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, NULL);
 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, NULL);
 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     } else {
 296         if (s->mon) {
 297             monitor_resume(s->mon);
 298         }
 299     }
 300
 301     if (s->fd != -1) {
 302         close(s->fd);
 303         s->fd = -1;
 304     }
 305
 306     return ret;
 307 }
 308
 309 void migrate_fd_put_notify(void *opaque)
 310 {
 311     FdMigrationState *s = opaque;
 312
 313     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 314     qemu_file_put_notify(s->file);
 315 }
 316
 317 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 318 {
 319     FdMigrationState *s = opaque;
 320     ssize_t ret;
 321
 322     do {
 323         ret = s->write(s, data, size);
 324     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 325
 326     if (ret == -1)
 327         ret = -(s->get_error(s));
 328
 329     if (ret == -EAGAIN) {
 330         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 331     } else if (ret < 0) {
 332         s->state = MIG_STATE_ERROR;
 333         notifier_list_notify(&migration_state_notifiers, NULL);
 334     }
 335
 336     return ret;
 337 }
 338
 339 void migrate_fd_connect(FdMigrationState *s)
 340 {
 341     int ret;
 342
 343     s->file = qemu_fopen_ops_buffered(s,
 344                                       s->bandwidth_limit,
 345                                       migrate_fd_put_buffer,
 346                                       migrate_fd_put_ready,
 347                                       migrate_fd_wait_for_unfreeze,
 348                                       migrate_fd_close);
 349
 350     DPRINTF("beginning savevm\n");
 351     ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
 352                                   s->mig_state.shared);
 353     if (ret < 0) {
 354         DPRINTF("failed, %d\n", ret);
 355         migrate_fd_error(s);
 356         return;
 357     }
 358
 359     migrate_fd_put_ready(s);
 360 }
 361
 362 void migrate_fd_put_ready(void *opaque)
 363 {
 364     FdMigrationState *s = opaque;
 365
 366     if (s->state != MIG_STATE_ACTIVE) {
 367         DPRINTF("put_ready returning because of non-active state\n");
 368         return;
 369     }
 370
 371     DPRINTF("iterate\n");
 372     if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
 373         int state;
 374         int old_vm_running = vm_running;
 375
 376         DPRINTF("done iterating\n");
 377         vm_stop(VMSTOP_MIGRATE);
 378
 379         if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
 380             if (old_vm_running) {
 381                 vm_start();
 382             }
 383             state = MIG_STATE_ERROR;
 384         } else {
 385             state = MIG_STATE_COMPLETED;
 386         }
 387         if (migrate_fd_cleanup(s) < 0) {
 388             if (old_vm_running) {
 389                 vm_start();
 390             }
 391             state = MIG_STATE_ERROR;
 392         }
 393         s->state = state;
 394         notifier_list_notify(&migration_state_notifiers, NULL);
 395     }
 396 }
 397
 398 int migrate_fd_get_status(MigrationState *mig_state)
 399 {
 400     FdMigrationState *s = migrate_to_fms(mig_state);
 401     return s->state;
 402 }
 403
 404 void migrate_fd_cancel(MigrationState *mig_state)
 405 {
 406     FdMigrationState *s = migrate_to_fms(mig_state);
 407
 408     if (s->state != MIG_STATE_ACTIVE)
 409         return;
 410
 411     DPRINTF("cancelling migration\n");
 412
 413     s->state = MIG_STATE_CANCELLED;
 414     notifier_list_notify(&migration_state_notifiers, NULL);
 415     qemu_savevm_state_cancel(s->mon, s->file);
 416
 417     migrate_fd_cleanup(s);
 418 }
 419
 420 void migrate_fd_release(MigrationState *mig_state)
 421 {
 422     FdMigrationState *s = migrate_to_fms(mig_state);
 423
 424     DPRINTF("releasing state\n");
 425
 426     if (s->state == MIG_STATE_ACTIVE) {
 427         s->state = MIG_STATE_CANCELLED;
 428         notifier_list_notify(&migration_state_notifiers, NULL);
 429         migrate_fd_cleanup(s);
 430     }
 431     g_free(s);
 432 }
 433
 434 void migrate_fd_wait_for_unfreeze(void *opaque)
 435 {
 436     FdMigrationState *s = opaque;
 437     int ret;
 438
 439     DPRINTF("wait for unfreeze\n");
 440     if (s->state != MIG_STATE_ACTIVE)
 441         return;
 442
 443     do {
 444         fd_set wfds;
 445
 446         FD_ZERO(&wfds);
 447         FD_SET(s->fd, &wfds);
 448
 449         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 450     } while (ret == -1 && (s->get_error(s)) == EINTR);
 451 }
 452
 453 int migrate_fd_close(void *opaque)
 454 {
 455     FdMigrationState *s = opaque;
 456
 457     if (s->mon) {
 458         monitor_resume(s->mon);
 459     }
 460     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 461     return s->close(s);
 462 }
 463
 464 void add_migration_state_change_notifier(Notifier *notify)
 465 {
 466     notifier_list_add(&migration_state_notifiers, notify);
 467 }
 468
 469 void remove_migration_state_change_notifier(Notifier *notify)
 470 {
 471     notifier_list_remove(&migration_state_notifiers, notify);
 472 }
 473
 474 int get_migration_state(void)
 475 {
 476     if (current_migration) {
 477         return migrate_fd_get_status(current_migration);
 478     } else {
 479         return MIG_STATE_ERROR;
 480     }
 481 }