system/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 #include "qemu/osdep.h"
  26 #include "monitor/monitor.h"
  27 #include "qemu/coroutine-tls.h"
  28 #include "qapi/error.h"
  29 #include "qapi/qapi-commands-machine.h"
  30 #include "qapi/qapi-commands-misc.h"
  31 #include "qapi/qapi-events-run-state.h"
  32 #include "qapi/qmp/qerror.h"
  33 #include "exec/gdbstub.h"
  34 #include "sysemu/hw_accel.h"
  35 #include "exec/cpu-common.h"
  36 #include "qemu/thread.h"
  37 #include "qemu/main-loop.h"
  38 #include "qemu/plugin.h"
  39 #include "sysemu/cpus.h"
  40 #include "qemu/guest-random.h"
  41 #include "hw/nmi.h"
  42 #include "sysemu/replay.h"
  43 #include "sysemu/runstate.h"
  44 #include "sysemu/cpu-timers.h"
  45 #include "sysemu/whpx.h"
  46 #include "hw/boards.h"
  47 #include "hw/hw.h"
  48 #include "trace.h"
  49
  50 #ifdef CONFIG_LINUX
  51
  52 #include <sys/prctl.h>
  53
  54 #ifndef PR_MCE_KILL
  55 #define PR_MCE_KILL 33
  56 #endif
  57
  58 #ifndef PR_MCE_KILL_SET
  59 #define PR_MCE_KILL_SET 1
  60 #endif
  61
  62 #ifndef PR_MCE_KILL_EARLY
  63 #define PR_MCE_KILL_EARLY 1
  64 #endif
  65
  66 #endif /* CONFIG_LINUX */
  67
  68 /* The Big QEMU Lock (BQL) */
  69 static QemuMutex bql;
  70
  71 /*
  72  * The chosen accelerator is supposed to register this.
  73  */
  74 static const AccelOpsClass *cpus_accel;
  75
  76 bool cpu_is_stopped(CPUState *cpu)
  77 {
  78     return cpu->stopped || !runstate_is_running();
  79 }
  80
  81 bool cpu_work_list_empty(CPUState *cpu)
  82 {
  83     return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list);
  84 }
  85
  86 bool cpu_thread_is_idle(CPUState *cpu)
  87 {
  88     if (cpu->stop || !cpu_work_list_empty(cpu)) {
  89         return false;
  90     }
  91     if (cpu_is_stopped(cpu)) {
  92         return true;
  93     }
  94     if (!cpu->halted || cpu_has_work(cpu)) {
  95         return false;
  96     }
  97     if (cpus_accel->cpu_thread_is_idle) {
  98         return cpus_accel->cpu_thread_is_idle(cpu);
  99     }
 100     return true;
 101 }
 102
 103 bool all_cpu_threads_idle(void)
 104 {
 105     CPUState *cpu;
 106
 107     CPU_FOREACH(cpu) {
 108         if (!cpu_thread_is_idle(cpu)) {
 109             return false;
 110         }
 111     }
 112     return true;
 113 }
 114
 115 /***********************************************************/
 116 void hw_error(const char *fmt, ...)
