coroutine: Rename qemu_coroutine_inc/dec_pool_size()
[qemu.git] / migration / migration.c
blob5a31b23bd6241702bbf195c7fbc8a7bb4b2daa90
1 /*
2 * QEMU live migration
4 * Copyright IBM, Corp. 2008
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
12 * Contributions after 2012-01-13 are licensed under the terms of the
13 * GNU GPL, version 2 or (at your option) any later version.
16 #include "qemu/osdep.h"
17 #include "qemu/cutils.h"
18 #include "qemu/error-report.h"
19 #include "qemu/main-loop.h"
20 #include "migration/blocker.h"
21 #include "exec.h"
22 #include "fd.h"
23 #include "socket.h"
24 #include "sysemu/runstate.h"
25 #include "sysemu/sysemu.h"
26 #include "sysemu/cpu-throttle.h"
27 #include "rdma.h"
28 #include "ram.h"
29 #include "migration/global_state.h"
30 #include "migration/misc.h"
31 #include "migration.h"
32 #include "savevm.h"
33 #include "qemu-file-channel.h"
34 #include "qemu-file.h"
35 #include "migration/vmstate.h"
36 #include "block/block.h"
37 #include "qapi/error.h"
38 #include "qapi/clone-visitor.h"
39 #include "qapi/qapi-visit-migration.h"
40 #include "qapi/qapi-visit-sockets.h"
41 #include "qapi/qapi-commands-migration.h"
42 #include "qapi/qapi-events-migration.h"
43 #include "qapi/qmp/qerror.h"
44 #include "qapi/qmp/qnull.h"
45 #include "qemu/rcu.h"
46 #include "block.h"
47 #include "postcopy-ram.h"
48 #include "qemu/thread.h"
49 #include "trace.h"
50 #include "exec/target_page.h"
51 #include "io/channel-buffer.h"
52 #include "migration/colo.h"
53 #include "hw/boards.h"
54 #include "hw/qdev-properties.h"
55 #include "hw/qdev-properties-system.h"
56 #include "monitor/monitor.h"
57 #include "net/announce.h"
58 #include "qemu/queue.h"
59 #include "multifd.h"
60 #include "qemu/yank.h"
61 #include "sysemu/cpus.h"
62 #include "yank_functions.h"
63 #include "sysemu/qtest.h"
65 #define MAX_THROTTLE (128 << 20) /* Migration transfer speed throttling */
67 /* Amount of time to allocate to each "chunk" of bandwidth-throttled
68 * data. */
69 #define BUFFER_DELAY 100
70 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
72 /* Time in milliseconds we are allowed to stop the source,
73 * for sending the last part */
74 #define DEFAULT_MIGRATE_SET_DOWNTIME 300
76 /* Maximum migrate downtime set to 2000 seconds */
77 #define MAX_MIGRATE_DOWNTIME_SECONDS 2000
78 #define MAX_MIGRATE_DOWNTIME (MAX_MIGRATE_DOWNTIME_SECONDS * 1000)
80 /* Default compression thread count */
81 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
82 /* Default decompression thread count, usually decompression is at
83 * least 4 times as fast as compression.*/
84 #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
85 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */
86 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
87 /* Define default autoconverge cpu throttle migration parameters */
88 #define DEFAULT_MIGRATE_THROTTLE_TRIGGER_THRESHOLD 50
89 #define DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL 20
90 #define DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT 10
91 #define DEFAULT_MIGRATE_MAX_CPU_THROTTLE 99
93 /* Migration XBZRLE default cache size */
94 #define DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE (64 * 1024 * 1024)
96 /* The delay time (in ms) between two COLO checkpoints */
97 #define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY (200 * 100)
98 #define DEFAULT_MIGRATE_MULTIFD_CHANNELS 2
99 #define DEFAULT_MIGRATE_MULTIFD_COMPRESSION MULTIFD_COMPRESSION_NONE
100 /* 0: means nocompress, 1: best speed, ... 9: best compress ratio */
101 #define DEFAULT_MIGRATE_MULTIFD_ZLIB_LEVEL 1
102 /* 0: means nocompress, 1: best speed, ... 20: best compress ratio */
103 #define DEFAULT_MIGRATE_MULTIFD_ZSTD_LEVEL 1
105 /* Background transfer rate for postcopy, 0 means unlimited, note
106 * that page requests can still exceed this limit.
108 #define DEFAULT_MIGRATE_MAX_POSTCOPY_BANDWIDTH 0
111 * Parameters for self_announce_delay giving a stream of RARP/ARP
112 * packets after migration.
114 #define DEFAULT_MIGRATE_ANNOUNCE_INITIAL 50
115 #define DEFAULT_MIGRATE_ANNOUNCE_MAX 550
116 #define DEFAULT_MIGRATE_ANNOUNCE_ROUNDS 5
117 #define DEFAULT_MIGRATE_ANNOUNCE_STEP 100
119 static NotifierList migration_state_notifiers =
120 NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
122 /* Messages sent on the return path from destination to source */
123 enum mig_rp_message_type {
124 MIG_RP_MSG_INVALID = 0, /* Must be 0 */
125 MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages */
126 MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */
128 MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */
129 MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */
130 MIG_RP_MSG_RECV_BITMAP, /* send recved_bitmap back to source */
131 MIG_RP_MSG_RESUME_ACK, /* tell source that we are ready to resume */
133 MIG_RP_MSG_MAX
136 /* Migration capabilities set */
137 struct MigrateCapsSet {
138 int size; /* Capability set size */
139 MigrationCapability caps[]; /* Variadic array of capabilities */
141 typedef struct MigrateCapsSet MigrateCapsSet;
143 /* Define and initialize MigrateCapsSet */
144 #define INITIALIZE_MIGRATE_CAPS_SET(_name, ...) \
145 MigrateCapsSet _name = { \
146 .size = sizeof((int []) { __VA_ARGS__ }) / sizeof(int), \
147 .caps = { __VA_ARGS__ } \
150 /* Background-snapshot compatibility check list */
151 static const
152 INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
153 MIGRATION_CAPABILITY_POSTCOPY_RAM,
154 MIGRATION_CAPABILITY_DIRTY_BITMAPS,
155 MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME,
156 MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE,
157 MIGRATION_CAPABILITY_RETURN_PATH,
158 MIGRATION_CAPABILITY_MULTIFD,
159 MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER,
160 MIGRATION_CAPABILITY_AUTO_CONVERGE,
161 MIGRATION_CAPABILITY_RELEASE_RAM,
162 MIGRATION_CAPABILITY_RDMA_PIN_ALL,
163 MIGRATION_CAPABILITY_COMPRESS,
164 MIGRATION_CAPABILITY_XBZRLE,
165 MIGRATION_CAPABILITY_X_COLO,
166 MIGRATION_CAPABILITY_VALIDATE_UUID);
168 /* When we add fault tolerance, we could have several
169 migrations at once. For now we don't need to add
170 dynamic creation of migration */
172 static MigrationState *current_migration;
173 static MigrationIncomingState *current_incoming;
175 static GSList *migration_blockers;
177 static bool migration_object_check(MigrationState *ms, Error **errp);
178 static int migration_maybe_pause(MigrationState *s,
179 int *current_active_state,
180 int new_state);
181 static void migrate_fd_cancel(MigrationState *s);
183 static bool migrate_allow_multi_channels = true;
185 void migrate_protocol_allow_multi_channels(bool allow)
187 migrate_allow_multi_channels = allow;
190 bool migrate_multi_channels_is_allowed(void)
192 return migrate_allow_multi_channels;
195 static gint page_request_addr_cmp(gconstpointer ap, gconstpointer bp)
197 uintptr_t a = (uintptr_t) ap, b = (uintptr_t) bp;
199 return (a > b) - (a < b);
202 void migration_object_init(void)
204 /* This can only be called once. */
205 assert(!current_migration);
206 current_migration = MIGRATION_OBJ(object_new(TYPE_MIGRATION));
209 * Init the migrate incoming object as well no matter whether
210 * we'll use it or not.
212 assert(!current_incoming);
213 current_incoming = g_new0(MigrationIncomingState, 1);
214 current_incoming->state = MIGRATION_STATUS_NONE;
215 current_incoming->postcopy_remote_fds =
216 g_array_new(FALSE, TRUE, sizeof(struct PostCopyFD));
217 qemu_mutex_init(&current_incoming->rp_mutex);
218 qemu_event_init(&current_incoming->main_thread_load_event, false);
219 qemu_sem_init(&current_incoming->postcopy_pause_sem_dst, 0);
220 qemu_sem_init(&current_incoming->postcopy_pause_sem_fault, 0);
221 qemu_mutex_init(&current_incoming->page_request_mutex);
222 current_incoming->page_requested = g_tree_new(page_request_addr_cmp);
224 migration_object_check(current_migration, &error_fatal);
226 blk_mig_init();
227 ram_mig_init();
228 dirty_bitmap_mig_init();
231 void migration_cancel(const Error *error)
233 if (error) {
234 migrate_set_error(current_migration, error);
236 migrate_fd_cancel(current_migration);
239 void migration_shutdown(void)
242 * When the QEMU main thread exit, the COLO thread
243 * may wait a semaphore. So, we should wakeup the
244 * COLO thread before migration shutdown.
246 colo_shutdown();
248 * Cancel the current migration - that will (eventually)
249 * stop the migration using this structure
251 migration_cancel(NULL);
252 object_unref(OBJECT(current_migration));
255 * Cancel outgoing migration of dirty bitmaps. It should
256 * at least unref used block nodes.
258 dirty_bitmap_mig_cancel_outgoing();
261 * Cancel incoming migration of dirty bitmaps. Dirty bitmaps
262 * are non-critical data, and their loss never considered as
263 * something serious.
265 dirty_bitmap_mig_cancel_incoming();
268 /* For outgoing */
269 MigrationState *migrate_get_current(void)
271 /* This can only be called after the object created. */
272 assert(current_migration);
273 return current_migration;
276 MigrationIncomingState *migration_incoming_get_current(void)
278 assert(current_incoming);
279 return current_incoming;
282 void migration_incoming_transport_cleanup(MigrationIncomingState *mis)
284 if (mis->socket_address_list) {
285 qapi_free_SocketAddressList(mis->socket_address_list);
286 mis->socket_address_list = NULL;
289 if (mis->transport_cleanup) {
290 mis->transport_cleanup(mis->transport_data);
291 mis->transport_data = mis->transport_cleanup = NULL;
295 void migration_incoming_state_destroy(void)
297 struct MigrationIncomingState *mis = migration_incoming_get_current();
299 if (mis->to_src_file) {
300 /* Tell source that we are done */
301 migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) != 0);
302 qemu_fclose(mis->to_src_file);
303 mis->to_src_file = NULL;
306 if (mis->from_src_file) {
307 migration_ioc_unregister_yank_from_file(mis->from_src_file);
308 qemu_fclose(mis->from_src_file);
309 mis->from_src_file = NULL;
311 if (mis->postcopy_remote_fds) {
312 g_array_free(mis->postcopy_remote_fds, TRUE);
313 mis->postcopy_remote_fds = NULL;
316 migration_incoming_transport_cleanup(mis);
317 qemu_event_reset(&mis->main_thread_load_event);
319 if (mis->page_requested) {
320 g_tree_destroy(mis->page_requested);
321 mis->page_requested = NULL;
324 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
327 static void migrate_generate_event(int new_state)
329 if (migrate_use_events()) {
330 qapi_event_send_migration(new_state);
334 static bool migrate_late_block_activate(void)
336 MigrationState *s;
338 s = migrate_get_current();
340 return s->enabled_capabilities[
341 MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE];
345 * Send a message on the return channel back to the source
346 * of the migration.
348 static int migrate_send_rp_message(MigrationIncomingState *mis,
349 enum mig_rp_message_type message_type,
350 uint16_t len, void *data)
352 int ret = 0;
354 trace_migrate_send_rp_message((int)message_type, len);
355 QEMU_LOCK_GUARD(&mis->rp_mutex);
358 * It's possible that the file handle got lost due to network
359 * failures.
361 if (!mis->to_src_file) {
362 ret = -EIO;
363 return ret;
366 qemu_put_be16(mis->to_src_file, (unsigned int)message_type);
367 qemu_put_be16(mis->to_src_file, len);
368 qemu_put_buffer(mis->to_src_file, data, len);
369 qemu_fflush(mis->to_src_file);
371 /* It's possible that qemu file got error during sending */
372 ret = qemu_file_get_error(mis->to_src_file);
374 return ret;
377 /* Request one page from the source VM at the given start address.
378 * rb: the RAMBlock to request the page in
379 * Start: Address offset within the RB
380 * Len: Length in bytes required - must be a multiple of pagesize
382 int migrate_send_rp_message_req_pages(MigrationIncomingState *mis,
383 RAMBlock *rb, ram_addr_t start)
385 uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */
386 size_t msglen = 12; /* start + len */
387 size_t len = qemu_ram_pagesize(rb);
388 enum mig_rp_message_type msg_type;
389 const char *rbname;
390 int rbname_len;
392 *(uint64_t *)bufc = cpu_to_be64((uint64_t)start);
393 *(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len);
396 * We maintain the last ramblock that we requested for page. Note that we
397 * don't need locking because this function will only be called within the
398 * postcopy ram fault thread.
400 if (rb != mis->last_rb) {
401 mis->last_rb = rb;
403 rbname = qemu_ram_get_idstr(rb);
404 rbname_len = strlen(rbname);
406 assert(rbname_len < 256);
408 bufc[msglen++] = rbname_len;
409 memcpy(bufc + msglen, rbname, rbname_len);
410 msglen += rbname_len;
411 msg_type = MIG_RP_MSG_REQ_PAGES_ID;
412 } else {
413 msg_type = MIG_RP_MSG_REQ_PAGES;
416 return migrate_send_rp_message(mis, msg_type, msglen, bufc);
419 int migrate_send_rp_req_pages(MigrationIncomingState *mis,
420 RAMBlock *rb, ram_addr_t start, uint64_t haddr)
422 void *aligned = (void *)(uintptr_t)ROUND_DOWN(haddr, qemu_ram_pagesize(rb));
423 bool received = false;
425 WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) {
426 received = ramblock_recv_bitmap_test_byte_offset(rb, start);
427 if (!received && !g_tree_lookup(mis->page_requested, aligned)) {
429 * The page has not been received, and it's not yet in the page
430 * request list. Queue it. Set the value of element to 1, so that
431 * things like g_tree_lookup() will return TRUE (1) when found.
433 g_tree_insert(mis->page_requested, aligned, (gpointer)1);
434 mis->page_requested_count++;
435 trace_postcopy_page_req_add(aligned, mis->page_requested_count);
440 * If the page is there, skip sending the message. We don't even need the
441 * lock because as long as the page arrived, it'll be there forever.
443 if (received) {
444 return 0;
447 return migrate_send_rp_message_req_pages(mis, rb, start);
450 static bool migration_colo_enabled;
451 bool migration_incoming_colo_enabled(void)
453 return migration_colo_enabled;
456 void migration_incoming_disable_colo(void)
458 ram_block_discard_disable(false);
459 migration_colo_enabled = false;
462 int migration_incoming_enable_colo(void)
464 if (ram_block_discard_disable(true)) {
465 error_report("COLO: cannot disable RAM discard");
466 return -EBUSY;
468 migration_colo_enabled = true;
469 return 0;
472 void migrate_add_address(SocketAddress *address)
474 MigrationIncomingState *mis = migration_incoming_get_current();
476 QAPI_LIST_PREPEND(mis->socket_address_list,
477 QAPI_CLONE(SocketAddress, address));
480 static void qemu_start_incoming_migration(const char *uri, Error **errp)
482 const char *p = NULL;
484 migrate_protocol_allow_multi_channels(false); /* reset it anyway */
485 qapi_event_send_migration(MIGRATION_STATUS_SETUP);
486 if (strstart(uri, "tcp:", &p) ||
487 strstart(uri, "unix:", NULL) ||
488 strstart(uri, "vsock:", NULL)) {
489 migrate_protocol_allow_multi_channels(true);
490 socket_start_incoming_migration(p ? p : uri, errp);
491 #ifdef CONFIG_RDMA
492 } else if (strstart(uri, "rdma:", &p)) {
493 rdma_start_incoming_migration(p, errp);
494 #endif
495 } else if (strstart(uri, "exec:", &p)) {
496 exec_start_incoming_migration(p, errp);
497 } else if (strstart(uri, "fd:", &p)) {
498 fd_start_incoming_migration(p, errp);
499 } else {
500 error_setg(errp, "unknown migration protocol: %s", uri);
504 static void process_incoming_migration_bh(void *opaque)
506 Error *local_err = NULL;
507 MigrationIncomingState *mis = opaque;
509 /* If capability late_block_activate is set:
510 * Only fire up the block code now if we're going to restart the
511 * VM, else 'cont' will do it.
