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 int qemu_start_incoming_migration(const char *uri)
  40 {
  41     const char *p;
  42     int ret;
  43
  44     if (strstart(uri, "tcp:", &p))
  45         ret = tcp_start_incoming_migration(p);
  46 #if !defined(WIN32)
  47     else if (strstart(uri, "exec:", &p))
  48         ret =  exec_start_incoming_migration(p);
  49     else if (strstart(uri, "unix:", &p))
  50         ret = unix_start_incoming_migration(p);
  51     else if (strstart(uri, "fd:", &p))
  52         ret = fd_start_incoming_migration(p);
  53 #endif
  54     else {
  55         fprintf(stderr, "unknown migration protocol: %s\n", uri);
  56         ret = -EPROTONOSUPPORT;
  57     }
  58     return ret;
  59 }
  60
  61 void process_incoming_migration(QEMUFile *f)
  62 {
  63     if (qemu_loadvm_state(f) < 0) {
  64         fprintf(stderr, "load of migration failed\n");
  65         exit(0);
  66     }
  67     qemu_announce_self();
  68     DPRINTF("successfully loaded vm state\n");
  69
  70     incoming_expected = false;
  71
  72     if (autostart)
  73         vm_start();
  74 }
  75
  76 int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
  77 {
  78     MigrationState *s = NULL;
  79     const char *p;
  80     int detach = qdict_get_try_bool(qdict, "detach", 0);
  81     int blk = qdict_get_try_bool(qdict, "blk", 0);
  82     int inc = qdict_get_try_bool(qdict, "inc", 0);
  83     const char *uri = qdict_get_str(qdict, "uri");
  84
  85     if (current_migration &&
  86         current_migration->get_status(current_migration) == MIG_STATE_ACTIVE) {
  87         monitor_printf(mon, "migration already in progress\n");
  88         return -1;
  89     }
  90
  91     if (qemu_savevm_state_blocked(mon)) {
  92         return -1;
  93     }
  94
  95     if (strstart(uri, "tcp:", &p)) {
  96         s = tcp_start_outgoing_migration(mon, p, max_throttle, detach,
  97                                          blk, inc);
  98 #if !defined(WIN32)
  99     } else if (strstart(uri, "exec:", &p)) {
 100         s = exec_start_outgoing_migration(mon, p, max_throttle, detach,
 101                                           blk, inc);
 102     } else if (strstart(uri, "unix:", &p)) {
 103         s = unix_start_outgoing_migration(mon, p, max_throttle, detach,
 104                                           blk, inc);
 105     } else if (strstart(uri, "fd:", &p)) {
 106         s = fd_start_outgoing_migration(mon, p, max_throttle, detach,
 107                                         blk, inc);
 108 #endif
 109     } else {
 110         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
 111         return -1;
 112     }
 113
 114     if (s == NULL) {
 115         monitor_printf(mon, "migration failed\n");
 116         return -1;
 117     }
 118
 119     if (current_migration) {
 120         current_migration->release(current_migration);
 121     }
 122
 123     current_migration = s;
 124     return 0;
 125 }
 126
 127 int do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
 128 {
 129     MigrationState *s = current_migration;
 130
 131     if (s)
 132         s->cancel(s);
 133
 134     return 0;
 135 }
 136
 137 int do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)
 138 {
 139     int64_t d;
 140     FdMigrationState *s;
 141
 142     d = qdict_get_int(qdict, "value");
 143     if (d < 0) {
 144         d = 0;
 145     }
 146     max_throttle = d;
 147
 148     s = migrate_to_fms(current_migration);
 149     if (s && s->file) {
 150         qemu_file_set_rate_limit(s->file, max_throttle);
 151     }
 152
 153     return 0;
 154 }
 155
 156 /* amount of nanoseconds we are willing to wait for migration to be down.
 157  * the choice of nanoseconds is because it is the maximum resolution that
 158  * get_clock() can achieve. It is an internal measure. All user-visible
 159  * units must be in seconds */
 160 static uint64_t max_downtime = 30000000;
 161
 162 uint64_t migrate_max_downtime(void)
 163 {
 164     return max_downtime;
 165 }
 166
 167 int do_migrate_set_downtime(Monitor *mon, const QDict *qdict,
 168                             QObject **ret_data)
 169 {
 170     double d;
 171
 172     d = qdict_get_double(qdict, "value") * 1e9;
 173     d = MAX(0, MIN(UINT64_MAX, d));
 174     max_downtime = (uint64_t)d;
 175
 176     return 0;
 177 }
 178
 179 static void migrate_print_status(Monitor *mon, const char *name,
 180                                  const QDict *status_dict)
 181 {
 182     QDict *qdict;
 183
 184     qdict = qobject_to_qdict(qdict_get(status_dict, name));
 185
 186     monitor_printf(mon, "transferred %s: %" PRIu64 " kbytes\n", name,
 187                         qdict_get_int(qdict, "transferred") >> 10);
 188     monitor_printf(mon, "remaining %s: %" PRIu64 " kbytes\n", name,
 189                         qdict_get_int(qdict, "remaining") >> 10);
 190     monitor_printf(mon, "total %s: %" PRIu64 " kbytes\n", name,
 191                         qdict_get_int(qdict, "total") >> 10);
 192 }
 193
 194 void do_info_migrate_print(Monitor *mon, const QObject *data)
 195 {
 196     QDict *qdict;
 197
 198     qdict = qobject_to_qdict(data);
 199
 200     monitor_printf(mon, "Migration status: %s\n",
 201                    qdict_get_str(qdict, "status"));
 202
 203     if (qdict_haskey(qdict, "ram")) {
 204         migrate_print_status(mon, "ram", qdict);
 205     }
 206
 207     if (qdict_haskey(qdict, "disk")) {
 208         migrate_print_status(mon, "disk", qdict);
 209     }
 210 }
 211
 212 static void migrate_put_status(QDict *qdict, const char *name,
