock();
 638         }
 639     case QEMU_CLOCK_HOST:
 640         now = get_clock_realtime();
 641         last = clock->last;
 642         clock->last = now;
 643         if (now < last) {
 644             notifier_list_notify(&clock->reset_notifiers, &now);
 645         }
 646         return now;
 647     }
 648 }
 649
 650 void qemu_register_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)
 651 {
 652     notifier_list_add(&clock->reset_notifiers, notifier);
 653 }
 654
 655 void qemu_unregister_clock_reset_notifier(QEMUClock *clock, Notifier *notifier)
 656 {
 657     notifier_remove(notifier);
 658 }
 659
 660 void init_clocks(void)
 661 {
 662     QEMUClockType type;
 663     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 664         if (!qemu_clocks[type]) {
 665             qemu_clocks[type] = qemu_clock_new(type);
 666             main_loop_tlg.tl[type] = qemu_clocks[type]->main_loop_timerlist;
 667         }
 668     }
 669
 670 #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
 671     prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
 672 #endif
 673 }
 674
 675 uint64_t timer_expire_time_ns(QEMUTimer *ts)
 676 {
 677     return timer_pending(ts) ? ts->expire_time : -1;
 678 }
 679
 680 bool qemu_run_all_timers(void)
 681 {
 682     bool progress = false;
 683     alarm_timer->pending = false;
 684
 685     /* vm time timers */
 686     QEMUClockType type;
 687     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
 688         progress |= qemu_run_timers(qemu_clock_ptr(type));
 689     }
 690
 691     /* rearm timer, if not periodic */
 692     if (alarm_timer->expired) {
 693         alarm_timer->expired = false;
 694         qemu_rearm_alarm_timer(alarm_timer);
 695     }
 696
 697     return progress;
 698 }
 699
 700 #ifdef _WIN32
 701 static void CALLBACK host_alarm_handler(PVOID lpParam, BOOLEAN unused)
 702 #else
 703 static void host_alarm_handler(int host_signum)
 704 #endif
 705 {
 706     struct qemu_alarm_timer *t = alarm_timer;
 707     if (!t)
 708         return;
 709
 710     t->expired = true;
 711     t->pending = true;
 712     qemu_notify_event();
 713 }
 714
 715 #if defined(__linux__)
 716
 717 #include "qemu/compatfd.h"
 718
 719 static int dynticks_start_timer(struct qemu_alarm_timer *t)
 720 {
 721     struct sigevent ev;
 722     timer_t host_timer;
 723     struct sigaction act;
 724
 725     sigfillset(&act.sa_mask);
 726     act.sa_flags = 0;
 727     act.sa_handler = host_alarm_handler;
 728
 729     sigaction(SIGALRM, &act, NULL);
 730
 731     /*
 732      * Initialize ev struct to 0 to avoid valgrind complaining
 733      * about uninitialized data in timer_create call
 734      */
 735     memset(&ev, 0, sizeof(ev));
 736     ev.sigev_value.sival_int = 0;
 737     ev.sigev_notify = SIGEV_SIGNAL;
 738 #ifdef CONFIG_SIGEV_THREAD_ID
 739     if (qemu_signalfd_available()) {
 740         ev.sigev_notify = SIGEV_THREAD_ID;
 741         ev._sigev_un._tid = qemu_get_thread_id();
 742     }
 743 #endif /* CONFIG_SIGEV_THREAD_ID */
 744     ev.sigev_signo = SIGALRM;
 745
 746     if (timer_create(CLOCK_REALTIME, &ev, &host_timer)) {
 747         perror("timer_create");
 748         return -1;
 749     }
 750
 751     t->timer = host_timer;
 752
 753     return 0;
 754 }
 755
 756 static void dynticks_stop_timer(struct qemu_alarm_timer *t)
 757 {
 758     timer_t host_timer = t->timer;
 759
 760     timer_delete(host_timer);
 761 }
 762
 763 static void dynticks_rearm_timer(struct qemu_alarm_timer *t,
 764                                  int64_t nearest_delta_ns)
 765 {
 766     timer_t host_timer = t->timer;
 767     struct itimerspec timeout;