 117 {
 118     va_list ap;
 119     CPUState *cpu;
 120
 121     va_start(ap, fmt);
 122     fprintf(stderr, "qemu: hardware error: ");
 123     vfprintf(stderr, fmt, ap);
 124     fprintf(stderr, "\n");
 125     CPU_FOREACH(cpu) {
 126         fprintf(stderr, "CPU #%d:\n", cpu->cpu_index);
 127         cpu_dump_state(cpu, stderr, CPU_DUMP_FPU);
 128     }
 129     va_end(ap);
 130     abort();
 131 }
 132
 133 void cpu_synchronize_all_states(void)
 134 {
 135     CPUState *cpu;
 136
 137     CPU_FOREACH(cpu) {
 138         cpu_synchronize_state(cpu);
 139     }
 140 }
 141
 142 void cpu_synchronize_all_post_reset(void)
 143 {
 144     CPUState *cpu;
 145
 146     CPU_FOREACH(cpu) {
 147         cpu_synchronize_post_reset(cpu);
 148     }
 149 }
 150
 151 void cpu_synchronize_all_post_init(void)
 152 {
 153     CPUState *cpu;
 154
 155     CPU_FOREACH(cpu) {
 156         cpu_synchronize_post_init(cpu);
 157     }
 158 }
 159
 160 void cpu_synchronize_all_pre_loadvm(void)
 161 {
 162     CPUState *cpu;
 163
 164     CPU_FOREACH(cpu) {
 165         cpu_synchronize_pre_loadvm(cpu);
 166     }
 167 }
 168
 169 void cpu_synchronize_state(CPUState *cpu)
 170 {
 171     if (cpus_accel->synchronize_state) {
 172         cpus_accel->synchronize_state(cpu);
 173     }
 174 }
 175
 176 void cpu_synchronize_post_reset(CPUState *cpu)
 177 {
 178     if (cpus_accel->synchronize_post_reset) {
 179         cpus_accel->synchronize_post_reset(cpu);
 180     }
 181 }
 182
 183 void cpu_synchronize_post_init(CPUState *cpu)
 184 {
 185     if (cpus_accel->synchronize_post_init) {
 186         cpus_accel->synchronize_post_init(cpu);
 187     }
 188 }
 189
 190 void cpu_synchronize_pre_loadvm(CPUState *cpu)
 191 {
 192     if (cpus_accel->synchronize_pre_loadvm) {
 193         cpus_accel->synchronize_pre_loadvm(cpu);
 194     }
 195 }
 196
 197 bool cpus_are_resettable(void)
 198 {
 199     if (cpus_accel->cpus_are_resettable) {
 200         return cpus_accel->cpus_are_resettable();
 201     }
 202     return true;
 203 }
 204
 205 void cpu_exec_reset_hold(CPUState *cpu)
 206 {
 207     if (cpus_accel->cpu_reset_hold) {
 208         cpus_accel->cpu_reset_hold(cpu);
 209     }
 210 }
 211
 212 int64_t cpus_get_virtual_clock(void)
 213 {
 214     /*
 215      * XXX
 216      *
 217      * need to check that cpus_accel is not NULL, because qcow2 calls
 218      * qemu_get_clock_ns(CLOCK_VIRTUAL) without any accel initialized and
 219      * with ticks disabled in some io-tests:
 220      * 030 040 041 060 099 120 127 140 156 161 172 181 191 192 195 203 229 249 256 267
 221      *
 222      * is this expected?
 223      *
 224      * XXX
 225      */
 226     if (cpus_accel && cpus_accel->get_virtual_clock) {
 227         return cpus_accel->get_virtual_clock();
 228     }
 229     return cpu_get_clock();
 230 }
 231
 232 /*
 233  * Signal the new virtual time to the accelerator. This is only needed
 234  * by accelerators that need to track the changes as we warp time.
 235  */
 236 void cpus_set_virtual_clock(int64_t new_time)
 237 {
 238     if (cpus_accel && cpus_accel->set_virtual_clock) {
 239         cpus_accel->set_virtual_clock(new_time);
 240     }
 241 }
 242
 243 /*
 244  * return the time elapsed in VM between vm_start and vm_stop.  Unless
 245  * icount is active, cpus_get_elapsed_ticks() uses units of the host CPU cycle
 246  * counter.
