cpus.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 /* Needed early for CONFIG_BSD etc. */
  26 #include "config-host.h"
  27
  28 #include "monitor.h"
  29 #include "sysemu.h"
  30 #include "gdbstub.h"
  31 #include "dma.h"
  32 #include "kvm.h"
  33
  34 #include "cpus.h"
  35
  36 #ifdef SIGRTMIN
  37 #define SIG_IPI (SIGRTMIN+4)
  38 #else
  39 #define SIG_IPI SIGUSR1
  40 #endif
  41
  42 static CPUState *cur_cpu;
  43 static CPUState *next_cpu;
  44
  45 /***********************************************************/
  46 void hw_error(const char *fmt, ...)
  47 {
  48     va_list ap;
  49     CPUState *env;
  50
  51     va_start(ap, fmt);
  52     fprintf(stderr, "qemu: hardware error: ");
  53     vfprintf(stderr, fmt, ap);
  54     fprintf(stderr, "\n");
  55     for(env = first_cpu; env != NULL; env = env->next_cpu) {
  56         fprintf(stderr, "CPU #%d:\n", env->cpu_index);
  57 #ifdef TARGET_I386
  58         cpu_dump_state(env, stderr, fprintf, X86_DUMP_FPU);
  59 #else
  60         cpu_dump_state(env, stderr, fprintf, 0);
  61 #endif
  62     }
  63     va_end(ap);
  64     abort();
  65 }
  66
  67 void cpu_synchronize_all_states(void)
  68 {
  69     CPUState *cpu;
  70
  71     for (cpu = first_cpu; cpu; cpu = cpu->next_cpu) {
  72         cpu_synchronize_state(cpu);
  73     }
  74 }
  75
  76 void cpu_synchronize_all_post_reset(void)
  77 {
  78     CPUState *cpu;
  79
  80     for (cpu = first_cpu; cpu; cpu = cpu->next_cpu) {
  81         cpu_synchronize_post_reset(cpu);
  82     }
  83 }
  84
  85 void cpu_synchronize_all_post_init(void)
  86 {
  87     CPUState *cpu;
  88
  89     for (cpu = first_cpu; cpu; cpu = cpu->next_cpu) {
  90         cpu_synchronize_post_init(cpu);
  91     }
  92 }
  93
  94 int cpu_is_stopped(CPUState *env)
  95 {
  96     return !vm_running || env->stopped;
  97 }
  98
  99 static void do_vm_stop(int reason)
 100 {
 101     if (vm_running) {
 102         cpu_disable_ticks();
 103         vm_running = 0;
 104         pause_all_vcpus();
 105         vm_state_notify(0, reason);
 106         monitor_protocol_event(QEVENT_STOP, NULL);
 107     }
 108 }
 109
 110 static int cpu_can_run(CPUState *env)
 111 {
 112     if (env->stop)
 113         return 0;
 114     if (env->stopped || !vm_running)
 115         return 0;
 116     return 1;
 117 }
 118
 119 static int cpu_has_work(CPUState *env)
 120 {
 121     if (env->stop)
 122         return 1;
 123     if (env->queued_work_first)
 124         return 1;
 125     if (env->stopped || !vm_running)
 126         return 0;
 127     if (!env->halted)
 128         return 1;
 129     if (qemu_cpu_has_work(env))
 130         return 1;
 131     return 0;
 132 }
 133
 134 static int tcg_has_work(void)
 135 {
 136     CPUState *env;
 137
 138     for (env = first_cpu; env != NULL; env = env->next_cpu)
 139         if (cpu_has_work(env))
 140             return 1;
 141     return 0;
 142 }
 143
 144 #ifndef _WIN32
 145 static int io_thread_fd = -1;
 146
 147 static void qemu_event_increment(void)
 148 {
 149     /* Write 8 bytes to be compatible with eventfd.  */
 150     static const uint64_t val = 1;
 151     ssize_t ret;
 152
 153     if (io_thread_fd == -1)
 154         return;
 155
 156     do {
 157         ret = write(io_thread_fd, &val, sizeof(val));
 158     } while (ret < 0 && errno == EINTR);
 159
 160     /* EAGAIN is fine, a read must be pending.  */
 161     if (ret < 0 && errno != EAGAIN) {
 162         fprintf(stderr, "qemu_event_increment: write() filed: %s\n",
 163                 strerror(errno));
 164         exit (1);
