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 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     if (autostart)
  71         vm_start();
  72 }
  73
  74 int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
  75 {
  76     MigrationState *s = NULL;
  77     const char *p;
  78     int detach = qdict_get_try_bool(qdict, "detach", 0);
  79     int blk = qdict_get_try_bool(qdict, "blk", 0);
  80     int inc = qdict_get_try_bool(qdict, "inc", 0);
  81     const char *uri = qdict_get_str(qdict, "uri");
  82
  83     if (current_migration &&
  84         current_migration->get_status(current_migration) == MIG_STATE_ACTIVE) {
  85         monitor_printf(mon, "migration already in progress\n");
  86         return -1;
  87     }
  88
  89     if (strstart(uri, "tcp:", &p)) {
  90         s = tcp_start_outgoing_migration(mon, p, max_throttle, detach,
  91                                          blk, inc);
  92 #if !defined(WIN32)
  93     } else if (strstart(uri, "exec:", &p)) {
  94         s = exec_start_outgoing_migration(mon, p, max_throttle, detach,
  95                                           blk, inc);
  96     } else if (strstart(uri, "unix:", &p)) {
  97         s = unix_start_outgoing_migration(mon, p, max_throttle, detach,
  98                                           blk, inc);
  99     } else if (strstart(uri, "fd:", &p)) {
 100         s = fd_start_outgoing_migration(mon, p, max_throttle, detach,
 101                                         blk, inc);
 102 #endif
 103     } else {
 104         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
 105         return -1;
 106     }
 107
 108     if (s == NULL) {
 109         monitor_printf(mon, "migration failed\n");
 110         return -1;
 111     }
 112
 113     if (current_migration) {
 114         current_migration->release(current_migration);
 115     }
 116
 117     current_migration = s;
 118     return 0;
 119 }
 120
 121 int do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
 122 {
 123     MigrationState *s = current_migration;
 124
 125     if (s)
 126         s->cancel(s);
 127
 128     return 0;
 129 }
 130
 131 int do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)
 132 {
 133     double d;
 134     FdMigrationState *s;
 135
 136     d = qdict_get_double(qdict, "value");
 137     d = MAX(0, MIN(UINT32_MAX, d));
 138     max_throttle = d;
 139
 140     s = migrate_to_fms(current_migration);
 141     if (s && s->file) {
 142         qemu_file_set_rate_limit(s->file, max_throttle);
 143     }
 144
 145     return 0;
 146 }
 147
 148 /* amount of nanoseconds we are willing to wait for migration to be down.
 149  * the choice of nanoseconds is because it is the maximum resolution that
 150  * get_clock() can achieve. It is an internal measure. All user-visible
 151  * units must be in seconds */
 152 static uint64_t max_downtime = 30000000;
 153
 154 uint64_t migrate_max_downtime(void)
 155 {
 156     return max_downtime;
 157 }
 158
 159 int do_migrate_set_downtime(Monitor *mon, const QDict *qdict,
 160                             QObject **ret_data)
 161 {
 162     double d;
 163
 164     d = qdict_get_double(qdict, "value") * 1e9;
 165     d = MAX(0, MIN(UINT64_MAX, d));
 166     max_downtime = (uint64_t)d;
 167
 168     return 0;
 169 }
 170
 171 static void migrate_print_status(Monitor *mon, const char *name,
 172                                  const QDict *status_dict)
 173 {
 174     QDict *qdict;
 175
 176     qdict = qobject_to_qdict(qdict_get(status_dict, name));
 177
 178     monitor_printf(mon, "transferred %s: %" PRIu64 " kbytes\n", name,
 179                         qdict_get_int(qdict, "transferred") >> 10);
 180     monitor_printf(mon, "remaining %s: %" PRIu64 " kbytes\n", name,
 181                         qdict_get_int(qdict, "remaining") >> 10);
