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