 247  */
 248 int64_t cpus_get_elapsed_ticks(void)
 249 {
 250     if (cpus_accel->get_elapsed_ticks) {
 251         return cpus_accel->get_elapsed_ticks();
 252     }
 253     return cpu_get_ticks();
 254 }
 255
 256 static void generic_handle_interrupt(CPUState *cpu, int mask)
 257 {
 258     cpu->interrupt_request |= mask;
 259
 260     if (!qemu_cpu_is_self(cpu)) {
 261         qemu_cpu_kick(cpu);
 262     }
 263 }
 264
 265 void cpu_interrupt(CPUState *cpu, int mask)
 266 {
 267     if (cpus_accel->handle_interrupt) {
 268         cpus_accel->handle_interrupt(cpu, mask);
 269     } else {
 270         generic_handle_interrupt(cpu, mask);
 271     }
 272 }
 273
 274 /*
 275  * True if the vm was previously suspended, and has not been woken or reset.
 276  */
 277 static int vm_was_suspended;
 278
 279 void vm_set_suspended(bool suspended)
 280 {
 281     vm_was_suspended = suspended;
 282 }
 283
 284 bool vm_get_suspended(void)
 285 {
 286     return vm_was_suspended;
 287 }
 288
 289 static int do_vm_stop(RunState state, bool send_stop)
 290 {
 291     int ret = 0;
 292     RunState oldstate = runstate_get();
 293
 294     if (runstate_is_live(oldstate)) {
 295         vm_was_suspended = (oldstate == RUN_STATE_SUSPENDED);
 296         runstate_set(state);
 297         cpu_disable_ticks();
 298         if (oldstate == RUN_STATE_RUNNING) {
 299             pause_all_vcpus();
 300         }
 301         vm_state_notify(0, state);
 302         if (send_stop) {
 303             qapi_event_send_stop();
 304         }
 305     }
 306
 307     bdrv_drain_all();
 308     ret = bdrv_flush_all();
 309     trace_vm_stop_flush_all(ret);
 310
 311     return ret;
 312 }
 313
 314 /* Special vm_stop() variant for terminating the process.  Historically clients
 315  * did not expect a QMP STOP event and so we need to retain compatibility.
 316  */
 317 int vm_shutdown(void)
 318 {
 319     return do_vm_stop(RUN_STATE_SHUTDOWN, false);
 320 }
 321
 322 bool cpu_can_run(CPUState *cpu)
 323 {
 324     if (cpu->stop) {
 325         return false;
 326     }
 327     if (cpu_is_stopped(cpu)) {
 328         return false;
 329     }
 330     return true;
 331 }
 332
 333 void cpu_handle_guest_debug(CPUState *cpu)
 334 {
 335     if (replay_running_debug()) {
 336         if (!cpu->singlestep_enabled) {
 337             /*
 338              * Report about the breakpoint and
 339              * make a single step to skip it
 340              */
 341             replay_breakpoint();
 342             cpu_single_step(cpu, SSTEP_ENABLE);
 343         } else {
 344             cpu_single_step(cpu, 0);
 345         }
 346     } else {
 347         gdb_set_stop_cpu(cpu);
 348         qemu_system_debug_request();
 349         cpu->stopped = true;
 350     }
 351 }
 352
 353 #ifdef CONFIG_LINUX
 354 static void sigbus_reraise(void)
 355 {
 356     sigset_t set;
 357     struct sigaction action;
 358
 359     memset(&action, 0, sizeof(action));
 360     action.sa_handler = SIG_DFL;
 361     if (!sigaction(SIGBUS, &action, NULL)) {
 362         raise(SIGBUS);
 363         sigemptyset(&set);
 364         sigaddset(&set, SIGBUS);
 365         pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 366     }
 367     perror("Failed to re-raise SIGBUS!");
 368     abort();
 369 }
 370
 371 static void sigbus_handler(int n, siginfo_t *siginfo, void *ctx)
 372 {
 373     if (siginfo->si_code != BUS_MCEERR_AO && siginfo->si_code != BUS_MCEERR_AR) {
 374         sigbus_reraise();
 375     }
 376
 377     if (current_cpu) {
 378         /* Called asynchronously in VCPU thread.  */
 379         if (kvm_on_sigbus_vcpu(current_cpu, siginfo->si_code, siginfo->si_addr)) {
 380             sigbus_reraise();
 381         }
 382     } else {
 383         /* Called synchronously (via signalfd) in main thread.  */
 384         if (kvm_on_sigbus(siginfo->si_code, siginfo->si_addr)) {
 385             sigbus_reraise();
 386         }
 387     }
 388 }
 389
 390 static void qemu_init_sigbus(void)
 391 {
 392     struct sigaction action;
 393
 394     /*
 395      * ALERT: when modifying this, take care that SIGBUS forwarding in
 396      * qemu_prealloc_mem() will continue working as expected.
