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 uint32_t max_throttle = (32 << 20);
  36
  37 static MigrationState *current_migration;
  38
  39 void qemu_start_incoming_migration(const char *uri)
  40 {
  41     const char *p;
  42
  43     if (strstart(uri, "tcp:", &p))
  44         tcp_start_incoming_migration(p);
  45 #if !defined(WIN32)
  46     else if (strstart(uri, "exec:", &p))
  47         exec_start_incoming_migration(p);
  48     else if (strstart(uri, "unix:", &p))
  49         unix_start_incoming_migration(p);
  50     else if (strstart(uri, "fd:", &p))
  51         fd_start_incoming_migration(p);
  52 #endif
  53     else
  54         fprintf(stderr, "unknown migration protocol: %s\n", uri);
  55 }
  56
  57 void do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
  58 {
  59     MigrationState *s = NULL;
  60     const char *p;
  61     int detach = qdict_get_int(qdict, "detach");
  62     const char *uri = qdict_get_str(qdict, "uri");
  63
  64     if (current_migration &&
  65         current_migration->get_status(current_migration) == MIG_STATE_ACTIVE) {
  66         monitor_printf(mon, "migration already in progress\n");
  67         return;
  68     }
  69
  70     if (strstart(uri, "tcp:", &p))
  71         s = tcp_start_outgoing_migration(mon, p, max_throttle, detach,
  72                                          (int)qdict_get_int(qdict, "blk"),
  73                                          (int)qdict_get_int(qdict, "inc"));
  74 #if !defined(WIN32)
  75     else if (strstart(uri, "exec:", &p))
  76         s = exec_start_outgoing_migration(mon, p, max_throttle, detach,
  77                                           (int)qdict_get_int(qdict, "blk"),
  78                                           (int)qdict_get_int(qdict, "inc"));
  79     else if (strstart(uri, "unix:", &p))
  80         s = unix_start_outgoing_migration(mon, p, max_throttle, detach,
  81                                           (int)qdict_get_int(qdict, "blk"),
  82                                           (int)qdict_get_int(qdict, "inc"));
  83     else if (strstart(uri, "fd:", &p))
  84         s = fd_start_outgoing_migration(mon, p, max_throttle, detach,
  85                                         (int)qdict_get_int(qdict, "blk"),
  86                                         (int)qdict_get_int(qdict, "inc"));
  87 #endif
  88     else
  89         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
  90
  91     if (s == NULL)
  92         monitor_printf(mon, "migration failed\n");
  93     else {
  94         if (current_migration)
  95             current_migration->release(current_migration);
  96
  97         current_migration = s;
  98     }
  99 }
 100
 101 void do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
 102 {
 103     MigrationState *s = current_migration;
 104
 105     if (s)
 106         s->cancel(s);
 107 }
 108
 109 void do_migrate_set_speed(Monitor *mon, const QDict *qdict)
 110 {
 111     double d;
 112     char *ptr;
 113     FdMigrationState *s;
 114     const char *value = qdict_get_str(qdict, "value");
 115
 116     d = strtod(value, &ptr);
 117     switch (*ptr) {
 118     case 'G': case 'g':
 119         d *= 1024;
 120     case 'M': case 'm':
 121         d *= 1024;
 122     case 'K': case 'k':
 123         d *= 1024;
 124     default:
 125         break;
 126     }
 127
 128     max_throttle = (uint32_t)d;
 129
 130     s = migrate_to_fms(current_migration);
 131     if (s && s->file) {
 132         qemu_file_set_rate_limit(s->file, max_throttle);
 133     }
 134 }
 135
 136 /* amount of nanoseconds we are willing to wait for migration to be down.