 165     }
 166 }
 167
 168 static void qemu_event_read(void *opaque)
 169 {
 170     int fd = (unsigned long)opaque;
 171     ssize_t len;
 172     char buffer[512];
 173
 174     /* Drain the notify pipe.  For eventfd, only 8 bytes will be read.  */
 175     do {
 176         len = read(fd, buffer, sizeof(buffer));
 177     } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
 178 }
 179
 180 static int qemu_event_init(void)
 181 {
 182     int err;
 183     int fds[2];
 184
 185     err = qemu_eventfd(fds);
 186     if (err == -1)
 187         return -errno;
 188
 189     err = fcntl_setfl(fds[0], O_NONBLOCK);
 190     if (err < 0)
 191         goto fail;
 192
 193     err = fcntl_setfl(fds[1], O_NONBLOCK);
 194     if (err < 0)
 195         goto fail;
 196
 197     qemu_set_fd_handler2(fds[0], NULL, qemu_event_read, NULL,
 198                          (void *)(unsigned long)fds[0]);
 199
 200     io_thread_fd = fds[1];
 201     return 0;
 202
 203 fail:
 204     close(fds[0]);
 205     close(fds[1]);
 206     return err;
 207 }
 208 #else
 209 HANDLE qemu_event_handle;
 210
 211 static void dummy_event_handler(void *opaque)
 212 {
 213 }
 214
 215 static int qemu_event_init(void)
 216 {
 217     qemu_event_handle = CreateEvent(NULL, FALSE, FALSE, NULL);
 218     if (!qemu_event_handle) {
 219         fprintf(stderr, "Failed CreateEvent: %ld\n", GetLastError());
 220         return -1;
 221     }
 222     qemu_add_wait_object(qemu_event_handle, dummy_event_handler, NULL);
 223     return 0;
 224 }
 225
 226 static void qemu_event_increment(void)
 227 {
 228     if (!SetEvent(qemu_event_handle)) {
 229         fprintf(stderr, "qemu_event_increment: SetEvent failed: %ld\n",
 230                 GetLastError());
 231         exit (1);
 232     }
 233 }
 234 #endif
 235
 236 #ifndef CONFIG_IOTHREAD
 237 int qemu_init_main_loop(void)
 238 {
 239     return qemu_event_init();
 240 }
 241
 242 void qemu_main_loop_start(void)
 243 {
 244 }
 245
 246 void qemu_init_vcpu(void *_env)
 247 {
 248     CPUState *env = _env;
 249
 250     env->nr_cores = smp_cores;
 251     env->nr_threads = smp_threads;
 252     if (kvm_enabled())
 253         kvm_init_vcpu(env);
 254     return;
 255 }
 256
 257 int qemu_cpu_self(void *env)
 258 {
 259     return 1;
 260 }
 261
 262 void run_on_cpu(CPUState *env, void (*func)(void *data), void *data)
 263 {
 264     func(data);
 265 }
 266
 267 void resume_all_vcpus(void)
 268 {
 269 }
 270
 271 void pause_all_vcpus(void)
 272 {
 273 }
 274
 275 void qemu_cpu_kick(void *env)
 276 {
 277     return;
 278 }
 279
 280 void qemu_notify_event(void)
 281 {
 282     CPUState *env = cpu_single_env;
 283
 284     qemu_event_increment ();
 285     if (env) {
 286         cpu_exit(env);
 287     }
 288     if (next_cpu && env != next_cpu) {
 289         cpu_exit(next_cpu);
 290     }
 291 }
 292
 293 void qemu_mutex_lock_iothread(void) {}
 294 void qemu_mutex_unlock_iothread(void) {}
 295
 296 void vm_stop(int reason)
 297 {
 298     do_vm_stop(reason);
 299 }
 300
 301 #else /* CONFIG_IOTHREAD */
 302
 303 #include "qemu-thread.h"
 304
 305 QemuMutex qemu_global_mutex;
 306 static QemuMutex qemu_fair_mutex;
 307
 308 static QemuThread io_thread;
 309
 310 static QemuThread *tcg_cpu_thread;
 311 static QemuCond *tcg_halt_cond;
 312
 313 static int qemu_system_ready;
 314 /* cpu creation */
 315 static QemuCond qemu_cpu_cond;
 316 /* system init */
 317 static QemuCond qemu_system_cond;
 318 static QemuCond qemu_pause_cond;
 319 static QemuCond qemu_work_cond;
 320
 321 static void tcg_init_ipi(void);