 768     int64_t current_ns;
 769
 770     if (nearest_delta_ns < MIN_TIMER_REARM_NS)
 771         nearest_delta_ns = MIN_TIMER_REARM_NS;
 772
 773     /* check whether a timer is already running */
 774     if (timer_gettime(host_timer, &timeout)) {
 775         perror("gettime");
 776         fprintf(stderr, "Internal timer error: aborting\n");
 777         exit(1);
 778     }
 779     current_ns = timeout.it_value.tv_sec * 1000000000LL + timeout.it_value.tv_nsec;
 780     if (current_ns && current_ns <= nearest_delta_ns)
 781         return;
 782
 783     timeout.it_interval.tv_sec = 0;
 784     timeout.it_interval.tv_nsec = 0; /* 0 for one-shot timer */
 785     timeout.it_value.tv_sec =  nearest_delta_ns / 1000000000;
 786     timeout.it_value.tv_nsec = nearest_delta_ns % 1000000000;
 787     if (timer_settime(host_timer, 0 /* RELATIVE */, &timeout, NULL)) {
 788         perror("settime");
 789         fprintf(stderr, "Internal timer error: aborting\n");
 790         exit(1);
 791     }
 792 }
 793
 794 #endif /* defined(__linux__) */
 795
 796 #if !defined(_WIN32)
 797
 798 static int unix_start_timer(struct qemu_alarm_timer *t)
 799 {
 800     struct sigaction act;
 801
 802     /* timer signal */
 803     sigfillset(&act.sa_mask);
 804     act.sa_flags = 0;
 805     act.sa_handler = host_alarm_handler;
 806
 807     sigaction(SIGALRM, &act, NULL);
 808     return 0;
 809 }
 810
 811 static void unix_rearm_timer(struct qemu_alarm_timer *t,
 812                              int64_t nearest_delta_ns)
 813 {
 814     struct itimerval itv;
 815     int err;
 816
 817     if (nearest_delta_ns < MIN_TIMER_REARM_NS)
 818         nearest_delta_ns = MIN_TIMER_REARM_NS;
 819
 820     itv.it_interval.tv_sec = 0;
 821     itv.it_interval.tv_usec = 0; /* 0 for one-shot timer */
 822     itv.it_value.tv_sec =  nearest_delta_ns / 1000000000;
 823     itv.it_value.tv_usec = (nearest_delta_ns % 1000000000) / 1000;
 824     err = setitimer(ITIMER_REAL, &itv, NULL);
 825     if (err) {
 826         perror("setitimer");
 827         fprintf(stderr, "Internal timer error: aborting\n");
 828         exit(1);
 829     }
 830 }
 831
 832 static void unix_stop_timer(struct qemu_alarm_timer *t)
 833 {
 834     struct itimerval itv;
 835
 836     memset(&itv, 0, sizeof(itv));
 837     setitimer(ITIMER_REAL, &itv, NULL);
 838 }
 839
 840 #endif /* !defined(_WIN32) */
 841
 842
 843 #ifdef _WIN32
 844
 845 static MMRESULT mm_timer;
 846 static TIMECAPS mm_tc;
 847
 848 static void CALLBACK mm_alarm_handler(UINT uTimerID, UINT uMsg,
 849                                       DWORD_PTR dwUser, DWORD_PTR dw1,
 850                                       DWORD_PTR dw2)
 851 {
 852     struct qemu_alarm_timer *t = alarm_timer;
 853     if (!t) {
 854         return;
 855     }
 856     t->expired = true;
 857     t->pending = true;
 858     qemu_notify_event();
 859 }
 860
 861 static int mm_start_timer(struct qemu_alarm_timer *t)
 862 {
 863     timeGetDevCaps(&mm_tc, sizeof(mm_tc));
 864     return 0;
 865 }
 866
 867 static void mm_stop_timer(struct qemu_alarm_timer *t)
 868 {
 869     if (mm_timer) {
 870         timeKillEvent(mm_timer);
 871     }
 872 }
 873
 874 static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta)
 875 {
 876     int64_t nearest_delta_ms = delta / 1000000;
 877     if (nearest_delta_ms < mm_tc.wPeriodMin) {
 878         nearest_delta_ms = mm_tc.wPeriodMin;
 879     } else if (nearest_delta_ms > mm_tc.wPeriodMax) {
 880         nearest_delta_ms = mm_tc.wPeriodMax;
 881     }
 882
 883     if (mm_timer) {
 884         timeKillEvent(mm_timer);
 885     }
 886     mm_timer = timeSetEvent((UINT)nearest_delta_ms,
