migration.c

   1 /*
   2  * QEMU live migration
   3  *
   4  * Copyright IBM, Corp. 2008
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu-common.h"
  15 #include "migration.h"
  16 #include "monitor.h"
  17 #include "buffered_file.h"
  18 #include "sysemu.h"
  19 #include "block.h"
  20 #include "qemu_socket.h"
  21 #include "block-migration.h"
  22 #include "qemu-objects.h"
  23
  24 //#define DEBUG_MIGRATION
  25
  26 #ifdef DEBUG_MIGRATION
  27 #define DPRINTF(fmt, ...) \
  28     do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
  29 #else
  30 #define DPRINTF(fmt, ...) \
  31     do { } while (0)
  32 #endif
  33
  34 /* Migration speed throttling */
  35 static int64_t max_throttle = (32 << 20);
  36
  37 static MigrationState *current_migration;
  38
  39 static NotifierList migration_state_notifiers =
  40     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
  41
  42 int qemu_start_incoming_migration(const char *uri)
  43 {
  44     const char *p;
  45     int ret;
  46
  47     if (strstart(uri, "tcp:", &p))
  48         ret = tcp_start_incoming_migration(p);
  49 #if !defined(WIN32)
  50     else if (strstart(uri, "exec:", &p))
  51         ret =  exec_start_incoming_migration(p);
  52     else if (strstart(uri, "unix:", &p))
  53         ret = unix_start_incoming_migration(p);
  54     else if (strstart(uri, "fd:", &p))
  55         ret = fd_start_incoming_migration(p);
  56 #endif
  57     else {
  58         fprintf(stderr, "unknown migration protocol: %s\n", uri);
  59         ret = -EPROTONOSUPPORT;
  60     }
  61     return ret;
  62 }
  63
  64 void process_incoming_migration(QEMUFile *f)
  65 {
  66     if (qemu_loadvm_state(f) < 0) {
  67         fprintf(stderr, "load of migration failed\n");
  68         exit(0);
  69     }
  70     qemu_announce_self();
  71     DPRINTF("successfully loaded vm state\n");
  72
  73     incoming_expected = false;
  74
  75     if (autostart)
  76         vm_start();
  77 }
  78
  79 int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
  80 {
  81     MigrationState *s = NULL;
  82     const char *p;
  83     int detach = qdict_get_try_bool(qdict, "detach", 0);
  84     int blk = qdict_get_try_bool(qdict, "blk", 0);
  85     int inc = qdict_get_try_bool(qdict, "inc", 0);
  86     const char *uri = qdict_get_str(qdict, "uri");
  87
  88     if (current_migration &&
  89         current_migration->get_status(current_migration) == MIG_STATE_ACTIVE) {
  90         monitor_printf(mon, "migration already in progress\n");
  91         return -1;
  92     }
  93
  94     if (qemu_savevm_state_blocked(mon)) {
  95         return -1;
  96     }
  97
  98     if (strstart(uri, "tcp:", &p)) {
  99         s = tcp_start_outgoing_migration(mon, p, max_throttle, detach,
 100                                          blk, inc);
 101 #if !defined(WIN32)
 102     } else if (strstart(uri, "exec:", &p)) {
 103         s = exec_start_outgoing_migration(mon, p, max_throttle, detach,
 104                                           blk, inc);
 105     } else if (strstart(uri, "unix:", &p)) {
 106         s = unix_start_outgoing_migration(mon, p, max_throttle, detach,
 107                                           blk, inc);
 108     } else if (strstart(uri, "fd:", &p)) {
 109         s = fd_start_outgoing_migration(mon, p, max_throttle, detach,
 110                                         blk, inc);
 111 #endif
 112     } else {
 113         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
 114         return -1;
 115     }
 116
 117     if (s == NULL) {
 118         monitor_printf(mon, "migration failed\n");
 119         return -1;
 120     }
 121
 122     if (current_migration) {
 123         current_migration->release(current_migration);
 124     }
 125
 126     current_migration = s;
 127     notifier_list_notify(&migration_state_notifiers);
 128     return 0;
 129 }
 130
 131 int do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
 132 {
 133     MigrationState *s = current_migration;
 134
 135     if (s)
 136         s->cancel(s);
 137
 138     return 0;
 139 }
 140
 141 int do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)
 142 {
 143     int64_t d;
 144     FdMigrationState *s;
 145
 146     d = qdict_get_int(qdict, "value");
 147     if (d < 0) {
 148         d = 0;
 149     }
 150     max_throttle = d;
 151
 152     s = migrate_to_fms(current_migration);
 153     if (s && s->file) {
 154         qemu_file_set_rate_limit(s->file, max_throttle);
 155     }
 156
 157     return 0;
 158 }
 159
 160 /* amount of nanoseconds we are willing to wait for migration to be down.
