/* * QEMU live migration * * Copyright IBM, Corp. 2008 * * Authors: * Anthony Liguori <aliguori@us.ibm.com> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * */ #include "qemu-common.h" #include "migration.h" #include "monitor.h" #include "buffered_file.h" #include "sysemu.h" #include "block.h" #include "qemu_socket.h" #include "block-migration.h" #include "qmp-commands.h" //#define DEBUG_MIGRATION #ifdef DEBUG_MIGRATION #define DPRINTF(fmt, ...) \ do { printf("migration: " fmt, ## __VA_ARGS__); } while (0) #else #define DPRINTF(fmt, ...) \ do { } while (0) #endif enum { MIG_STATE_ERROR, MIG_STATE_SETUP, MIG_STATE_CANCELLED, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED, }; #define MAX_THROTTLE (32 << 20) /* Migration speed throttling */ static NotifierList migration_state_notifiers = NOTIFIER_LIST_INITIALIZER(migration_state_notifiers); /* When we add fault tolerance, we could have several migrations at once. For now we don't need to add dynamic creation of migration */ static MigrationState *migrate_get_current(void) { static MigrationState current_migration = { .state = MIG_STATE_SETUP, .bandwidth_limit = MAX_THROTTLE, }; return ¤t_migration; } int qemu_start_incoming_migration(const char *uri) { const char *p; int ret; if (strstart(uri, "tcp:", &p)) ret = tcp_start_incoming_migration(p); #if !defined(WIN32) else if (strstart(uri, "exec:", &p)) ret = exec_start_incoming_migration(p); else if (strstart(uri, "unix:", &p)) ret = unix_start_incoming_migration(p); else if (strstart(uri, "fd:", &p)) ret = fd_start_incoming_migration(p); #endif else { fprintf(stderr, "unknown migration protocol: %s\n", uri); ret = -EPROTONOSUPPORT; } return ret; } void process_incoming_migration(QEMUFile *f) { if (qemu_loadvm_state(f) < 0) { fprintf(stderr, "load of migration failed\n"); exit(0); } qemu_announce_self(); DPRINTF("successfully loaded vm state\n"); /* Make sure all file formats flush their mutable metadata */ bdrv_invalidate_cache_all(); if (autostart) { vm_start(); } else { runstate_set(RUN_STATE_PRELAUNCH); } } /* amount of nanoseconds we are willing to wait for migration to be down. * the choice of nanoseconds is because it is the maximum resolution that * get_clock() can achieve. It is an internal measure. All user-visible * units must be in seconds */ static uint64_t max_downtime = 30000000; uint64_t migrate_max_downtime(void) { return max_downtime; } MigrationInfo *qmp_query_migrate(Error **errp) { MigrationInfo *info = g_malloc0(sizeof(*info)); MigrationState *s = migrate_get_current(); switch (s->state) { case MIG_STATE_SETUP: /* no migration has happened ever */ break; case MIG_STATE_ACTIVE: info->has_status = true; info->status = g_strdup("active"); info->has_ram = true; info->ram = g_malloc0(sizeof(*info->ram)); info->ram->transferred = ram_bytes_transferred(); info->ram->remaining = ram_bytes_remaining(); info->ram->total = ram_bytes_total(); if (blk_mig_active()) { info->has_disk = true; info->disk = g_malloc0(sizeof(*info->disk)); info->disk->transferred = blk_mig_bytes_transferred(); info->disk->remaining = blk_mig_bytes_remaining(); info->disk->total = blk_mig_bytes_total(); } break; case MIG_STATE_COMPLETED: info->has_status = true; info->status = g_strdup("completed"); break; case MIG_STATE_ERROR: info->has_status = true; info->status = g_strdup("failed"); break; case MIG_STATE_CANCELLED: info->has_status = true; info->status = g_strdup("cancelled"); break; } return info; } /* shared migration helpers */ static void migrate_fd_monitor_suspend(MigrationState *s, Monitor *mon) { if (monitor_suspend(mon) == 0) { DPRINTF("suspending monitor\n"); } else { monitor_printf(mon, "terminal does not allow synchronous " "migration, continuing detached\n"); } } static int migrate_fd_cleanup(MigrationState *s) { int ret = 0; qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); if (s->file) { DPRINTF("closing file\n"); if (qemu_fclose(s->file) != 0) { ret = -1; } s->file = NULL; } else { if (s->mon) { monitor_resume(s->mon); } } if (s->fd != -1) { close(s->fd); s->fd = -1; } return ret; } void migrate_fd_error(MigrationState *s) { DPRINTF("setting error state\n"); s->state = MIG_STATE_ERROR; notifier_list_notify(&migration_state_notifiers, s); migrate_fd_cleanup(s); } static void migrate_fd_completed(MigrationState *s) { DPRINTF("setting completed state\n"); if (migrate_fd_cleanup(s) < 0) { s->state = MIG_STATE_ERROR; } else { s->state = MIG_STATE_COMPLETED; runstate_set(RUN_STATE_POSTMIGRATE); } notifier_list_notify(&migration_state_notifiers, s); } static void migrate_fd_put_notify(void *opaque) { MigrationState *s = opaque; qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); qemu_file_put_notify(s->file); if (s->file && qemu_file_get_error(s->file)) { migrate_fd_error(s); } } static ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size) { MigrationState *s = opaque; ssize_t ret; if (s->state != MIG_STATE_ACTIVE) { return -EIO; } do { ret = s->write(s, data, size); } while (ret == -1 && ((s->get_error(s)) == EINTR)); if (ret == -1) ret = -(s->get_error(s)); if (ret == -EAGAIN) { qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s); } return