512 * This causes file locking to happen; so we don't want it to happen
513 * unless we really are starting the VM.
515 if (!migrate_late_block_activate() ||
516 (autostart && (!global_state_received() ||
517 global_state_get_runstate() == RUN_STATE_RUNNING))) {
518 /* Make sure all file formats throw away their mutable metadata.
519 * If we get an error here, just don't restart the VM yet. */
520 bdrv_activate_all(&local_err);
521 if (local_err) {
522 error_report_err(local_err);
523 local_err = NULL;
524 autostart = false;
529 * This must happen after all error conditions are dealt with and
530 * we're sure the VM is going to be running on this host.
532 qemu_announce_self(&mis->announce_timer, migrate_announce_params());
534 if (multifd_load_cleanup(&local_err) != 0) {
535 error_report_err(local_err);
536 autostart = false;
538 /* If global state section was not received or we are in running
539 state, we need to obey autostart. Any other state is set with
540 runstate_set. */
542 dirty_bitmap_mig_before_vm_start();
544 if (!global_state_received() ||
545 global_state_get_runstate() == RUN_STATE_RUNNING) {
546 if (autostart) {
547 vm_start();
548 } else {
549 runstate_set(RUN_STATE_PAUSED);
551 } else if (migration_incoming_colo_enabled()) {
552 migration_incoming_disable_colo();
553 vm_start();
554 } else {
555 runstate_set(global_state_get_runstate());
558 * This must happen after any state changes since as soon as an external
559 * observer sees this event they might start to prod at the VM assuming
560 * it's ready to use.
562 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
563 MIGRATION_STATUS_COMPLETED);
564 qemu_bh_delete(mis->bh);
565 migration_incoming_state_destroy();
568 static void process_incoming_migration_co(void *opaque)
570 MigrationIncomingState *mis = migration_incoming_get_current();
571 PostcopyState ps;
572 int ret;
573 Error *local_err = NULL;
575 assert(mis->from_src_file);
576 mis->migration_incoming_co = qemu_coroutine_self();
577 mis->largest_page_size = qemu_ram_pagesize_largest();
578 postcopy_state_set(POSTCOPY_INCOMING_NONE);
579 migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
580 MIGRATION_STATUS_ACTIVE);
581 ret = qemu_loadvm_state(mis->from_src_file);
583 ps = postcopy_state_get();
584 trace_process_incoming_migration_co_end(ret, ps);
585 if (ps != POSTCOPY_INCOMING_NONE) {
586 if (ps == POSTCOPY_INCOMING_ADVISE) {
588 * Where a migration had postcopy enabled (and thus went to advise)
589 * but managed to complete within the precopy period, we can use
590 * the normal exit.
592 postcopy_ram_incoming_cleanup(mis);
593 } else if (ret >= 0) {
595 * Postcopy was started, cleanup should happen at the end of the
596 * postcopy thread.
598 trace_process_incoming_migration_co_postcopy_end_main();
599 return;
601 /* Else if something went wrong then just fall out of the normal exit */
604 /* we get COLO info, and know if we are in COLO mode */
605 if (!ret && migration_incoming_colo_enabled()) {
606 /* Make sure all file formats throw away their mutable metadata */
607 bdrv_activate_all(&local_err);
608 if (local_err) {
609 error_report_err(local_err);
610 goto fail;
613 qemu_thread_create(&mis->colo_incoming_thread, "COLO incoming",
614 colo_process_incoming_thread, mis, QEMU_THREAD_JOINABLE);
615 mis->have_colo_incoming_thread = true;
616 qemu_coroutine_yield();
618 qemu_mutex_unlock_iothread();
619 /* Wait checkpoint incoming thread exit before free resource */
620 qemu_thread_join(&mis->colo_incoming_thread);
621 qemu_mutex_lock_iothread();
622 /* We hold the global iothread lock, so it is safe here */
623 colo_release_ram_cache();
626 if (ret < 0) {
627 error_report("load of migration failed: %s", strerror(-ret));
628 goto fail;
630 mis->bh = qemu_bh_new(process_incoming_migration_bh, mis);
631 qemu_bh_schedule(mis->bh);
632 mis->migration_incoming_co = NULL;
633 return;
634 fail:
635 local_err = NULL;
636 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
637 MIGRATION_STATUS_FAILED);
638 qemu_fclose(mis->from_src_file);
639 if (multifd_load_cleanup(&local_err) != 0) {
640 error_report_err(local_err);
642 exit(EXIT_FAILURE);
646 * migration_incoming_setup: Setup incoming migration
647 * @f: file for main migration channel
648 * @errp: where to put errors
650 * Returns: %true on success, %false on error.
652 static bool migration_incoming_setup(QEMUFile *f, Error **errp)
654 MigrationIncomingState *mis = migration_incoming_get_current();
656 if (multifd_load_setup(errp) != 0) {
657 return false;
660 if (!mis->from_src_file) {
661 mis->from_src_file = f;
663 qemu_file_set_blocking(f, false);
664 return true;
667 void migration_incoming_process(void)
669 Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, NULL);
670 qemu_coroutine_enter(co);
673 /* Returns true if recovered from a paused migration, otherwise false */
674 static bool postcopy_try_recover(void)
676 MigrationIncomingState *mis = migration_incoming_get_current();
678 if (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
679 /* Resumed from a paused postcopy migration */
681 /* This should be set already in migration_incoming_setup() */
682 assert(mis->from_src_file);
683 /* Postcopy has standalone thread to do vm load */
684 qemu_file_set_blocking(mis->from_src_file, true);
686 /* Re-configure the return path */
687 mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
689 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_PAUSED,
690 MIGRATION_STATUS_POSTCOPY_RECOVER);
693 * Here, we only wake up the main loading thread (while the
694 * fault thread will still be waiting), so that we can receive
695 * commands from source now, and answer it if needed. The
696 * fault thread will be woken up afterwards until we are sure
697 * that source is ready to reply to page requests.
699 qemu_sem_post(&mis->postcopy_pause_sem_dst);
700 return true;
703 return false;
706 void migration_fd_process_incoming(QEMUFile *f, Error **errp)
708 if (!migration_incoming_setup(f, errp)) {
709 return;
711 if (postcopy_try_recover()) {
712 return;
714 migration_incoming_process();
717 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
719 MigrationIncomingState *mis = migration_incoming_get_current();
720 Error *local_err = NULL;
721 bool start_migration;
723 if (!mis->from_src_file) {
724 /* The first connection (multifd may have multiple) */
725 QEMUFile *f = qemu_fopen_channel_input(ioc);
727 if (!migration_incoming_setup(f, errp)) {
728 return;
732 * Common migration only needs one channel, so we can start
733 * right now. Multifd needs more than one channel, we wait.
735 start_migration = !migrate_use_multifd();
736 } else {
737 /* Multiple connections */
738 assert(migrate_use_multifd());
739 start_migration = multifd_recv_new_channel(ioc, &local_err);
740 if (local_err) {
741 error_propagate(errp, local_err);
742 return;
746 if (start_migration) {
747 /* If it's a recovery, we're done */
748 if (postcopy_try_recover()) {
749 return;
751 migration_incoming_process();
756 * @migration_has_all_channels: We have received all channels that we need
758 * Returns true when we have got connections to all the channels that
759 * we need for migration.
761 bool migration_has_all_channels(void)
763 MigrationIncomingState *mis = migration_incoming_get_current();
764 bool all_channels;
766 all_channels = multifd_recv_all_channels_created();
768 return all_channels && mis->from_src_file != NULL;
772 * Send a 'SHUT' message on the return channel with the given value
773 * to indicate that we've finished with the RP. Non-0 value indicates
774 * error.
776 void migrate_send_rp_shut(MigrationIncomingState *mis,
777 uint32_t value)
779 uint32_t buf;
781 buf = cpu_to_be32(value);
782 migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
786 * Send a 'PONG' message on the return channel with the given value
787 * (normally in response to a 'PING')
789 void migrate_send_rp_pong(MigrationIncomingState *mis,
790 uint32_t value)
792 uint32_t buf;
794 buf = cpu_to_be32(value);
795 migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
798 void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
799 char *block_name)
801 char buf[512];
802 int len;
803 int64_t res;
806 * First, we send the header part. It contains only the len of
807 * idstr, and the idstr itself.
809 len = strlen(block_name);
810 buf[0] = len;
811 memcpy(buf + 1, block_name, len);
813 if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {
814 error_report("%s: MSG_RP_RECV_BITMAP only used for recovery",
815 __func__);
816 return;
819 migrate_send_rp_message(mis, MIG_RP_MSG_RECV_BITMAP, len + 1, buf);
822 * Next, we dump the received bitmap to the stream.
824 * TODO: currently we are safe since we are the only one that is
825 * using the to_src_file handle (fault thread is still paused),
826 * and it's ok even not taking the mutex. However the best way is
827 * to take the lock before sending the message header, and release
828 * the lock after sending the bitmap.
830 qemu_mutex_lock(&mis->rp_mutex);
831 res = ramblock_recv_bitmap_send(mis->to_src_file, block_name);
832 qemu_mutex_unlock(&mis->rp_mutex);
834 trace_migrate_send_rp_recv_bitmap(block_name, res);
837 void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value)
839 uint32_t buf;
841 buf = cpu_to_be32(value);
842 migrate_send_rp_message(mis, MIG_RP_MSG_RESUME_ACK, sizeof(buf), &buf);
845 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
847 MigrationCapabilityStatusList *head = NULL, **tail = &head;
848 MigrationCapabilityStatus *caps;
849 MigrationState *s = migrate_get_current();
850 int i;
852 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
853 #ifndef CONFIG_LIVE_BLOCK_MIGRATION
854 if (i == MIGRATION_CAPABILITY_BLOCK) {
855 continue;
857 #endif
858 caps = g_malloc0(sizeof(*caps));
859 caps->capability = i;
860 caps->state = s->enabled_capabilities[i];
861 QAPI_LIST_APPEND(tail, caps);
864 return head;
867 MigrationParameters *qmp_query_migrate_parameters(Error **errp)
869 MigrationParameters *params;
870 MigrationState *s = migrate_get_current();
872 /* TODO use QAPI_CLONE() instead of duplicating it inline */
873 params = g_malloc0(sizeof(*params));
874 params->has_compress_level = true;
875 params->compress_level = s->parameters.compress_level;
876 params->has_compress_threads = true;
877 params->compress_threads = s->parameters.compress_threads;
878 params->has_compress_wait_thread = true;
879 params->compress_wait_thread = s->parameters.compress_wait_thread;
880 params->has_decompress_threads = true;
881 params->decompress_threads = s->parameters.decompress_threads;
882 params->has_throttle_trigger_threshold = true;
883 params->throttle_trigger_threshold = s->parameters.throttle_trigger_threshold;
884 params->has_cpu_throttle_initial = true;
885 params->cpu_throttle_initial = s->parameters.cpu_throttle_initial;
886 params->has_cpu_throttle_increment = true;
887 params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
888 params->has_cpu_throttle_tailslow = true;
889 params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
890 params->has_tls_creds = true;
891 params->tls_creds = g_strdup(s->parameters.tls_creds);
892 params->has_tls_hostname = true;
893 params->tls_hostname = g_strdup(s->parameters.tls_hostname);
894 params->has_tls_authz = true;
895 params->tls_authz = g_strdup(s->parameters.tls_authz ?
896 s->parameters.tls_authz : "");
897 params->has_max_bandwidth = true;
898 params->max_bandwidth = s->parameters.max_bandwidth;
899 params->has_downtime_limit = true;
900 params->downtime_limit = s->parameters.downtime_limit;
901 params->has_x_checkpoint_delay = true;
902 params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
903 params->has_block_incremental = true;
904 params->block_incremental = s->parameters.block_incremental;
905 params->has_multifd_channels = true;
906 params->multifd_channels = s->parameters.multifd_channels;
907 params->has_multifd_compression = true;
908 params->multifd_compression = s->parameters.multifd_compression;
909 params->has_multifd_zlib_level = true;
910 params->multifd_zlib_level = s->parameters.multifd_zlib_level;
911 params->has_multifd_zstd_level = true;
912 params->multifd_zstd_level = s->parameters.multifd_zstd_level;
913 params->has_xbzrle_cache_size = true;
914 params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
915 params->has_max_postcopy_bandwidth = true;
916 params->max_postcopy_bandwidth = s->parameters.max_postcopy_bandwidth;
917 params->has_max_cpu_throttle = true;
918 params->max_cpu_throttle = s->parameters.max_cpu_throttle;
919 params->has_announce_initial = true;
920 params->announce_initial = s->parameters.announce_initial;
921 params->has_announce_max = true;
922 params->announce_max = s->parameters.announce_max;
923 params->has_announce_rounds = true;
924 params->announce_rounds = s->parameters.announce_rounds;
925 params->has_announce_step = true;
926 params->announce_step = s->parameters.announce_step;
928 if (s->parameters.has_block_bitmap_mapping) {
929 params->has_block_bitmap_mapping = true;
930 params->block_bitmap_mapping =
931 QAPI_CLONE(BitmapMigrationNodeAliasList,
932 s->parameters.block_bitmap_mapping);
935 return params;
938 AnnounceParameters *migrate_announce_params(void)
940 static AnnounceParameters ap;
942 MigrationState *s = migrate_get_current();
944 ap.initial = s->parameters.announce_initial;
945 ap.max = s->parameters.announce_max;
946 ap.rounds = s->parameters.announce_rounds;
947 ap.step = s->parameters.announce_step;
949 return &ap;
953 * Return true if we're already in the middle of a migration
954 * (i.e. any of the active or setup states)
956 bool migration_is_setup_or_active(int state)
958 switch (state) {
959 case MIGRATION_STATUS_ACTIVE:
960 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
961 case MIGRATION_STATUS_POSTCOPY_PAUSED:
962 case MIGRATION_STATUS_POSTCOPY_RECOVER:
963 case MIGRATION_STATUS_SETUP:
964 case MIGRATION_STATUS_PRE_SWITCHOVER:
965 case MIGRATION_STATUS_DEVICE:
966 case MIGRATION_STATUS_WAIT_UNPLUG:
967 case MIGRATION_STATUS_COLO:
968 return true;
970 default:
971 return false;
976 bool migration_is_running(int state)
978 switch (state) {
979 case MIGRATION_STATUS_ACTIVE:
980 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
981 case MIGRATION_STATUS_POSTCOPY_PAUSED:
982 case MIGRATION_STATUS_POSTCOPY_RECOVER:
983 case MIGRATION_STATUS_SETUP:
984 case MIGRATION_STATUS_PRE_SWITCHOVER:
985 case MIGRATION_STATUS_DEVICE:
986 case MIGRATION_STATUS_WAIT_UNPLUG:
987 case MIGRATION_STATUS_CANCELLING:
988 return true;
990 default:
991 return false;
996 static void populate_time_info(MigrationInfo *info, MigrationState *s)
998 info->has_status = true;
999 info->has_setup_time = true;
1000 info->setup_time = s->setup_time;
1001 if (s->state == MIGRATION_STATUS_COMPLETED) {
1002 info->has_total_time = true;
1003 info->total_time = s->total_time;
1004 info->has_downtime = true;
1005 info->downtime = s->downtime;
1006 } else {
1007 info->has_total_time = true;
1008 info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) -
1009 s->start_time;
1010 info->has_expected_downtime = true;
1011 info->expected_downtime = s->expected_downtime;
1015 static void populate_ram_info(MigrationInfo *info, MigrationState *s)
1017 size_t page_size = qemu_target_page_size();
1019 info->has_ram = true;
1020 info->ram = g_malloc0(sizeof(*info->ram));
1021 info->ram->transferred = ram_counters.transferred;
1022 info->ram->total = ram_bytes_total();
1023 info->ram->duplicate = ram_counters.duplicate;
1024 /* legacy value. It is not used anymore */
1025 info->ram->skipped = 0;
1026 info->ram->normal = ram_counters.normal;
1027 info->ram->normal_bytes = ram_counters.normal * page_size;
1028 info->ram->mbps = s->mbps;
1029 info->ram->dirty_sync_count = ram_counters.dirty_sync_count;
1030 info->ram->postcopy_requests = ram_counters.postcopy_requests;
1031 info->ram->page_size = page_size;
1032 info->ram->multifd_bytes = ram_counters.multifd_bytes;
1033 info->ram->pages_per_second = s->pages_per_second;
1034 info->ram->precopy_bytes = ram_counters.precopy_bytes;
1035 info->ram->downtime_bytes = ram_counters.downtime_bytes;
1036 info->ram->postcopy_bytes = ram_counters.postcopy_bytes;
1038 if (migrate_use_xbzrle()) {
1039 info->has_xbzrle_cache = true;
1040 info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
1041 info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
1042 info->xbzrle_cache->bytes = xbzrle_counters.bytes;
1043 info->xbzrle_cache->pages = xbzrle_counters.pages;
1044 info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss;
1045 info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate;
1046 info->xbzrle_cache->encoding_rate = xbzrle_counters.encoding_rate;
1047 info->xbzrle_cache->overflow = xbzrle_counters.overflow;
1050 if (migrate_use_compression()) {
1051 info->has_compression = true;
1052 info->compression = g_malloc0(sizeof(*info->compression));
1053 info->compression->pages = compression_counters.pages;
1054 info->compression->busy = compression_counters.busy;
1055 info->compression->busy_rate = compression_counters.busy_rate;
1056 info->compression->compressed_size =
1057 compression_counters.compressed_size;
1058 info->compression->compression_rate =
1059 compression_counters.compression_rate;
1062 if (cpu_throttle_active()) {
1063 info->has_cpu_throttle_percentage = true;
1064 info->cpu_throttle_percentage = cpu_throttle_get_percentage();
1067 if (s->state != MIGRATION_STATUS_COMPLETED) {
1068 info->ram->remaining = ram_bytes_remaining();
1069 info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate;
1073 static void populate_disk_info(MigrationInfo *info)
1075 if (blk_mig_active()) {
1076 info->has_disk = true;
1077 info->disk = g_malloc0(sizeof(*info->disk));
1078 info->disk->transferred = blk_mig_bytes_transferred();
1079 info->disk->remaining = blk_mig_bytes_remaining();
1080 info->disk->total = blk_mig_bytes_total();
1084 static void fill_source_migration_info(MigrationInfo *info)
1086 MigrationState *s = migrate_get_current();
1087 int state = qatomic_read(&s->state);
1088 GSList *cur_blocker = migration_blockers;
1090 info->blocked_reasons = NULL;
1093 * There are two types of reasons a migration might be blocked;
1094 * a) devices marked in VMState as non-migratable, and
1095 * b) Explicit migration blockers
1096 * We need to add both of them here.
