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 #endif
  47     else
  48         fprintf(stderr, "unknown migration protocol: %s\n", uri);
  49 }
  50
  51 void do_migrate(Monitor *mon, int detach, const char *uri)
  52 {
  53     MigrationState *s = NULL;
  54     const char *p;
  55
  56     if (strstart(uri, "tcp:", &p))
  57         s = tcp_start_outgoing_migration(p, max_throttle, detach);
  58 #if !defined(WIN32)
  59     else if (strstart(uri, "exec:", &p))
  60         s = exec_start_outgoing_migration(p, max_throttle, detach);
  61 #endif
  62     else
  63         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
  64
  65     if (s == NULL)
  66         monitor_printf(mon, "migration failed\n");
  67     else {
  68         if (current_migration)
  69             current_migration->release(current_migration);
  70
  71         current_migration = s;
  72     }
  73 }
  74
  75 void do_migrate_cancel(Monitor *mon)
  76 {
  77     MigrationState *s = current_migration;
  78
  79     if (s)
  80         s->cancel(s);
  81 }
  82
  83 void do_migrate_set_speed(Monitor *mon, const char *value)
  84 {
  85     double d;
  86     char *ptr;
  87
  88     d = strtod(value, &ptr);
  89     switch (*ptr) {
  90     case 'G': case 'g':
  91         d *= 1024;
  92     case 'M': case 'm':
  93         d *= 1024;
  94     case 'K': case 'k':
  95         d *= 1024;
  96     default:
  97         break;
  98     }
  99
 100     max_throttle = (uint32_t)d;
 101 }
 102
 103 void do_info_migrate(Monitor *mon)
 104 {
 105     MigrationState *s = current_migration;
 106
 107     if (s) {
 108         monitor_printf(mon, "Migration status: ");
 109         switch (s->get_status(s)) {
 110         case MIG_STATE_ACTIVE:
 111             monitor_printf(mon, "active\n");
 112             break;
 113         case MIG_STATE_COMPLETED:
 114             monitor_printf(mon, "completed\n");
 115             break;
 116         case MIG_STATE_ERROR:
 117             monitor_printf(mon, "failed\n");
 118             break;
 119         case MIG_STATE_CANCELLED:
 120             monitor_printf(mon, "cancelled\n");
 121             break;
 122         }
 123     }
 124 }
 125
 126 /* shared migration helpers */
 127
 128 void migrate_fd_monitor_suspend(FdMigrationState *s)
 129 {
 130     s->mon_resume = cur_mon;
 131     if (monitor_suspend(cur_mon) == 0)
 132         dprintf("suspending monitor\n");
 133     else
 134         monitor_printf(cur_mon, "terminal does not allow synchronous "
 135                        "migration, continuing detached\n");
 136 }
 137
 138 void migrate_fd_error(FdMigrationState *s)
 139 {
 140     dprintf("setting error state\n");
 141     s->state = MIG_STATE_ERROR;
 142     migrate_fd_cleanup(s);
 143 }
 144
 145 void migrate_fd_cleanup(FdMigrationState *s)
 146 {
 147     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 148
 149     if (s->file) {
 150         dprintf("closing file\n");
 151         qemu_fclose(s->file);
 152     }
 153
 154     if (s->fd != -1)
 155         close(s->fd);
 156
 157     /* Don't resume monitor until we've flushed all of the buffers */
 158     if (s->mon_resume)
 159         monitor_resume(s->mon_resume);
 160
 161     s->fd = -1;
 162 }
 163
 164 void migrate_fd_put_notify(void *opaque)
 165 {
 166     FdMigrationState *s = opaque;
 167
 168     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 169     qemu_file_put_notify(s->file);
 170 }
 171
 172 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 173 {
 174     FdMigrationState *s = opaque;
 175     ssize_t ret;
 176
 177     do {
 178         ret = s->write(s, data, size);
 179     } while (ret == -1 && ((s->get_error(s)) == EINTR || (s->get_error(s)) == EWOULDBLOCK));
 180
 181     if (ret == -1)
 182         ret = -(s->get_error(s));
 183
 184     if (ret == -EAGAIN)
 185         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 186
 187     return ret;
 188 }
 189
 190 void migrate_fd_connect(FdMigrationState *s)
 191 {
 192     int ret;
 193
 194     s->file = qemu_fopen_ops_buffered(s,
 195                                       s->bandwidth_limit,
 196                                       migrate_fd_put_buffer,
 197                                       migrate_fd_put_ready,
 198                                       migrate_fd_wait_for_unfreeze,
 199                                       migrate_fd_close);
 200
 201     dprintf("beginning savevm\n");
 202     ret = qemu_savevm_state_begin(s->file);
 203     if (ret < 0) {
 204         dprintf("failed, %d\n", ret);
 205         migrate_fd_error(s);
 206         return;
 207     }
 208
 209     migrate_fd_put_ready(s);
 210 }
 211
 212 void migrate_fd_put_ready(void *opaque)
 213 {
 214     FdMigrationState *s = opaque;
 215
 216     if (s->state != MIG_STATE_ACTIVE) {
 217         dprintf("put_ready returning because of non-active state\n");
 218         return;
 219     }
 220
 221     dprintf("iterate\n");
 222     if (qemu_savevm_state_iterate(s->file) == 1) {
 223         int state;
 224         dprintf("done iterating\n");
 225         vm_stop(0);
 226
 227         bdrv_flush_all();
 228         if ((qemu_savevm_state_complete(s->file)) < 0) {
 229             vm_start();
 230             state = MIG_STATE_ERROR;
 231         } else {
 232             state = MIG_STATE_COMPLETED;
 233         }
 234         migrate_fd_cleanup(s);
 235         s->state = state;
 236     }
 237 }
 238
 239 int migrate_fd_get_status(MigrationState *mig_state)
 240 {
 241     FdMigrationState *s = migrate_to_fms(mig_state);
 242     return s->state;
 243 }
 244
 245 void migrate_fd_cancel(MigrationState *mig_state)
 246 {
 247     FdMigrationState *s = migrate_to_fms(mig_state);
 248
 249     if (s->state != MIG_STATE_ACTIVE)
 250         return;
 251
 252     dprintf("cancelling migration\n");
 253
 254     s->state = MIG_STATE_CANCELLED;
 255
 256     migrate_fd_cleanup(s);
 257 }
 258
 259 void migrate_fd_release(MigrationState *mig_state)
 260 {
 261     FdMigrationState *s = migrate_to_fms(mig_state);
 262
 263     dprintf("releasing state\n");
 264
 265     if (s->state == MIG_STATE_ACTIVE) {
 266         s->state = MIG_STATE_CANCELLED;
 267         migrate_fd_cleanup(s);
 268     }
 269     free(s);
 270 }
 271
 272 void migrate_fd_wait_for_unfreeze(void *opaque)
 273 {
 274     FdMigrationState *s = opaque;
 275     int ret;
 276
 277     dprintf("wait for unfreeze\n");
 278     if (s->state != MIG_STATE_ACTIVE)
 279         return;
 280
 281     do {
 282         fd_set wfds;
 283
 284         FD_ZERO(&wfds);
 285         FD_SET(s->fd, &wfds);
 286
 287         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 288     } while (ret == -1 && (s->get_error(s)) == EINTR);
 289 }
 290
 291 int migrate_fd_close(void *opaque)
 292 {
 293     FdMigrationState *s = opaque;
 294     return s->close(s);
 295 }