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 int 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 -1;
  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         return -1;
  91     }
  92
  93     if (s == NULL) {
  94         monitor_printf(mon, "migration failed\n");
  95         return -1;
  96     }
  97
  98     if (current_migration) {
  99         current_migration->release(current_migration);
 100     }
 101
 102     current_migration = s;
 103     return 0;
 104 }
 105
 106 int do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
 107 {
 108     MigrationState *s = current_migration;
 109
 110     if (s)
 111         s->cancel(s);
 112
 113     return 0;
 114 }
 115
 116 int do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)
 117 {
 118     double d;
 119     FdMigrationState *s;
 120
 121     d = qdict_get_double(qdict, "value");
 122     d = MAX(0, MIN(UINT32_MAX, d));
 123     max_throttle = d;
 124
 125     s = migrate_to_fms(current_migration);
 126     if (s && s->file) {
 127         qemu_file_set_rate_limit(s->file, max_throttle);
 128     }
 129
 130     return 0;
 131 }
 132
 133 /* amount of nanoseconds we are willing to wait for migration to be down.
 134  * the choice of nanoseconds is because it is the maximum resolution that
 135  * get_clock() can achieve. It is an internal measure. All user-visible
 136  * units must be in seconds */
 137 static uint64_t max_downtime = 30000000;
 138
 139 uint64_t migrate_max_downtime(void)
 140 {
 141     return max_downtime;
 142 }
 143
 144 int do_migrate_set_downtime(Monitor *mon, const QDict *qdict,
 145                             QObject **ret_data)
 146 {
 147     double d;
 148
 149     d = qdict_get_double(qdict, "value") * 1e9;
 150     d = MAX(0, MIN(UINT64_MAX, d));
 151     max_downtime = (uint64_t)d;
 152
 153     return 0;
 154 }
 155
 156 static void migrate_print_status(Monitor *mon, const char *name,
 157                                  const QDict *status_dict)
 158 {
 159     QDict *qdict;
 160
 161     qdict = qobject_to_qdict(qdict_get(status_dict, name));
 162
 163     monitor_printf(mon, "transferred %s: %" PRIu64 " kbytes\n", name,
 164                         qdict_get_int(qdict, "transferred") >> 10);
 165     monitor_printf(mon, "remaining %s: %" PRIu64 " kbytes\n", name,
 166                         qdict_get_int(qdict, "remaining") >> 10);
 167     monitor_printf(mon, "total %s: %" PRIu64 " kbytes\n", name,
 168                         qdict_get_int(qdict, "total") >> 10);
 169 }
 170
 171 void do_info_migrate_print(Monitor *mon, const QObject *data)
 172 {
 173     QDict *qdict;
 174
 175     qdict = qobject_to_qdict(data);
 176
 177     monitor_printf(mon, "Migration status: %s\n",
 178                    qdict_get_str(qdict, "status"));
 179
 180     if (qdict_haskey(qdict, "ram")) {
 181         migrate_print_status(mon, "ram", qdict);
 182     }
 183
 184     if (qdict_haskey(qdict, "disk")) {
 185         migrate_print_status(mon, "disk", qdict);
 186     }
 187 }
 188
 189 static void migrate_put_status(QDict *qdict, const char *name,
 190                                uint64_t trans, uint64_t rem, uint64_t total)
 191 {
 192     QObject *obj;
 193
 194     obj = qobject_from_jsonf("{ 'transferred': %" PRId64 ", "
 195                                "'remaining': %" PRId64 ", "
 196                                "'total': %" PRId64 " }", trans, rem, total);
 197     qdict_put_obj(qdict, name, obj);
 198 }
 199
 200 /**
 201  * do_info_migrate(): Migration status
 202  *
 203  * Return a QDict. If migration is active there will be another
 204  * QDict with RAM migration status and if block migration is active
 205  * another one with block migration status.