1098 qemu_savevm_non_migratable_list(&info->blocked_reasons);
1100 while (cur_blocker) {
1101 QAPI_LIST_PREPEND(info->blocked_reasons,
1102 g_strdup(error_get_pretty(cur_blocker->data)));
1103 cur_blocker = g_slist_next(cur_blocker);
1105 info->has_blocked_reasons = info->blocked_reasons != NULL;
1107 switch (state) {
1108 case MIGRATION_STATUS_NONE:
1109 /* no migration has happened ever */
1110 /* do not overwrite destination migration status */
1111 return;
1112 case MIGRATION_STATUS_SETUP:
1113 info->has_status = true;
1114 info->has_total_time = false;
1115 break;
1116 case MIGRATION_STATUS_ACTIVE:
1117 case MIGRATION_STATUS_CANCELLING:
1118 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
1119 case MIGRATION_STATUS_PRE_SWITCHOVER:
1120 case MIGRATION_STATUS_DEVICE:
1121 case MIGRATION_STATUS_POSTCOPY_PAUSED:
1122 case MIGRATION_STATUS_POSTCOPY_RECOVER:
1123 /* TODO add some postcopy stats */
1124 populate_time_info(info, s);
1125 populate_ram_info(info, s);
1126 populate_disk_info(info);
1127 populate_vfio_info(info);
1128 break;
1129 case MIGRATION_STATUS_COLO:
1130 info->has_status = true;
1131 /* TODO: display COLO specific information (checkpoint info etc.) */
1132 break;
1133 case MIGRATION_STATUS_COMPLETED:
1134 populate_time_info(info, s);
1135 populate_ram_info(info, s);
1136 populate_vfio_info(info);
1137 break;
1138 case MIGRATION_STATUS_FAILED:
1139 info->has_status = true;
1140 if (s->error) {
1141 info->has_error_desc = true;
1142 info->error_desc = g_strdup(error_get_pretty(s->error));
1144 break;
1145 case MIGRATION_STATUS_CANCELLED:
1146 info->has_status = true;
1147 break;
1148 case MIGRATION_STATUS_WAIT_UNPLUG:
1149 info->has_status = true;
1150 break;
1152 info->status = state;
1155 typedef enum WriteTrackingSupport {
1156 WT_SUPPORT_UNKNOWN = 0,
1157 WT_SUPPORT_ABSENT,
1158 WT_SUPPORT_AVAILABLE,
1159 WT_SUPPORT_COMPATIBLE
1160 } WriteTrackingSupport;
1162 static
1163 WriteTrackingSupport migrate_query_write_tracking(void)
1165 /* Check if kernel supports required UFFD features */
1166 if (!ram_write_tracking_available()) {
1167 return WT_SUPPORT_ABSENT;
1170 * Check if current memory configuration is
1171 * compatible with required UFFD features.
1173 if (!ram_write_tracking_compatible()) {
1174 return WT_SUPPORT_AVAILABLE;
1177 return WT_SUPPORT_COMPATIBLE;
1181 * @migration_caps_check - check capability validity
1183 * @cap_list: old capability list, array of bool
1184 * @params: new capabilities to be applied soon
1185 * @errp: set *errp if the check failed, with reason
1187 * Returns true if check passed, otherwise false.
1189 static bool migrate_caps_check(bool *cap_list,
1190 MigrationCapabilityStatusList *params,
1191 Error **errp)
1193 MigrationCapabilityStatusList *cap;
1194 bool old_postcopy_cap;
1195 MigrationIncomingState *mis = migration_incoming_get_current();
1197 old_postcopy_cap = cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM];
1199 for (cap = params; cap; cap = cap->next) {
1200 cap_list[cap->value->capability] = cap->value->state;
1203 #ifndef CONFIG_LIVE_BLOCK_MIGRATION
1204 if (cap_list[MIGRATION_CAPABILITY_BLOCK]) {
1205 error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) "
1206 "block migration");
1207 error_append_hint(errp, "Use drive_mirror+NBD instead.\n");
1208 return false;
1210 #endif
1212 #ifndef CONFIG_REPLICATION
1213 if (cap_list[MIGRATION_CAPABILITY_X_COLO]) {
1214 error_setg(errp, "QEMU compiled without replication module"
1215 " can't enable COLO");
1216 error_append_hint(errp, "Please enable replication before COLO.\n");
1217 return false;
1219 #endif
1221 if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
1222 /* This check is reasonably expensive, so only when it's being
1223 * set the first time, also it's only the destination that needs
1224 * special support.
1226 if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) &&
1227 !postcopy_ram_supported_by_host(mis)) {
1228 /* postcopy_ram_supported_by_host will have emitted a more
1229 * detailed message
1231 error_setg(errp, "Postcopy is not supported");
1232 return false;
1235 if (cap_list[MIGRATION_CAPABILITY_X_IGNORE_SHARED]) {
1236 error_setg(errp, "Postcopy is not compatible with ignore-shared");
1237 return false;
1241 if (cap_list[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) {
1242 WriteTrackingSupport wt_support;
1243 int idx;
1245 * Check if 'background-snapshot' capability is supported by
1246 * host kernel and compatible with guest memory configuration.
1248 wt_support = migrate_query_write_tracking();
1249 if (wt_support < WT_SUPPORT_AVAILABLE) {
1250 error_setg(errp, "Background-snapshot is not supported by host kernel");
1251 return false;
1253 if (wt_support < WT_SUPPORT_COMPATIBLE) {
1254 error_setg(errp, "Background-snapshot is not compatible "
1255 "with guest memory configuration");
1256 return false;
1260 * Check if there are any migration capabilities
1261 * incompatible with 'background-snapshot'.
1263 for (idx = 0; idx < check_caps_background_snapshot.size; idx++) {
1264 int incomp_cap = check_caps_background_snapshot.caps[idx];
1265 if (cap_list[incomp_cap]) {
1266 error_setg(errp,
1267 "Background-snapshot is not compatible with %s",
1268 MigrationCapability_str(incomp_cap));
1269 return false;
1274 /* incoming side only */
1275 if (runstate_check(RUN_STATE_INMIGRATE) &&
1276 !migrate_multi_channels_is_allowed() &&
1277 cap_list[MIGRATION_CAPABILITY_MULTIFD]) {
1278 error_setg(errp, "multifd is not supported by current protocol");
1279 return false;
1282 return true;
1285 static void fill_destination_migration_info(MigrationInfo *info)
1287 MigrationIncomingState *mis = migration_incoming_get_current();
1289 if (mis->socket_address_list) {
1290 info->has_socket_address = true;
1291 info->socket_address =
1292 QAPI_CLONE(SocketAddressList, mis->socket_address_list);
1295 switch (mis->state) {
1296 case MIGRATION_STATUS_NONE:
1297 return;
1298 case MIGRATION_STATUS_SETUP:
1299 case MIGRATION_STATUS_CANCELLING:
1300 case MIGRATION_STATUS_CANCELLED:
1301 case MIGRATION_STATUS_ACTIVE:
1302 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
1303 case MIGRATION_STATUS_POSTCOPY_PAUSED:
1304 case MIGRATION_STATUS_POSTCOPY_RECOVER:
1305 case MIGRATION_STATUS_FAILED:
1306 case MIGRATION_STATUS_COLO:
1307 info->has_status = true;
1308 break;
1309 case MIGRATION_STATUS_COMPLETED:
1310 info->has_status = true;
1311 fill_destination_postcopy_migration_info(info);
1312 break;
1314 info->status = mis->state;
1317 MigrationInfo *qmp_query_migrate(Error **errp)
1319 MigrationInfo *info = g_malloc0(sizeof(*info));
1321 fill_destination_migration_info(info);
1322 fill_source_migration_info(info);
1324 return info;
1327 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
1328 Error **errp)
1330 MigrationState *s = migrate_get_current();
1331 MigrationCapabilityStatusList *cap;
1332 bool cap_list[MIGRATION_CAPABILITY__MAX];
1334 if (migration_is_running(s->state)) {
1335 error_setg(errp, QERR_MIGRATION_ACTIVE);
1336 return;
1339 memcpy(cap_list, s->enabled_capabilities, sizeof(cap_list));
1340 if (!migrate_caps_check(cap_list, params, errp)) {
1341 return;
1344 for (cap = params; cap; cap = cap->next) {
1345 s->enabled_capabilities[cap->value->capability] = cap->value->state;
1350 * Check whether the parameters are valid. Error will be put into errp
1351 * (if provided). Return true if valid, otherwise false.
1353 static bool migrate_params_check(MigrationParameters *params, Error **errp)
1355 if (params->has_compress_level &&
1356 (params->compress_level > 9)) {
1357 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
1358 "a value between 0 and 9");
1359 return false;
1362 if (params->has_compress_threads && (params->compress_threads < 1)) {
1363 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1364 "compress_threads",
1365 "a value between 1 and 255");
1366 return false;
1369 if (params->has_decompress_threads && (params->decompress_threads < 1)) {
1370 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1371 "decompress_threads",
1372 "a value between 1 and 255");
1373 return false;
1376 if (params->has_throttle_trigger_threshold &&
1377 (params->throttle_trigger_threshold < 1 ||
1378 params->throttle_trigger_threshold > 100)) {
1379 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1380 "throttle_trigger_threshold",
1381 "an integer in the range of 1 to 100");
1382 return false;
1385 if (params->has_cpu_throttle_initial &&
1386 (params->cpu_throttle_initial < 1 ||
1387 params->cpu_throttle_initial > 99)) {
1388 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1389 "cpu_throttle_initial",
1390 "an integer in the range of 1 to 99");
1391 return false;
1394 if (params->has_cpu_throttle_increment &&
1395 (params->cpu_throttle_increment < 1 ||
1396 params->cpu_throttle_increment > 99)) {
1397 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1398 "cpu_throttle_increment",
1399 "an integer in the range of 1 to 99");
1400 return false;
1403 if (params->has_max_bandwidth && (params->max_bandwidth > SIZE_MAX)) {
1404 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1405 "max_bandwidth",
1406 "an integer in the range of 0 to "stringify(SIZE_MAX)
1407 " bytes/second");
1408 return false;
1411 if (params->has_downtime_limit &&
1412 (params->downtime_limit > MAX_MIGRATE_DOWNTIME)) {
1413 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1414 "downtime_limit",
1415 "an integer in the range of 0 to "
1416 stringify(MAX_MIGRATE_DOWNTIME)" ms");
1417 return false;
1420 /* x_checkpoint_delay is now always positive */
1422 if (params->has_multifd_channels && (params->multifd_channels < 1)) {
1423 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1424 "multifd_channels",
1425 "a value between 1 and 255");
1426 return false;
1429 if (params->has_multifd_zlib_level &&
1430 (params->multifd_zlib_level > 9)) {
1431 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "multifd_zlib_level",
1432 "a value between 0 and 9");
1433 return false;
1436 if (params->has_multifd_zstd_level &&
1437 (params->multifd_zstd_level > 20)) {
1438 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "multifd_zstd_level",
1439 "a value between 0 and 20");
1440 return false;
1443 if (params->has_xbzrle_cache_size &&
1444 (params->xbzrle_cache_size < qemu_target_page_size() ||
1445 !is_power_of_2(params->xbzrle_cache_size))) {
1446 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1447 "xbzrle_cache_size",
1448 "a power of two no less than the target page size");
1449 return false;
1452 if (params->has_max_cpu_throttle &&
1453 (params->max_cpu_throttle < params->cpu_throttle_initial ||
1454 params->max_cpu_throttle > 99)) {
1455 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1456 "max_cpu_throttle",
1457 "an integer in the range of cpu_throttle_initial to 99");
1458 return false;
1461 if (params->has_announce_initial &&
1462 params->announce_initial > 100000) {
1463 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1464 "announce_initial",
1465 "a value between 0 and 100000");
1466 return false;
1468 if (params->has_announce_max &&
1469 params->announce_max > 100000) {
1470 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1471 "announce_max",
1472 "a value between 0 and 100000");
1473 return false;
1475 if (params->has_announce_rounds &&
1476 params->announce_rounds > 1000) {
1477 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1478 "announce_rounds",
1479 "a value between 0 and 1000");
1480 return false;
1482 if (params->has_announce_step &&
1483 (params->announce_step < 1 ||
1484 params->announce_step > 10000)) {
1485 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1486 "announce_step",
1487 "a value between 0 and 10000");
1488 return false;
1491 if (params->has_block_bitmap_mapping &&
1492 !check_dirty_bitmap_mig_alias_map(params->block_bitmap_mapping, errp)) {
1493 error_prepend(errp, "Invalid mapping given for block-bitmap-mapping: ");
1494 return false;
1497 return true;
1500 static void migrate_params_test_apply(MigrateSetParameters *params,
1501 MigrationParameters *dest)
1503 *dest = migrate_get_current()->parameters;
1505 /* TODO use QAPI_CLONE() instead of duplicating it inline */
1507 if (params->has_compress_level) {
1508 dest->compress_level = params->compress_level;
1511 if (params->has_compress_threads) {
1512 dest->compress_threads = params->compress_threads;
1515 if (params->has_compress_wait_thread) {
1516 dest->compress_wait_thread = params->compress_wait_thread;
1519 if (params->has_decompress_threads) {
1520 dest->decompress_threads = params->decompress_threads;
1523 if (params->has_throttle_trigger_threshold) {
1524 dest->throttle_trigger_threshold = params->throttle_trigger_threshold;
1527 if (params->has_cpu_throttle_initial) {
1528 dest->cpu_throttle_initial = params->cpu_throttle_initial;
1531 if (params->has_cpu_throttle_increment) {
1532 dest->cpu_throttle_increment = params->cpu_throttle_increment;
1535 if (params->has_cpu_throttle_tailslow) {
1536 dest->cpu_throttle_tailslow = params->cpu_throttle_tailslow;
1539 if (params->has_tls_creds) {
1540 assert(params->tls_creds->type == QTYPE_QSTRING);
1541 dest->tls_creds = params->tls_creds->u.s;
1544 if (params->has_tls_hostname) {
1545 assert(params->tls_hostname->type == QTYPE_QSTRING);
1546 dest->tls_hostname = params->tls_hostname->u.s;
1549 if (params->has_max_bandwidth) {
1550 dest->max_bandwidth = params->max_bandwidth;
1553 if (params->has_downtime_limit) {
1554 dest->downtime_limit = params->downtime_limit;
1557 if (params->has_x_checkpoint_delay) {
1558 dest->x_checkpoint_delay = params->x_checkpoint_delay;
