/* * QEMU live migration * * Copyright IBM, Corp. 2008 * * Authors: * Anthony Liguori * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * * Contributions after 2012-01-13 are licensed under the terms of the * GNU GPL, version 2 or (at your option) any later version. */ #include "qemu/osdep.h" #include "qemu/cutils.h" #include "qemu/error-report.h" #include "qemu/main-loop.h" #include "migration/blocker.h" #include "exec.h" #include "fd.h" #include "socket.h" #include "rdma.h" #include "ram.h" #include "migration/global_state.h" #include "migration/misc.h" #include "migration.h" #include "savevm.h" #include "qemu-file-channel.h" #include "qemu-file.h" #include "migration/vmstate.h" #include "sysemu/sysemu.h" #include "block/block.h" #include "qapi/qmp/qerror.h" #include "qapi/util.h" #include "qemu/sockets.h" #include "qemu/rcu.h" #include "block.h" #include "postcopy-ram.h" #include "qemu/thread.h" #include "qmp-commands.h" #include "trace.h" #include "qapi-event.h" #include "qom/cpu.h" #include "exec/memory.h" #include "exec/address-spaces.h" #include "exec/target_page.h" #include "io/channel-buffer.h" #include "migration/colo.h" #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ /* Amount of time to allocate to each "chunk" of bandwidth-throttled * data. */ #define BUFFER_DELAY 100 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY) /* Time in milliseconds we are allowed to stop the source, * for sending the last part */ #define DEFAULT_MIGRATE_SET_DOWNTIME 300 /* Maximum migrate downtime set to 2000 seconds */ #define MAX_MIGRATE_DOWNTIME_SECONDS 2000 #define MAX_MIGRATE_DOWNTIME (MAX_MIGRATE_DOWNTIME_SECONDS * 1000) /* Default compression thread count */ #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8 /* Default decompression thread count, usually decompression is at * least 4 times as fast as compression.*/ #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */ #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1 /* Define default autoconverge cpu throttle migration parameters */ #define DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL 20 #define DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT 10 /* Migration XBZRLE default cache size */ #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024) /* The delay time (in ms) between two COLO checkpoints * Note: Please change this default value to 10000 when we support hybrid mode. */ #define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200 static NotifierList migration_state_notifiers = NOTIFIER_LIST_INITIALIZER(migration_state_notifiers); static bool deferred_incoming; /* Messages sent on the return path from destination to source */ enum mig_rp_message_type { MIG_RP_MSG_INVALID = 0, /* Must be 0 */ MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages */ MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */ MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */ MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */ MIG_RP_MSG_MAX }; /* When we add fault tolerance, we could have several migrations at once. For now we don't need to add dynamic creation of migration */ /* For outgoing */ MigrationState *migrate_get_current(void) { static bool once; static MigrationState current_migration = { .state = MIGRATION_STATUS_NONE, .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE, .mbps = -1, .parameters = { .compress_level = DEFAULT_MIGRATE_COMPRESS_LEVEL, .compress_threads = DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT, .decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT, .cpu_throttle_initial = DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL, .cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT, .max_bandwidth = MAX_THROTTLE, .downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME, .x_checkpoint_delay = DEFAULT_MIGRATE_X_CHECKPOINT_DELAY, }, }; if (!once) { current_migration.parameters.tls_creds = g_strdup(""); current_migration.parameters.tls_hostname = g_strdup(""); once = true; } return ¤t_migration; } MigrationIncomingState *migration_incoming_get_current(void) { static bool once; static MigrationIncomingState mis_current; if (!once) { mis_current.state = MIGRATION_STATUS_NONE; memset(&mis_current, 0, sizeof(MigrationIncomingState)); qemu_mutex_init(&mis_current.rp_mutex); qemu_event_init(&mis_current.main_thread_load_event, false); once = true; } return &mis_current; } void migration_incoming_state_destroy(void) { struct MigrationIncomingState *mis = migration_incoming_get_current(); if (mis->to_src_file) { /* Tell source that we are done */ migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) != 0); qemu_fclose(mis->to_src_file); mis->to_src_file = NULL; } if (mis->from_src_file) { qemu_fclose(mis->from_src_file); mis->from_src_file = NULL; } qemu_event_destroy(&mis->main_thread_load_event); } static void migrate_generate_event(int new_state) { if (migrate_use_events()) { qapi_event_send_migration(new_state, &error_abort); } } /* * Called on -incoming with a defer: uri. * The migration can be started later after any parameters have been * changed. */ static void deferred_incoming_migration(Error **errp) { if (deferred_incoming) { error_setg(errp, "Incoming migration already deferred"); } deferred_incoming = true; } /* * Send a message on the return channel back to the source * of the migration. */ static void migrate_send_rp_message(MigrationIncomingState *mis, enum mig_rp_message_type message_type, uint16_t len, void *data) { trace_migrate_send_rp_message((int)message_type, len); qemu_mutex_lock(&mis->rp_mutex); qemu_put_be16(mis->to_src_file, (unsigned int)message_type); qemu_put_be16(mis->to_src_file, len); qemu_put_buffer(mis->to_src_file, data, len); qemu_fflush(mis->to_src_file); qemu_mutex_unlock(&mis->rp_mutex); } /* Request a range of pages from the source VM at the given * start address. * rbname: Name of the RAMBlock to request the page in, if NULL it's the same * as the last request (a name must have been given previously) * Start: Address offset within the RB * Len: Length in bytes required - must be a multiple of pagesize */ void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname, ram_addr_t start, size_t len) { uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */ size_t msglen = 12; /* start + len */ *(uint64_t *)bufc = cpu_to_be64((uint64_t)start); *(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len); if (rbname) { int rbname_len = strlen(rbname); assert(rbname_len < 256); bufc[msglen++] = rbname_len; memcpy(bufc + msglen, rbname, rbname_len); msglen += rbname_len; migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES_ID, msglen, bufc); } else { migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES, msglen, bufc); } } void qemu_start_incoming_migration(const char *uri, Error **errp) { const char *p; qapi_event_send_migration(MIGRATION_STATUS_SETUP, &error_abort); if (!strcmp(uri, "defer")) { deferred_incoming_migration(errp); } else if (strstart(uri, "tcp:", &p)) { tcp_start_incoming_migration(p, errp); #ifdef CONFIG_RDMA } else if (strstart(uri, "rdma:", &p)) { rdma_start_incoming_migration(p, errp); #endif } else if (strstart(uri, "exec:", &p)) { exec_start_incoming_migration(p, errp); } else if (strstart(uri, "unix:", &p)) { unix_start_incoming_migration(p, errp); } else if (strstart(uri, "fd:", &p)) { fd_start_incoming_migration(p, errp); } else { error_setg(errp, "unknown migration protocol: %s", uri); } } static void process_incoming_migration_bh(void *opaque) { Error *local_err = NULL; MigrationIncomingState *mis = opaque; /* Make sure all file formats flush their mutable metadata. * If we get an error here, just don't restart the VM yet. */ bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); local_err = NULL; autostart = false; } /* * This must happen after all error conditions are dealt with and * we're sure the VM is going to be running on this host. */ qemu_announce_self(); /* If global state section was not received or we are in running state, we need to obey autostart. Any other state is set with runstate_set. */ if (!global_state_received() || global_state_get_runstate() == RUN_STATE_RUNNING) { if (autostart) { vm_start(); } else { runstate_set(RUN_STATE_PAUSED); } } else { runstate_set(global_state_get_runstate()); } migrate_decompress_threads_join(); /* * This must happen after any state changes since as soon as an external * observer sees this event they might start to prod at the VM assuming * it's ready to use. */ migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_COMPLETED); qemu_bh_delete(mis->bh); migration_incoming_state_destroy(); } static void process_incoming_migration_co(void *opaque) { QEMUFile *f = opaque; MigrationIncomingState *mis = migration_incoming_get_current(); PostcopyState ps; int ret; mis->from_src_file = f; mis->largest_page_size = qemu_ram_pagesize_largest(); postcopy_state_set(POSTCOPY_INCOMING_NONE); migrate_set_state(&mis->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_ACTIVE); ret = qemu_loadvm_state(f); ps = postcopy_state_get(); trace_process_incoming_migration_co_end(ret, ps); if (ps != POSTCOPY_INCOMING_NONE) { if (ps == POSTCOPY_INCOMING_ADVISE) { /* * Where a migration had postcopy enabled (and thus went to advise) * but managed to complete within the precopy period, we can use * the normal exit. */ postcopy_ram_incoming_cleanup(mis); } else if (ret >= 0) { /* * Postcopy was started, cleanup should happen at the end of the * postcopy thread. */ trace_process_incoming_migration_co_postcopy_end_main(); return; } /* Else if something went wrong then just fall out of the normal exit */ } /* we get COLO info, and know if we are in COLO mode */ if (!ret && migration_incoming_enable_colo()) { mis->migration_incoming_co = qemu_coroutine_self(); qemu_thread_create(&mis->colo_incoming_thread, "COLO incoming", colo_process_incoming_thread, mis, QEMU_THREAD_JOINABLE); mis->have_colo_incoming_thread = true; qemu_coroutine_yield(); /* Wait checkpoint incoming thread exit before free resource */ qemu_thread_join(&mis->colo_incoming_thread); } if (ret < 0) { migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_FAILED); error_report("load of migration failed: %s", strerror(-ret)); migrate_decompress_threads_join(); exit(EXIT_FAILURE); } free_xbzrle_decoded_buf(); mis->bh = qemu_bh_new(process_incoming_migration_bh, mis); qemu_bh_schedule(mis->bh); } void migration_fd_process_incoming(QEMUFile *f) { Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, f); migrate_decompress_threads_create(); qemu_file_set_blocking(f, false); qemu_coroutine_enter(co); } /* * Send a 'SHUT' message on the return channel with the given value * to indicate that we've finished with the RP. Non-0 value indicates * error. */ void migrate_send_rp_shut(MigrationIncomingState *mis, uint32_t value) { uint32_t buf; buf = cpu_to_be32(value); migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf); } /* * Send a 'PONG' message on the return channel with the given value * (normally in response to a 'PING') */ void migrate_send_rp_pong(MigrationIncomingState *mis, uint32_t value) { uint32_t buf; buf = cpu_to_be32(value); migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf); } MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp) { MigrationCapabilityStatusList *head = NULL; MigrationCapabilityStatusList *caps; MigrationState *s = migrate_get_current(); int i; caps = NULL; /* silence compiler warning */ for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { #ifndef CONFIG_LIVE_BLOCK_MIGRATION if (i == MIGRATION_CAPABILITY_BLOCK) { continue; } #endif if (i == MIGRATION_CAPABILITY_X_COLO && !colo_supported()) { continue; } if (head == NULL) { head = g_malloc0(sizeof(*caps)); caps = head; } else { caps->next = g_malloc0(sizeof(*caps)); caps = caps->next; } caps->value = g_malloc(sizeof(*caps->value)); caps->value->capability = i; caps->value->state = s->enabled_capabilities[i]; } return head; } MigrationParameters *qmp_query_migrate_parameters(Error **errp) { MigrationParameters *params; MigrationState *s = migrate_get_current(); params = g_malloc0(sizeof(*params)); params->has_compress_level = true; params->compress_level = s->parameters.compress_level; params->has_compress_threads = true; params->compress_threads = s->parameters.compress_threads; params->has_decompress_threads = true; params->decompress_threads = s->parameters.decompress_threads; params->has_cpu_throttle_initial = true; params->cpu_throttle_initial = s->parameters.cpu_throttle_initial; params->has_cpu_throttle_increment = true; params->cpu_throttle_increment = s->parameters.cpu_throttle_increment; params->has_tls_creds = !!s->parameters.tls_creds; params->tls_creds = g_strdup(s->parameters.tls_creds); params->has_tls_hostname = !!s->parameters.tls_hostname; params->tls_hostname = g_strdup(s->parameters.tls_hostname); params->has_max_bandwidth = true; params->max_bandwidth = s->parameters.max_bandwidth; params->has_downtime_limit = true; params->downtime_limit = s->parameters.downtime_limit; params->has_x_checkpoint_delay = true; params->x_checkpoint_delay = s->parameters.x_checkpoint_delay; params->has_block_incremental = true; params->block_incremental = s->parameters.block_incremental; return params; } /* * Return true if we're already in the middle of a migration * (i.e. any of the active or setup states) */ static bool migration_is_setup_or_active(int state) { switch (state) { case MIGRATION_STATUS_ACTIVE: case MIGRATION_STATUS_POSTCOPY_ACTIVE: case MIGRATION_STATUS_SETUP: return true; default: return false; } } static void populate_ram_info(MigrationInfo *info, MigrationState *s) { info->has_ram = true; info->ram = g_malloc0(sizeof(*info->ram)); info->ram->transferred = ram_counters.transferred; info->ram->total = ram_bytes_total(); info->ram->duplicate = ram_counters.duplicate; /* legacy value. It is not used anymore */ info->ram->skipped = 0; info->ram->normal = ram_counters.normal; info->ram->normal_bytes = ram_counters.normal * qemu_target_page_size(); info->ram->mbps = s->mbps; info->ram->dirty_sync_count = ram_counters.dirty_sync_count; info->ram->postcopy_requests = ram_counters.postcopy_requests; info->ram->page_size = qemu_target_page_size(); if (migrate_use_xbzrle()) { info->has_xbzrle_cache = true; info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache)); info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size(); info->xbzrle_cache->bytes = xbzrle_counters.bytes; info->xbzrle_cache->pages = xbzrle_counters.pages; info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss; info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate; info->xbzrle_cache->overflow = xbzrle_counters.overflow; } if (cpu_throttle_active()) { info->has_cpu_throttle_percentage = true; info->cpu_throttle_percentage = cpu_throttle_get_percentage(); } if (s->state != MIGRATION_STATUS_COMPLETED) { info->ram->remaining = ram_bytes_remaining(); info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate; } } static void populate_disk_info(MigrationInfo *info) { 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(); } } MigrationInfo *qmp_query_migrate(Error **errp) { MigrationInfo *info = g_malloc0(sizeof(*info)); MigrationState *s = migrate_get_current(); switch (s->state) { case MIGRATION_STATUS_NONE: /* no migration has happened ever */ break; case MIGRATION_STATUS_SETUP: info->has_status = true; info->has_total_time = false; break; case MIGRATION_STATUS_ACTIVE: case MIGRATION_STATUS_CANCELLING: case MIGRATION_STATUS_POSTCOPY_ACTIVE: /* TODO add some postcopy stats */ info->has_status = true; info->has_total_time = true; info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->total_time; info->has_expected_downtime = true; info->expected_downtime = s->expected_downtime; info->has_setup_time = true; info->setup_time = s->setup_time; populate_ram_info(info, s); populate_disk_info(info); break; case MIGRATION_STATUS_COLO: info->has_status = true; /* TODO: display COLO specific information (checkpoint info etc.) */ break; case MIGRATION_STATUS_COMPLETED: info->has_status = true; info->has_total_time = true; info->total_time = s->total_time; info->has_downtime = true; info->downtime = s->downtime; info->has_setup_time = true; info->setup_time = s->setup_time; populate_ram_info(info, s); break; case MIGRATION_STATUS_FAILED: info->has_status = true; if (s->error) { info->has_error_desc = true; info->error_desc = g_strdup(error_get_pretty(s->error)); } break; case MIGRATION_STATUS_CANCELLED: info->has_status = true; break; } info->status = s->state; return info; } void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params, Error **errp) { MigrationState *s = migrate_get_current(); MigrationCapabilityStatusList *cap; bool old_postcopy_cap = migrate_postcopy_ram(); if (migration_is_setup_or_active(s->state)) { error_setg(errp, QERR_MIGRATION_ACTIVE); return; } for (cap = params; cap; cap = cap->next) { #ifndef CONFIG_LIVE_BLOCK_MIGRATION if (cap->value->capability == MIGRATION_CAPABILITY_BLOCK && cap->value->state) { error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) " "block migration"); error_append_hint(errp, "Use drive_mirror+NBD instead.\n"); continue; } #endif if (cap->value->capability == MIGRATION_CAPABILITY_X_COLO) { if (!colo_supported()) { error_setg(errp, "COLO is not currently supported, please" " configure with --enable-colo option in order to" " support COLO feature"); continue; } } s->enabled_capabilities[cap->value->capability] = cap->value->state; } if (migrate_postcopy_ram()) { if (migrate_use_compression()) { /* The decompression threads asynchronously write into RAM * rather than use the atomic copies needed to avoid * userfaulting. It should be possible to fix the decompression * threads for compatibility in future. */ error_report("Postcopy is not currently compatible with " "compression"); s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] = false; } /* This check is reasonably expensive, so only when it's being * set the first time, also it's only the destination that needs * special support. */ if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) && !postcopy_ram_supported_by_host()) { /* postcopy_ram_supported_by_host will have emitted a more * detailed message */ error_report("Postcopy is not supported"); s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] = false; } } } void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp) { MigrationState *s = migrate_get_current(); if (params->has_compress_level && (params->compress_level < 0 || params->compress_level > 9)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level", "is invalid, it should be in the range of 0 to 9"); return; } if (params->has_compress_threads && (params->compress_threads < 1 || params->compress_threads > 255)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_threads", "is invalid, it should be in the range of 1 to 255"); return; } if (params->has_decompress_threads && (params->decompress_threads < 1 || params->decompress_threads > 255)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "decompress_threads", "is invalid, it should be in the range of 1 to 255"); return; } if (params->has_cpu_throttle_initial && (params->cpu_throttle_initial < 1 || params->cpu_throttle_initial > 99)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu_throttle_initial", "an integer in the range of 1 to 99"); return; } if (params->has_cpu_throttle_increment && (params->cpu_throttle_increment < 1 || params->cpu_throttle_increment > 99)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu_throttle_increment", "an integer in the range of 1 to 99"); return; } if (params->has_max_bandwidth && (params->max_bandwidth < 0 || params->max_bandwidth > SIZE_MAX)) { error_setg(errp, "Parameter 'max_bandwidth' expects an integer in the" " range of 0 to %zu bytes/second", SIZE_MAX); return; } if (params->has_downtime_limit && (params->downtime_limit < 0 || params->downtime_limit > MAX_MIGRATE_DOWNTIME)) { error_setg(errp, "Parameter 'downtime_limit' expects an integer in " "the range of 0 to %d milliseconds", MAX_MIGRATE_DOWNTIME); return; } if (params->has_x_checkpoint_delay && (params->x_checkpoint_delay < 0)) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "x_checkpoint_delay", "is invalid, it should be positive"); } if (params->has_compress_level) { s->parameters.compress_level = params->compress_level; } if (params->has_compress_threads) { s->parameters.compress_threads = params->compress_threads; } if (params->has_decompress_threads) { s->parameters.decompress_threads = params->decompress_threads; } if (params->has_cpu_throttle_initial) { s->parameters.cpu_throttle_initial = params->cpu_throttle_initial; } if (params->has_cpu_throttle_increment) { s->parameters.cpu_throttle_increment = params->cpu_throttle_increment; } if (params->has_tls_creds) { g_free(s->parameters.tls_creds); s->parameters.tls_creds = g_strdup(params->tls_creds); } if (params->has_tls_hostname) { g_free(s->parameters.tls_hostname); s->parameters.tls_hostname = g_strdup(params->tls_hostname); } if (params->has_max_bandwidth) { s->parameters.max_bandwidth = params->max_bandwidth; if (s->to_dst_file) { qemu_file_set_rate_limit(s->to_dst_file, s->parameters.max_bandwidth / XFER_LIMIT_RATIO); } } if (params->has_downtime_limit) { s->parameters.downtime_limit = params->downtime_limit; } if (params->has_x_checkpoint_delay) { s->parameters.x_checkpoint_delay = params->x_checkpoint_delay; if (migration_in_colo_state()) { colo_checkpoint_notify(s); } } if (params->has_block_incremental) { s->parameters.block_incremental = params->block_incremental; } } void qmp_migrate_start_postcopy(Error **errp) { MigrationState *s = migrate_get_current(); if (!migrate_postcopy_ram()) { error_setg(errp, "Enable postcopy with migrate_set_capability before" " the start of migration"); return; } if (s->state == MIGRATION_STATUS_NONE) { error_setg(errp, "Postcopy must be started after migration has been" " started"); return; } /* * we don't error if migration has finished since that would be racy * with issuing this command. */ atomic_set(&s->start_postcopy, true); } /* shared migration helpers */ void migrate_set_state(int *state, int old_state, int new_state) { if (atomic_cmpxchg(state, old_state, new_state) == old_state) { trace_migrate_set_state(new_state); migrate_generate_event(new_state); } } void migrate_set_block_enabled(bool value, Error **errp) { MigrationCapabilityStatusList *cap; cap = g_new0(MigrationCapabilityStatusList, 1); cap->value = g_new0(MigrationCapabilityStatus, 1); cap->value->capability = MIGRATION_CAPABILITY_BLOCK; cap->value->state = value; qmp_migrate_set_capabilities(cap, errp); qapi_free_MigrationCapabilityStatusList(cap); } static void migrate_set_block_incremental(MigrationState *s, bool value) { s->parameters.block_incremental = value; } static void block_cleanup_parameters(MigrationState *s) { if (s->must_remove_block_options) { /* setting to false can never fail */ migrate_set_block_enabled(false, &error_abort); migrate_set_block_incremental(s, false); s->must_remove_block_options = false; } } static void migrate_fd_cleanup(void *opaque) { MigrationState *s = opaque; qemu_bh_delete(s->cleanup_bh); s->cleanup_bh = NULL; if (s->to_dst_file) { trace_migrate_fd_cleanup(); qemu_mutex_unlock_iothread(); if (s->migration_thread_running) { qemu_thread_join(&s->thread); s->migration_thread_running = false; } qemu_mutex_lock_iothread(); migrate_compress_threads_join(); qemu_fclose(s->to_dst_file); s->to_dst_file = NULL; } assert((s->state != MIGRATION_STATUS_ACTIVE) && (s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE)); if (s->state == MIGRATION_STATUS_CANCELLING) { migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING, MIGRATION_STATUS_CANCELLED); } notifier_list_notify(&migration_state_notifiers, s); block_cleanup_parameters(s); } void migrate_fd_error(MigrationState *s, const Error *error) { trace_migrate_fd_error(error_get_pretty(error)); assert(s->to_dst_file == NULL); migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_FAILED); if (!s->error) { s->error = error_copy(error); } notifier_list_notify(&migration_state_notifiers, s); block_cleanup_parameters(s); } static void migrate_fd_cancel(MigrationState *s) { int old_state ; QEMUFile *f = migrate_get_current()->to_dst_file; trace_migrate_fd_cancel(); if (s->rp_state.from_dst_file) { /* shutdown the rp socket, so causing the rp thread to shutdown */ qemu_file_shutdown(s->rp_state.from_dst_file); } do { old_state = s->state; if (!migration_is_setup_or_active(old_state)) { break; } migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING); } while (s->state != MIGRATION_STATUS_CANCELLING); /* * If we're unlucky the migration code might be stuck somewhere in a * send/write while the network has failed and is waiting to timeout; * if we've got shutdown(2) available then we can force it to quit. * The outgoing qemu file gets closed in migrate_fd_cleanup that is * called in a bh, so there is no race against this cancel. */ if (s->state == MIGRATION_STATUS_CANCELLING && f) { qemu_file_shutdown(f); } if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) { Error *local_err = NULL; bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); } else { s->block_inactive = false; } } block_cleanup_parameters(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_remove(notify); } bool migration_in_setup(MigrationState *s) { return s->state == MIGRATION_STATUS_SETUP; } bool migration_has_finished(MigrationState *s) { return s->state == MIGRATION_STATUS_COMPLETED; } bool