 206  *
 207  * The main QDict contains the following:
 208  *
 209  * - "status": migration status
 210  * - "ram": only present if "status" is "active", it is a QDict with the
 211  *   following RAM information (in bytes):
 212  *          - "transferred": amount transferred
 213  *          - "remaining": amount remaining
 214  *          - "total": total
 215  * - "disk": only present if "status" is "active" and it is a block migration,
 216  *   it is a QDict with the following disk information (in bytes):
 217  *          - "transferred": amount transferred
 218  *          - "remaining": amount remaining
 219  *          - "total": total
 220  *
 221  * Examples:
 222  *
 223  * 1. Migration is "completed":
 224  *
 225  * { "status": "completed" }
 226  *
 227  * 2. Migration is "active" and it is not a block migration:
 228  *
 229  * { "status": "active",
 230  *            "ram": { "transferred": 123, "remaining": 123, "total": 246 } }
 231  *
 232  * 3. Migration is "active" and it is a block migration:
 233  *
 234  * { "status": "active",
 235  *   "ram": { "total": 1057024, "remaining": 1053304, "transferred": 3720 },
 236  *   "disk": { "total": 20971520, "remaining": 20880384, "transferred": 91136 }}
 237  */
 238 void do_info_migrate(Monitor *mon, QObject **ret_data)
 239 {
 240     QDict *qdict;
 241     MigrationState *s = current_migration;
 242
 243     if (s) {
 244         switch (s->get_status(s)) {
 245         case MIG_STATE_ACTIVE:
 246             qdict = qdict_new();
 247             qdict_put(qdict, "status", qstring_from_str("active"));
 248
 249             migrate_put_status(qdict, "ram", ram_bytes_transferred(),
 250                                ram_bytes_remaining(), ram_bytes_total());
 251
 252             if (blk_mig_active()) {
 253                 migrate_put_status(qdict, "disk", blk_mig_bytes_transferred(),
 254                                    blk_mig_bytes_remaining(),
 255                                    blk_mig_bytes_total());
 256             }
 257
 258             *ret_data = QOBJECT(qdict);
 259             break;
 260         case MIG_STATE_COMPLETED:
 261             *ret_data = qobject_from_jsonf("{ 'status': 'completed' }");
 262             break;
 263         case MIG_STATE_ERROR:
 264             *ret_data = qobject_from_jsonf("{ 'status': 'failed' }");
 265             break;
 266         case MIG_STATE_CANCELLED:
 267             *ret_data = qobject_from_jsonf("{ 'status': 'cancelled' }");
 268             break;
 269         }
 270     }
 271 }
 272
 273 /* shared migration helpers */
 274
 275 void migrate_fd_monitor_suspend(FdMigrationState *s, Monitor *mon)
 276 {
 277     s->mon = mon;
 278     if (monitor_suspend(mon) == 0) {
 279         DPRINTF("suspending monitor\n");
 280     } else {
 281         monitor_printf(mon, "terminal does not allow synchronous "
 282                        "migration, continuing detached\n");
 283     }
 284 }
 285
 286 void migrate_fd_error(FdMigrationState *s)
 287 {
 288     DPRINTF("setting error state\n");
 289     s->state = MIG_STATE_ERROR;
 290     migrate_fd_cleanup(s);
 291 }
 292
 293 void migrate_fd_cleanup(FdMigrationState *s)
 294 {
 295     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 296
 297     if (s->file) {
 298         DPRINTF("closing file\n");
 299         qemu_fclose(s->file);
 300         s->file = NULL;
 301     }
 302
 303     if (s->fd != -1)
 304         close(s->fd);
 305
 306     /* Don't resume monitor until we've flushed all of the buffers */
 307     if (s->mon) {
 308         monitor_resume(s->mon);
 309     }
 310
 311     s->fd = -1;
 312 }
 313
 314 void migrate_fd_put_notify(void *opaque)
 315 {
 316     FdMigrationState *s = opaque;
 317
 318     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 319     qemu_file_put_notify(s->file);