 137  * the choice of nanoseconds is because it is the maximum resolution that
 138  * get_clock() can achieve. It is an internal measure. All user-visible
 139  * units must be in seconds */
 140 static uint64_t max_downtime = 30000000;
 141
 142 uint64_t migrate_max_downtime(void)
 143 {
 144     return max_downtime;
 145 }
 146
 147 void do_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 148 {
 149     char *ptr;
 150     double d;
 151     const char *value = qdict_get_str(qdict, "value");
 152
 153     d = strtod(value, &ptr);
 154     if (!strcmp(ptr,"ms")) {
 155         d *= 1000000;
 156     } else if (!strcmp(ptr,"us")) {
 157         d *= 1000;
 158     } else if (!strcmp(ptr,"ns")) {
 159     } else {
 160         /* all else considered to be seconds */
 161         d *= 1000000000;
 162     }
 163
 164     max_downtime = (uint64_t)d;
 165 }
 166
 167 static void migrate_print_status(Monitor *mon, const char *name,
 168                                  const QDict *status_dict)
 169 {
 170     QDict *qdict;
 171
 172     qdict = qobject_to_qdict(qdict_get(status_dict, name));
 173
 174     monitor_printf(mon, "transferred %s: %" PRIu64 " kbytes\n", name,
 175                         qdict_get_int(qdict, "transferred") >> 10);
 176     monitor_printf(mon, "remaining %s: %" PRIu64 " kbytes\n", name,
 177                         qdict_get_int(qdict, "remaining") >> 10);
 178     monitor_printf(mon, "total %s: %" PRIu64 " kbytes\n", name,
 179                         qdict_get_int(qdict, "total") >> 10);
 180 }
 181
 182 void do_info_migrate_print(Monitor *mon, const QObject *data)
 183 {
 184     QDict *qdict;
 185
 186     qdict = qobject_to_qdict(data);
 187
 188     monitor_printf(mon, "Migration status: %s\n",
 189                    qdict_get_str(qdict, "status"));
 190
 191     if (qdict_haskey(qdict, "ram")) {
 192         migrate_print_status(mon, "ram", qdict);
 193     }
 194
 195     if (qdict_haskey(qdict, "disk")) {
 196         migrate_print_status(mon, "disk", qdict);
 197     }
 198 }
 199
 200 static void migrate_put_status(QDict *qdict, const char *name,
 201                                uint64_t trans, uint64_t rem, uint64_t total)
 202 {
 203     QObject *obj;
 204
 205     obj = qobject_from_jsonf("{ 'transferred': %" PRId64 ", "
 206                                "'remaining': %" PRId64 ", "
 207                                "'total': %" PRId64 " }", trans, rem, total);
 208     assert(obj != NULL);
 209
 210     qdict_put_obj(qdict, name, obj);
 211 }
 212
 213 /**
 214  * do_info_migrate(): Migration status
 215  *
 216  * Return a QDict. If migration is active there will be another
 217  * QDict with RAM migration status and if block migration is active
 218  * another one with block migration status.
 219  *
 220  * The main QDict contains the following:
 221  *
 222  * - "status": migration status
 223  * - "ram": only present if "status" is "active", it is a QDict with the
 224  *   following RAM information (in bytes):
 225  *          - "transferred": amount transferred
 226  *          - "remaining": amount remaining
 227  *          - "total": total
 228  * - "disk": only present if "status" is "active" and it is a block migration,
 229  *   it is a QDict with the following disk information (in bytes):
 230  *          - "transferred": amount transferred
 231  *          - "remaining": amount remaining
 232  *          - "total": total
 233  *
 234  * Examples:
 235  *
 236  * 1. Migration is "completed":
 237  *
 238  * { "status": "completed" }
 239  *
 240  * 2. Migration is "active" and it is not a block migration:
 241  *
 242  * { "status": "active",
 243  *            "ram": { "transferred": 123, "remaining": 123, "total": 246 } }
 244  *
 245  * 3. Migration is "active" and it is a block migration:
 246  *
 247  * { "status": "active",
 248  *   "ram": { "total": 1057024, "remaining": 1053304, "transferred": 3720 },
 249  *   "disk": { "total": 20971520, "remaining": 20880384, "transferred": 91136 }}
 250  */
 251 void do_info_migrate(Monitor *mon, QObject **ret_data)
 252 {
 253     QDict *qdict;
 254     MigrationState *s = current_migration;
 255
 256     if (s) {
 257         switch (s->get_status(s)) {
 258         case MIG_STATE_ACTIVE:
 259             qdict = qdict_new();
 260             qdict_put(qdict, "status", qstring_from_str("active"));
 261
 262             migrate_put_status(qdict, "ram", ram_bytes_transferred(),
 263                                ram_bytes_remaining(), ram_bytes_total());
 264
 265             if (blk_mig_active()) {
 266                 migrate_put_status(qdict, "disk", blk_mig_bytes_transferred(),
 267                                    blk_mig_bytes_remaining(),
 268                                    blk_mig_bytes_total());
 269             }
 270
 271             *ret_data = QOBJECT(qdict);
 272             break;
 273         case MIG_STATE_COMPLETED:
 274             *ret_data = qobject_from_jsonf("{ 'status': 'completed' }");
 275             break;
 276         case MIG_STATE_ERROR:
 277             *ret_data = qobject_from_jsonf("{ 'status': 'failed' }");
 278             break;
 279         case MIG_STATE_CANCELLED:
 280             *ret_data = qobject_from_jsonf("{ 'status': 'cancelled' }");
 281             break;
 282         }
 283         assert(*ret_data != NULL);
 284     }
 285 }
 286
 287 /* shared migration helpers */
 288
 289 void migrate_fd_monitor_suspend(FdMigrationState *s, Monitor *mon)
 290 {
 291     s->mon = mon;
 292     if (monitor_suspend(mon) == 0) {
 293         dprintf("suspending monitor\n");
 294     } else {
 295         monitor_printf(mon, "terminal does not allow synchronous "
 296                        "migration, continuing detached\n");
 297     }
 298 }
 299
 300 void migrate_fd_error(FdMigrationState *s)
 301 {
 302     dprintf("setting error state\n");
 303     s->state = MIG_STATE_ERROR;
 304     migrate_fd_cleanup(s);
 305 }
 306
 307 void migrate_fd_cleanup(FdMigrationState *s)
 308 {
 309     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 310
 311     if (s->file) {
 312         dprintf("closing file\n");
 313         qemu_fclose(s->file);
 314         s->file = NULL;
 315     }
 316
 317     if (s->fd != -1)
 318         close(s->fd);
 319
 320     /* Don't resume monitor until we've flushed all of the buffers */
 321     if (s->mon) {
 322         monitor_resume(s->mon);
 323     }
 324
 325     s->fd = -1;
 326 }
 327
 328 void migrate_fd_put_notify(void *opaque)
 329 {
 330     FdMigrationState *s = opaque;
 331
 332     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 333     qemu_file_put_notify(s->file);
 334 }
 335
 336 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 337 {
 338     FdMigrationState *s = opaque;
 339     ssize_t ret;
 340
 341     do {
 342         ret = s->write(s, data, size);
 343     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 344
 345     if (ret == -1)
 346         ret = -(s->get_error(s));
 347
 348     if (ret == -EAGAIN)
 349         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 350
 351     return ret;
 352 }
 353
 354 void migrate_fd_connect(FdMigrationState *s)
 355 {
 356     int ret;
 357
 358     s->file = qemu_fopen_ops_buffered(s,
 359                                       s->bandwidth_limit,
 360                                       migrate_fd_put_buffer,
 361                                       migrate_fd_put_ready,
 362                                       migrate_fd_wait_for_unfreeze,
 363                                       migrate_fd_close);
 364
 365     dprintf("beginning savevm\n");
 366     ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
 367                                   s->mig_state.shared);
 368     if (ret < 0) {
 369         dprintf("failed, %d\n", ret);
 370         migrate_fd_error(s);
 371         return;
 372     }
 373
 374     migrate_fd_put_ready(s);
 375 }
 376
 377 void migrate_fd_put_ready(void *opaque)
 378 {
 379     FdMigrationState *s = opaque;
 380
 381     if (s->state != MIG_STATE_ACTIVE) {
 382         dprintf("put_ready returning because of non-active state\n");
 383         return;
 384     }
 385
 386     dprintf("iterate\n");
 387     if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
 388         int state;
 389         int old_vm_running = vm_running;
 390
 391         dprintf("done iterating\n");
 392         vm_stop(0);
 393
 394         qemu_aio_flush();
 395         bdrv_flush_all();
 396         if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
 397             if (old_vm_running) {
 398                 vm_start();
 399             }
 400             state = MIG_STATE_ERROR;
 401         } else {
 402             state = MIG_STATE_COMPLETED;
 403         }
 404         migrate_fd_cleanup(s);
 405         s->state = state;
 406     }
 407 }
 408
 409 int migrate_fd_get_status(MigrationState *mig_state)
 410 {
 411     FdMigrationState *s = migrate_to_fms(mig_state);
 412     return s->state;
 413 }
 414
 415 void migrate_fd_cancel(MigrationState *mig_state)
 416 {
 417     FdMigrationState *s = migrate_to_fms(mig_state);
 418
 419     if (s->state != MIG_STATE_ACTIVE)
 420         return;
 421
 422     dprintf("cancelling migration\n");
 423
 424     s->state = MIG_STATE_CANCELLED;
 425     qemu_savevm_state_cancel(s->mon, s->file);
 426
 427     migrate_fd_cleanup(s);
 428 }
 429
 430 void migrate_fd_release(MigrationState *mig_state)
 431 {
 432     FdMigrationState *s = migrate_to_fms(mig_state);
 433
 434     dprintf("releasing state\n");
 435
 436     if (s->state == MIG_STATE_ACTIVE) {
 437         s->state = MIG_STATE_CANCELLED;
 438         migrate_fd_cleanup(s);
 439     }
 440     free(s);
 441 }
 442
 443 void migrate_fd_wait_for_unfreeze(void *opaque)
 444 {
 445     FdMigrationState *s = opaque;
 446     int ret;
 447
 448     dprintf("wait for unfreeze\n");
 449     if (s->state != MIG_STATE_ACTIVE)
 450         return;
 451
 452     do {
 453         fd_set wfds;
 454
 455         FD_ZERO(&wfds);
 456         FD_SET(s->fd, &wfds);
 457
 458         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 459     } while (ret == -1 && (s->get_error(s)) == EINTR);
 460 }
 461
 462 int migrate_fd_close(void *opaque)
 463 {
 464     FdMigrationState *s = opaque;
 465
 466     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 467     return s->close(s);
 468 }