1561 if (params->has_block_incremental) {
1562 dest->block_incremental = params->block_incremental;
1564 if (params->has_multifd_channels) {
1565 dest->multifd_channels = params->multifd_channels;
1567 if (params->has_multifd_compression) {
1568 dest->multifd_compression = params->multifd_compression;
1570 if (params->has_xbzrle_cache_size) {
1571 dest->xbzrle_cache_size = params->xbzrle_cache_size;
1573 if (params->has_max_postcopy_bandwidth) {
1574 dest->max_postcopy_bandwidth = params->max_postcopy_bandwidth;
1576 if (params->has_max_cpu_throttle) {
1577 dest->max_cpu_throttle = params->max_cpu_throttle;
1579 if (params->has_announce_initial) {
1580 dest->announce_initial = params->announce_initial;
1582 if (params->has_announce_max) {
1583 dest->announce_max = params->announce_max;
1585 if (params->has_announce_rounds) {
1586 dest->announce_rounds = params->announce_rounds;
1588 if (params->has_announce_step) {
1589 dest->announce_step = params->announce_step;
1592 if (params->has_block_bitmap_mapping) {
1593 dest->has_block_bitmap_mapping = true;
1594 dest->block_bitmap_mapping = params->block_bitmap_mapping;
1598 static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
1600 MigrationState *s = migrate_get_current();
1602 /* TODO use QAPI_CLONE() instead of duplicating it inline */
1604 if (params->has_compress_level) {
1605 s->parameters.compress_level = params->compress_level;
1608 if (params->has_compress_threads) {
1609 s->parameters.compress_threads = params->compress_threads;
1612 if (params->has_compress_wait_thread) {
1613 s->parameters.compress_wait_thread = params->compress_wait_thread;
1616 if (params->has_decompress_threads) {
1617 s->parameters.decompress_threads = params->decompress_threads;
1620 if (params->has_throttle_trigger_threshold) {
1621 s->parameters.throttle_trigger_threshold = params->throttle_trigger_threshold;
1624 if (params->has_cpu_throttle_initial) {
1625 s->parameters.cpu_throttle_initial = params->cpu_throttle_initial;
1628 if (params->has_cpu_throttle_increment) {
1629 s->parameters.cpu_throttle_increment = params->cpu_throttle_increment;
1632 if (params->has_cpu_throttle_tailslow) {
1633 s->parameters.cpu_throttle_tailslow = params->cpu_throttle_tailslow;
1636 if (params->has_tls_creds) {
1637 g_free(s->parameters.tls_creds);
1638 assert(params->tls_creds->type == QTYPE_QSTRING);
1639 s->parameters.tls_creds = g_strdup(params->tls_creds->u.s);
1642 if (params->has_tls_hostname) {
1643 g_free(s->parameters.tls_hostname);
1644 assert(params->tls_hostname->type == QTYPE_QSTRING);
1645 s->parameters.tls_hostname = g_strdup(params->tls_hostname->u.s);
1648 if (params->has_tls_authz) {
1649 g_free(s->parameters.tls_authz);
1650 assert(params->tls_authz->type == QTYPE_QSTRING);
1651 s->parameters.tls_authz = g_strdup(params->tls_authz->u.s);
1654 if (params->has_max_bandwidth) {
1655 s->parameters.max_bandwidth = params->max_bandwidth;
1656 if (s->to_dst_file && !migration_in_postcopy()) {
1657 qemu_file_set_rate_limit(s->to_dst_file,
1658 s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
1662 if (params->has_downtime_limit) {
1663 s->parameters.downtime_limit = params->downtime_limit;
1666 if (params->has_x_checkpoint_delay) {
1667 s->parameters.x_checkpoint_delay = params->x_checkpoint_delay;
1668 if (migration_in_colo_state()) {
1669 colo_checkpoint_notify(s);
1673 if (params->has_block_incremental) {
1674 s->parameters.block_incremental = params->block_incremental;
1676 if (params->has_multifd_channels) {
1677 s->parameters.multifd_channels = params->multifd_channels;
1679 if (params->has_multifd_compression) {
1680 s->parameters.multifd_compression = params->multifd_compression;
1682 if (params->has_xbzrle_cache_size) {
1683 s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
1684 xbzrle_cache_resize(params->xbzrle_cache_size, errp);
1686 if (params->has_max_postcopy_bandwidth) {
1687 s->parameters.max_postcopy_bandwidth = params->max_postcopy_bandwidth;
1688 if (s->to_dst_file && migration_in_postcopy()) {
1689 qemu_file_set_rate_limit(s->to_dst_file,
1690 s->parameters.max_postcopy_bandwidth / XFER_LIMIT_RATIO);
1693 if (params->has_max_cpu_throttle) {
1694 s->parameters.max_cpu_throttle = params->max_cpu_throttle;
1696 if (params->has_announce_initial) {
1697 s->parameters.announce_initial = params->announce_initial;
1699 if (params->has_announce_max) {
1700 s->parameters.announce_max = params->announce_max;
1702 if (params->has_announce_rounds) {
1703 s->parameters.announce_rounds = params->announce_rounds;
1705 if (params->has_announce_step) {
1706 s->parameters.announce_step = params->announce_step;
1709 if (params->has_block_bitmap_mapping) {
1710 qapi_free_BitmapMigrationNodeAliasList(
1711 s->parameters.block_bitmap_mapping);
1713 s->parameters.has_block_bitmap_mapping = true;
1714 s->parameters.block_bitmap_mapping =
1715 QAPI_CLONE(BitmapMigrationNodeAliasList,
1716 params->block_bitmap_mapping);
1720 void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
1722 MigrationParameters tmp;
1724 /* TODO Rewrite "" to null instead */
1725 if (params->has_tls_creds
1726 && params->tls_creds->type == QTYPE_QNULL) {
1727 qobject_unref(params->tls_creds->u.n);
1728 params->tls_creds->type = QTYPE_QSTRING;
1729 params->tls_creds->u.s = strdup("");
1731 /* TODO Rewrite "" to null instead */
1732 if (params->has_tls_hostname
1733 && params->tls_hostname->type == QTYPE_QNULL) {
1734 qobject_unref(params->tls_hostname->u.n);
1735 params->tls_hostname->type = QTYPE_QSTRING;
1736 params->tls_hostname->u.s = strdup("");
1739 migrate_params_test_apply(params, &tmp);
1741 if (!migrate_params_check(&tmp, errp)) {
1742 /* Invalid parameter */
1743 return;
1746 migrate_params_apply(params, errp);
1750 void qmp_migrate_start_postcopy(Error **errp)
1752 MigrationState *s = migrate_get_current();
1754 if (!migrate_postcopy()) {
1755 error_setg(errp, "Enable postcopy with migrate_set_capability before"
1756 " the start of migration");
1757 return;
1760 if (s->state == MIGRATION_STATUS_NONE) {
1761 error_setg(errp, "Postcopy must be started after migration has been"
1762 " started");
1763 return;
1766 * we don't error if migration has finished since that would be racy
1767 * with issuing this command.
1769 qatomic_set(&s->start_postcopy, true);
1772 /* shared migration helpers */
1774 void migrate_set_state(int *state, int old_state, int new_state)
1776 assert(new_state < MIGRATION_STATUS__MAX);
1777 if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
1778 trace_migrate_set_state(MigrationStatus_str(new_state));
1779 migrate_generate_event(new_state);
1783 static MigrationCapabilityStatus *migrate_cap_add(MigrationCapability index,
1784 bool state)
1786 MigrationCapabilityStatus *cap;
1788 cap = g_new0(MigrationCapabilityStatus, 1);
1789 cap->capability = index;
1790 cap->state = state;
1792 return cap;
1795 void migrate_set_block_enabled(bool value, Error **errp)
1797 MigrationCapabilityStatusList *cap = NULL;
1799 QAPI_LIST_PREPEND(cap, migrate_cap_add(MIGRATION_CAPABILITY_BLOCK, value));
1800 qmp_migrate_set_capabilities(cap, errp);
1801 qapi_free_MigrationCapabilityStatusList(cap);
1804 static void migrate_set_block_incremental(MigrationState *s, bool value)
1806 s->parameters.block_incremental = value;
1809 static void block_cleanup_parameters(MigrationState *s)
1811 if (s->must_remove_block_options) {
1812 /* setting to false can never fail */
1813 migrate_set_block_enabled(false, &error_abort);
1814 migrate_set_block_incremental(s, false);
1815 s->must_remove_block_options = false;
1819 static void migrate_fd_cleanup(MigrationState *s)
1821 qemu_bh_delete(s->cleanup_bh);
1822 s->cleanup_bh = NULL;
1824 g_free(s->hostname);
1825 s->hostname = NULL;
1827 qemu_savevm_state_cleanup();
1829 if (s->to_dst_file) {
1830 QEMUFile *tmp;
1832 trace_migrate_fd_cleanup();
1833 qemu_mutex_unlock_iothread();
1834 if (s->migration_thread_running) {
1835 qemu_thread_join(&s->thread);
1836 s->migration_thread_running = false;
1838 qemu_mutex_lock_iothread();
1840 multifd_save_cleanup();
1841 qemu_mutex_lock(&s->qemu_file_lock);
1842 tmp = s->to_dst_file;
1843 s->to_dst_file = NULL;
1844 qemu_mutex_unlock(&s->qemu_file_lock);
1846 * Close the file handle without the lock to make sure the
1847 * critical section won't block for long.
1849 migration_ioc_unregister_yank_from_file(tmp);
1850 qemu_fclose(tmp);
1853 assert(!migration_is_active(s));
1855 if (s->state == MIGRATION_STATUS_CANCELLING) {
1856 migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING,
1857 MIGRATION_STATUS_CANCELLED);
1860 if (s->error) {
1861 /* It is used on info migrate. We can't free it */
1862 error_report_err(error_copy(s->error));
1864 notifier_list_notify(&migration_state_notifiers, s);
1865 block_cleanup_parameters(s);
1866 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
1869 static void migrate_fd_cleanup_schedule(MigrationState *s)
1872 * Ref the state for bh, because it may be called when
1873 * there're already no other refs
1875 object_ref(OBJECT(s));
1876 qemu_bh_schedule(s->cleanup_bh);
1879 static void migrate_fd_cleanup_bh(void *opaque)
1881 MigrationState *s = opaque;
1882 migrate_fd_cleanup(s);
1883 object_unref(OBJECT(s));
1886 void migrate_set_error(MigrationState *s, const Error *error)
1888 QEMU_LOCK_GUARD(&s->error_mutex);
1889 if (!s->error) {
1890 s->error = error_copy(error);
1894 static void migrate_error_free(MigrationState *s)
1896 QEMU_LOCK_GUARD(&s->error_mutex);
1897 if (s->error) {
1898 error_free(s->error);
1899 s->error = NULL;
1903 void migrate_fd_error(MigrationState *s, const Error *error)
1905 trace_migrate_fd_error(error_get_pretty(error));
1906 assert(s->to_dst_file == NULL);
1907 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
1908 MIGRATION_STATUS_FAILED);
1909 migrate_set_error(s, error);
1912 static void migrate_fd_cancel(MigrationState *s)
1914 int old_state ;
1915 QEMUFile *f = migrate_get_current()->to_dst_file;
1916 trace_migrate_fd_cancel();
1918 WITH_QEMU_LOCK_GUARD(&s->qemu_file_lock) {
1919 if (s->rp_state.from_dst_file) {
1920 /* shutdown the rp socket, so causing the rp thread to shutdown */
1921 qemu_file_shutdown(s->rp_state.from_dst_file);
1925 do {
1926 old_state = s->state;
1927 if (!migration_is_running(old_state)) {
1928 break;
1930 /* If the migration is paused, kick it out of the pause */
1931 if (old_state == MIGRATION_STATUS_PRE_SWITCHOVER) {
1932 qemu_sem_post(&s->pause_sem);
1934 migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING);
1935 } while (s->state != MIGRATION_STATUS_CANCELLING);
1938 * If we're unlucky the migration code might be stuck somewhere in a
1939 * send/write while the network has failed and is waiting to timeout;
1940 * if we've got shutdown(2) available then we can force it to quit.
1941 * The outgoing qemu file gets closed in migrate_fd_cleanup that is
1942 * called in a bh, so there is no race against this cancel.
1944 if (s->state == MIGRATION_STATUS_CANCELLING && f) {
1945 qemu_file_shutdown(f);
1947 if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) {
1948 Error *local_err = NULL;
1950 bdrv_activate_all(&local_err);
1951 if (local_err) {
1952 error_report_err(local_err);
1953 } else {
1954 s->block_inactive = false;
1959 void add_migration_state_change_notifier(Notifier *notify)
1961 notifier_list_add(&migration_state_notifiers, notify);
1964 void remove_migration_state_change_notifier(Notifier *notify)
1966 notifier_remove(notify);
1969 bool migration_in_setup(MigrationState *s)
1971 return s->state == MIGRATION_STATUS_SETUP;
1974 bool migration_has_finished(MigrationState *s)
1976 return s->state == MIGRATION_STATUS_COMPLETED;
1979 bool migration_has_failed(MigrationState *s)
1981 return (s->state == MIGRATION_STATUS_CANCELLED ||
1982 s->state == MIGRATION_STATUS_FAILED);
1985 bool migration_in_postcopy(void)
1987 MigrationState *s = migrate_get_current();
1989 switch (s->state) {
1990 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
1991 case MIGRATION_STATUS_POSTCOPY_PAUSED:
1992 case MIGRATION_STATUS_POSTCOPY_RECOVER:
1993 return true;
1994 default:
1995 return false;
1999 bool migration_in_postcopy_after_devices(MigrationState *s)
2001 return migration_in_postcopy() && s->postcopy_after_devices;
2004 bool migration_in_incoming_postcopy(void)
2006 PostcopyState ps = postcopy_state_get();
2008 return ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END;
2011 bool migration_in_bg_snapshot(void)
2013 MigrationState *s = migrate_get_current();
2015 return migrate_background_snapshot() &&
2016 migration_is_setup_or_active(s->state);
2019 bool migration_is_idle(void)
2021 MigrationState *s = current_migration;
2023 if (!s) {
2024 return true;
2027 switch (s->state) {
2028 case MIGRATION_STATUS_NONE:
2029 case MIGRATION_STATUS_CANCELLED:
2030 case MIGRATION_STATUS_COMPLETED:
2031 case MIGRATION_STATUS_FAILED:
2032 return true;
2033 case MIGRATION_STATUS_SETUP:
2034 case MIGRATION_STATUS_CANCELLING:
2035 case MIGRATION_STATUS_ACTIVE:
2036 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
2037 case MIGRATION_STATUS_COLO:
2038 case MIGRATION_STATUS_PRE_SWITCHOVER:
2039 case MIGRATION_STATUS_DEVICE:
2040 case MIGRATION_STATUS_WAIT_UNPLUG:
2041 return false;
2042 case MIGRATION_STATUS__MAX:
2043 g_assert_not_reached();
2046 return false;
2049 bool migration_is_active(MigrationState *s)
2051 return (s->state == MIGRATION_STATUS_ACTIVE ||
2052 s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
2055 void migrate_init(MigrationState *s)
2058 * Reinitialise all migration state, except
2059 * parameters/capabilities that the user set, and
2060 * locks.