 322 static void kvm_init_ipi(CPUState *env);
 323 static void unblock_io_signals(void);
 324
 325 int qemu_init_main_loop(void)
 326 {
 327     int ret;
 328
 329     ret = qemu_event_init();
 330     if (ret)
 331         return ret;
 332
 333     qemu_cond_init(&qemu_pause_cond);
 334     qemu_mutex_init(&qemu_fair_mutex);
 335     qemu_mutex_init(&qemu_global_mutex);
 336     qemu_mutex_lock(&qemu_global_mutex);
 337
 338     unblock_io_signals();
 339     qemu_thread_self(&io_thread);
 340
 341     return 0;
 342 }
 343
 344 void qemu_main_loop_start(void)
 345 {
 346     qemu_system_ready = 1;
 347     qemu_cond_broadcast(&qemu_system_cond);
 348 }
 349
 350 void run_on_cpu(CPUState *env, void (*func)(void *data), void *data)
 351 {
 352     struct qemu_work_item wi;
 353
 354     if (qemu_cpu_self(env)) {
 355         func(data);
 356         return;
 357     }
 358
 359     wi.func = func;
 360     wi.data = data;
 361     if (!env->queued_work_first)
 362         env->queued_work_first = &wi;
 363     else
 364         env->queued_work_last->next = &wi;
 365     env->queued_work_last = &wi;
 366     wi.next = NULL;
 367     wi.done = false;
 368
 369     qemu_cpu_kick(env);
 370     while (!wi.done) {
 371         CPUState *self_env = cpu_single_env;
 372
 373         qemu_cond_wait(&qemu_work_cond, &qemu_global_mutex);
 374         cpu_single_env = self_env;
 375     }
 376 }
 377
 378 static void flush_queued_work(CPUState *env)
 379 {
 380     struct qemu_work_item *wi;
 381
 382     if (!env->queued_work_first)
 383         return;
 384
 385     while ((wi = env->queued_work_first)) {
 386         env->queued_work_first = wi->next;
 387         wi->func(wi->data);
 388         wi->done = true;
 389     }
 390     env->queued_work_last = NULL;
 391     qemu_cond_broadcast(&qemu_work_cond);
 392 }
 393
 394 static void qemu_wait_io_event_common(CPUState *env)
 395 {
 396     if (env->stop) {
 397         env->stop = 0;
 398         env->stopped = 1;
 399         qemu_cond_signal(&qemu_pause_cond);
 400     }
 401     flush_queued_work(env);
 402 }
 403
 404 static void qemu_wait_io_event(CPUState *env)
 405 {
 406     while (!tcg_has_work())
 407         qemu_cond_timedwait(env->halt_cond, &qemu_global_mutex, 1000);
 408
 409     qemu_mutex_unlock(&qemu_global_mutex);
 410
 411     /*
 412      * Users of qemu_global_mutex can be starved, having no chance
 413      * to acquire it since this path will get to it first.
 414      * So use another lock to provide fairness.
 415      */
 416     qemu_mutex_lock(&qemu_fair_mutex);
 417     qemu_mutex_unlock(&qemu_fair_mutex);
 418
 419     qemu_mutex_lock(&qemu_global_mutex);
 420     qemu_wait_io_event_common(env);
 421 }
 422
 423 static void qemu_kvm_eat_signal(CPUState *env, int timeout)
 424 {
 425     struct timespec ts;
 426     int r, e;
 427     siginfo_t siginfo;
 428     sigset_t waitset;
 429
 430     ts.tv_sec = timeout / 1000;
 431     ts.tv_nsec = (timeout % 1000) * 1000000;
 432
 433     sigemptyset(&waitset);
 434     sigaddset(&waitset, SIG_IPI);
 435
 436     qemu_mutex_unlock(&qemu_global_mutex);
 437     r = sigtimedwait(&waitset, &siginfo, &ts);
 438     e = errno;
 439     qemu_mutex_lock(&qemu_global_mutex);
 440
 441     if (r == -1 && !(e == EAGAIN || e == EINTR)) {
 442         fprintf(stderr, "sigtimedwait: %s\n", strerror(e));
 443         exit(1);
 444     }
 445 }
 446
 447 static void qemu_kvm_wait_io_event(CPUState *env)
 448 {
 449     while (!cpu_has_work(env))
 450         qemu_cond_timedwait(env->halt_cond, &qemu_global_mutex, 1000);
 451