 161  * the choice of nanoseconds is because it is the maximum resolution that
 162  * get_clock() can achieve. It is an internal measure. All user-visible
 163  * units must be in seconds */
 164 static uint64_t max_downtime = 30000000;
 165
 166 uint64_t migrate_max_downtime(void)
 167 {
 168     return max_downtime;
 169 }
 170
 171 int do_migrate_set_downtime(Monitor *mon, const QDict *qdict,
 172                             QObject **ret_data)
 173 {
 174     double d;
 175
 176     d = qdict_get_double(qdict, "value") * 1e9;
 177     d = MAX(0, MIN(UINT64_MAX, d));
 178     max_downtime = (uint64_t)d;
 179
 180     return 0;
 181 }
 182
 183 static void migrate_print_status(Monitor *mon, const char *name,
 184                                  const QDict *status_dict)
 185 {
 186     QDict *qdict;
 187
 188     qdict = qobject_to_qdict(qdict_get(status_dict, name));
 189
 190     monitor_printf(mon, "transferred %s: %" PRIu64 " kbytes\n", name,
 191                         qdict_get_int(qdict, "transferred") >> 10);
 192     monitor_printf(mon, "remaining %s: %" PRIu64 " kbytes\n", name,
 193                         qdict_get_int(qdict, "remaining") >> 10);
 194     monitor_printf(mon, "total %s: %" PRIu64 " kbytes\n", name,
 195                         qdict_get_int(qdict, "total") >> 10);
 196 }
 197
 198 void do_info_migrate_print(Monitor *mon, const QObject *data)
 199 {
 200     QDict *qdict;
 201
 202     qdict = qobject_to_qdict(data);
 203
 204     monitor_printf(mon, "Migration status: %s\n",
 205                    qdict_get_str(qdict, "status"));
 206
 207     if (qdict_haskey(qdict, "ram")) {
 208         migrate_print_status(mon, "ram", qdict);
 209     }
 210
 211     if (qdict_haskey(qdict, "disk")) {
 212         migrate_print_status(mon, "disk", qdict);
 213     }
 214 }
 215
 216 static void migrate_put_status(QDict *qdict, const char *name,
 217                                uint64_t trans, uint64_t rem, uint64_t total)
 218 {
 219     QObject *obj;
 220
 221     obj = qobject_from_jsonf("{ 'transferred': %" PRId64 ", "
 222                                "'remaining': %" PRId64 ", "
 223                                "'total': %" PRId64 " }", trans, rem, total);
 224     qdict_put_obj(qdict, name, obj);
 225 }
 226
 227 void do_info_migrate(Monitor *mon, QObject **ret_data)
 228 {
 229     QDict *qdict;
 230     MigrationState *s = current_migration;
 231
 232     if (s) {
 233         switch (s->get_status(s)) {
 234         case MIG_STATE_ACTIVE:
 235             qdict = qdict_new();
 236             qdict_put(qdict, "status", qstring_from_str("active"));
 237
 238             migrate_put_status(qdict, "ram", ram_bytes_transferred(),
 239                                ram_bytes_remaining(), ram_bytes_total());
 240
 241             if (blk_mig_active()) {
 242                 migrate_put_status(qdict, "disk", blk_mig_bytes_transferred(),
 243                                    blk_mig_bytes_remaining(),
 244                                    blk_mig_bytes_total());
 245             }
 246
 247             *ret_data = QOBJECT(qdict);
 248             break;
 249         case MIG_STATE_COMPLETED:
 250             *ret_data = qobject_from_jsonf("{ 'status': 'completed' }");
 251             break;
 252         case MIG_STATE_ERROR:
 253             *ret_data = qobject_from_jsonf("{ 'status': 'failed' }");
 254             break;
 255         case MIG_STATE_CANCELLED:
 256             *ret_data = qobject_from_jsonf("{ 'status': 'cancelled' }");
 257             break;
 258         }
 259     }
 260 }
 261
 262 /* shared migration helpers */
 263
 264 void migrate_fd_monitor_suspend(FdMigrationState *s, Monitor *mon)
 265 {
 266     s->mon = mon;
 267     if (monitor_suspend(mon) == 0) {
 268         DPRINTF("suspending monitor\n");
 269     } else {
 270         monitor_printf(mon, "terminal does not allow synchronous "
 271                        "migration, continuing detached\n");
 272     }
 273 }
 274
 275 void migrate_fd_error(FdMigrationState *s)
 276 {
 277     DPRINTF("setting error state\n");
 278     s->state = MIG_STATE_ERROR;
 279     notifier_list_notify(&migration_state_notifiers);
 280     migrate_fd_cleanup(s);
 281 }
 282
 283 int migrate_fd_cleanup(FdMigrationState *s)
 284 {
 285     int ret = 0;
 286
 287     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 288
 289     if (s->file) {
 290         DPRINTF("closing file\n");
 291         if (qemu_fclose(s->file) != 0) {
 292             ret = -1;
 293         }
 294         s->file = NULL;
 295     }
 296
 297     if (s->fd != -1)
 298         close(s->fd);
 299
 300     /* Don't resume monitor until we've flushed all of the buffers */
 301     if (s->mon) {
 302         monitor_resume(s->mon);
 303     }
 304
 305     s->fd = -1;
 306
 307     return ret;
 308 }
 309
 310 void migrate_fd_put_notify(void *opaque)
 311 {
 312     FdMigrationState *s = opaque;