2062 s->cleanup_bh = 0;
2063 s->vm_start_bh = 0;
2064 s->to_dst_file = NULL;
2065 s->state = MIGRATION_STATUS_NONE;
2066 s->rp_state.from_dst_file = NULL;
2067 s->rp_state.error = false;
2068 s->mbps = 0.0;
2069 s->pages_per_second = 0.0;
2070 s->downtime = 0;
2071 s->expected_downtime = 0;
2072 s->setup_time = 0;
2073 s->start_postcopy = false;
2074 s->postcopy_after_devices = false;
2075 s->migration_thread_running = false;
2076 error_free(s->error);
2077 s->error = NULL;
2078 s->hostname = NULL;
2080 migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);
2082 s->start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
2083 s->total_time = 0;
2084 s->vm_was_running = false;
2085 s->iteration_initial_bytes = 0;
2086 s->threshold_size = 0;
2089 int migrate_add_blocker_internal(Error *reason, Error **errp)
2091 /* Snapshots are similar to migrations, so check RUN_STATE_SAVE_VM too. */
2092 if (runstate_check(RUN_STATE_SAVE_VM) || !migration_is_idle()) {
2093 error_propagate_prepend(errp, error_copy(reason),
2094 "disallowing migration blocker "
2095 "(migration/snapshot in progress) for: ");
2096 return -EBUSY;
2099 migration_blockers = g_slist_prepend(migration_blockers, reason);
2100 return 0;
2103 int migrate_add_blocker(Error *reason, Error **errp)
2105 if (only_migratable) {
2106 error_propagate_prepend(errp, error_copy(reason),
2107 "disallowing migration blocker "
2108 "(--only-migratable) for: ");
2109 return -EACCES;
2112 return migrate_add_blocker_internal(reason, errp);
2115 void migrate_del_blocker(Error *reason)
2117 migration_blockers = g_slist_remove(migration_blockers, reason);
2120 void qmp_migrate_incoming(const char *uri, Error **errp)
2122 Error *local_err = NULL;
2123 static bool once = true;
2125 if (!once) {
2126 error_setg(errp, "The incoming migration has already been started");
2127 return;
2129 if (!runstate_check(RUN_STATE_INMIGRATE)) {
2130 error_setg(errp, "'-incoming' was not specified on the command line");
2131 return;
2134 if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
2135 return;
2138 qemu_start_incoming_migration(uri, &local_err);
2140 if (local_err) {
2141 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
2142 error_propagate(errp, local_err);
2143 return;
2146 once = false;
2149 void qmp_migrate_recover(const char *uri, Error **errp)
2151 MigrationIncomingState *mis = migration_incoming_get_current();
2154 * Don't even bother to use ERRP_GUARD() as it _must_ always be set by
2155 * callers (no one should ignore a recover failure); if there is, it's a
2156 * programming error.
2158 assert(errp);
2160 if (mis->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
2161 error_setg(errp, "Migrate recover can only be run "
2162 "when postcopy is paused.");
2163 return;
2166 /* If there's an existing transport, release it */
2167 migration_incoming_transport_cleanup(mis);
2170 * Note that this call will never start a real migration; it will
2171 * only re-setup the migration stream and poke existing migration
2172 * to continue using that newly established channel.
2174 qemu_start_incoming_migration(uri, errp);
2177 void qmp_migrate_pause(Error **errp)
2179 MigrationState *ms = migrate_get_current();
2180 MigrationIncomingState *mis = migration_incoming_get_current();
2181 int ret;
2183 if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
2184 /* Source side, during postcopy */
2185 qemu_mutex_lock(&ms->qemu_file_lock);
2186 ret = qemu_file_shutdown(ms->to_dst_file);
2187 qemu_mutex_unlock(&ms->qemu_file_lock);
2188 if (ret) {
2189 error_setg(errp, "Failed to pause source migration");
2191 return;
2194 if (mis->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
2195 ret = qemu_file_shutdown(mis->from_src_file);
2196 if (ret) {
2197 error_setg(errp, "Failed to pause destination migration");
2199 return;
2202 error_setg(errp, "migrate-pause is currently only supported "
2203 "during postcopy-active state");
2206 bool migration_is_blocked(Error **errp)
2208 if (qemu_savevm_state_blocked(errp)) {
2209 return true;
2212 if (migration_blockers) {
2213 error_propagate(errp, error_copy(migration_blockers->data));
2214 return true;
2217 return false;
2220 /* Returns true if continue to migrate, or false if error detected */
2221 static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
2222 bool resume, Error **errp)
2224 Error *local_err = NULL;
2226 if (resume) {
2227 if (s->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
2228 error_setg(errp, "Cannot resume if there is no "
2229 "paused migration");
2230 return false;
2234 * Postcopy recovery won't work well with release-ram
2235 * capability since release-ram will drop the page buffer as
2236 * long as the page is put into the send buffer. So if there
2237 * is a network failure happened, any page buffers that have
2238 * not yet reached the destination VM but have already been
2239 * sent from the source VM will be lost forever. Let's refuse
2240 * the client from resuming such a postcopy migration.
2241 * Luckily release-ram was designed to only be used when src
2242 * and destination VMs are on the same host, so it should be
2243 * fine.
2245 if (migrate_release_ram()) {
2246 error_setg(errp, "Postcopy recovery cannot work "
2247 "when release-ram capability is set");
2248 return false;
2251 /* This is a resume, skip init status */
2252 return true;
2255 if (migration_is_running(s->state)) {
2256 error_setg(errp, QERR_MIGRATION_ACTIVE);
2257 return false;
2260 if (runstate_check(RUN_STATE_INMIGRATE)) {
2261 error_setg(errp, "Guest is waiting for an incoming migration");
2262 return false;
2265 if (runstate_check(RUN_STATE_POSTMIGRATE)) {
2266 error_setg(errp, "Can't migrate the vm that was paused due to "
2267 "previous migration");
2268 return false;
2271 if (migration_is_blocked(errp)) {
2272 return false;
2275 if (blk || blk_inc) {
2276 if (migrate_colo_enabled()) {
2277 error_setg(errp, "No disk migration is required in COLO mode");
2278 return false;
2280 if (migrate_use_block() || migrate_use_block_incremental()) {
2281 error_setg(errp, "Command options are incompatible with "
2282 "current migration capabilities");
2283 return false;
2285 migrate_set_block_enabled(true, &local_err);
2286 if (local_err) {
2287 error_propagate(errp, local_err);
2288 return false;
2290 s->must_remove_block_options = true;
2293 if (blk_inc) {
2294 migrate_set_block_incremental(s, true);
2297 migrate_init(s);
2299 * set ram_counters compression_counters memory to zero for a
2300 * new migration
2302 memset(&ram_counters, 0, sizeof(ram_counters));
2303 memset(&compression_counters, 0, sizeof(compression_counters));
2305 return true;
2308 void qmp_migrate(const char *uri, bool has_blk, bool blk,
2309 bool has_inc, bool inc, bool has_detach, bool detach,
2310 bool has_resume, bool resume, Error **errp)
2312 Error *local_err = NULL;
2313 MigrationState *s = migrate_get_current();
2314 const char *p = NULL;
2316 if (!migrate_prepare(s, has_blk && blk, has_inc && inc,
2317 has_resume && resume, errp)) {
2318 /* Error detected, put into errp */
2319 return;
2322 if (!(has_resume && resume)) {
2323 if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
2324 return;
2328 migrate_protocol_allow_multi_channels(false);
2329 if (strstart(uri, "tcp:", &p) ||
2330 strstart(uri, "unix:", NULL) ||
2331 strstart(uri, "vsock:", NULL)) {
2332 migrate_protocol_allow_multi_channels(true);
2333 socket_start_outgoing_migration(s, p ? p : uri, &local_err);
2334 #ifdef CONFIG_RDMA
2335 } else if (strstart(uri, "rdma:", &p)) {
2336 rdma_start_outgoing_migration(s, p, &local_err);
2337 #endif
2338 } else if (strstart(uri, "exec:", &p)) {
2339 exec_start_outgoing_migration(s, p, &local_err);
2340 } else if (strstart(uri, "fd:", &p)) {
2341 fd_start_outgoing_migration(s, p, &local_err);
2342 } else {
2343 if (!(has_resume && resume)) {
2344 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
2346 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
2347 "a valid migration protocol");
2348 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
2349 MIGRATION_STATUS_FAILED);
2350 block_cleanup_parameters(s);
2351 return;
2354 if (local_err) {
2355 if (!(has_resume && resume)) {
2356 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
2358 migrate_fd_error(s, local_err);
2359 error_propagate(errp, local_err);
2360 return;
2364 void qmp_migrate_cancel(Error **errp)
2366 migration_cancel(NULL);
2369 void qmp_migrate_continue(MigrationStatus state, Error **errp)
2371 MigrationState *s = migrate_get_current();
2372 if (s->state != state) {
2373 error_setg(errp, "Migration not in expected state: %s",
2374 MigrationStatus_str(s->state));
2375 return;
2377 qemu_sem_post(&s->pause_sem);
2380 bool migrate_release_ram(void)
2382 MigrationState *s;
2384 s = migrate_get_current();
2386 return s->enabled_capabilities[MIGRATION_CAPABILITY_RELEASE_RAM];
2389 bool migrate_postcopy_ram(void)
2391 MigrationState *s;
2393 s = migrate_get_current();
2395 return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM];
2398 bool migrate_postcopy(void)
2400 return migrate_postcopy_ram() || migrate_dirty_bitmaps();
2403 bool migrate_auto_converge(void)
2405 MigrationState *s;
2407 s = migrate_get_current();
2409 return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
2412 bool migrate_zero_blocks(void)
2414 MigrationState *s;
2416 s = migrate_get_current();
2418 return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
2421 bool migrate_postcopy_blocktime(void)
2423 MigrationState *s;
2425 s = migrate_get_current();
2427 return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME];
2430 bool migrate_use_compression(void)
2432 MigrationState *s;
2434 s = migrate_get_current();
2436 return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
2439 int migrate_compress_level(void)
2441 MigrationState *s;
2443 s = migrate_get_current();
2445 return s->parameters.compress_level;
2448 int migrate_compress_threads(void)
2450 MigrationState *s;
2452 s = migrate_get_current();
2454 return s->parameters.compress_threads;
2457 int migrate_compress_wait_thread(void)
2459 MigrationState *s;
2461 s = migrate_get_current();
2463 return s->parameters.compress_wait_thread;
2466 int migrate_decompress_threads(void)
2468 MigrationState *s;
2470 s = migrate_get_current();
2472 return s->parameters.decompress_threads;
2475 bool migrate_dirty_bitmaps(void)
2477 MigrationState *s;
2479 s = migrate_get_current();
2481 return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
2484 bool migrate_ignore_shared(void)
2486 MigrationState *s;
2488 s = migrate_get_current();
2490 return s->enabled_capabilities[MIGRATION_CAPABILITY_X_IGNORE_SHARED];
2493 bool migrate_validate_uuid(void)
2495 MigrationState *s;
2497 s = migrate_get_current();
2499 return s->enabled_capabilities[MIGRATION_CAPABILITY_VALIDATE_UUID];
2502 bool migrate_use_events(void)
2504 MigrationState *s;
2506 s = migrate_get_current();
2508 return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
2511 bool migrate_use_multifd(void)
2513 MigrationState *s;
2515 s = migrate_get_current();
2517 return s->enabled_capabilities[MIGRATION_CAPABILITY_MULTIFD];
2520 bool migrate_pause_before_switchover(void)
2522 MigrationState *s;
2524 s = migrate_get_current();
2526 return s->enabled_capabilities[
2527 MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER];
2530 int migrate_multifd_channels(void)
2532 MigrationState *s;
2534 s = migrate_get_current();
2536 return s->parameters.multifd_channels;
2539 MultiFDCompression migrate_multifd_compression(void)
2541 MigrationState *s;
2543 s = migrate_get_current();
2545 return s->parameters.multifd_compression;
2548 int migrate_multifd_zlib_level(void)
2550 MigrationState *s;
2552 s = migrate_get_current();
2554 return s->parameters.multifd_zlib_level;
2557 int migrate_multifd_zstd_level(void)
2559 MigrationState *s;
2561 s = migrate_get_current();
2563 return s->parameters.multifd_zstd_level;
2566 int migrate_use_xbzrle(void)
2568 MigrationState *s;
2570 s = migrate_get_current();
2572 return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
2575 uint64_t migrate_xbzrle_cache_size(void)
2577 MigrationState *s;
2579 s = migrate_get_current();
2581 return s->parameters.xbzrle_cache_size;
2584 static int64_t migrate_max_postcopy_bandwidth(void)
2586 MigrationState *s;
2588 s = migrate_get_current();
2590 return s->parameters.max_postcopy_bandwidth;
2593 bool migrate_use_block(void)
2595 MigrationState *s;
2597 s = migrate_get_current();
2599 return s->enabled_capabilities[MIGRATION_CAPABILITY_BLOCK];
2602 bool migrate_use_return_path(void)
2604 MigrationState *s;
2606 s = migrate_get_current();
2608 return s->enabled_capabilities[MIGRATION_CAPABILITY_RETURN_PATH];
2611 bool migrate_use_block_incremental(void)
2613 MigrationState *s;
2615 s = migrate_get_current();
2617 return s->parameters.block_incremental;
2620 bool migrate_background_snapshot(void)
2622 MigrationState *s;
2624 s = migrate_get_current();
2626 return s->enabled_capabilities[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT];
2629 /* migration thread support */
2631 * Something bad happened to the RP stream, mark an error
2632 * The caller shall print or trace something to indicate why
2634 static void mark_source_rp_bad(MigrationState *s)
2636 s->rp_state.error = true;
2639 static struct rp_cmd_args {
2640 ssize_t len; /* -1 = variable */
2641 const char *name;
2642 } rp_cmd_args[] = {
2643 [MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" },
2644 [MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" },
2645 [MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" },
2646 [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" },
2647 [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" },
2648 [MIG_RP_MSG_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" },
2649 [MIG_RP_MSG_RESUME_ACK] = { .len = 4, .name = "RESUME_ACK" },
2650 [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" },
2654 * Process a request for pages received on the return path,
2655 * We're allowed to send more than requested (e.g. to round to our page size)
2656 * and we don't need to send pages that have already been sent.
2658 static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname,
2659 ram_addr_t start, size_t len)
2661 long our_host_ps = qemu_real_host_page_size();
2663 trace_migrate_handle_rp_req_pages(rbname, start, len);
2666 * Since we currently insist on matching page sizes, just sanity check
2667 * we're being asked for whole host pages.