 182     monitor_printf(mon, "total %s: %" PRIu64 " kbytes\n", name,
 183                         qdict_get_int(qdict, "total") >> 10);
 184 }
 185
 186 void do_info_migrate_print(Monitor *mon, const QObject *data)
 187 {
 188     QDict *qdict;
 189
 190     qdict = qobject_to_qdict(data);
 191
 192     monitor_printf(mon, "Migration status: %s\n",
 193                    qdict_get_str(qdict, "status"));
 194
 195     if (qdict_haskey(qdict, "ram")) {
 196         migrate_print_status(mon, "ram", qdict);
 197     }
 198
 199     if (qdict_haskey(qdict, "disk")) {
 200         migrate_print_status(mon, "disk", qdict);
 201     }
 202 }
 203
 204 static void migrate_put_status(QDict *qdict, const char *name,
 205                                uint64_t trans, uint64_t rem, uint64_t total)
 206 {
 207     QObject *obj;
 208
 209     obj = qobject_from_jsonf("{ 'transferred': %" PRId64 ", "
 210                                "'remaining': %" PRId64 ", "
 211                                "'total': %" PRId64 " }", trans, rem, total);
 212     qdict_put_obj(qdict, name, obj);
 213 }
 214
 215 void do_info_migrate(Monitor *mon, QObject **ret_data)
 216 {
 217     QDict *qdict;
 218     MigrationState *s = current_migration;
 219
 220     if (s) {
 221         switch (s->get_status(s)) {
 222         case MIG_STATE_ACTIVE:
 223             qdict = qdict_new();
 224             qdict_put(qdict, "status", qstring_from_str("active"));
 225
 226             migrate_put_status(qdict, "ram", ram_bytes_transferred(),
 227                                ram_bytes_remaining(), ram_bytes_total());
 228
 229             if (blk_mig_active()) {
 230                 migrate_put_status(qdict, "disk", blk_mig_bytes_transferred(),
 231                                    blk_mig_bytes_remaining(),
 232                                    blk_mig_bytes_total());
 233             }
 234
 235             *ret_data = QOBJECT(qdict);
 236             break;
 237         case MIG_STATE_COMPLETED:
 238             *ret_data = qobject_from_jsonf("{ 'status': 'completed' }");
 239             break;
 240         case MIG_STATE_ERROR:
 241             *ret_data = qobject_from_jsonf("{ 'status': 'failed' }");
 242             break;
 243         case MIG_STATE_CANCELLED:
 244             *ret_data = qobject_from_jsonf("{ 'status': 'cancelled' }");
 245             break;
 246         }
 247     }
 248 }
 249
 250 /* shared migration helpers */
 251
 252 void migrate_fd_monitor_suspend(FdMigrationState *s, Monitor *mon)
 253 {
 254     s->mon = mon;
 255     if (monitor_suspend(mon) == 0) {
 256         DPRINTF("suspending monitor\n");
 257     } else {
 258         monitor_printf(mon, "terminal does not allow synchronous "
 259                        "migration, continuing detached\n");
 260     }
 261 }
 262
 263 void migrate_fd_error(FdMigrationState *s)
 264 {
 265     DPRINTF("setting error state\n");
 266     s->state = MIG_STATE_ERROR;
 267     migrate_fd_cleanup(s);
 268 }
 269
 270 int migrate_fd_cleanup(FdMigrationState *s)
 271 {
 272     int ret = 0;
 273
 274     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 275
 276     if (s->file) {
 277         DPRINTF("closing file\n");
 278         if (qemu_fclose(s->file) != 0) {
 279             ret = -1;
 280         }
 281         s->file = NULL;
 282     }
 283
 284     if (s->fd != -1)
 285         close(s->fd);
 286
 287     /* Don't resume monitor until we've flushed all of the buffers */
 288     if (s->mon) {
 289         monitor_resume(s->mon);
 290     }
 291
 292     s->fd = -1;
 293
 294     return ret;
 295 }
 296
 297 void migrate_fd_put_notify(void *opaque)
 298 {
 299     FdMigrationState *s = opaque;
 300
 301     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 302     qemu_file_put_notify(s->file);
 303 }
 304
 305 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 306 {