 313
 314     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 315     qemu_file_put_notify(s->file);
 316 }
 317
 318 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 319 {
 320     FdMigrationState *s = opaque;
 321     ssize_t ret;
 322
 323     do {
 324         ret = s->write(s, data, size);
 325     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 326
 327     if (ret == -1)
 328         ret = -(s->get_error(s));
 329
 330     if (ret == -EAGAIN) {
 331         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 332     } else if (ret < 0) {
 333         if (s->mon) {
 334             monitor_resume(s->mon);
 335         }
 336         s->state = MIG_STATE_ERROR;
 337         notifier_list_notify(&migration_state_notifiers);
 338     }
 339
 340     return ret;
 341 }
 342
 343 void migrate_fd_connect(FdMigrationState *s)
 344 {
 345     int ret;
 346
 347     s->file = qemu_fopen_ops_buffered(s,
 348                                       s->bandwidth_limit,
 349                                       migrate_fd_put_buffer,
 350                                       migrate_fd_put_ready,
 351                                       migrate_fd_wait_for_unfreeze,
 352                                       migrate_fd_close);
 353
 354     DPRINTF("beginning savevm\n");
 355     ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
 356                                   s->mig_state.shared);
 357     if (ret < 0) {
 358         DPRINTF("failed, %d\n", ret);
 359         migrate_fd_error(s);
 360         return;
 361     }
 362
 363     migrate_fd_put_ready(s);
 364 }
 365
 366 void migrate_fd_put_ready(void *opaque)
 367 {
 368     FdMigrationState *s = opaque;
 369
 370     if (s->state != MIG_STATE_ACTIVE) {
 371         DPRINTF("put_ready returning because of non-active state\n");
 372         return;
 373     }
 374
 375     DPRINTF("iterate\n");
 376     if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
 377         int state;
 378         int old_vm_running = vm_running;
 379
 380         DPRINTF("done iterating\n");
 381         vm_stop(VMSTOP_MIGRATE);
 382
 383         if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
 384             if (old_vm_running) {
 385                 vm_start();
 386             }
 387             state = MIG_STATE_ERROR;
 388         } else {
 389             state = MIG_STATE_COMPLETED;
 390         }
 391         if (migrate_fd_cleanup(s) < 0) {
 392             if (old_vm_running) {
 393                 vm_start();
 394             }
 395             state = MIG_STATE_ERROR;
 396         }
 397         s->state = state;
 398         notifier_list_notify(&migration_state_notifiers);
 399     }
 400 }
 401
 402 int migrate_fd_get_status(MigrationState *mig_state)
 403 {
 404     FdMigrationState *s = migrate_to_fms(mig_state);
 405     return s->state;
 406 }
 407
 408 void migrate_fd_cancel(MigrationState *mig_state)
 409 {
 410     FdMigrationState *s = migrate_to_fms(mig_state);
 411
 412     if (s->state != MIG_STATE_ACTIVE)
 413         return;
 414
 415     DPRINTF("cancelling migration\n");
 416
 417     s->state = MIG_STATE_CANCELLED;
 418     notifier_list_notify(&migration_state_notifiers);
 419     qemu_savevm_state_cancel(s->mon, s->file);
 420
 421     migrate_fd_cleanup(s);
 422 }
 423
 424 void migrate_fd_release(MigrationState *mig_state)
 425 {
 426     FdMigrationState *s = migrate_to_fms(mig_state);
 427
 428     DPRINTF("releasing state\n");
 429
 430     if (s->state == MIG_STATE_ACTIVE) {
 431         s->state = MIG_STATE_CANCELLED;
 432         notifier_list_notify(&migration_state_notifiers);
 433         migrate_fd_cleanup(s);
 434     }
 435     qemu_free(s);
 436 }
 437
 438 void migrate_fd_wait_for_unfreeze(void *opaque)
 439 {
 440     FdMigrationState *s = opaque;
 441     int ret;
 442
 443     DPRINTF("wait for unfreeze\n");
 444     if (s->state != MIG_STATE_ACTIVE)
 445         return;
 446
 447     do {
 448         fd_set wfds;
 449
 450         FD_ZERO(&wfds);
 451         FD_SET(s->fd, &wfds);
 452
 453         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 454     } while (ret == -1 && (s->get_error(s)) == EINTR);
 455 }
 456
 457 int migrate_fd_close(void *opaque)
 458 {
 459     FdMigrationState *s = opaque;
 460
 461     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 462     return s->close(s);
 463 }
 464
 465 void add_migration_state_change_notifier(Notifier *notify)
 466 {
 467     notifier_list_add(&migration_state_notifiers, notify);
 468 }
 469
 470 void remove_migration_state_change_notifier(Notifier *notify)
 471 {
 472     notifier_list_remove(&migration_state_notifiers, notify);
 473 }
 474
 475 int get_migration_state(void)
 476 {
 477     if (current_migration) {
 478         return migrate_fd_get_status(current_migration);
 479     } else {
 480         return MIG_STATE_ERROR;
 481     }
 482 }