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
  22 //#define DEBUG_MIGRATION
  23
  24 #ifdef DEBUG_MIGRATION
  25 #define dprintf(fmt, ...) \
  26     do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
  27 #else
  28 #define dprintf(fmt, ...) \
  29     do { } while (0)
  30 #endif
  31
  32 /* Migration speed throttling */
  33 static uint32_t max_throttle = (32 << 20);
  34
  35 static MigrationState *current_migration;
  36
  37 void qemu_start_incoming_migration(const char *uri)
  38 {
  39     const char *p;
  40
  41     if (strstart(uri, "tcp:", &p))
  42         tcp_start_incoming_migration(p);
  43 #if !defined(WIN32)
  44     else if (strstart(uri, "exec:", &p))
  45         exec_start_incoming_migration(p);
  46     else if (strstart(uri, "unix:", &p))
  47         unix_start_incoming_migration(p);
  48     else if (strstart(uri, "fd:", &p))
  49         fd_start_incoming_migration(p);
  50 #endif
  51     else
  52         fprintf(stderr, "unknown migration protocol: %s\n", uri);
  53 }
  54
  55 void do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)
  56 {
  57     MigrationState *s = NULL;
  58     const char *p;
  59     int detach = qdict_get_int(qdict, "detach");
  60     const char *uri = qdict_get_str(qdict, "uri");
  61
  62     if (strstart(uri, "tcp:", &p))
  63         s = tcp_start_outgoing_migration(p, max_throttle, detach,
  64                                          (int)qdict_get_int(qdict, "blk"),
  65                                          (int)qdict_get_int(qdict, "inc"));
  66 #if !defined(WIN32)
  67     else if (strstart(uri, "exec:", &p))
  68         s = exec_start_outgoing_migration(p, max_throttle, detach,
  69                                           (int)qdict_get_int(qdict, "blk"),
  70                                           (int)qdict_get_int(qdict, "inc"));
  71     else if (strstart(uri, "unix:", &p))
  72         s = unix_start_outgoing_migration(p, max_throttle, detach,
  73                                           (int)qdict_get_int(qdict, "blk"),
  74                                           (int)qdict_get_int(qdict, "inc"));
  75     else if (strstart(uri, "fd:", &p))
  76         s = fd_start_outgoing_migration(mon, p, max_throttle, detach,
  77                                         (int)qdict_get_int(qdict, "blk"),
  78                                         (int)qdict_get_int(qdict, "inc"));
  79 #endif
  80     else
  81         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
  82
  83     if (s == NULL)
  84         monitor_printf(mon, "migration failed\n");
  85     else {
  86         if (current_migration)
  87             current_migration->release(current_migration);
  88
  89         current_migration = s;
  90     }
  91 }
  92
  93 void do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
  94 {
  95     MigrationState *s = current_migration;
  96
  97     if (s)
  98         s->cancel(s);
  99 }
 100
 101 void do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)
 102 {
 103     double d;
 104     char *ptr;
 105     FdMigrationState *s;
 106     const char *value = qdict_get_str(qdict, "value");
 107
 108     d = strtod(value, &ptr);
 109     switch (*ptr) {
 110     case 'G': case 'g':
 111         d *= 1024;
 112     case 'M': case 'm':
 113         d *= 1024;
 114     case 'K': case 'k':
 115         d *= 1024;
 116     default:
 117         break;
 118     }
 119
 120     max_throttle = (uint32_t)d;
 121     s = migrate_to_fms(current_migration);
 122
 123     if (s) {
 124         qemu_file_set_rate_limit(s->file, max_throttle);
 125     }
 126
 127 }
 128
 129 /* amount of nanoseconds we are willing to wait for migration to be down.
 130  * the choice of nanoseconds is because it is the maximum resolution that
 131  * get_clock() can achieve. It is an internal measure. All user-visible
 132  * units must be in seconds */
 133 static uint64_t max_downtime = 30000000;
 134
 135 uint64_t migrate_max_downtime(void)
 136 {
 137     return max_downtime;
 138 }
 139
 140 void do_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 141 {
 142     char *ptr;
 143     double d;
 144     const char *value = qdict_get_str(qdict, "value");
 145
 146     d = strtod(value, &ptr);
 147     if (!strcmp(ptr,"ms")) {
 148         d *= 1000000;
 149     } else if (!strcmp(ptr,"us")) {
 150         d *= 1000;
 151     } else if (!strcmp(ptr,"ns")) {
 152     } else {
 153         /* all else considered to be seconds */
 154         d *= 1000000000;
 155     }
 156
 157     max_downtime = (uint64_t)d;
 158 }
 159
 160 void do_info_migrate(Monitor *mon)
 161 {
 162     MigrationState *s = current_migration;
 163
 164     if (s) {
 165         monitor_printf(mon, "Migration status: ");
 166         switch (s->get_status(s)) {
 167         case MIG_STATE_ACTIVE:
 168             monitor_printf(mon, "active\n");
 169             monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n", ram_bytes_transferred() >> 10);
 170             monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n", ram_bytes_remaining() >> 10);
 171             monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n", ram_bytes_total() >> 10);
 172             break;
 173         case MIG_STATE_COMPLETED:
 174             monitor_printf(mon, "completed\n");
 175             break;
 176         case MIG_STATE_ERROR:
 177             monitor_printf(mon, "failed\n");
 178             break;
 179         case MIG_STATE_CANCELLED:
 180             monitor_printf(mon, "cancelled\n");
 181             break;
 182         }
 183     }
 184 }
 185
 186 /* shared migration helpers */
 187
 188 void migrate_fd_monitor_suspend(FdMigrationState *s)
 189 {
 190     s->mon_resume = cur_mon;
 191     if (monitor_suspend(cur_mon) == 0)
 192         dprintf("suspending monitor\n");
 193     else
 194         monitor_printf(cur_mon, "terminal does not allow synchronous "
 195                        "migration, continuing detached\n");
 196 }
 197
 198 void migrate_fd_error(FdMigrationState *s)
 199 {
 200     dprintf("setting error state\n");
 201     s->state = MIG_STATE_ERROR;
 202     migrate_fd_cleanup(s);
 203 }
 204
 205 void migrate_fd_cleanup(FdMigrationState *s)
 206 {
 207     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 208
 209     if (s->file) {
 210         dprintf("closing file\n");
 211         qemu_fclose(s->file);
 212     }
 213
 214     if (s->fd != -1)
 215         close(s->fd);
 216
 217     /* Don't resume monitor until we've flushed all of the buffers */
 218     if (s->mon_resume)
 219         monitor_resume(s->mon_resume);
 220
 221     s->fd = -1;
 222 }
 223
 224 void migrate_fd_put_notify(void *opaque)
 225 {
 226     FdMigrationState *s = opaque;
 227
 228     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 229     qemu_file_put_notify(s->file);
 230 }
 231
 232 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 233 {
 234     FdMigrationState *s = opaque;
 235     ssize_t ret;
 236
 237     do {
 238         ret = s->write(s, data, size);
 239     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 240
 241     if (ret == -1)
 242         ret = -(s->get_error(s));
 243
 244     if (ret == -EAGAIN)
 245         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 246
 247     return ret;
 248 }
 249
 250 void migrate_fd_connect(FdMigrationState *s)
 251 {
 252     int ret;
 253
 254     s->file = qemu_fopen_ops_buffered(s,
 255                                       s->bandwidth_limit,
 256                                       migrate_fd_put_buffer,
 257                                       migrate_fd_put_ready,
 258                                       migrate_fd_wait_for_unfreeze,
 259                                       migrate_fd_close);
 260
 261     dprintf("beginning savevm\n");
 262     ret = qemu_savevm_state_begin(s->file, s->mig_state.blk,
 263                                   s->mig_state.shared);
 264     if (ret < 0) {
 265         dprintf("failed, %d\n", ret);
 266         migrate_fd_error(s);
 267         return;
 268     }
 269
 270     migrate_fd_put_ready(s);
 271 }
 272
 273 void migrate_fd_put_ready(void *opaque)
 274 {
 275     FdMigrationState *s = opaque;
 276
 277     if (s->state != MIG_STATE_ACTIVE) {
 278         dprintf("put_ready returning because of non-active state\n");
 279         return;
 280     }
 281
 282     dprintf("iterate\n");
 283     if (qemu_savevm_state_iterate(s->file) == 1) {
 284         int state;
 285         int old_vm_running = vm_running;
 286
 287         dprintf("done iterating\n");
 288         vm_stop(0);
 289
 290         qemu_aio_flush();
 291         bdrv_flush_all();
 292         if ((qemu_savevm_state_complete(s->file)) < 0) {
 293             if (old_vm_running) {
 294                 vm_start();
 295             }
 296             state = MIG_STATE_ERROR;
 297         } else {
 298             state = MIG_STATE_COMPLETED;
 299         }
 300         migrate_fd_cleanup(s);
 301         s->state = state;
 302     }
 303 }
 304
 305 int migrate_fd_get_status(MigrationState *mig_state)
 306 {
 307     FdMigrationState *s = migrate_to_fms(mig_state);
 308     return s->state;
 309 }
 310
 311 void migrate_fd_cancel(MigrationState *mig_state)
 312 {
 313     FdMigrationState *s = migrate_to_fms(mig_state);
 314
 315     if (s->state != MIG_STATE_ACTIVE)
 316         return;
 317
 318     dprintf("cancelling migration\n");
 319
 320     s->state = MIG_STATE_CANCELLED;
 321
 322     migrate_fd_cleanup(s);
 323 }
 324
 325 void migrate_fd_release(MigrationState *mig_state)
 326 {
 327     FdMigrationState *s = migrate_to_fms(mig_state);
 328
 329     dprintf("releasing state\n");
 330
 331     if (s->state == MIG_STATE_ACTIVE) {
 332         s->state = MIG_STATE_CANCELLED;
 333         migrate_fd_cleanup(s);
 334     }
 335     free(s);
 336 }
 337
 338 void migrate_fd_wait_for_unfreeze(void *opaque)
 339 {
 340     FdMigrationState *s = opaque;
 341     int ret;
 342
 343     dprintf("wait for unfreeze\n");
 344     if (s->state != MIG_STATE_ACTIVE)
 345         return;
 346
 347     do {
 348         fd_set wfds;
 349
 350         FD_ZERO(&wfds);
 351         FD_SET(s->fd, &wfds);
 352
 353         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 354     } while (ret == -1 && (s->get_error(s)) == EINTR);
 355 }
 356
 357 int migrate_fd_close(void *opaque)
 358 {
 359     FdMigrationState *s = opaque;
 360
 361     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 362     return s->close(s);
 363 }