2669 if (!QEMU_IS_ALIGNED(start, our_host_ps) ||
2670 !QEMU_IS_ALIGNED(len, our_host_ps)) {
2671 error_report("%s: Misaligned page request, start: " RAM_ADDR_FMT
2672 " len: %zd", __func__, start, len);
2673 mark_source_rp_bad(ms);
2674 return;
2677 if (ram_save_queue_pages(rbname, start, len)) {
2678 mark_source_rp_bad(ms);
2682 /* Return true to retry, false to quit */
2683 static bool postcopy_pause_return_path_thread(MigrationState *s)
2685 trace_postcopy_pause_return_path();
2687 qemu_sem_wait(&s->postcopy_pause_rp_sem);
2689 trace_postcopy_pause_return_path_continued();
2691 return true;
2694 static int migrate_handle_rp_recv_bitmap(MigrationState *s, char *block_name)
2696 RAMBlock *block = qemu_ram_block_by_name(block_name);
2698 if (!block) {
2699 error_report("%s: invalid block name '%s'", __func__, block_name);
2700 return -EINVAL;
2703 /* Fetch the received bitmap and refresh the dirty bitmap */
2704 return ram_dirty_bitmap_reload(s, block);
2707 static int migrate_handle_rp_resume_ack(MigrationState *s, uint32_t value)
2709 trace_source_return_path_thread_resume_ack(value);
2711 if (value != MIGRATION_RESUME_ACK_VALUE) {
2712 error_report("%s: illegal resume_ack value %"PRIu32,
2713 __func__, value);
2714 return -1;
2717 /* Now both sides are active. */
2718 migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_RECOVER,
2719 MIGRATION_STATUS_POSTCOPY_ACTIVE);
2721 /* Notify send thread that time to continue send pages */
2722 qemu_sem_post(&s->rp_state.rp_sem);
2724 return 0;
2727 /* Release ms->rp_state.from_dst_file in a safe way */
2728 static void migration_release_from_dst_file(MigrationState *ms)
2730 QEMUFile *file;
2732 WITH_QEMU_LOCK_GUARD(&ms->qemu_file_lock) {
2734 * Reset the from_dst_file pointer first before releasing it, as we
2735 * can't block within lock section
2737 file = ms->rp_state.from_dst_file;
2738 ms->rp_state.from_dst_file = NULL;
2741 qemu_fclose(file);
2745 * Handles messages sent on the return path towards the source VM
2748 static void *source_return_path_thread(void *opaque)
2750 MigrationState *ms = opaque;
2751 QEMUFile *rp = ms->rp_state.from_dst_file;
2752 uint16_t header_len, header_type;
2753 uint8_t buf[512];
2754 uint32_t tmp32, sibling_error;
2755 ram_addr_t start = 0; /* =0 to silence warning */
2756 size_t len = 0, expected_len;
2757 int res;
2759 trace_source_return_path_thread_entry();
2760 rcu_register_thread();
2762 retry:
2763 while (!ms->rp_state.error && !qemu_file_get_error(rp) &&
2764 migration_is_setup_or_active(ms->state)) {
2765 trace_source_return_path_thread_loop_top();
2766 header_type = qemu_get_be16(rp);
2767 header_len = qemu_get_be16(rp);
2769 if (qemu_file_get_error(rp)) {
2770 mark_source_rp_bad(ms);
2771 goto out;
2774 if (header_type >= MIG_RP_MSG_MAX ||
2775 header_type == MIG_RP_MSG_INVALID) {
2776 error_report("RP: Received invalid message 0x%04x length 0x%04x",
2777 header_type, header_len);
2778 mark_source_rp_bad(ms);
2779 goto out;
2782 if ((rp_cmd_args[header_type].len != -1 &&
2783 header_len != rp_cmd_args[header_type].len) ||
2784 header_len > sizeof(buf)) {
2785 error_report("RP: Received '%s' message (0x%04x) with"
2786 "incorrect length %d expecting %zu",
2787 rp_cmd_args[header_type].name, header_type, header_len,
2788 (size_t)rp_cmd_args[header_type].len);
2789 mark_source_rp_bad(ms);
2790 goto out;
2793 /* We know we've got a valid header by this point */
2794 res = qemu_get_buffer(rp, buf, header_len);
2795 if (res != header_len) {
2796 error_report("RP: Failed reading data for message 0x%04x"
2797 " read %d expected %d",
2798 header_type, res, header_len);
2799 mark_source_rp_bad(ms);
2800 goto out;
2803 /* OK, we have the message and the data */
2804 switch (header_type) {
2805 case MIG_RP_MSG_SHUT:
2806 sibling_error = ldl_be_p(buf);
2807 trace_source_return_path_thread_shut(sibling_error);
2808 if (sibling_error) {
2809 error_report("RP: Sibling indicated error %d", sibling_error);
2810 mark_source_rp_bad(ms);
2813 * We'll let the main thread deal with closing the RP
2814 * we could do a shutdown(2) on it, but we're the only user
2815 * anyway, so there's nothing gained.
2817 goto out;
2819 case MIG_RP_MSG_PONG:
2820 tmp32 = ldl_be_p(buf);
2821 trace_source_return_path_thread_pong(tmp32);
2822 break;
2824 case MIG_RP_MSG_REQ_PAGES:
2825 start = ldq_be_p(buf);
2826 len = ldl_be_p(buf + 8);
2827 migrate_handle_rp_req_pages(ms, NULL, start, len);
2828 break;
2830 case MIG_RP_MSG_REQ_PAGES_ID:
2831 expected_len = 12 + 1; /* header + termination */
2833 if (header_len >= expected_len) {
2834 start = ldq_be_p(buf);
2835 len = ldl_be_p(buf + 8);
2836 /* Now we expect an idstr */
2837 tmp32 = buf[12]; /* Length of the following idstr */
2838 buf[13 + tmp32] = '\0';
2839 expected_len += tmp32;
2841 if (header_len != expected_len) {
2842 error_report("RP: Req_Page_id with length %d expecting %zd",
2843 header_len, expected_len);
2844 mark_source_rp_bad(ms);
2845 goto out;
2847 migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len);
2848 break;
2850 case MIG_RP_MSG_RECV_BITMAP:
2851 if (header_len < 1) {
2852 error_report("%s: missing block name", __func__);
2853 mark_source_rp_bad(ms);
2854 goto out;
2856 /* Format: len (1B) + idstr (<255B). This ends the idstr. */
2857 buf[buf[0] + 1] = '\0';
2858 if (migrate_handle_rp_recv_bitmap(ms, (char *)(buf + 1))) {
2859 mark_source_rp_bad(ms);
2860 goto out;
2862 break;
2864 case MIG_RP_MSG_RESUME_ACK:
2865 tmp32 = ldl_be_p(buf);
2866 if (migrate_handle_rp_resume_ack(ms, tmp32)) {
2867 mark_source_rp_bad(ms);
2868 goto out;
2870 break;
2872 default:
2873 break;
2877 out:
2878 res = qemu_file_get_error(rp);
2879 if (res) {
2880 if (res && migration_in_postcopy()) {
2882 * Maybe there is something we can do: it looks like a
2883 * network down issue, and we pause for a recovery.
2885 migration_release_from_dst_file(ms);
2886 rp = NULL;
2887 if (postcopy_pause_return_path_thread(ms)) {
2889 * Reload rp, reset the rest. Referencing it is safe since
2890 * it's reset only by us above, or when migration completes
2892 rp = ms->rp_state.from_dst_file;
2893 ms->rp_state.error = false;
2894 goto retry;
2898 trace_source_return_path_thread_bad_end();
2899 mark_source_rp_bad(ms);
2902 trace_source_return_path_thread_end();
2903 migration_release_from_dst_file(ms);
2904 rcu_unregister_thread();
2905 return NULL;
2908 static int open_return_path_on_source(MigrationState *ms,
2909 bool create_thread)
2911 ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->to_dst_file);
2912 if (!ms->rp_state.from_dst_file) {
2913 return -1;
2916 trace_open_return_path_on_source();
2918 if (!create_thread) {
2919 /* We're done */
2920 return 0;
2923 qemu_thread_create(&ms->rp_state.rp_thread, "return path",
2924 source_return_path_thread, ms, QEMU_THREAD_JOINABLE);
2925 ms->rp_state.rp_thread_created = true;
2927 trace_open_return_path_on_source_continue();
2929 return 0;
2932 /* Returns 0 if the RP was ok, otherwise there was an error on the RP */
2933 static int await_return_path_close_on_source(MigrationState *ms)
2936 * If this is a normal exit then the destination will send a SHUT and the
2937 * rp_thread will exit, however if there's an error we need to cause
2938 * it to exit.
2940 if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) {
2942 * shutdown(2), if we have it, will cause it to unblock if it's stuck
2943 * waiting for the destination.
2945 qemu_file_shutdown(ms->rp_state.from_dst_file);
2946 mark_source_rp_bad(ms);
2948 trace_await_return_path_close_on_source_joining();
2949 qemu_thread_join(&ms->rp_state.rp_thread);
2950 ms->rp_state.rp_thread_created = false;
2951 trace_await_return_path_close_on_source_close();
2952 return ms->rp_state.error;
2956 * Switch from normal iteration to postcopy
2957 * Returns non-0 on error
2959 static int postcopy_start(MigrationState *ms)
2961 int ret;
2962 QIOChannelBuffer *bioc;
2963 QEMUFile *fb;
2964 int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
2965 int64_t bandwidth = migrate_max_postcopy_bandwidth();
2966 bool restart_block = false;
2967 int cur_state = MIGRATION_STATUS_ACTIVE;
2968 if (!migrate_pause_before_switchover()) {
2969 migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE,
2970 MIGRATION_STATUS_POSTCOPY_ACTIVE);
2973 trace_postcopy_start();
2974 qemu_mutex_lock_iothread();
2975 trace_postcopy_start_set_run();
2977 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
2978 global_state_store();
2979 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
2980 if (ret < 0) {
2981 goto fail;
2984 ret = migration_maybe_pause(ms, &cur_state,
2985 MIGRATION_STATUS_POSTCOPY_ACTIVE);
2986 if (ret < 0) {
2987 goto fail;
2990 ret = bdrv_inactivate_all();
2991 if (ret < 0) {
2992 goto fail;
2994 restart_block = true;
2997 * Cause any non-postcopiable, but iterative devices to
2998 * send out their final data.
3000 qemu_savevm_state_complete_precopy(ms->to_dst_file, true, false);
3003 * in Finish migrate and with the io-lock held everything should
3004 * be quiet, but we've potentially still got dirty pages and we
3005 * need to tell the destination to throw any pages it's already received
3006 * that are dirty
3008 if (migrate_postcopy_ram()) {
3009 ram_postcopy_send_discard_bitmap(ms);
3013 * send rest of state - note things that are doing postcopy
3014 * will notice we're in POSTCOPY_ACTIVE and not actually
3015 * wrap their state up here
3017 /* 0 max-postcopy-bandwidth means unlimited */
3018 if (!bandwidth) {
3019 qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX);
3020 } else {
3021 qemu_file_set_rate_limit(ms->to_dst_file, bandwidth / XFER_LIMIT_RATIO);
3023 if (migrate_postcopy_ram()) {
3024 /* Ping just for debugging, helps line traces up */
3025 qemu_savevm_send_ping(ms->to_dst_file, 2);
3029 * While loading the device state we may trigger page transfer
3030 * requests and the fd must be free to process those, and thus
3031 * the destination must read the whole device state off the fd before
3032 * it starts processing it. Unfortunately the ad-hoc migration format
3033 * doesn't allow the destination to know the size to read without fully
3034 * parsing it through each devices load-state code (especially the open
3035 * coded devices that use get/put).
3036 * So we wrap the device state up in a package with a length at the start;
3037 * to do this we use a qemu_buf to hold the whole of the device state.
3039 bioc = qio_channel_buffer_new(4096);
3040 qio_channel_set_name(QIO_CHANNEL(bioc), "migration-postcopy-buffer");
3041 fb = qemu_fopen_channel_output(QIO_CHANNEL(bioc));
3042 object_unref(OBJECT(bioc));
3045 * Make sure the receiver can get incoming pages before we send the rest
3046 * of the state
3048 qemu_savevm_send_postcopy_listen(fb);
3050 qemu_savevm_state_complete_precopy(fb, false, false);
3051 if (migrate_postcopy_ram()) {
3052 qemu_savevm_send_ping(fb, 3);
3055 qemu_savevm_send_postcopy_run(fb);
3057 /* <><> end of stuff going into the package */
3059 /* Last point of recovery; as soon as we send the package the destination
3060 * can open devices and potentially start running.
3061 * Lets just check again we've not got any errors.
3063 ret = qemu_file_get_error(ms->to_dst_file);
3064 if (ret) {
3065 error_report("postcopy_start: Migration stream errored (pre package)");
3066 goto fail_closefb;
3069 restart_block = false;
3071 /* Now send that blob */
3072 if (qemu_savevm_send_packaged(ms->to_dst_file, bioc->data, bioc->usage)) {
3073 goto fail_closefb;
3075 qemu_fclose(fb);
3077 /* Send a notify to give a chance for anything that needs to happen
3078 * at the transition to postcopy and after the device state; in particular
3079 * spice needs to trigger a transition now
3081 ms->postcopy_after_devices = true;
3082 notifier_list_notify(&migration_state_notifiers, ms);
3084 ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop;
3086 qemu_mutex_unlock_iothread();
3088 if (migrate_postcopy_ram()) {
3090 * Although this ping is just for debug, it could potentially be
3091 * used for getting a better measurement of downtime at the source.
3093 qemu_savevm_send_ping(ms->to_dst_file, 4);
3096 if (migrate_release_ram()) {
3097 ram_postcopy_migrated_memory_release(ms);
3100 ret = qemu_file_get_error(ms->to_dst_file);
3101 if (ret) {
3102 error_report("postcopy_start: Migration stream errored");
3103 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
3104 MIGRATION_STATUS_FAILED);
3107 return ret;
3109 fail_closefb:
3110 qemu_fclose(fb);
3111 fail:
3112 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
3113 MIGRATION_STATUS_FAILED);
3114 if (restart_block) {
3115 /* A failure happened early enough that we know the destination hasn't
3116 * accessed block devices, so we're safe to recover.
3118 Error *local_err = NULL;
3120 bdrv_activate_all(&local_err);
3121 if (local_err) {
3122 error_report_err(local_err);
3125 qemu_mutex_unlock_iothread();
3126 return -1;
3130 * migration_maybe_pause: Pause if required to by
3131 * migrate_pause_before_switchover called with the iothread locked
3132 * Returns: 0 on success
3134 static int migration_maybe_pause(MigrationState *s,
3135 int *current_active_state,
3136 int new_state)
3138 if (!migrate_pause_before_switchover()) {
3139 return 0;
3142 /* Since leaving this state is not atomic with posting the semaphore
3143 * it's possible that someone could have issued multiple migrate_continue
3144 * and the semaphore is incorrectly positive at this point;
3145 * the docs say it's undefined to reinit a semaphore that's already
3146 * init'd, so use timedwait to eat up any existing posts.
3148 while (qemu_sem_timedwait(&s->pause_sem, 1) == 0) {
3149 /* This block intentionally left blank */
3153 * If the migration is cancelled when it is in the completion phase,
3154 * the migration state is set to MIGRATION_STATUS_CANCELLING.
3155 * So we don't need to wait a semaphore, otherwise we would always
3156 * wait for the 'pause_sem' semaphore.
3158 if (s->state != MIGRATION_STATUS_CANCELLING) {
3159 qemu_mutex_unlock_iothread();
3160 migrate_set_state(&s->state, *current_active_state,
3161 MIGRATION_STATUS_PRE_SWITCHOVER);
3162 qemu_sem_wait(&s->pause_sem);
3163 migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER,
3164 new_state);
3165 *current_active_state = new_state;
3166 qemu_mutex_lock_iothread();
3169 return s->state == new_state ? 0 : -EINVAL;
3173 * migration_completion: Used by migration_thread when there's not much left.
3174 * The caller 'breaks' the loop when this returns.
3176 * @s: Current migration state
3178 static void migration_completion(MigrationState *s)
3180 int ret;
3181 int current_active_state = s->state;
3183 if (s->state == MIGRATION_STATUS_ACTIVE) {
3184 qemu_mutex_lock_iothread();
3185 s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3186 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
3187 s->vm_was_running = runstate_is_running();
3188 ret = global_state_store();
3190 if (!ret) {
3191 bool inactivate = !migrate_colo_enabled();
3192 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
3193 trace_migration_completion_vm_stop(ret);
3194 if (ret >= 0) {
3195 ret = migration_maybe_pause(s, &current_active_state,
3196 MIGRATION_STATUS_DEVICE);
3198 if (ret >= 0) {
3199 qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
3200 ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false,
3201 inactivate);
3203 if (inactivate && ret >= 0) {
3204 s->block_inactive = true;
3207 qemu_mutex_unlock_iothread();
3209 if (ret < 0) {
3210 goto fail;
3212 } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
3213 trace_migration_completion_postcopy_end();
3215 qemu_mutex_lock_iothread();
3216 qemu_savevm_state_complete_postcopy(s->to_dst_file);
3217 qemu_mutex_unlock_iothread();
3219 trace_migration_completion_postcopy_end_after_complete();
3220 } else {
3221 goto fail;
3225 * If rp was opened we must clean up the thread before
3226 * cleaning everything else up (since if there are no failures
3227 * it will wait for the destination to send it's status in
3228 * a SHUT command).
3230 if (s->rp_state.rp_thread_created) {
3231 int rp_error;
3232 trace_migration_return_path_end_before();
3233 rp_error = await_return_path_close_on_source(s);
3234 trace_migration_return_path_end_after(rp_error);
3235 if (rp_error) {
3236 goto fail_invalidate;
3240 if (qemu_file_get_error(s->to_dst_file)) {
3241 trace_migration_completion_file_err();
3242 goto fail_invalidate;
3245 if (migrate_colo_enabled() && s->state == MIGRATION_STATUS_ACTIVE) {
3246 /* COLO does not support postcopy */
3247 migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
3248 MIGRATION_STATUS_COLO);
3249 } else {
3250 migrate_set_state(&s->state, current_active_state,
3251 MIGRATION_STATUS_COMPLETED);
3254 return;
3256 fail_invalidate:
3257 /* If not doing postcopy, vm_start() will be called: let's regain
3258 * control on images.