 320 }
 321
 322 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 323 {
 324     FdMigrationState *s = opaque;
 325     ssize_t ret;
 326
 327     do {
 328         ret = s->write(s, data, size);
 329     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 330
 331     if (ret == -1)
 332         ret = -(s->get_error(s));
 333
 334     if (ret == -EAGAIN)
 335         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 336
 337     return ret;
 338 }
 339
 340 void migrate_fd_connect(FdMigrationState *s)
 341 {
 342     int ret;
 343
 344     s->file = qemu_fopen_ops_buffered(s,
 345                                       s->bandwidth_limit,
 346                                       migrate_fd_put_buffer,
 347                                       migrate_fd_put_ready,
 348                                       migrate_fd_wait_for_unfreeze,
 349                                       migrate_fd_close);
 350
 351     DPRINTF("beginning savevm\n");
 352     ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
 353                                   s->mig_state.shared);
 354     if (ret < 0) {
 355         DPRINTF("failed, %d\n", ret);
 356         migrate_fd_error(s);
 357         return;
 358     }
 359
 360     migrate_fd_put_ready(s);
 361 }
 362
 363 void migrate_fd_put_ready(void *opaque)
 364 {
 365     FdMigrationState *s = opaque;
 366
 367     if (s->state != MIG_STATE_ACTIVE) {
 368         DPRINTF("put_ready returning because of non-active state\n");
 369         return;
 370     }
 371
 372     DPRINTF("iterate\n");
 373     if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
 374         int state;
 375         int old_vm_running = vm_running;
 376
 377         DPRINTF("done iterating\n");
 378         vm_stop(0);
 379
 380         qemu_aio_flush();
 381         bdrv_flush_all();
 382         if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
 383             if (old_vm_running) {
 384                 vm_start();
 385             }
 386             state = MIG_STATE_ERROR;
 387         } else {
 388             state = MIG_STATE_COMPLETED;
 389         }
 390         migrate_fd_cleanup(s);
 391         s->state = state;
 392     }
 393 }
 394
 395 int migrate_fd_get_status(MigrationState *mig_state)
 396 {
 397     FdMigrationState *s = migrate_to_fms(mig_state);
 398     return s->state;
 399 }
 400
 401 void migrate_fd_cancel(MigrationState *mig_state)
 402 {
 403     FdMigrationState *s = migrate_to_fms(mig_state);
 404
 405     if (s->state != MIG_STATE_ACTIVE)
 406         return;
 407
 408     DPRINTF("cancelling migration\n");
 409
 410     s->state = MIG_STATE_CANCELLED;
 411     qemu_savevm_state_cancel(s->mon, s->file);
 412
 413     migrate_fd_cleanup(s);
 414 }
 415
 416 void migrate_fd_release(MigrationState *mig_state)
 417 {
 418     FdMigrationState *s = migrate_to_fms(mig_state);
 419
 420     DPRINTF("releasing state\n");
 421
 422     if (s->state == MIG_STATE_ACTIVE) {
 423         s->state = MIG_STATE_CANCELLED;
 424         migrate_fd_cleanup(s);
 425     }
 426     free(s);
 427 }
 428
 429 void migrate_fd_wait_for_unfreeze(void *opaque)
 430 {
 431     FdMigrationState *s = opaque;
 432     int ret;
 433
 434     DPRINTF("wait for unfreeze\n");
 435     if (s->state != MIG_STATE_ACTIVE)
 436         return;
 437
 438     do {
 439         fd_set wfds;
 440
 441         FD_ZERO(&wfds);
 442         FD_SET(s->fd, &wfds);
 443
 444         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 445     } while (ret == -1 && (s->get_error(s)) == EINTR);
 446 }
 447
 448 int migrate_fd_close(void *opaque)
 449 {
 450     FdMigrationState *s = opaque;
 451
 452     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 453     return s->close(s);
 454 }