 397      */
 398     memset(&action, 0, sizeof(action));
 399     action.sa_flags = SA_SIGINFO;
 400     action.sa_sigaction = sigbus_handler;
 401     sigaction(SIGBUS, &action, NULL);
 402
 403     prctl(PR_MCE_KILL, PR_MCE_KILL_SET, PR_MCE_KILL_EARLY, 0, 0);
 404 }
 405 #else /* !CONFIG_LINUX */
 406 static void qemu_init_sigbus(void)
 407 {
 408 }
 409 #endif /* !CONFIG_LINUX */
 410
 411 static QemuThread io_thread;
 412
 413 /* cpu creation */
 414 static QemuCond qemu_cpu_cond;
 415 /* system init */
 416 static QemuCond qemu_pause_cond;
 417
 418 void qemu_init_cpu_loop(void)
 419 {
 420     qemu_init_sigbus();
 421     qemu_cond_init(&qemu_cpu_cond);
 422     qemu_cond_init(&qemu_pause_cond);
 423     qemu_mutex_init(&bql);
 424
 425     qemu_thread_get_self(&io_thread);
 426 }
 427
 428 void run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data)
 429 {
 430     do_run_on_cpu(cpu, func, data, &bql);
 431 }
 432
 433 static void qemu_cpu_stop(CPUState *cpu, bool exit)
 434 {
 435     g_assert(qemu_cpu_is_self(cpu));
 436     cpu->stop = false;
 437     cpu->stopped = true;
 438     if (exit) {
 439         cpu_exit(cpu);
 440     }
 441     qemu_cond_broadcast(&qemu_pause_cond);
 442 }
 443
 444 void qemu_wait_io_event_common(CPUState *cpu)
 445 {
 446     qatomic_set_mb(&cpu->thread_kicked, false);
 447     if (cpu->stop) {
 448         qemu_cpu_stop(cpu, false);
 449     }
 450     process_queued_cpu_work(cpu);
 451 }
 452
 453 void qemu_wait_io_event(CPUState *cpu)
 454 {
 455     bool slept = false;
 456
 457     while (cpu_thread_is_idle(cpu)) {
 458         if (!slept) {
 459             slept = true;
 460             qemu_plugin_vcpu_idle_cb(cpu);
 461         }
 462         qemu_cond_wait(cpu->halt_cond, &bql);
 463     }
 464     if (slept) {
 465         qemu_plugin_vcpu_resume_cb(cpu);
 466     }
 467
 468     qemu_wait_io_event_common(cpu);
 469 }
 470
 471 void cpus_kick_thread(CPUState *cpu)
 472 {
 473     if (cpu->thread_kicked) {
 474         return;
 475     }
 476     cpu->thread_kicked = true;
 477
 478 #ifndef _WIN32
 479     int err = pthread_kill(cpu->thread->thread, SIG_IPI);
 480     if (err && err != ESRCH) {
 481         fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
 482         exit(1);
 483     }
 484 #else
 485     qemu_sem_post(&cpu->sem);
 486 #endif
 487 }
 488
 489 void qemu_cpu_kick(CPUState *cpu)
 490 {
 491     qemu_cond_broadcast(cpu->halt_cond);
 492     if (cpus_accel->kick_vcpu_thread) {
 493         cpus_accel->kick_vcpu_thread(cpu);
 494     } else { /* default */
 495         cpus_kick_thread(cpu);
 496     }
 497 }
 498
 499 void qemu_cpu_kick_self(void)
 500 {
 501     assert(current_cpu);
 502     cpus_kick_thread(current_cpu);
 503 }
 504
 505 bool qemu_cpu_is_self(CPUState *cpu)
 506 {
 507     return qemu_thread_is_self(cpu->thread);
 508 }
 509
 510 bool qemu_in_vcpu_thread(void)
 511 {
 512     return current_cpu && qemu_cpu_is_self(current_cpu);
 513 }
 514
 515 QEMU_DEFINE_STATIC_CO_TLS(bool, bql_locked)
 516
 517 bool bql_locked(void)
 518 {
 519     return get_bql_locked();
 520 }
 521
 522 bool qemu_in_main_thread(void)
 523 {
 524     return bql_locked();
 525 }
 526
 527 /*
 528  * The BQL is taken from so many places that it is worth profiling the
 529  * callers directly, instead of funneling them all through a single function.