3260 if (s->state == MIGRATION_STATUS_ACTIVE ||
3261 s->state == MIGRATION_STATUS_DEVICE) {
3262 Error *local_err = NULL;
3264 qemu_mutex_lock_iothread();
3265 bdrv_activate_all(&local_err);
3266 if (local_err) {
3267 error_report_err(local_err);
3268 } else {
3269 s->block_inactive = false;
3271 qemu_mutex_unlock_iothread();
3274 fail:
3275 migrate_set_state(&s->state, current_active_state,
3276 MIGRATION_STATUS_FAILED);
3280 * bg_migration_completion: Used by bg_migration_thread when after all the
3281 * RAM has been saved. The caller 'breaks' the loop when this returns.
3283 * @s: Current migration state
3285 static void bg_migration_completion(MigrationState *s)
3287 int current_active_state = s->state;
3290 * Stop tracking RAM writes - un-protect memory, un-register UFFD
3291 * memory ranges, flush kernel wait queues and wake up threads
3292 * waiting for write fault to be resolved.
3294 ram_write_tracking_stop();
3296 if (s->state == MIGRATION_STATUS_ACTIVE) {
3298 * By this moment we have RAM content saved into the migration stream.
3299 * The next step is to flush the non-RAM content (device state)
3300 * right after the ram content. The device state has been stored into
3301 * the temporary buffer before RAM saving started.
3303 qemu_put_buffer(s->to_dst_file, s->bioc->data, s->bioc->usage);
3304 qemu_fflush(s->to_dst_file);
3305 } else if (s->state == MIGRATION_STATUS_CANCELLING) {
3306 goto fail;
3309 if (qemu_file_get_error(s->to_dst_file)) {
3310 trace_migration_completion_file_err();
3311 goto fail;
3314 migrate_set_state(&s->state, current_active_state,
3315 MIGRATION_STATUS_COMPLETED);
3316 return;
3318 fail:
3319 migrate_set_state(&s->state, current_active_state,
3320 MIGRATION_STATUS_FAILED);
3323 bool migrate_colo_enabled(void)
3325 MigrationState *s = migrate_get_current();
3326 return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO];
3329 typedef enum MigThrError {
3330 /* No error detected */
3331 MIG_THR_ERR_NONE = 0,
3332 /* Detected error, but resumed successfully */
3333 MIG_THR_ERR_RECOVERED = 1,
3334 /* Detected fatal error, need to exit */
3335 MIG_THR_ERR_FATAL = 2,
3336 } MigThrError;
3338 static int postcopy_resume_handshake(MigrationState *s)
3340 qemu_savevm_send_postcopy_resume(s->to_dst_file);
3342 while (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
3343 qemu_sem_wait(&s->rp_state.rp_sem);
3346 if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
3347 return 0;
3350 return -1;
3353 /* Return zero if success, or <0 for error */
3354 static int postcopy_do_resume(MigrationState *s)
3356 int ret;
3359 * Call all the resume_prepare() hooks, so that modules can be
3360 * ready for the migration resume.
3362 ret = qemu_savevm_state_resume_prepare(s);
3363 if (ret) {
3364 error_report("%s: resume_prepare() failure detected: %d",
3365 __func__, ret);
3366 return ret;
3370 * Last handshake with destination on the resume (destination will
3371 * switch to postcopy-active afterwards)
3373 ret = postcopy_resume_handshake(s);
3374 if (ret) {
3375 error_report("%s: handshake failed: %d", __func__, ret);
3376 return ret;
3379 return 0;
3383 * We don't return until we are in a safe state to continue current
3384 * postcopy migration. Returns MIG_THR_ERR_RECOVERED if recovered, or
3385 * MIG_THR_ERR_FATAL if unrecovery failure happened.
3387 static MigThrError postcopy_pause(MigrationState *s)
3389 assert(s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
3391 while (true) {
3392 QEMUFile *file;
3395 * Current channel is possibly broken. Release it. Note that this is
3396 * guaranteed even without lock because to_dst_file should only be
3397 * modified by the migration thread. That also guarantees that the
3398 * unregister of yank is safe too without the lock. It should be safe
3399 * even to be within the qemu_file_lock, but we didn't do that to avoid
3400 * taking more mutex (yank_lock) within qemu_file_lock. TL;DR: we make
3401 * the qemu_file_lock critical section as small as possible.
3403 assert(s->to_dst_file);
3404 migration_ioc_unregister_yank_from_file(s->to_dst_file);
3405 qemu_mutex_lock(&s->qemu_file_lock);
3406 file = s->to_dst_file;
3407 s->to_dst_file = NULL;
3408 qemu_mutex_unlock(&s->qemu_file_lock);
3410 qemu_file_shutdown(file);
3411 qemu_fclose(file);
3413 migrate_set_state(&s->state, s->state,
3414 MIGRATION_STATUS_POSTCOPY_PAUSED);
3416 error_report("Detected IO failure for postcopy. "
3417 "Migration paused.");
3420 * We wait until things fixed up. Then someone will setup the
3421 * status back for us.
3423 while (s->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
3424 qemu_sem_wait(&s->postcopy_pause_sem);
3427 if (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
3428 /* Woken up by a recover procedure. Give it a shot */
3431 * Firstly, let's wake up the return path now, with a new
3432 * return path channel.
3434 qemu_sem_post(&s->postcopy_pause_rp_sem);
3436 /* Do the resume logic */
3437 if (postcopy_do_resume(s) == 0) {
3438 /* Let's continue! */
3439 trace_postcopy_pause_continued();
3440 return MIG_THR_ERR_RECOVERED;
3441 } else {
3443 * Something wrong happened during the recovery, let's
3444 * pause again. Pause is always better than throwing
3445 * data away.
3447 continue;
3449 } else {
3450 /* This is not right... Time to quit. */
3451 return MIG_THR_ERR_FATAL;
3456 static MigThrError migration_detect_error(MigrationState *s)
3458 int ret;
3459 int state = s->state;
3460 Error *local_error = NULL;
3462 if (state == MIGRATION_STATUS_CANCELLING ||
3463 state == MIGRATION_STATUS_CANCELLED) {
3464 /* End the migration, but don't set the state to failed */
3465 return MIG_THR_ERR_FATAL;
3468 /* Try to detect any file errors */
3469 ret = qemu_file_get_error_obj(s->to_dst_file, &local_error);
3470 if (!ret) {
3471 /* Everything is fine */
3472 assert(!local_error);
3473 return MIG_THR_ERR_NONE;
3476 if (local_error) {
3477 migrate_set_error(s, local_error);
3478 error_free(local_error);
3481 if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret) {
3483 * For postcopy, we allow the network to be down for a
3484 * while. After that, it can be continued by a
3485 * recovery phase.
3487 return postcopy_pause(s);
3488 } else {
3490 * For precopy (or postcopy with error outside IO), we fail
3491 * with no time.
3493 migrate_set_state(&s->state, state, MIGRATION_STATUS_FAILED);
3494 trace_migration_thread_file_err();
3496 /* Time to stop the migration, now. */
3497 return MIG_THR_ERR_FATAL;
3501 /* How many bytes have we transferred since the beginning of the migration */
3502 static uint64_t migration_total_bytes(MigrationState *s)
3504 return qemu_ftell(s->to_dst_file) + ram_counters.multifd_bytes;
3507 static void migration_calculate_complete(MigrationState *s)
3509 uint64_t bytes = migration_total_bytes(s);
3510 int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3511 int64_t transfer_time;
3513 s->total_time = end_time - s->start_time;
3514 if (!s->downtime) {
3516 * It's still not set, so we are precopy migration. For
3517 * postcopy, downtime is calculated during postcopy_start().
3519 s->downtime = end_time - s->downtime_start;
3522 transfer_time = s->total_time - s->setup_time;
3523 if (transfer_time) {
3524 s->mbps = ((double) bytes * 8.0) / transfer_time / 1000;
3528 static void update_iteration_initial_status(MigrationState *s)
3531 * Update these three fields at the same time to avoid mismatch info lead
3532 * wrong speed calculation.
3534 s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3535 s->iteration_initial_bytes = migration_total_bytes(s);
3536 s->iteration_initial_pages = ram_get_total_transferred_pages();
3539 static void migration_update_counters(MigrationState *s,
3540 int64_t current_time)
3542 uint64_t transferred, transferred_pages, time_spent;
3543 uint64_t current_bytes; /* bytes transferred since the beginning */
3544 double bandwidth;
3546 if (current_time < s->iteration_start_time + BUFFER_DELAY) {
3547 return;
3550 current_bytes = migration_total_bytes(s);
3551 transferred = current_bytes - s->iteration_initial_bytes;
3552 time_spent = current_time - s->iteration_start_time;
3553 bandwidth = (double)transferred / time_spent;
3554 s->threshold_size = bandwidth * s->parameters.downtime_limit;
3556 s->mbps = (((double) transferred * 8.0) /
3557 ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
3559 transferred_pages = ram_get_total_transferred_pages() -
3560 s->iteration_initial_pages;
3561 s->pages_per_second = (double) transferred_pages /
3562 (((double) time_spent / 1000.0));
3565 * if we haven't sent anything, we don't want to
3566 * recalculate. 10000 is a small enough number for our purposes
3568 if (ram_counters.dirty_pages_rate && transferred > 10000) {
3569 s->expected_downtime = ram_counters.remaining / bandwidth;
3572 qemu_file_reset_rate_limit(s->to_dst_file);
3574 update_iteration_initial_status(s);
3576 trace_migrate_transferred(transferred, time_spent,
3577 bandwidth, s->threshold_size);
3580 /* Migration thread iteration status */
3581 typedef enum {
3582 MIG_ITERATE_RESUME, /* Resume current iteration */
3583 MIG_ITERATE_SKIP, /* Skip current iteration */
3584 MIG_ITERATE_BREAK, /* Break the loop */
3585 } MigIterateState;
3588 * Return true if continue to the next iteration directly, false
3589 * otherwise.
3591 static MigIterateState migration_iteration_run(MigrationState *s)
3593 uint64_t pending_size, pend_pre, pend_compat, pend_post;
3594 bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE;
3596 qemu_savevm_state_pending(s->to_dst_file, s->threshold_size, &pend_pre,
3597 &pend_compat, &pend_post);
3598 pending_size = pend_pre + pend_compat + pend_post;
3600 trace_migrate_pending(pending_size, s->threshold_size,
3601 pend_pre, pend_compat, pend_post);
3603 if (pending_size && pending_size >= s->threshold_size) {
3604 /* Still a significant amount to transfer */
3605 if (!in_postcopy && pend_pre <= s->threshold_size &&
3606 qatomic_read(&s->start_postcopy)) {
3607 if (postcopy_start(s)) {
3608 error_report("%s: postcopy failed to start", __func__);
3610 return MIG_ITERATE_SKIP;
3612 /* Just another iteration step */
3613 qemu_savevm_state_iterate(s->to_dst_file, in_postcopy);
3614 } else {
3615 trace_migration_thread_low_pending(pending_size);
3616 migration_completion(s);
3617 return MIG_ITERATE_BREAK;
3620 return MIG_ITERATE_RESUME;
3623 static void migration_iteration_finish(MigrationState *s)
3625 /* If we enabled cpu throttling for auto-converge, turn it off. */
3626 cpu_throttle_stop();
3628 qemu_mutex_lock_iothread();
3629 switch (s->state) {
3630 case MIGRATION_STATUS_COMPLETED:
3631 migration_calculate_complete(s);
3632 runstate_set(RUN_STATE_POSTMIGRATE);
3633 break;
3634 case MIGRATION_STATUS_COLO:
3635 if (!migrate_colo_enabled()) {
3636 error_report("%s: critical error: calling COLO code without "
3637 "COLO enabled", __func__);
3639 migrate_start_colo_process(s);
3640 s->vm_was_running = true;
3641 /* Fallthrough */
3642 case MIGRATION_STATUS_FAILED:
3643 case MIGRATION_STATUS_CANCELLED:
3644 case MIGRATION_STATUS_CANCELLING:
3645 if (s->vm_was_running) {
3646 if (!runstate_check(RUN_STATE_SHUTDOWN)) {
3647 vm_start();
3649 } else {
3650 if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
3651 runstate_set(RUN_STATE_POSTMIGRATE);
3654 break;
3656 default:
3657 /* Should not reach here, but if so, forgive the VM. */
3658 error_report("%s: Unknown ending state %d", __func__, s->state);
3659 break;
3661 migrate_fd_cleanup_schedule(s);
3662 qemu_mutex_unlock_iothread();
3665 static void bg_migration_iteration_finish(MigrationState *s)
3667 qemu_mutex_lock_iothread();
3668 switch (s->state) {
3669 case MIGRATION_STATUS_COMPLETED:
3670 migration_calculate_complete(s);
3671 break;
3673 case MIGRATION_STATUS_ACTIVE:
3674 case MIGRATION_STATUS_FAILED:
3675 case MIGRATION_STATUS_CANCELLED:
3676 case MIGRATION_STATUS_CANCELLING:
3677 break;
3679 default:
3680 /* Should not reach here, but if so, forgive the VM. */
3681 error_report("%s: Unknown ending state %d", __func__, s->state);
3682 break;
3685 migrate_fd_cleanup_schedule(s);
3686 qemu_mutex_unlock_iothread();
3690 * Return true if continue to the next iteration directly, false
3691 * otherwise.
3693 static MigIterateState bg_migration_iteration_run(MigrationState *s)
3695 int res;
3697 res = qemu_savevm_state_iterate(s->to_dst_file, false);
3698 if (res > 0) {
3699 bg_migration_completion(s);
3700 return MIG_ITERATE_BREAK;
3703 return MIG_ITERATE_RESUME;
3706 void migration_make_urgent_request(void)
3708 qemu_sem_post(&migrate_get_current()->rate_limit_sem);
3711 void migration_consume_urgent_request(void)
3713 qemu_sem_wait(&migrate_get_current()->rate_limit_sem);
3716 /* Returns true if the rate limiting was broken by an urgent request */
3717 bool migration_rate_limit(void)
3719 int64_t now = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3720 MigrationState *s = migrate_get_current();
3722 bool urgent = false;
3723 migration_update_counters(s, now);
3724 if (qemu_file_rate_limit(s->to_dst_file)) {
3726 if (qemu_file_get_error(s->to_dst_file)) {
3727 return false;
3730 * Wait for a delay to do rate limiting OR
3731 * something urgent to post the semaphore.
3733 int ms = s->iteration_start_time + BUFFER_DELAY - now;
3734 trace_migration_rate_limit_pre(ms);
3735 if (qemu_sem_timedwait(&s->rate_limit_sem, ms) == 0) {
3737 * We were woken by one or more urgent things but
3738 * the timedwait will have consumed one of them.
3739 * The service routine for the urgent wake will dec
3740 * the semaphore itself for each item it consumes,
3741 * so add this one we just eat back.
3743 qemu_sem_post(&s->rate_limit_sem);
3744 urgent = true;
3746 trace_migration_rate_limit_post(urgent);
3748 return urgent;
3752 * if failover devices are present, wait they are completely
3753 * unplugged
3756 static void qemu_savevm_wait_unplug(MigrationState *s, int old_state,
3757 int new_state)
3759 if (qemu_savevm_state_guest_unplug_pending()) {
3760 migrate_set_state(&s->state, old_state, MIGRATION_STATUS_WAIT_UNPLUG);
3762 while (s->state == MIGRATION_STATUS_WAIT_UNPLUG &&
3763 qemu_savevm_state_guest_unplug_pending()) {
3764 qemu_sem_timedwait(&s->wait_unplug_sem, 250);
3766 if (s->state != MIGRATION_STATUS_WAIT_UNPLUG) {
3767 int timeout = 120; /* 30 seconds */
3769 * migration has been canceled
3770 * but as we have started an unplug we must wait the end
3771 * to be able to plug back the card
3773 while (timeout-- && qemu_savevm_state_guest_unplug_pending()) {
3774 qemu_sem_timedwait(&s->wait_unplug_sem, 250);
3776 if (qemu_savevm_state_guest_unplug_pending() &&
3777 !qtest_enabled()) {
3778 warn_report("migration: partially unplugged device on "
3779 "failure");
3783 migrate_set_state(&s->state, MIGRATION_STATUS_WAIT_UNPLUG, new_state);
3784 } else {
3785 migrate_set_state(&s->state, old_state, new_state);
3790 * Master migration thread on the source VM.