migration_has_failed(MigrationState *s) { return (s->state == MIGRATION_STATUS_CANCELLED || s->state == MIGRATION_STATUS_FAILED); } bool migration_in_postcopy(void) { MigrationState *s = migrate_get_current(); return (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE); } bool migration_in_postcopy_after_devices(MigrationState *s) { return migration_in_postcopy() && s->postcopy_after_devices; } bool migration_is_idle(void) { MigrationState *s = migrate_get_current(); switch (s->state) { case MIGRATION_STATUS_NONE: case MIGRATION_STATUS_CANCELLED: case MIGRATION_STATUS_COMPLETED: case MIGRATION_STATUS_FAILED: return true; case MIGRATION_STATUS_SETUP: case MIGRATION_STATUS_CANCELLING: case MIGRATION_STATUS_ACTIVE: case MIGRATION_STATUS_POSTCOPY_ACTIVE: case MIGRATION_STATUS_COLO: return false; case MIGRATION_STATUS__MAX: g_assert_not_reached(); } return false; } MigrationState *migrate_init(void) { MigrationState *s = migrate_get_current(); /* * Reinitialise all migration state, except * parameters/capabilities that the user set, and * locks. */ s->bytes_xfer = 0; s->xfer_limit = 0; s->cleanup_bh = 0; s->to_dst_file = NULL; s->state = MIGRATION_STATUS_NONE; s->rp_state.from_dst_file = NULL; s->rp_state.error = false; s->mbps = 0.0; s->downtime = 0; s->expected_downtime = 0; s->setup_time = 0; s->start_postcopy = false; s->postcopy_after_devices = false; s->migration_thread_running = false; error_free(s->error); s->error = NULL; migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP); s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); return s; } static GSList *migration_blockers; int migrate_add_blocker(Error *reason, Error **errp) { if (only_migratable) { error_propagate(errp, error_copy(reason)); error_prepend(errp, "disallowing migration blocker " "(--only_migratable) for: "); return -EACCES; } if (migration_is_idle()) { migration_blockers = g_slist_prepend(migration_blockers, reason); return 0; } error_propagate(errp, error_copy(reason)); error_prepend(errp, "disallowing migration blocker (migration in " "progress) for: "); return -EBUSY; } void migrate_del_blocker(Error *reason) { migration_blockers = g_slist_remove(migration_blockers, reason); } void qmp_migrate_incoming(const char *uri, Error **errp) { Error *local_err = NULL; static bool once = true; if (!deferred_incoming) { error_setg(errp, "For use with '-incoming defer'"); return; } if (!once) { error_setg(errp, "The incoming migration has already been started"); } qemu_start_incoming_migration(uri, &local_err); if (local_err) { error_propagate(errp, local_err); return; } once = false; } bool migration_is_blocked(Error **errp) { if (qemu_savevm_state_blocked(errp)) { return true; } if (migration_blockers) { error_propagate(errp, error_copy(migration_blockers->data)); return true; } return false; } void qmp_migrate(const char *uri, bool has_blk, bool blk, bool has_inc, bool inc, bool has_detach, bool detach, Error **errp) { Error *local_err = NULL; MigrationState *s = migrate_get_current(); const char *p; if (migration_is_setup_or_active(s->state) || s->state == MIGRATION_STATUS_CANCELLING || s->state == MIGRATION_STATUS_COLO) { error_setg(errp, QERR_MIGRATION_ACTIVE); return; } if (runstate_check(RUN_STATE_INMIGRATE)) { error_setg(errp, "Guest is waiting for an incoming migration"); return; } if (migration_is_blocked(errp)) { return; } if ((has_blk && blk) || (has_inc && inc)) { if (migrate_use_block() || migrate_use_block_incremental()) { error_setg(errp, "Command options are incompatible with " "current migration capabilities"); return; } migrate_set_block_enabled(true, &local_err); if (local_err) { error_propagate(errp, local_err); return; } s->must_remove_block_options = true; } if (has_inc && inc) { migrate_set_block_incremental(s, true); } s = migrate_init(); if (strstart(uri, "tcp:", &p)) { tcp_start_outgoing_migration(s, p, &local_err); #ifdef CONFIG_RDMA } else if (strstart(uri, "rdma:", &p)) { rdma_start_outgoing_migration(s, p, &local_err); #endif } else if (strstart(uri, "exec:", &p)) { exec_start_outgoing_migration(s, p, &local_err); } else if (strstart(uri, "unix:", &p)) { unix_start_outgoing_migration(s, p, &local_err); } else if (strstart(uri, "fd:", &p)) { fd_start_outgoing_migration(s, p, &local_err); } else { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol"); migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_FAILED); return; } if (local_err) { migrate_fd_error(s, local_err); error_propagate(errp, local_err); return; } } void qmp_migrate_cancel(Error **errp) { migrate_fd_cancel(migrate_get_current()); } void qmp_migrate_set_cache_size(int64_t value, Error **errp) { MigrationState *s = migrate_get_current(); int64_t new_size; /* Check for truncation */ if (value != (size_t)value) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", "exceeding address space"); return; } /* Cache should not be larger than guest ram size */ if (value > ram_bytes_total()) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", "exceeds guest ram size "); return; } new_size = xbzrle_cache_resize(value); if (new_size < 0) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", "is smaller than page size"); return; } s->xbzrle_cache_size = new_size; } int64_t qmp_query_migrate_cache_size(Error **errp) { return migrate_xbzrle_cache_size(); } void qmp_migrate_set_speed(int64_t value, Error **errp) { MigrationParameters p = { .has_max_bandwidth = true, .max_bandwidth = value, }; qmp_migrate_set_parameters(&p, errp); } void qmp_migrate_set_downtime(double value, Error **errp) { if (value < 0 || value > MAX_MIGRATE_DOWNTIME_SECONDS) { error_setg(errp, "Parameter 'downtime_limit' expects an integer in " "the range of 0 to %d seconds", MAX_MIGRATE_DOWNTIME_SECONDS); return; } value *= 1000; /* Convert to milliseconds */ value = MAX(0, MIN(INT64_MAX, value)); MigrationParameters p = { .has_downtime_limit = true, .downtime_limit = value, }; qmp_migrate_set_parameters(&p, errp); } bool migrate_release_ram(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_RELEASE_RAM]; } bool migrate_postcopy_ram(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM]; } bool migrate_auto_converge(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE]; } bool migrate_zero_blocks(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS]; } bool migrate_use_compression(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS]; } int