 452     qemu_kvm_eat_signal(env, 0);
 453     qemu_wait_io_event_common(env);
 454 }
 455
 456 static int qemu_cpu_exec(CPUState *env);
 457
 458 static void *kvm_cpu_thread_fn(void *arg)
 459 {
 460     CPUState *env = arg;
 461
 462     qemu_mutex_lock(&qemu_global_mutex);
 463     qemu_thread_self(env->thread);
 464     if (kvm_enabled())
 465         kvm_init_vcpu(env);
 466
 467     kvm_init_ipi(env);
 468
 469     /* signal CPU creation */
 470     env->created = 1;
 471     qemu_cond_signal(&qemu_cpu_cond);
 472
 473     /* and wait for machine initialization */
 474     while (!qemu_system_ready)
 475         qemu_cond_timedwait(&qemu_system_cond, &qemu_global_mutex, 100);
 476
 477     while (1) {
 478         if (cpu_can_run(env))
 479             qemu_cpu_exec(env);
 480         qemu_kvm_wait_io_event(env);
 481     }
 482
 483     return NULL;
 484 }
 485
 486 static void *tcg_cpu_thread_fn(void *arg)
 487 {
 488     CPUState *env = arg;
 489
 490     tcg_init_ipi();
 491     qemu_thread_self(env->thread);
 492
 493     /* signal CPU creation */
 494     qemu_mutex_lock(&qemu_global_mutex);
 495     for (env = first_cpu; env != NULL; env = env->next_cpu)
 496         env->created = 1;
 497     qemu_cond_signal(&qemu_cpu_cond);
 498
 499     /* and wait for machine initialization */
 500     while (!qemu_system_ready)
 501         qemu_cond_timedwait(&qemu_system_cond, &qemu_global_mutex, 100);
 502
 503     while (1) {
 504         tcg_cpu_exec();
 505         qemu_wait_io_event(cur_cpu);
 506     }
 507
 508     return NULL;
 509 }
 510
 511 void qemu_cpu_kick(void *_env)
 512 {
 513     CPUState *env = _env;
 514     qemu_cond_broadcast(env->halt_cond);
 515     qemu_thread_signal(env->thread, SIG_IPI);
 516 }
 517
 518 int qemu_cpu_self(void *_env)
 519 {
 520     CPUState *env = _env;
 521     QemuThread this;
 522
 523     qemu_thread_self(&this);
 524
 525     return qemu_thread_equal(&this, env->thread);
 526 }
 527
 528 static void cpu_signal(int sig)
 529 {
 530     if (cpu_single_env)
 531         cpu_exit(cpu_single_env);
 532     exit_request = 1;
 533 }
 534
 535 static void tcg_init_ipi(void)
 536 {
 537     sigset_t set;
 538     struct sigaction sigact;
 539
 540     memset(&sigact, 0, sizeof(sigact));
 541     sigact.sa_handler = cpu_signal;
 542     sigaction(SIG_IPI, &sigact, NULL);
 543
 544     sigemptyset(&set);
 545     sigaddset(&set, SIG_IPI);
 546     pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 547 }
 548
 549 static void dummy_signal(int sig)
 550 {
 551 }
 552
 553 static void kvm_init_ipi(CPUState *env)
 554 {
 555     int r;
 556     sigset_t set;
 557     struct sigaction sigact;
 558
 559     memset(&sigact, 0, sizeof(sigact));
 560     sigact.sa_handler = dummy_signal;
 561     sigaction(SIG_IPI, &sigact, NULL);
 562
 563     pthread_sigmask(SIG_BLOCK, NULL, &set);
 564     sigdelset(&set, SIG_IPI);
 565     r = kvm_set_signal_mask(env, &set);
 566     if (r) {
 567         fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(r));
 568         exit(1);
 569     }
 570 }
 571
 572 static void unblock_io_signals(void)
 573 {
 574     sigset_t set;
 575
 576     sigemptyset(&set);
 577     sigaddset(&set, SIGUSR2);
 578     sigaddset(&set, SIGIO);
 579     sigaddset(&set, SIGALRM);
 580     pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 581
 582     sigemptyset(&set);
 583     sigaddset(&set, SIG_IPI);
 584     pthread_sigmask(SIG_BLOCK, &set, NULL);
 585 }
 586
 587 void qemu_mutex_lock_iothread(void)
 588 {
 589     if (kvm_enabled()) {
 590         qemu_mutex_lock(&qemu_fair_mutex);