 887                             mm_tc.wPeriodMin,
 888                             mm_alarm_handler,
 889                             (DWORD_PTR)t,
 890                             TIME_ONESHOT | TIME_CALLBACK_FUNCTION);
 891
 892     if (!mm_timer) {
 893         fprintf(stderr, "Failed to re-arm win32 alarm timer\n");
 894         timeEndPeriod(mm_tc.wPeriodMin);
 895         exit(1);
 896     }
 897 }
 898
 899 static int win32_start_timer(struct qemu_alarm_timer *t)
 900 {
 901     HANDLE hTimer;
 902     BOOLEAN success;
 903
 904     /* If you call ChangeTimerQueueTimer on a one-shot timer (its period
 905        is zero) that has already expired, the timer is not updated.  Since
 906        creating a new timer is relatively expensive, set a bogus one-hour
 907        interval in the dynticks case.  */
 908     success = CreateTimerQueueTimer(&hTimer,
 909                           NULL,
 910                           host_alarm_handler,
 911                           t,
 912                           1,
 913                           3600000,
 914                           WT_EXECUTEINTIMERTHREAD);
 915
 916     if (!success) {
 917         fprintf(stderr, "Failed to initialize win32 alarm timer: %ld\n",
 918                 GetLastError());
 919         return -1;
 920     }
 921
 922     t->timer = hTimer;
 923     return 0;
 924 }
 925
 926 static void win32_stop_timer(struct qemu_alarm_timer *t)
 927 {
 928     HANDLE hTimer = t->timer;
 929
 930     if (hTimer) {
 931         DeleteTimerQueueTimer(NULL, hTimer, NULL);
 932     }
 933 }
 934
 935 static void win32_rearm_timer(struct qemu_alarm_timer *t,
 936                               int64_t nearest_delta_ns)
 937 {
 938     HANDLE hTimer = t->timer;
 939     int64_t nearest_delta_ms;
 940     BOOLEAN success;
 941
 942     nearest_delta_ms = nearest_delta_ns / 1000000;
 943     if (nearest_delta_ms < 1) {
 944         nearest_delta_ms = 1;
 945     }
 946     /* ULONG_MAX can be 32 bit */
 947     if (nearest_delta_ms > ULONG_MAX) {
 948         nearest_delta_ms = ULONG_MAX;
 949     }
 950     success = ChangeTimerQueueTimer(NULL,
 951                                     hTimer,
 952                                     (unsigned long) nearest_delta_ms,
 953                                     3600000);
 954
 955     if (!success) {
 956         fprintf(stderr, "Failed to rearm win32 alarm timer: %ld\n",
 957                 GetLastError());
 958         exit(-1);
 959     }
 960
 961 }
 962
 963 #endif /* _WIN32 */
 964
 965 static void quit_timers(void)
 966 {
 967     struct qemu_alarm_timer *t = alarm_timer;
 968     alarm_timer = NULL;
 969     t->stop(t);
 970 }
 971
 972 #ifdef CONFIG_POSIX
 973 static void reinit_timers(void)
 974 {
 975     struct qemu_alarm_timer *t = alarm_timer;
 976     t->stop(t);
 977     if (t->start(t)) {
 978         fprintf(stderr, "Internal timer error: aborting\n");
 979         exit(1);
 980     }
 981     qemu_rearm_alarm_timer(t);
 982 }
 983 #endif /* CONFIG_POSIX */
 984
 985 int init_timer_alarm(void)
 986 {
 987     struct qemu_alarm_timer *t = NULL;
 988     int i, err = -1;
 989
 990     if (alarm_timer) {
 991         return 0;
 992     }
 993
 994     for (i = 0; alarm_timers[i].name; i++) {
 995         t = &alarm_timers[i];
 996
 997         err = t->start(t);
 998         if (!err)
 999             break;
1000     }
1001
1002     if (err) {
1003         err = -ENOENT;
1004         goto fail;
1005     }
1006
1007     atexit(quit_timers);
1008 #ifdef CONFIG_POSIX
1009     pthread_atfork(NULL, NULL, reinit_timers);
1010 #endif
1011     alarm_timer = t;
1012     return 0;
1013
1014 fail:
1015     return err;
1016 }
1017