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 (current_migration &&
  63         current_migration->get_status(current_migration) == MIG_STATE_ACTIVE) {
  64         monitor_printf(mon, "migration already in progress\n");
  65         return;
  66     }
  67
  68     if (strstart(uri, "tcp:", &p))
  69         s = tcp_start_outgoing_migration(p, max_throttle, detach,
  70                                          (int)qdict_get_int(qdict, "blk"),
  71                                          (int)qdict_get_int(qdict, "inc"));
  72 #if !defined(WIN32)
  73     else if (strstart(uri, "exec:", &p))
  74         s = exec_start_outgoing_migration(p, max_throttle, detach,
  75                                           (int)qdict_get_int(qdict, "blk"),
  76                                           (int)qdict_get_int(qdict, "inc"));
  77     else if (strstart(uri, "unix:", &p))
  78         s = unix_start_outgoing_migration(p, max_throttle, detach,
  79                                           (int)qdict_get_int(qdict, "blk"),
  80                                           (int)qdict_get_int(qdict, "inc"));
  81     else if (strstart(uri, "fd:", &p))
  82         s = fd_start_outgoing_migration(mon, p, max_throttle, detach,
  83                                         (int)qdict_get_int(qdict, "blk"),
  84                                         (int)qdict_get_int(qdict, "inc"));
  85 #endif
  86     else
  87         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
  88
  89     if (s == NULL)
  90         monitor_printf(mon, "migration failed\n");
  91     else {
  92         if (current_migration)
  93             current_migration->release(current_migration);
  94
  95         current_migration = s;
  96     }
  97 }
  98
  99 void do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)
 100 {
 101     MigrationState *s = current_migration;
 102
 103     if (s)
 104         s->cancel(s);
 105 }
 106
 107 void do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)
 108 {
 109     double d;
 110     char *ptr;
 111     FdMigrationState *s;
 112     const char *value = qdict_get_str(qdict, "value");
 113
 114     d = strtod(value, &ptr);
 115     switch (*ptr) {
 116     case 'G': case 'g':
 117         d *= 1024;
 118     case 'M': case 'm':
 119         d *= 1024;
 120     case 'K': case 'k':
 121         d *= 1024;
 122     default:
 123         break;
 124     }
 125
 126     max_throttle = (uint32_t)d;
 127
 128     s = migrate_to_fms(current_migration);
 129     if (s && s->file) {
 130         qemu_file_set_rate_limit(s->file, max_throttle);
 131     }
 132 }
 133
 134 /* amount of nanoseconds we are willing to wait for migration to be down.
 135  * the choice of nanoseconds is because it is the maximum resolution that
 136  * get_clock() can achieve. It is an internal measure. All user-visible
 137  * units must be in seconds */
 138 static uint64_t max_downtime = 30000000;
 139
 140 uint64_t migrate_max_downtime(void)
 141 {
 142     return max_downtime;
 143 }
 144
 145 void do_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 146 {
 147     char *ptr;
 148     double d;
 149     const char *value = qdict_get_str(qdict, "value");
 150
 151     d = strtod(value, &ptr);
 152     if (!strcmp(ptr,"ms")) {
 153         d *= 1000000;
 154     } else if (!strcmp(ptr,"us")) {
 155         d *= 1000;
 156     } else if (!strcmp(ptr,"ns")) {
 157     } else {
 158         /* all else considered to be seconds */
 159         d *= 1000000000;
 160     }
 161
 162     max_downtime = (uint64_t)d;
 163 }
 164
 165 void do_info_migrate(Monitor *mon)
 166 {
 167     MigrationState *s = current_migration;
 168
 169     if (s) {
 170         monitor_printf(mon, "Migration status: ");
 171         switch (s->get_status(s)) {
 172         case MIG_STATE_ACTIVE:
 173             monitor_printf(mon, "active\n");
 174             monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n", ram_bytes_transferred() >> 10);
 175             monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n", ram_bytes_remaining() >> 10);
 176             monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n", ram_bytes_total() >> 10);
 177             break;
 178         case MIG_STATE_COMPLETED:
 179             monitor_printf(mon, "completed\n");
 180             break;
 181         case MIG_STATE_ERROR:
 182             monitor_printf(mon, "failed\n");
 183             break;
 184         case MIG_STATE_CANCELLED:
 185             monitor_printf(mon, "cancelled\n");
 186             break;
 187         }
 188     }
 189 }
 190
 191 /* shared migration helpers */
 192
 193 void migrate_fd_monitor_suspend(FdMigrationState *s)
 194 {
 195     s->mon_resume = cur_mon;
 196     if (monitor_suspend(cur_mon) == 0)