 591         qemu_mutex_lock(&qemu_global_mutex);
 592         qemu_mutex_unlock(&qemu_fair_mutex);
 593     } else {
 594         qemu_mutex_lock(&qemu_fair_mutex);
 595         if (qemu_mutex_trylock(&qemu_global_mutex)) {
 596             qemu_thread_signal(tcg_cpu_thread, SIG_IPI);
 597             qemu_mutex_lock(&qemu_global_mutex);
 598         }
 599         qemu_mutex_unlock(&qemu_fair_mutex);
 600     }
 601 }
 602
 603 void qemu_mutex_unlock_iothread(void)
 604 {
 605     qemu_mutex_unlock(&qemu_global_mutex);
 606 }
 607
 608 static int all_vcpus_paused(void)
 609 {
 610     CPUState *penv = first_cpu;
 611
 612     while (penv) {
 613         if (!penv->stopped)
 614             return 0;
 615         penv = (CPUState *)penv->next_cpu;
 616     }
 617
 618     return 1;
 619 }
 620
 621 void pause_all_vcpus(void)
 622 {
 623     CPUState *penv = first_cpu;
 624
 625     while (penv) {
 626         penv->stop = 1;
 627         qemu_cpu_kick(penv);
 628         penv = (CPUState *)penv->next_cpu;
 629     }
 630
 631     while (!all_vcpus_paused()) {
 632         qemu_cond_timedwait(&qemu_pause_cond, &qemu_global_mutex, 100);
 633         penv = first_cpu;
 634         while (penv) {
 635             qemu_cpu_kick(penv);
 636             penv = (CPUState *)penv->next_cpu;
 637         }
 638     }
 639 }
 640
 641 void resume_all_vcpus(void)
 642 {
 643     CPUState *penv = first_cpu;
 644
 645     while (penv) {
 646         penv->stop = 0;
 647         penv->stopped = 0;
 648         qemu_cpu_kick(penv);
 649         penv = (CPUState *)penv->next_cpu;
 650     }
 651 }
 652
 653 static void tcg_init_vcpu(void *_env)
 654 {
 655     CPUState *env = _env;
 656     /* share a single thread for all cpus with TCG */
 657     if (!tcg_cpu_thread) {
 658         env->thread = qemu_mallocz(sizeof(QemuThread));
 659         env->halt_cond = qemu_mallocz(sizeof(QemuCond));
 660         qemu_cond_init(env->halt_cond);
 661         qemu_thread_create(env->thread, tcg_cpu_thread_fn, env);
 662         while (env->created == 0)
 663             qemu_cond_timedwait(&qemu_cpu_cond, &qemu_global_mutex, 100);
 664         tcg_cpu_thread = env->thread;
 665         tcg_halt_cond = env->halt_cond;
 666     } else {
 667         env->thread = tcg_cpu_thread;
 668         env->halt_cond = tcg_halt_cond;
 669     }
 670 }
 671
 672 static void kvm_start_vcpu(CPUState *env)
 673 {
 674     env->thread = qemu_mallocz(sizeof(QemuThread));
 675     env->halt_cond = qemu_mallocz(sizeof(QemuCond));
 676     qemu_cond_init(env->halt_cond);
 677     qemu_thread_create(env->thread, kvm_cpu_thread_fn, env);
 678     while (env->created == 0)
 679         qemu_cond_timedwait(&qemu_cpu_cond, &qemu_global_mutex, 100);
 680 }
 681
 682 void qemu_init_vcpu(void *_env)
 683 {
 684     CPUState *env = _env;
 685
 686     env->nr_cores = smp_cores;
 687     env->nr_threads = smp_threads;
 688     if (kvm_enabled())
 689         kvm_start_vcpu(env);
 690     else
 691         tcg_init_vcpu(env);
 692 }
 693
 694 void qemu_notify_event(void)
 695 {
 696     qemu_event_increment();
 697 }
 698
 699 static void qemu_system_vmstop_request(int reason)
 700 {
 701     vmstop_requested = reason;
 702     qemu_notify_event();
 703 }
 704
 705 void vm_stop(int reason)
 706 {
 707     QemuThread me;
 708     qemu_thread_self(&me);
 709
 710     if (!qemu_thread_equal(&me, &io_thread)) {
 711         qemu_system_vmstop_request(reason);
 712         /*
 713          * FIXME: should not return to device code in case
 714          * vm_stop() has been requested.
