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