 530  */
 531 void bql_lock_impl(const char *file, int line)
 532 {
 533     QemuMutexLockFunc bql_lock_fn = qatomic_read(&bql_mutex_lock_func);
 534
 535     g_assert(!bql_locked());
 536     bql_lock_fn(&bql, file, line);
 537     set_bql_locked(true);
 538 }
 539
 540 void bql_unlock(void)
 541 {
 542     g_assert(bql_locked());
 543     set_bql_locked(false);
 544     qemu_mutex_unlock(&bql);
 545 }
 546
 547 void qemu_cond_wait_bql(QemuCond *cond)
 548 {
 549     qemu_cond_wait(cond, &bql);
 550 }
 551
 552 void qemu_cond_timedwait_bql(QemuCond *cond, int ms)
 553 {
 554     qemu_cond_timedwait(cond, &bql, ms);
 555 }
 556
 557 /* signal CPU creation */
 558 void cpu_thread_signal_created(CPUState *cpu)
 559 {
 560     cpu->created = true;
 561     qemu_cond_signal(&qemu_cpu_cond);
 562 }
 563
 564 /* signal CPU destruction */
 565 void cpu_thread_signal_destroyed(CPUState *cpu)
 566 {
 567     cpu->created = false;
 568     qemu_cond_signal(&qemu_cpu_cond);
 569 }
 570
 571
 572 static bool all_vcpus_paused(void)
 573 {
 574     CPUState *cpu;
 575
 576     CPU_FOREACH(cpu) {
 577         if (!cpu->stopped) {
 578             return false;
 579         }
 580     }
 581
 582     return true;
 583 }
 584
 585 void pause_all_vcpus(void)
 586 {
 587     CPUState *cpu;
 588
 589     qemu_clock_enable(QEMU_CLOCK_VIRTUAL, false);
 590     CPU_FOREACH(cpu) {
 591         if (qemu_cpu_is_self(cpu)) {
 592             qemu_cpu_stop(cpu, true);
 593         } else {
 594             cpu->stop = true;
 595             qemu_cpu_kick(cpu);
 596         }
 597     }
 598
 599     /* We need to drop the replay_lock so any vCPU threads woken up
 600      * can finish their replay tasks
 601      */
 602     replay_mutex_unlock();
 603
 604     while (!all_vcpus_paused()) {
 605         qemu_cond_wait(&qemu_pause_cond, &bql);
 606         CPU_FOREACH(cpu) {
 607             qemu_cpu_kick(cpu);
 608         }
 609     }
 610
 611     bql_unlock();
 612     replay_mutex_lock();
 613     bql_lock();
 614 }
 615
 616 void cpu_resume(CPUState *cpu)
 617 {
 618     cpu->stop = false;
 619     cpu->stopped = false;
 620     qemu_cpu_kick(cpu);
 621 }
 622
 623 void resume_all_vcpus(void)
 624 {
 625     CPUState *cpu;
 626
 627     if (!runstate_is_running()) {
 628         return;
 629     }
 630
 631     qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
 632     CPU_FOREACH(cpu) {
 633         cpu_resume(cpu);
 634     }
 635 }
 636
 637 void cpu_remove_sync(CPUState *cpu)
 638 {
 639     cpu->stop = true;
 640     cpu->unplug = true;
 641     qemu_cpu_kick(cpu);
 642     bql_unlock();
 643     qemu_thread_join(cpu->thread);
 644     bql_lock();
 645 }
 646
 647 void cpus_register_accel(const AccelOpsClass *ops)
 648 {
 649     assert(ops != NULL);