migrate_compress_level(void) { MigrationState *s; s = migrate_get_current(); return s->parameters.compress_level; } int migrate_compress_threads(void) { MigrationState *s; s = migrate_get_current(); return s->parameters.compress_threads; } int migrate_decompress_threads(void) { MigrationState *s; s = migrate_get_current(); return s->parameters.decompress_threads; } bool migrate_use_events(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS]; } int migrate_use_xbzrle(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE]; } int64_t migrate_xbzrle_cache_size(void) { MigrationState *s; s = migrate_get_current(); return s->xbzrle_cache_size; } bool migrate_use_block(void) { MigrationState *s; s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_BLOCK]; } bool migrate_use_block_incremental(void) { MigrationState *s; s = migrate_get_current(); return s->parameters.block_incremental; } /* migration thread support */ /* * Something bad happened to the RP stream, mark an error * The caller shall print or trace something to indicate why */ static void mark_source_rp_bad(MigrationState *s) { s->rp_state.error = true; } static struct rp_cmd_args { ssize_t len; /* -1 = variable */ const char *name; } rp_cmd_args[] = { [MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" }, [MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" }, [MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" }, [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" }, [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" }, [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" }, }; /* * Process a request for pages received on the return path, * We're allowed to send more than requested (e.g. to round to our page size) * and we don't need to send pages that have already been sent. */ static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname, ram_addr_t start, size_t len) { long our_host_ps = getpagesize(); trace_migrate_handle_rp_req_pages(rbname, start, len); /* * Since we currently insist on matching page sizes, just sanity check * we're being asked for whole host pages. */ if (start & (our_host_ps-1) || (len & (our_host_ps-1))) { error_report("%s: Misaligned page request, start: " RAM_ADDR_FMT " len: %zd", __func__, start, len); mark_source_rp_bad(ms); return; } if (ram_save_queue_pages(rbname, start, len)) { mark_source_rp_bad(ms); } } /* * Handles messages sent on the return path towards the source VM * */ static void *source_return_path_thread(void *opaque) { MigrationState *ms = opaque; QEMUFile *rp = ms->rp_state.from_dst_file; uint16_t header_len, header_type; uint8_t buf[512]; uint32_t tmp32, sibling_error; ram_addr_t start = 0; /* =0 to silence warning */ size_t len = 0, expected_len; int res; trace_source_return_path_thread_entry(); while (!ms->rp_state.error && !qemu_file_get_error(rp) && migration_is_setup_or_active(ms->state)) { trace_source_return_path_thread_loop_top(); header_type = qemu_get_be16(rp); header_len = qemu_get_be16(rp); if (header_type >= MIG_RP_MSG_MAX || header_type == MIG_RP_MSG_INVALID) { error_report("RP: Received invalid message 0x%04x length 0x%04x", header_type, header_len); mark_source_rp_bad(ms); goto out; } if ((rp_cmd_args[header_type].len != -1 && header_len != rp_cmd_args[header_type].len) || header_len > sizeof(buf)) { error_report("RP: Received '%s' message (0x%04x) with" "incorrect length %d expecting %zu", rp_cmd_args[header_type].name, header_type, header_len, (size_t)rp_cmd_args[header_type].len); mark_source_rp_bad(ms); goto out; } /* We know we've got a valid header by this point */ res = qemu_get_buffer(rp, buf, header_len); if (res != header_len) { error_report("RP: Failed reading data for message 0x%04x" " read %d expected %d", header_type, res, header_len); mark_source_rp_bad(ms); goto out; } /* OK, we have the message and the data */ switch (header_type) { case MIG_RP_MSG_SHUT: sibling_error = ldl_be_p(buf); trace_source_return_path_thread_shut(sibling_error); if (sibling_error) { error_report("RP: Sibling indicated error %d", sibling_error); mark_source_rp_bad(ms); } /* * We'll let the main thread deal with closing the RP * we could do a shutdown(2) on it, but we're the only user * anyway, so there's nothing gained. */ goto out; case MIG_RP_MSG_PONG: tmp32 = ldl_be_p(buf); trace_source_return_path_thread_pong(tmp32); break; case MIG_RP_MSG_REQ_PAGES: start = ldq_be_p(buf); len = ldl_be_p(buf + 8); migrate_handle_rp_req_pages(ms, NULL, start, len); break; case MIG_RP_MSG_REQ_PAGES_ID: expected_len = 12 + 1; /* header + termination */ if (header_len >= expected_len) { start = ldq_be_p(buf); len = ldl_be_p(buf + 8); /* Now we expect an idstr */ tmp32 = buf[12]; /* Length of the following idstr */ buf[13 + tmp32] = '\0'; expected_len += tmp32; } if (header_len != expected_len) { error_report("RP: Req_Page_id with length %d expecting %zd", header_len, expected_len); mark_source_rp_bad(ms); goto out; } migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len); break; default: break; } } if (qemu_file_get_error(rp)) { trace_source_return_path_thread_bad_end(); mark_source_rp_bad(ms); } trace_source_return_path_thread_end(); out: ms->rp_state.from_dst_file = NULL; qemu_fclose(rp); return NULL; } static int open_return_path_on_source(MigrationState *ms) { ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->to_dst_file); if (!ms->rp_state.from_dst_file) { return -1; } trace_open_return_path_on_source(); qemu_thread_create(&ms->rp_state.rp_thread, "return path", source_return_path_thread, ms, QEMU_THREAD_JOINABLE); trace_open_return_path_on_source_continue(); return 0; } /* Returns 0 if the RP was ok, otherwise there was an error on the RP */ static int await_return_path_close_on_source(MigrationState *ms) { /* * If this is a normal exit then the destination will send a SHUT and the * rp_thread will exit, however if there's an error we need to cause * it to exit. */ if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) { /* * shutdown(2), if we have it, will cause it to unblock if it's stuck * waiting for the destination. */ qemu_file_shutdown(ms->rp_state.from_dst_file); mark_source_rp_bad(ms); } trace_await_return_path_close_on_source_joining(); qemu_thread_join(&ms->rp_state.rp_thread); trace_await_return_path_close_on_source_close(); return ms->rp_state.error; } /* * Switch from normal iteration to postcopy * Returns non-0 on error */ static int postcopy_start(MigrationState *ms, bool *old_vm_running) { int ret; QIOChannelBuffer *bioc; QEMUFile *fb; int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); bool restart_block = false; migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_POSTCOPY_ACTIVE); trace_postcopy_start(); qemu_mutex_lock_iothread(); trace_postcopy_start_set_run(); qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); *old_vm_running = runstate_is_running(); global_state_store(); ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); if (ret < 0) { goto fail; } ret = bdrv_inactivate_all(); if (ret < 0) { goto fail; } restart_block = true; /* * Cause any non-postcopiable, but iterative devices to * send out their final data. */ qemu_savevm_state_complete_precopy(ms->to_dst_file, true); /* * in Finish migrate and with the io-lock held everything should * be quiet, but we've potentially still got dirty pages and we * need to tell the destination to throw any pages it's already received * that are dirty */ if (ram_postcopy_send_discard_bitmap(ms)) { error_report("postcopy send discard bitmap failed"); goto fail; } /* * send rest of state - note things that are doing postcopy * will notice we're in POSTCOPY_ACTIVE and not actually * wrap their state up here */ qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX); /* Ping just for debugging, helps line traces up */ qemu_savevm_send_ping(ms->to_dst_file, 2); /* * While loading the device state we may trigger page transfer * requests and the fd must be free to process those, and thus * the destination must read the whole device state off the fd before * it starts processing it. Unfortunately the ad-hoc migration format * doesn't allow the destination to know the size to read without fully * parsing it through each devices load-state code (especially the open * coded devices that use get/put). * So we wrap the device state up in a package with a length at the start; * to do this we use a qemu_buf to hold the whole of the device state. */ bioc = qio_channel_buffer_new(4096); qio_channel_set_name(QIO_CHANNEL(bioc), "migration-postcopy-buffer"); fb = qemu_fopen_channel_output(QIO_CHANNEL(bioc)); object_unref(OBJECT(bioc)); /* * Make sure the receiver can get incoming pages before we send the rest * of the state */ qemu_savevm_send_postcopy_listen(fb); qemu_savevm_state_complete_precopy(fb, false); qemu_savevm_send_ping(fb, 3); qemu_savevm_send_postcopy_run(fb); /* <><> end of stuff going into the package */ /* Last point of recovery; as soon as we send the package the destination * can open devices and potentially start running. * Lets just check again we've not got any errors. */ ret = qemu_file_get_error(ms->to_dst_file); if (ret) { error_report("postcopy_start: Migration stream errored (pre package)"); goto fail_closefb; } restart_block = false; /* Now send that blob */ if (qemu_savevm_send_packaged(ms->to_dst_file, bioc->data, bioc->usage)) { goto fail_closefb; } qemu_fclose(fb); /* Send a notify to give a chance for anything that needs to happen * at the transition to postcopy and after the device state; in particular * spice needs to trigger a transition now */ ms->postcopy_after_devices = true; notifier_list_notify(&migration_state_notifiers, ms); ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop; qemu_mutex_unlock_iothread(); /* * Although this ping is just for debug, it could potentially be * used for getting a better measurement of downtime at the source. */ qemu_savevm_send_ping(ms->to_dst_file, 4); if (migrate_release_ram()) { ram_postcopy_migrated_memory_release(ms); } ret = qemu_file_get_error(ms->to_dst_file); if (ret) { error_report("postcopy_start: Migration stream errored"); migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, MIGRATION_STATUS_FAILED); } return ret; fail_closefb: qemu_fclose(fb); fail: migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, MIGRATION_STATUS_FAILED); if (restart_block) { /* A failure happened early enough that we know the destination hasn't * accessed block devices, so we're safe to recover. */ Error *local_err = NULL; bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); } } qemu_mutex_unlock_iothread(); return -1; } /** * migration_completion: Used by migration_thread when there's not much left. * The caller 'breaks' the loop when this returns. * * @s: Current migration state * @current_active_state: The migration state we expect to be in * @*old_vm_running: Pointer to old_vm_running flag * @*start_time: Pointer to time to update */ static void migration_completion(MigrationState *s, int current_active_state, bool *old_vm_running, int64_t *start_time) { int ret; if (s->state == MIGRATION_STATUS_ACTIVE) { qemu_mutex_lock_iothread(); *start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); *old_vm_running = runstate_is_running(); ret = global_state_store(); if (!ret) { ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); if (ret >= 0) { qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX); qemu_savevm_state_complete_precopy(s->to_dst_file, false); } /* * Don't mark the image with BDRV_O_INACTIVE flag if * we will go into COLO stage later. */ if (ret >= 0 && !migrate_colo_enabled()) { ret = bdrv_inactivate_all(); if (ret >= 0) { s->block_inactive = true; } } } qemu_mutex_unlock_iothread(); if (ret < 0) { goto fail; } } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { trace_migration_completion_postcopy_end(); qemu_savevm_state_complete_postcopy(s->to_dst_file); trace_migration_completion_postcopy_end_after_complete(); } /* * If rp was opened we must clean up the thread before * cleaning everything else up (since if there are no failures * it will wait for the destination to send it's status in * a SHUT command). */ if (s->rp_state.from_dst_file) { int rp_error; trace_migration_return_path_end_before(); rp_error = await_return_path_close_on_source(s); trace_migration_return_path_end_after(rp_error); if (rp_error) { goto fail_invalidate; } } if (qemu_file_get_error(s->to_dst_file)) { trace_migration_completion_file_err(); goto fail_invalidate; } if (!migrate_colo_enabled()) { migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_COMPLETED); } return; fail_invalidate: /* If not doing postcopy, vm_start() will be called: let's regain * control on images. */ if (s->state == MIGRATION_STATUS_ACTIVE) { Error *local_err = NULL; qemu_mutex_lock_iothread(); bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); } else { s->block_inactive = false; } qemu_mutex_unlock_iothread(); } fail: migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_FAILED); } bool migrate_colo_enabled(void) { MigrationState *s = migrate_get_current(); return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO]; } /* * Master migration thread on the source VM. * It drives the migration and pumps the data down the outgoing channel. */ static void *migration_thread(void *opaque) { MigrationState *s = opaque; /* Used by the bandwidth calcs, updated later */ int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); int64_t initial_bytes = 0; /* * The final stage happens when the remaining data is smaller than * this threshold; it's calculated from the requested downtime and * measured bandwidth */ int64_t threshold_size = 0; int64_t start_time = initial_time; int64_t end_time; bool old_vm_running = false; bool entered_postcopy = false; /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */ enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE; bool enable_colo = migrate_colo_enabled(); rcu_register_thread(); qemu_savevm_state_header(s->to_dst_file); /* * If we opened the return path, we need to make sure dst has it * opened as well. */ if (s->rp_state.from_dst_file) { /* Now tell the dest that it should open its end so it can reply */ qemu_savevm_send_open_return_path(s->to_dst_file); /* And do a ping that will make stuff easier to debug */ qemu_savevm_send_ping(s->to_dst_file, 1); } if (migrate_postcopy_ram()) { /* * Tell the destination that we *might* want to do postcopy later; * if the other end can't do postcopy it should fail now, nice and * early. */ qemu_savevm_send_postcopy_advise(s->to_dst_file); } qemu_savevm_state_begin(s->to_dst_file); s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start; migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_ACTIVE); trace_migration_thread_setup_complete(); while (s->state == MIGRATION_STATUS_ACTIVE || s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { int64_t current_time; uint64_t pending_size; if (!qemu_file_rate_limit(s->to_dst_file)) { uint64_t pend_post, pend_nonpost; qemu_savevm_state_pending(s->to_dst_file, threshold_size, &pend_nonpost, &pend_post); pending_size = pend_nonpost + pend_post; trace_migrate_pending(pending_size, threshold_size, pend_post, pend_nonpost); if (pending_size && pending_size >= threshold_size) { /* Still a significant amount to transfer */ if (migrate_postcopy_ram() && s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE && pend_nonpost <= threshold_size && atomic_read(&s->start_postcopy)) { if (!postcopy_start(s, &old_vm_running)) { current_active_state = MIGRATION_STATUS_POSTCOPY_ACTIVE; entered_postcopy = true; } continue; } /* Just another iteration step */ qemu_savevm_state_iterate(s->to_dst_file, entered_postcopy); } else { trace_migration_thread_low_pending(pending_size); migration_completion(s, current_active_state, &old_vm_running, &start_time); break; } } if (qemu_file_get_error(s->to_dst_file)) { migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_FAILED); trace_migration_thread_file_err(); break; } current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); if (current_time >= initial_time + BUFFER_DELAY) { uint64_t transferred_bytes = qemu_ftell(s->to_dst_file) - initial_bytes; uint64_t time_spent = current_time - initial_time; double bandwidth = (double)transferred_bytes / time_spent; threshold_size = bandwidth * s->parameters.downtime_limit; s->mbps = (((double) transferred_bytes * 8.0) / ((double) time_spent / 1000.0)) / 1000.0 / 1000.0; trace_migrate_transferred(transferred_bytes, time_spent, bandwidth, threshold_size); /* if we haven't sent anything, we don't want to recalculate 10000 is a small enough number for our purposes */ if (ram_counters.dirty_pages_rate && transferred_bytes > 10000) { s->expected_downtime = ram_counters.dirty_pages_rate * qemu_target_page_size() / bandwidth; } qemu_file_reset_rate_limit(s->to_dst_file); initial_time = current_time; initial_bytes = qemu_ftell(s->to_dst_file); } if (qemu_file_rate_limit(s->to_dst_file)) { /* usleep expects microseconds */ g_usleep((initial_time + BUFFER_DELAY - current_time)*1000); } } trace_migration_thread_after_loop(); /* If we enabled cpu throttling for auto-converge, turn it off. */ cpu_throttle_stop(); end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); qemu_mutex_lock_iothread(); /* * The resource has been allocated by migration will be reused in COLO * process, so don't release them. */ if (!enable_colo) { qemu_savevm_state_cleanup(); } if (s->state == MIGRATION_STATUS_COMPLETED) { uint64_t transferred_bytes = qemu_ftell(s->to_dst_file); s->total_time = end_time - s->total_time; if (!entered_postcopy) { s->downtime = end_time - start_time; } if (s->total_time) { s->mbps = (((double) transferred_bytes * 8.0) / ((double) s->total_time)) / 1000; } runstate_set(RUN_STATE_POSTMIGRATE); } else { if (s->state == MIGRATION_STATUS_ACTIVE && enable_colo) { migrate_start_colo_process(s); qemu_savevm_state_cleanup(); /* * Fixme: we will run VM in COLO no matter its old running state. * After exited COLO, we will keep running. */ old_vm_running = true; } if (old_vm_running && !entered_postcopy) { vm_start(); } else { if (runstate_check(RUN_STATE_FINISH_MIGRATE)) { runstate_set(RUN_STATE_POSTMIGRATE); } } } qemu_bh_schedule(s->cleanup_bh); qemu_mutex_unlock_iothread(); rcu_unregister_thread(); return NULL; } void migrate_fd_connect(MigrationState *s) { s->expected_downtime = s->parameters.downtime_limit; s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s); qemu_file_set_blocking(s->to_dst_file, true); qemu_file_set_rate_limit(s->to_dst_file, s->parameters.max_bandwidth / XFER_LIMIT_RATIO); /* Notify before starting migration thread */ notifier_list_notify(&migration_state_notifiers, s); /* * Open the return path; currently for postcopy but other things might * also want it. */ if (migrate_postcopy_ram()) { if (open_return_path_on_source(s)) { error_report("Unable to open return-path for postcopy"); migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, MIGRATION_STATUS_FAILED); migrate_fd_cleanup(s); return; } } migrate_compress_threads_create(); qemu_thread_create(&s->thread, "live_migration", migration_thread, s, QEMU_THREAD_JOINABLE); s->migration_thread_running = true; }