 715          */
 716         if (cpu_single_env) {
 717             cpu_exit(cpu_single_env);
 718             cpu_single_env->stop = 1;
 719         }
 720         return;
 721     }
 722     do_vm_stop(reason);
 723 }
 724
 725 #endif
 726
 727 static int qemu_cpu_exec(CPUState *env)
 728 {
 729     int ret;
 730 #ifdef CONFIG_PROFILER
 731     int64_t ti;
 732 #endif
 733
 734 #ifdef CONFIG_PROFILER
 735     ti = profile_getclock();
 736 #endif
 737     if (use_icount) {
 738         int64_t count;
 739         int decr;
 740         qemu_icount -= (env->icount_decr.u16.low + env->icount_extra);
 741         env->icount_decr.u16.low = 0;
 742         env->icount_extra = 0;
 743         count = qemu_icount_round (qemu_next_deadline());
 744         qemu_icount += count;
 745         decr = (count > 0xffff) ? 0xffff : count;
 746         count -= decr;
 747         env->icount_decr.u16.low = decr;
 748         env->icount_extra = count;
 749     }
 750     ret = cpu_exec(env);
 751 #ifdef CONFIG_PROFILER
 752     qemu_time += profile_getclock() - ti;
 753 #endif
 754     if (use_icount) {
 755         /* Fold pending instructions back into the
 756            instruction counter, and clear the interrupt flag.  */
 757         qemu_icount -= (env->icount_decr.u16.low
 758                         + env->icount_extra);
 759         env->icount_decr.u32 = 0;
 760         env->icount_extra = 0;
 761     }
 762     return ret;
 763 }
 764
 765 bool tcg_cpu_exec(void)
 766 {
 767     int ret = 0;
 768
 769     if (next_cpu == NULL)
 770         next_cpu = first_cpu;
 771     for (; next_cpu != NULL; next_cpu = next_cpu->next_cpu) {
 772         CPUState *env = cur_cpu = next_cpu;
 773
 774         qemu_clock_enable(vm_clock,
 775                           (cur_cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);
 776
 777         if (qemu_alarm_pending())
 778             break;
 779         if (cpu_can_run(env))
 780             ret = qemu_cpu_exec(env);
 781         else if (env->stop)
 782             break;
 783
 784         if (ret == EXCP_DEBUG) {
 785             gdb_set_stop_cpu(env);
 786             debug_requested = EXCP_DEBUG;
 787             break;
 788         }
 789     }
 790     return tcg_has_work();
 791 }
 792
 793 void set_numa_modes(void)
 794 {
 795     CPUState *env;
 796     int i;
 797
 798     for (env = first_cpu; env != NULL; env = env->next_cpu) {
 799         for (i = 0; i < nb_numa_nodes; i++) {
 800             if (node_cpumask[i] & (1 << env->cpu_index)) {
 801                 env->numa_node = i;
 802             }
 803         }
 804     }
 805 }
 806
 807 void set_cpu_log(const char *optarg)
 808 {
 809     int mask;
 810     const CPULogItem *item;
 811
 812     mask = cpu_str_to_log_mask(optarg);
 813     if (!mask) {
 814         printf("Log items (comma separated):\n");
 815         for (item = cpu_log_items; item->mask != 0; item++) {
 816             printf("%-10s %s\n", item->name, item->help);
 817         }
 818         exit(1);
 819     }
 820     cpu_set_log(mask);
 821 }
 822
 823 /* Return the virtual CPU time, based on the instruction counter.  */
 824 int64_t cpu_get_icount(void)
 825 {
 826     int64_t icount;
 827     CPUState *env = cpu_single_env;;
 828
 829     icount = qemu_icount;
 830     if (env) {
 831         if (!can_do_io(env)) {
 832             fprintf(stderr, "Bad clock read\n");
 833         }
 834         icount -= (env->icount_decr.u16.low + env->icount_extra);
 835     }
 836     return qemu_icount_bias + (icount << icount_time_shift);
 837 }
 838
 839 void list_cpus(FILE *f, int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
 840                const char *optarg)
 841 {
 842     /* XXX: implement xxx_cpu_list for targets that still miss it */
 843 #if defined(cpu_list_id)
 844     cpu_list_id(f, cpu_fprintf, optarg);
 845 #elif defined(cpu_list)
 846     cpu_list(f, cpu_fprintf); /* deprecated */
 847 #endif
 848 }