 307     FdMigrationState *s = opaque;
 308     ssize_t ret;
 309
 310     do {
 311         ret = s->write(s, data, size);
 312     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 313
 314     if (ret == -1)
 315         ret = -(s->get_error(s));
 316
 317     if (ret == -EAGAIN)
 318         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 319
 320     return ret;
 321 }
 322
 323 void migrate_fd_connect(FdMigrationState *s)
 324 {
 325     int ret;
 326
 327     s->file = qemu_fopen_ops_buffered(s,
 328                                       s->bandwidth_limit,
 329                                       migrate_fd_put_buffer,
 330                                       migrate_fd_put_ready,
 331                                       migrate_fd_wait_for_unfreeze,
 332                                       migrate_fd_close);
 333
 334     DPRINTF("beginning savevm\n");
 335     ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
 336                                   s->mig_state.shared);
 337     if (ret < 0) {
 338         DPRINTF("failed, %d\n", ret);
 339         migrate_fd_error(s);
 340         return;
 341     }
 342
 343     migrate_fd_put_ready(s);
 344 }
 345
 346 void migrate_fd_put_ready(void *opaque)
 347 {
 348     FdMigrationState *s = opaque;
 349
 350     if (s->state != MIG_STATE_ACTIVE) {
 351         DPRINTF("put_ready returning because of non-active state\n");
 352         return;
 353     }
 354
 355     DPRINTF("iterate\n");
 356     if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
 357         int state;
 358         int old_vm_running = vm_running;
 359
 360         DPRINTF("done iterating\n");
 361         vm_stop(0);
 362
 363         qemu_aio_flush();
 364         bdrv_flush_all();
 365         if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
 366             if (old_vm_running) {
 367                 vm_start();
 368             }
 369             state = MIG_STATE_ERROR;
 370         } else {
 371             state = MIG_STATE_COMPLETED;
 372         }
 373         if (migrate_fd_cleanup(s) < 0) {
 374             if (old_vm_running) {
 375                 vm_start();
 376             }
 377             state = MIG_STATE_ERROR;
 378         }
 379         s->state = state;
 380     }
 381 }
 382
 383 int migrate_fd_get_status(MigrationState *mig_state)
 384 {
 385     FdMigrationState *s = migrate_to_fms(mig_state);
 386     return s->state;
 387 }
 388
 389 void migrate_fd_cancel(MigrationState *mig_state)
 390 {
 391     FdMigrationState *s = migrate_to_fms(mig_state);
 392
 393     if (s->state != MIG_STATE_ACTIVE)
 394         return;
 395
 396     DPRINTF("cancelling migration\n");
 397
 398     s->state = MIG_STATE_CANCELLED;
 399     qemu_savevm_state_cancel(s->mon, s->file);
 400
 401     migrate_fd_cleanup(s);
 402 }
 403
 404 void migrate_fd_release(MigrationState *mig_state)
 405 {
 406     FdMigrationState *s = migrate_to_fms(mig_state);
 407
 408     DPRINTF("releasing state\n");
 409
 410     if (s->state == MIG_STATE_ACTIVE) {
 411         s->state = MIG_STATE_CANCELLED;
 412         migrate_fd_cleanup(s);
 413     }
 414     qemu_free(s);
 415 }
 416
 417 void migrate_fd_wait_for_unfreeze(void *opaque)
 418 {
 419     FdMigrationState *s = opaque;
 420     int ret;
 421
 422     DPRINTF("wait for unfreeze\n");
 423     if (s->state != MIG_STATE_ACTIVE)
 424         return;
 425
 426     do {
 427         fd_set wfds;
 428
 429         FD_ZERO(&wfds);
 430         FD_SET(s->fd, &wfds);
 431
 432         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 433     } while (ret == -1 && (s->get_error(s)) == EINTR);
 434 }
 435
 436 int migrate_fd_close(void *opaque)
 437 {
 438     FdMigrationState *s = opaque;
 439
 440     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 441     return s->close(s);
 442 }