 650     assert(ops->create_vcpu_thread != NULL); /* mandatory */
 651     cpus_accel = ops;
 652 }
 653
 654 const AccelOpsClass *cpus_get_accel(void)
 655 {
 656     /* broken if we call this early */
 657     assert(cpus_accel);
 658     return cpus_accel;
 659 }
 660
 661 void qemu_init_vcpu(CPUState *cpu)
 662 {
 663     MachineState *ms = MACHINE(qdev_get_machine());
 664
 665     cpu->nr_cores = machine_topo_get_cores_per_socket(ms);
 666     cpu->nr_threads =  ms->smp.threads;
 667     cpu->stopped = true;
 668     cpu->random_seed = qemu_guest_random_seed_thread_part1();
 669
 670     if (!cpu->as) {
 671         /* If the target cpu hasn't set up any address spaces itself,
 672          * give it the default one.
 673          */
 674         cpu->num_ases = 1;
 675         cpu_address_space_init(cpu, 0, "cpu-memory", cpu->memory);
 676     }
 677
 678     /* accelerators all implement the AccelOpsClass */
 679     g_assert(cpus_accel != NULL && cpus_accel->create_vcpu_thread != NULL);
 680     cpus_accel->create_vcpu_thread(cpu);
 681
 682     while (!cpu->created) {
 683         qemu_cond_wait(&qemu_cpu_cond, &bql);
 684     }
 685 }
 686
 687 void cpu_stop_current(void)
 688 {
 689     if (current_cpu) {
 690         current_cpu->stop = true;
 691         cpu_exit(current_cpu);
 692     }
 693 }
 694
 695 int vm_stop(RunState state)
 696 {
 697     if (qemu_in_vcpu_thread()) {
 698         qemu_system_vmstop_request_prepare();
 699         qemu_system_vmstop_request(state);
 700         /*
 701          * FIXME: should not return to device code in case
 702          * vm_stop() has been requested.
 703          */
 704         cpu_stop_current();
 705         return 0;
 706     }
 707
 708     return do_vm_stop(state, true);
 709 }
 710
 711 /**
 712  * Prepare for (re)starting the VM.
 713  * Returns 0 if the vCPUs should be restarted, -1 on an error condition,
 714  * and 1 otherwise.
 715  */
 716 int vm_prepare_start(bool step_pending)
 717 {
 718     int ret = vm_was_suspended ? 1 : 0;
 719     RunState state = vm_was_suspended ? RUN_STATE_SUSPENDED : RUN_STATE_RUNNING;
 720     RunState requested;
 721
 722     qemu_vmstop_requested(&requested);
 723     if (runstate_is_running() && requested == RUN_STATE__MAX) {
 724         return -1;
 725     }
 726
 727     /* Ensure that a STOP/RESUME pair of events is emitted if a
 728      * vmstop request was pending.  The BLOCK_IO_ERROR event, for
 729      * example, according to documentation is always followed by
 730      * the STOP event.
 731      */
 732     if (runstate_is_running()) {
 733         qapi_event_send_stop();
 734         qapi_event_send_resume();
 735         return -1;
 736     }
 737
 738     /*
 739      * WHPX accelerator needs to know whether we are going to step
 740      * any CPUs, before starting the first one.