 213                                uint64_t trans, uint64_t rem, uint64_t total)
 214 {
 215     QObject *obj;
 216
 217     obj = qobject_from_jsonf("{ 'transferred': %" PRId64 ", "
 218                                "'remaining': %" PRId64 ", "
 219                                "'total': %" PRId64 " }", trans, rem, total);
 220     qdict_put_obj(qdict, name, obj);
 221 }
 222
 223 void do_info_migrate(Monitor *mon, QObject **ret_data)
 224 {
 225     QDict *qdict;
 226     MigrationState *s = current_migration;
 227
 228     if (s) {
 229         switch (s->get_status(s)) {
 230         case MIG_STATE_ACTIVE:
 231             qdict = qdict_new();
 232             qdict_put(qdict, "status", qstring_from_str("active"));
 233
 234             migrate_put_status(qdict, "ram", ram_bytes_transferred(),
 235                                ram_bytes_remaining(), ram_bytes_total());
 236
 237             if (blk_mig_active()) {
 238                 migrate_put_status(qdict, "disk", blk_mig_bytes_transferred(),
 239                                    blk_mig_bytes_remaining(),
 240                                    blk_mig_bytes_total());
 241             }
 242
 243             *ret_data = QOBJECT(qdict);
 244             break;
 245         case MIG_STATE_COMPLETED:
 246             *ret_data = qobject_from_jsonf("{ 'status': 'completed' }");
 247             break;
 248         case MIG_STATE_ERROR:
 249             *ret_data = qobject_from_jsonf("{ 'status': 'failed' }");
 250             break;
 251         case MIG_STATE_CANCELLED:
 252             *ret_data = qobject_from_jsonf("{ 'status': 'cancelled' }");
 253             break;
 254         }
 255     }
 256 }
 257
 258 /* shared migration helpers */
 259
 260 void migrate_fd_monitor_suspend(FdMigrationState *s, Monitor *mon)
 261 {
 262     s->mon = mon;
 263     if (monitor_suspend(mon) == 0) {
 264         DPRINTF("suspending monitor\n");
 265     } else {
 266         monitor_printf(mon, "terminal does not allow synchronous "
 267                        "migration, continuing detached\n");
 268     }
 269 }
 270
 271 void migrate_fd_error(FdMigrationState *s)
 272 {
 273     DPRINTF("setting error state\n");
 274     s->state = MIG_STATE_ERROR;
 275     migrate_fd_cleanup(s);
 276 }
 277
 278 int migrate_fd_cleanup(FdMigrationState *s)
 279 {
 280     int ret = 0;
 281
 282     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 283
 284     if (s->file) {
 285         DPRINTF("closing file\n");
 286         if (qemu_fclose(s->file) != 0) {
 287             ret = -1;
 288         }
 289         s->file = NULL;
 290     }
 291
 292     if (s->fd != -1)
 293         close(s->fd);
 294
 295     /* Don't resume monitor until we've flushed all of the buffers */
 296     if (s->mon) {
 297         monitor_resume(s->mon);
 298     }
 299
 300     s->fd = -1;
 301
 302     return ret;
 303 }
 304
 305 void migrate_fd_put_notify(void *opaque)
 306 {
 307     FdMigrationState *s = opaque;
 308
 309     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 310     qemu_file_put_notify(s->file);
 311 }
 312
 313 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 314 {
 315     FdMigrationState *s = opaque;
 316     ssize_t ret;
 317
 318     do {
 319         ret = s->write(s, data, size);
 320     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 321
 322     if (ret == -1)
 323         ret = -(s->get_error(s));
 324
 325     if (ret == -EAGAIN) {
 326         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 327     } else if (ret < 0) {
 328         if (s->mon) {
 329             monitor_resume(s->mon);
 330         }
 331         s->state = MIG_STATE_ERROR;
 332     }
 333
 334     return ret;
 335 }
 336
 337 void migrate_fd_connect(FdMigrationState *s)
 338 {
 339     int ret;
 340
 341     s->file = qemu_fopen_ops_buffered(s,
 342                                       s->bandwidth_limit,
 343                                       migrate_fd_put_buffer,
 344                                       migrate_fd_put_ready,
 345                                       migrate_fd_wait_for_unfreeze,
 346                                       migrate_fd_close);
 347
 348     DPRINTF("beginning savevm\n");
 349     ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
 350                                   s->mig_state.shared);
 351     if (ret < 0) {
 352         DPRINTF("failed, %d\n", ret);
 353         migrate_fd_error(s);
 354         return;
 355     }
 356
 357     migrate_fd_put_ready(s);
 358 }
 359
 360 void migrate_fd_put_ready(void *opaque)
 361 {
 362     FdMigrationState *s = opaque;
 363
 364     if (s->state != MIG_STATE_ACTIVE) {
 365         DPRINTF("put_ready returning because of non-active state\n");
 366         return;
 367     }
 368
 369     DPRINTF("iterate\n");
 370     if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
 371         int state;
 372         int old_vm_running = vm_running;
 373
 374         DPRINTF("done iterating\n");
 375         vm_stop(0);
 376
 377         if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
 378             if (old_vm_running) {
 379                 vm_start();
 380             }
 381             state = MIG_STATE_ERROR;
 382         } else {
 383             state = MIG_STATE_COMPLETED;
 384         }
 385         if (migrate_fd_cleanup(s) < 0) {
 386             if (old_vm_running) {
 387                 vm_start();
 388             }
 389             state = MIG_STATE_ERROR;
 390         }
 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     qemu_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 }