 197         dprintf("suspending monitor\n");
 198     else
 199         monitor_printf(cur_mon, "terminal does not allow synchronous "
 200                        "migration, continuing detached\n");
 201 }
 202
 203 void migrate_fd_error(FdMigrationState *s)
 204 {
 205     dprintf("setting error state\n");
 206     s->state = MIG_STATE_ERROR;
 207     migrate_fd_cleanup(s);
 208 }
 209
 210 void migrate_fd_cleanup(FdMigrationState *s)
 211 {
 212     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 213
 214     if (s->file) {
 215         dprintf("closing file\n");
 216         qemu_fclose(s->file);
 217         s->file = NULL;
 218     }
 219
 220     if (s->fd != -1)
 221         close(s->fd);
 222
 223     /* Don't resume monitor until we've flushed all of the buffers */
 224     if (s->mon_resume)
 225         monitor_resume(s->mon_resume);
 226
 227     s->fd = -1;
 228 }
 229
 230 void migrate_fd_put_notify(void *opaque)
 231 {
 232     FdMigrationState *s = opaque;
 233
 234     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 235     qemu_file_put_notify(s->file);
 236 }
 237
 238 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 239 {
 240     FdMigrationState *s = opaque;
 241     ssize_t ret;
 242
 243     do {
 244         ret = s->write(s, data, size);
 245     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 246
 247     if (ret == -1)
 248         ret = -(s->get_error(s));
 249
 250     if (ret == -EAGAIN)
 251         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 252
 253     return ret;
 254 }
 255
 256 void migrate_fd_connect(FdMigrationState *s)
 257 {
 258     int ret;
 259
 260     s->file = qemu_fopen_ops_buffered(s,
 261                                       s->bandwidth_limit,
 262                                       migrate_fd_put_buffer,
 263                                       migrate_fd_put_ready,
 264                                       migrate_fd_wait_for_unfreeze,
 265                                       migrate_fd_close);
 266
 267     dprintf("beginning savevm\n");
 268     ret = qemu_savevm_state_begin(s->file, s->mig_state.blk,
 269                                   s->mig_state.shared);
 270     if (ret < 0) {
 271         dprintf("failed, %d\n", ret);
 272         migrate_fd_error(s);
 273         return;
 274     }
 275
 276     migrate_fd_put_ready(s);
 277 }
 278
 279 void migrate_fd_put_ready(void *opaque)
 280 {
 281     FdMigrationState *s = opaque;
 282
 283     if (s->state != MIG_STATE_ACTIVE) {
 284         dprintf("put_ready returning because of non-active state\n");
 285         return;
 286     }
 287
 288     dprintf("iterate\n");
 289     if (qemu_savevm_state_iterate(s->file) == 1) {
 290         int state;
 291         int old_vm_running = vm_running;
 292
 293         dprintf("done iterating\n");
 294         vm_stop(0);
 295
 296         qemu_aio_flush();
 297         bdrv_flush_all();
 298         if ((qemu_savevm_state_complete(s->file)) < 0) {
 299             if (old_vm_running) {
 300                 vm_start();
 301             }
 302             state = MIG_STATE_ERROR;
 303         } else {
 304             state = MIG_STATE_COMPLETED;
 305         }
 306         migrate_fd_cleanup(s);
 307         s->state = state;
 308     }
 309 }
 310
 311 int migrate_fd_get_status(MigrationState *mig_state)
 312 {
 313     FdMigrationState *s = migrate_to_fms(mig_state);
 314     return s->state;
 315 }
 316
 317 void migrate_fd_cancel(MigrationState *mig_state)
 318 {
 319     FdMigrationState *s = migrate_to_fms(mig_state);
 320
 321     if (s->state != MIG_STATE_ACTIVE)
 322         return;
 323
 324     dprintf("cancelling migration\n");
 325
 326     s->state = MIG_STATE_CANCELLED;
 327
 328     migrate_fd_cleanup(s);
 329 }
 330
 331 void migrate_fd_release(MigrationState *mig_state)
 332 {
 333     FdMigrationState *s = migrate_to_fms(mig_state);
 334
 335     dprintf("releasing state\n");
 336
 337     if (s->state == MIG_STATE_ACTIVE) {
 338         s->state = MIG_STATE_CANCELLED;
 339         migrate_fd_cleanup(s);
 340     }
 341     free(s);
 342 }
 343
 344 void migrate_fd_wait_for_unfreeze(void *opaque)
 345 {
 346     FdMigrationState *s = opaque;
 347     int ret;
 348
 349     dprintf("wait for unfreeze\n");
 350     if (s->state != MIG_STATE_ACTIVE)
 351         return;
 352
 353     do {
 354         fd_set wfds;
 355
 356         FD_ZERO(&wfds);
 357         FD_SET(s->fd, &wfds);
 358
 359         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 360     } while (ret == -1 && (s->get_error(s)) == EINTR);
 361 }
 362
 363 int migrate_fd_close(void *opaque)
 364 {
 365     FdMigrationState *s = opaque;
 366
 367     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 368     return s->close(s);
 369 }