 741      */
 742     if (cpus_accel->synchronize_pre_resume) {
 743         cpus_accel->synchronize_pre_resume(step_pending);
 744     }
 745
 746     /* We are sending this now, but the CPUs will be resumed shortly later */
 747     qapi_event_send_resume();
 748
 749     cpu_enable_ticks();
 750     runstate_set(state);
 751     vm_state_notify(1, state);
 752     vm_was_suspended = false;
 753     return ret;
 754 }
 755
 756 void vm_start(void)
 757 {
 758     if (!vm_prepare_start(false)) {
 759         resume_all_vcpus();
 760     }
 761 }
 762
 763 void vm_resume(RunState state)
 764 {
 765     if (runstate_is_live(state)) {
 766         vm_start();
 767     } else {
 768         runstate_set(state);
 769     }
 770 }
 771
 772 /* does a state transition even if the VM is already stopped,
 773    current state is forgotten forever */
 774 int vm_stop_force_state(RunState state)
 775 {
 776     if (runstate_is_live(runstate_get())) {
 777         return vm_stop(state);
 778     } else {
 779         int ret;
 780         runstate_set(state);
 781
 782         bdrv_drain_all();
 783         /* Make sure to return an error if the flush in a previous vm_stop()
 784          * failed. */
 785         ret = bdrv_flush_all();
 786         trace_vm_stop_flush_all(ret);
 787         return ret;
 788     }
 789 }
 790
 791 void qmp_memsave(int64_t addr, int64_t size, const char *filename,
 792                  bool has_cpu, int64_t cpu_index, Error **errp)
 793 {
 794     FILE *f;
 795     uint32_t l;
 796     CPUState *cpu;
 797     uint8_t buf[1024];
 798     int64_t orig_addr = addr, orig_size = size;
 799
 800     if (!has_cpu) {
 801         cpu_index = 0;
 802     }
 803
 804     cpu = qemu_get_cpu(cpu_index);
 805     if (cpu == NULL) {
 806         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu-index",
 807                    "a CPU number");
 808         return;
 809     }
 810
 811     f = fopen(filename, "wb");
 812     if (!f) {
 813         error_setg_file_open(errp, errno, filename);
 814         return;
 815     }
 816
 817     while (size != 0) {
 818         l = sizeof(buf);
 819         if (l > size)
 820             l = size;
 821         if (cpu_memory_rw_debug(cpu, addr, buf, l, 0) != 0) {
 822             error_setg(errp, "Invalid addr 0x%016" PRIx64 "/size %" PRId64
 823                              " specified", orig_addr, orig_size);
 824             goto exit;
 825         }
 826         if (fwrite(buf, 1, l, f) != l) {
 827             error_setg(errp, "writing memory to '%s' failed",
 828                        filename);
 829             goto exit;
 830         }
 831         addr += l;
 832         size -= l;
 833     }
 834
 835 exit:
 836     fclose(f);
 837 }
 838
 839 void qmp_pmemsave(int64_t addr, int64_t size, const char *filename,
 840                   Error **errp)
 841 {
 842     FILE *f;
 843     uint32_t l;
 844     uint8_t buf[1024];
 845
 846     f = fopen(filename, "wb");
 847     if (!f) {
 848         error_setg_file_open(errp, errno, filename);
 849         return;
 850     }
 851
 852     while (size != 0) {
 853         l = sizeof(buf);
 854         if (l > size)
 855             l = size;
 856         cpu_physical_memory_read(addr, buf, l);
 857         if (fwrite(buf, 1, l, f) != l) {
 858             error_setg(errp, "writing memory to '%s' failed",
 859                        filename);
 860             goto exit;
 861         }
 862         addr += l;
 863         size -= l;
 864     }
 865
 866 exit:
 867     fclose(f);
 868 }
 869
 870 void qmp_inject_nmi(Error **errp)
 871 {
 872     nmi_monitor_handle(monitor_get_cpu_index(monitor_cur()), errp);
 873 }
 874