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_error(FdMigrationState *s)
 129 {
 130     dprintf("setting error state\n");
 131     s->state = MIG_STATE_ERROR;
 132     migrate_fd_cleanup(s);
 133 }
 134
 135 void migrate_fd_cleanup(FdMigrationState *s)
 136 {
 137     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 138
 139     if (s->file) {
 140         dprintf("closing file\n");
 141         qemu_fclose(s->file);
 142     }
 143
 144     if (s->fd != -1)
 145         close(s->fd);
 146
 147     /* Don't resume monitor until we've flushed all of the buffers */
 148     if (s->detach == 2) {
 149         monitor_resume(cur_mon);
 150         s->detach = 0;
 151     }
 152
 153     s->fd = -1;
 154 }
 155
 156 void migrate_fd_put_notify(void *opaque)
 157 {
 158     FdMigrationState *s = opaque;
 159
 160     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 161     qemu_file_put_notify(s->file);
 162 }
 163
 164 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 165 {
 166     FdMigrationState *s = opaque;
 167     ssize_t ret;
 168
 169     do {
 170         ret = s->write(s, data, size);
 171     } while (ret == -1 && ((s->get_error(s)) == EINTR || (s->get_error(s)) == EWOULDBLOCK));
 172
 173     if (ret == -1)
 174         ret = -(s->get_error(s));
 175
 176     if (ret == -EAGAIN)
 177         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 178
 179     return ret;
 180 }
 181
 182 void migrate_fd_connect(FdMigrationState *s)
 183 {
 184     int ret;
 185
 186     s->file = qemu_fopen_ops_buffered(s,
 187                                       s->bandwidth_limit,
 188                                       migrate_fd_put_buffer,
 189                                       migrate_fd_put_ready,
 190                                       migrate_fd_wait_for_unfreeze,
 191                                       migrate_fd_close);
 192
 193     dprintf("beginning savevm\n");
 194     ret = qemu_savevm_state_begin(s->file);
 195     if (ret < 0) {
 196         dprintf("failed, %d\n", ret);
 197         migrate_fd_error(s);
 198         return;
 199     }
 200
 201     migrate_fd_put_ready(s);
 202 }
 203
 204 void migrate_fd_put_ready(void *opaque)
 205 {
 206     FdMigrationState *s = opaque;
 207
 208     if (s->state != MIG_STATE_ACTIVE) {
 209         dprintf("put_ready returning because of non-active state\n");
 210         return;
 211     }
 212
 213     dprintf("iterate\n");
 214     if (qemu_savevm_state_iterate(s->file) == 1) {
 215         dprintf("done iterating\n");
 216         vm_stop(0);
 217
 218         bdrv_flush_all();
 219         qemu_savevm_state_complete(s->file);
 220         s->state = MIG_STATE_COMPLETED;
 221         migrate_fd_cleanup(s);
 222     }
 223 }
 224
 225 int migrate_fd_get_status(MigrationState *mig_state)
 226 {
 227     FdMigrationState *s = migrate_to_fms(mig_state);
 228     return s->state;
 229 }
 230
 231 void migrate_fd_cancel(MigrationState *mig_state)
 232 {
 233     FdMigrationState *s = migrate_to_fms(mig_state);
 234
 235     if (s->state != MIG_STATE_ACTIVE)
 236         return;
 237
 238     dprintf("cancelling migration\n");
 239
 240     s->state = MIG_STATE_CANCELLED;
 241
 242     migrate_fd_cleanup(s);
 243 }
 244
 245 void migrate_fd_release(MigrationState *mig_state)
 246 {
 247     FdMigrationState *s = migrate_to_fms(mig_state);
 248
 249     dprintf("releasing state\n");
 250
 251     if (s->state == MIG_STATE_ACTIVE) {
 252         s->state = MIG_STATE_CANCELLED;
 253         migrate_fd_cleanup(s);
 254     }
 255     free(s);
 256 }
 257
 258 void migrate_fd_wait_for_unfreeze(void *opaque)
 259 {
 260     FdMigrationState *s = opaque;
 261     int ret;
 262
 263     dprintf("wait for unfreeze\n");
 264     if (s->state != MIG_STATE_ACTIVE)
 265         return;
 266
 267     do {
 268         fd_set wfds;
 269
 270         FD_ZERO(&wfds);
 271         FD_SET(s->fd, &wfds);
 272
 273         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 274     } while (ret == -1 && (s->get_error(s)) == EINTR);
 275 }
 276
 277 int migrate_fd_close(void *opaque)
 278 {
 279     FdMigrationState *s = opaque;
 280     return s->close(s);
 281 }