ret; } static void migrate_fd_put_ready(void *opaque) { MigrationState *s = opaque; int ret; if (s->state != MIG_STATE_ACTIVE) { DPRINTF("put_ready returning because of non-active state\n"); return; } DPRINTF("iterate\n"); ret = qemu_savevm_state_iterate(s->mon, s->file); if (ret < 0) { migrate_fd_error(s); } else if (ret == 1) { int old_vm_running = runstate_is_running(); DPRINTF("done iterating\n"); vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); if (qemu_savevm_state_complete(s->mon, s->file) < 0) { migrate_fd_error(s); } else { migrate_fd_completed(s); } if (s->state != MIG_STATE_COMPLETED) { if (old_vm_running) { vm_start(); } } } } static void migrate_fd_cancel(MigrationState *s) { if (s->state != MIG_STATE_ACTIVE) return; DPRINTF("cancelling migration\n"); s->state = MIG_STATE_CANCELLED; notifier_list_notify(&migration_state_notifiers, s); qemu_savevm_state_cancel(s->mon, s->file); migrate_fd_cleanup(s); } static void migrate_fd_wait_for_unfreeze(void *opaque) { MigrationState *s = opaque; int ret; DPRINTF("wait for unfreeze\n"); if (s->state != MIG_STATE_ACTIVE) return; do { fd_set wfds; FD_ZERO(&wfds); FD_SET(s->fd, &wfds); ret = select(s->fd + 1, NULL, &wfds, NULL, NULL); } while (ret == -1 && (s->get_error(s)) == EINTR); if (ret == -1) { qemu_file_set_error(s->file, -s->get_error(s)); } } static int migrate_fd_close(void *opaque) { MigrationState *s = opaque; if (s->mon) { monitor_resume(s->mon); } qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); return s->close(s); } void add_migration_state_change_notifier(Notifier *notify) { notifier_list_add(&migration_state_notifiers, notify); } void remove_migration_state_change_notifier(Notifier *notify) { notifier_list_remove(&migration_state_notifiers, notify); } bool migration_is_active(MigrationState *s) { return s->state == MIG_STATE_ACTIVE; } bool migration_has_finished(MigrationState *s) { return s->state == MIG_STATE_COMPLETED; } bool migration_has_failed(MigrationState *s) { return (s->state == MIG_STATE_CANCELLED || s->state == MIG_STATE_ERROR); } void migrate_fd_connect(MigrationState *s) { int ret; s->state = MIG_STATE_ACTIVE; s->file = qemu_fopen_ops_buffered(s, s->bandwidth_limit, migrate_fd_put_buffer, migrate_fd_put_ready, migrate_fd_wait_for_unfreeze, migrate_fd_close); DPRINTF("beginning savevm\n"); ret = qemu_savevm_state_begin(s->mon, s->file, s->blk, s->shared); if (ret < 0) { DPRINTF("failed, %d\n", ret); migrate_fd_error(s); return; } migrate_fd_put_ready(s); } static MigrationState *migrate_init(Monitor *mon, int detach, int blk, int inc) { MigrationState *s = migrate_get_current(); int64_t bandwidth_limit = s->bandwidth_limit; memset(s, 0, sizeof(*s)); s->bandwidth_limit = bandwidth_limit; s->blk = blk; s->shared = inc; /* s->mon is used for two things: - pass fd in fd migration - suspend/resume monitor for not detached migration */ s->mon = mon; s->bandwidth_limit = bandwidth_limit; s->state = MIG_STATE_SETUP; if (!detach) { migrate_fd_monitor_suspend(s, mon); } return s; } static GSList *migration_blockers; void migrate_add_blocker(Error *reason) { migration_blockers = g_slist_prepend(migration_blockers, reason); } void migrate_del_blocker(Error *reason) { migration_blockers = g_slist_remove(migration_blockers, reason); } int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data) { MigrationState *s = migrate_get_current(); const char *p; int detach = qdict_get_try_bool(qdict, "detach", 0); int blk = qdict_get_try_bool(qdict, "blk", 0); int inc = qdict_get_try_bool(qdict, "inc", 0); const char *uri = qdict_get_str(qdict, "uri"); int ret; if (s->state == MIG_STATE_ACTIVE) { monitor_printf(mon, "migration already in progress\n"); return -1; } if (qemu_savevm_state_blocked(mon)) { return -1; } if (migration_blockers) { Error *err = migration_blockers->data; qerror_report_err(err); return -1; } s = migrate_init(mon, detach, blk, inc); if (strstart(uri, "tcp:", &p)) { ret = tcp_start_outgoing_migration(s, p); #if !defined(WIN32) } else if (strstart(uri, "exec:", &p)) { ret = exec_start_outgoing_migration(s, p); } else if (strstart(uri, "unix:", &p)) { ret = unix_start_outgoing_migration(s, p); } else if (strstart(uri, "fd:", &p)) { ret = fd_start_outgoing_migration(s, p); #endif } else { monitor_printf(mon, "unknown migration protocol: %s\n", uri); ret = -EINVAL; } if (ret < 0) { monitor_printf(mon, "migration failed: %s\n", strerror(-ret)); return ret; } if (detach) { s->mon = NULL; } notifier_list_notify(&migration_state_notifiers, s); return 0; } int do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data) { migrate_fd_cancel(migrate_get_current()); return 0; } int do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data) { int64_t d; MigrationState *s; d = qdict_get_int(qdict, "value"); if (d < 0) { d = 0; } s = migrate_get_current(); s->bandwidth_limit = d; qemu_file_set_rate_limit(s->file, s->bandwidth_limit); return 0; } int do_migrate_set_downtime(Monitor *mon, const QDict *qdict, QObject **ret_data) { double d; d = qdict_get_double(qdict, "value") * 1e9; d = MAX(0, MIN(UINT64_MAX, d)); max_downtime = (uint64_t)d; return 0; }