3791 * It drives the migration and pumps the data down the outgoing channel.
3793 static void *migration_thread(void *opaque)
3795 MigrationState *s = opaque;
3796 int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
3797 MigThrError thr_error;
3798 bool urgent = false;
3800 rcu_register_thread();
3802 object_ref(OBJECT(s));
3803 update_iteration_initial_status(s);
3805 qemu_savevm_state_header(s->to_dst_file);
3808 * If we opened the return path, we need to make sure dst has it
3809 * opened as well.
3811 if (s->rp_state.rp_thread_created) {
3812 /* Now tell the dest that it should open its end so it can reply */
3813 qemu_savevm_send_open_return_path(s->to_dst_file);
3815 /* And do a ping that will make stuff easier to debug */
3816 qemu_savevm_send_ping(s->to_dst_file, 1);
3819 if (migrate_postcopy()) {
3821 * Tell the destination that we *might* want to do postcopy later;
3822 * if the other end can't do postcopy it should fail now, nice and
3823 * early.
3825 qemu_savevm_send_postcopy_advise(s->to_dst_file);
3828 if (migrate_colo_enabled()) {
3829 /* Notify migration destination that we enable COLO */
3830 qemu_savevm_send_colo_enable(s->to_dst_file);
3833 qemu_savevm_state_setup(s->to_dst_file);
3835 qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
3836 MIGRATION_STATUS_ACTIVE);
3838 s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
3840 trace_migration_thread_setup_complete();
3842 while (migration_is_active(s)) {
3843 if (urgent || !qemu_file_rate_limit(s->to_dst_file)) {
3844 MigIterateState iter_state = migration_iteration_run(s);
3845 if (iter_state == MIG_ITERATE_SKIP) {
3846 continue;
3847 } else if (iter_state == MIG_ITERATE_BREAK) {
3848 break;
3853 * Try to detect any kind of failures, and see whether we
3854 * should stop the migration now.
3856 thr_error = migration_detect_error(s);
3857 if (thr_error == MIG_THR_ERR_FATAL) {
3858 /* Stop migration */
3859 break;
3860 } else if (thr_error == MIG_THR_ERR_RECOVERED) {
3862 * Just recovered from a e.g. network failure, reset all
3863 * the local variables. This is important to avoid
3864 * breaking transferred_bytes and bandwidth calculation
3866 update_iteration_initial_status(s);
3869 urgent = migration_rate_limit();
3872 trace_migration_thread_after_loop();
3873 migration_iteration_finish(s);
3874 object_unref(OBJECT(s));
3875 rcu_unregister_thread();
3876 return NULL;
3879 static void bg_migration_vm_start_bh(void *opaque)
3881 MigrationState *s = opaque;
3883 qemu_bh_delete(s->vm_start_bh);
3884 s->vm_start_bh = NULL;
3886 vm_start();
3887 s->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->downtime_start;
3891 * Background snapshot thread, based on live migration code.
3892 * This is an alternative implementation of live migration mechanism
3893 * introduced specifically to support background snapshots.
3895 * It takes advantage of userfault_fd write protection mechanism introduced
3896 * in v5.7 kernel. Compared to existing dirty page logging migration much
3897 * lesser stream traffic is produced resulting in smaller snapshot images,
3898 * simply cause of no page duplicates can get into the stream.
3900 * Another key point is that generated vmstate stream reflects machine state
3901 * 'frozen' at the beginning of snapshot creation compared to dirty page logging
3902 * mechanism, which effectively results in that saved snapshot is the state of VM
3903 * at the end of the process.
3905 static void *bg_migration_thread(void *opaque)
3907 MigrationState *s = opaque;
3908 int64_t setup_start;
3909 MigThrError thr_error;
3910 QEMUFile *fb;
3911 bool early_fail = true;
3913 rcu_register_thread();
3914 object_ref(OBJECT(s));
3916 qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
3918 setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
3920 * We want to save vmstate for the moment when migration has been
3921 * initiated but also we want to save RAM content while VM is running.
3922 * The RAM content should appear first in the vmstate. So, we first
3923 * stash the non-RAM part of the vmstate to the temporary buffer,
3924 * then write RAM part of the vmstate to the migration stream
3925 * with vCPUs running and, finally, write stashed non-RAM part of
3926 * the vmstate from the buffer to the migration stream.
3928 s->bioc = qio_channel_buffer_new(512 * 1024);
3929 qio_channel_set_name(QIO_CHANNEL(s->bioc), "vmstate-buffer");
3930 fb = qemu_fopen_channel_output(QIO_CHANNEL(s->bioc));
3931 object_unref(OBJECT(s->bioc));
3933 update_iteration_initial_status(s);
3936 * Prepare for tracking memory writes with UFFD-WP - populate
3937 * RAM pages before protecting.
3939 #ifdef __linux__
3940 ram_write_tracking_prepare();
3941 #endif
3943 qemu_savevm_state_header(s->to_dst_file);
3944 qemu_savevm_state_setup(s->to_dst_file);
3946 qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
3947 MIGRATION_STATUS_ACTIVE);
3949 s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
3951 trace_migration_thread_setup_complete();
3952 s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3954 qemu_mutex_lock_iothread();
3957 * If VM is currently in suspended state, then, to make a valid runstate
3958 * transition in vm_stop_force_state() we need to wakeup it up.
3960 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
3961 s->vm_was_running = runstate_is_running();
3963 if (global_state_store()) {
3964 goto fail;
3966 /* Forcibly stop VM before saving state of vCPUs and devices */
3967 if (vm_stop_force_state(RUN_STATE_PAUSED)) {
3968 goto fail;
3971 * Put vCPUs in sync with shadow context structures, then
3972 * save their state to channel-buffer along with devices.
3974 cpu_synchronize_all_states();
3975 if (qemu_savevm_state_complete_precopy_non_iterable(fb, false, false)) {
3976 goto fail;
3979 * Since we are going to get non-iterable state data directly
3980 * from s->bioc->data, explicit flush is needed here.
3982 qemu_fflush(fb);
3984 /* Now initialize UFFD context and start tracking RAM writes */
3985 if (ram_write_tracking_start()) {
3986 goto fail;
3988 early_fail = false;
3991 * Start VM from BH handler to avoid write-fault lock here.
3992 * UFFD-WP protection for the whole RAM is already enabled so
3993 * calling VM state change notifiers from vm_start() would initiate
3994 * writes to virtio VQs memory which is in write-protected region.
3996 s->vm_start_bh = qemu_bh_new(bg_migration_vm_start_bh, s);
3997 qemu_bh_schedule(s->vm_start_bh);
3999 qemu_mutex_unlock_iothread();
4001 while (migration_is_active(s)) {
4002 MigIterateState iter_state = bg_migration_iteration_run(s);
4003 if (iter_state == MIG_ITERATE_SKIP) {
4004 continue;
4005 } else if (iter_state == MIG_ITERATE_BREAK) {
4006 break;
4010 * Try to detect any kind of failures, and see whether we
4011 * should stop the migration now.
4013 thr_error = migration_detect_error(s);
4014 if (thr_error == MIG_THR_ERR_FATAL) {
4015 /* Stop migration */
4016 break;
4019 migration_update_counters(s, qemu_clock_get_ms(QEMU_CLOCK_REALTIME));
4022 trace_migration_thread_after_loop();
4024 fail:
4025 if (early_fail) {
4026 migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
4027 MIGRATION_STATUS_FAILED);
4028 qemu_mutex_unlock_iothread();
4031 bg_migration_iteration_finish(s);
4033 qemu_fclose(fb);
4034 object_unref(OBJECT(s));
4035 rcu_unregister_thread();
4037 return NULL;
4040 void migrate_fd_connect(MigrationState *s, Error *error_in)
4042 Error *local_err = NULL;
4043 int64_t rate_limit;
4044 bool resume = s->state == MIGRATION_STATUS_POSTCOPY_PAUSED;
4047 * If there's a previous error, free it and prepare for another one.
4048 * Meanwhile if migration completes successfully, there won't have an error
4049 * dumped when calling migrate_fd_cleanup().
4051 migrate_error_free(s);
4053 s->expected_downtime = s->parameters.downtime_limit;
4054 if (resume) {
4055 assert(s->cleanup_bh);
4056 } else {
4057 assert(!s->cleanup_bh);
4058 s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup_bh, s);
4060 if (error_in) {
4061 migrate_fd_error(s, error_in);
4062 if (resume) {
4064 * Don't do cleanup for resume if channel is invalid, but only dump
4065 * the error. We wait for another channel connect from the user.
4066 * The error_report still gives HMP user a hint on what failed.
4067 * It's normally done in migrate_fd_cleanup(), but call it here
4068 * explicitly.
4070 error_report_err(error_copy(s->error));
4071 } else {
4072 migrate_fd_cleanup(s);
4074 return;
4077 if (resume) {
4078 /* This is a resumed migration */
4079 rate_limit = s->parameters.max_postcopy_bandwidth /
4080 XFER_LIMIT_RATIO;
4081 } else {
4082 /* This is a fresh new migration */
4083 rate_limit = s->parameters.max_bandwidth / XFER_LIMIT_RATIO;
4085 /* Notify before starting migration thread */
4086 notifier_list_notify(&migration_state_notifiers, s);
4089 qemu_file_set_rate_limit(s->to_dst_file, rate_limit);
4090 qemu_file_set_blocking(s->to_dst_file, true);
4093 * Open the return path. For postcopy, it is used exclusively. For
4094 * precopy, only if user specified "return-path" capability would
4095 * QEMU uses the return path.
4097 if (migrate_postcopy_ram() || migrate_use_return_path()) {
4098 if (open_return_path_on_source(s, !resume)) {
4099 error_report("Unable to open return-path for postcopy");
4100 migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
4101 migrate_fd_cleanup(s);
4102 return;
4106 if (resume) {
4107 /* Wakeup the main migration thread to do the recovery */
4108 migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_PAUSED,
4109 MIGRATION_STATUS_POSTCOPY_RECOVER);
4110 qemu_sem_post(&s->postcopy_pause_sem);
4111 return;
4114 if (multifd_save_setup(&local_err) != 0) {
4115 error_report_err(local_err);
4116 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
4117 MIGRATION_STATUS_FAILED);
4118 migrate_fd_cleanup(s);
4119 return;
4122 if (migrate_background_snapshot()) {
4123 qemu_thread_create(&s->thread, "bg_snapshot",
4124 bg_migration_thread, s, QEMU_THREAD_JOINABLE);
4125 } else {
4126 qemu_thread_create(&s->thread, "live_migration",
4127 migration_thread, s, QEMU_THREAD_JOINABLE);
4129 s->migration_thread_running = true;
4132 void migration_global_dump(Monitor *mon)
4134 MigrationState *ms = migrate_get_current();
4136 monitor_printf(mon, "globals:\n");
4137 monitor_printf(mon, "store-global-state: %s\n",
4138 ms->store_global_state ? "on" : "off");
4139 monitor_printf(mon, "only-migratable: %s\n",
4140 only_migratable ? "on" : "off");
4141 monitor_printf(mon, "send-configuration: %s\n",
4142 ms->send_configuration ? "on" : "off");
4143 monitor_printf(mon, "send-section-footer: %s\n",
4144 ms->send_section_footer ? "on" : "off");
4145 monitor_printf(mon, "decompress-error-check: %s\n",
4146 ms->decompress_error_check ? "on" : "off");
4147 monitor_printf(mon, "clear-bitmap-shift: %u\n",
4148 ms->clear_bitmap_shift);
4151 #define DEFINE_PROP_MIG_CAP(name, x) \
4152 DEFINE_PROP_BOOL(name, MigrationState, enabled_capabilities[x], false)
4154 static Property migration_properties[] = {
4155 DEFINE_PROP_BOOL("store-global-state", MigrationState,
4156 store_global_state, true),
4157 DEFINE_PROP_BOOL("send-configuration", MigrationState,
4158 send_configuration, true),
4159 DEFINE_PROP_BOOL("send-section-footer", MigrationState,
4160 send_section_footer, true),
4161 DEFINE_PROP_BOOL("decompress-error-check", MigrationState,
4162 decompress_error_check, true),
4163 DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState,
4164 clear_bitmap_shift, CLEAR_BITMAP_SHIFT_DEFAULT),
4166 /* Migration parameters */
4167 DEFINE_PROP_UINT8("x-compress-level", MigrationState,
4168 parameters.compress_level,
4169 DEFAULT_MIGRATE_COMPRESS_LEVEL),
4170 DEFINE_PROP_UINT8("x-compress-threads", MigrationState,
4171 parameters.compress_threads,
4172 DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT),
4173 DEFINE_PROP_BOOL("x-compress-wait-thread", MigrationState,
4174 parameters.compress_wait_thread, true),
4175 DEFINE_PROP_UINT8("x-decompress-threads", MigrationState,
4176 parameters.decompress_threads,
4177 DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT),
4178 DEFINE_PROP_UINT8("x-throttle-trigger-threshold", MigrationState,
4179 parameters.throttle_trigger_threshold,
4180 DEFAULT_MIGRATE_THROTTLE_TRIGGER_THRESHOLD),
4181 DEFINE_PROP_UINT8("x-cpu-throttle-initial", MigrationState,
4182 parameters.cpu_throttle_initial,
4183 DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL),
4184 DEFINE_PROP_UINT8("x-cpu-throttle-increment", MigrationState,
4185 parameters.cpu_throttle_increment,
4186 DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT),
4187 DEFINE_PROP_BOOL("x-cpu-throttle-tailslow", MigrationState,
4188 parameters.cpu_throttle_tailslow, false),
4189 DEFINE_PROP_SIZE("x-max-bandwidth", MigrationState,
4190 parameters.max_bandwidth, MAX_THROTTLE),
4191 DEFINE_PROP_UINT64("x-downtime-limit", MigrationState,
4192 parameters.downtime_limit,
4193 DEFAULT_MIGRATE_SET_DOWNTIME),
4194 DEFINE_PROP_UINT32("x-checkpoint-delay", MigrationState,
4195 parameters.x_checkpoint_delay,
4196 DEFAULT_MIGRATE_X_CHECKPOINT_DELAY),
4197 DEFINE_PROP_UINT8("multifd-channels", MigrationState,
4198 parameters.multifd_channels,
4199 DEFAULT_MIGRATE_MULTIFD_CHANNELS),
4200 DEFINE_PROP_MULTIFD_COMPRESSION("multifd-compression", MigrationState,
4201 parameters.multifd_compression,
4202 DEFAULT_MIGRATE_MULTIFD_COMPRESSION),
4203 DEFINE_PROP_UINT8("multifd-zlib-level", MigrationState,
4204 parameters.multifd_zlib_level,
4205 DEFAULT_MIGRATE_MULTIFD_ZLIB_LEVEL),
4206 DEFINE_PROP_UINT8("multifd-zstd-level", MigrationState,
4207 parameters.multifd_zstd_level,
4208 DEFAULT_MIGRATE_MULTIFD_ZSTD_LEVEL),
4209 DEFINE_PROP_SIZE("xbzrle-cache-size", MigrationState,
4210 parameters.xbzrle_cache_size,
4211 DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE),
4212 DEFINE_PROP_SIZE("max-postcopy-bandwidth", MigrationState,
4213 parameters.max_postcopy_bandwidth,
4214 DEFAULT_MIGRATE_MAX_POSTCOPY_BANDWIDTH),
4215 DEFINE_PROP_UINT8("max-cpu-throttle", MigrationState,
4216 parameters.max_cpu_throttle,
4217 DEFAULT_MIGRATE_MAX_CPU_THROTTLE),
4218 DEFINE_PROP_SIZE("announce-initial", MigrationState,
4219 parameters.announce_initial,
4220 DEFAULT_MIGRATE_ANNOUNCE_INITIAL),
4221 DEFINE_PROP_SIZE("announce-max", MigrationState,
4222 parameters.announce_max,
4223 DEFAULT_MIGRATE_ANNOUNCE_MAX),
4224 DEFINE_PROP_SIZE("announce-rounds", MigrationState,
4225 parameters.announce_rounds,
4226 DEFAULT_MIGRATE_ANNOUNCE_ROUNDS),
4227 DEFINE_PROP_SIZE("announce-step", MigrationState,
4228 parameters.announce_step,
4229 DEFAULT_MIGRATE_ANNOUNCE_STEP),
4231 /* Migration capabilities */
4232 DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
4233 DEFINE_PROP_MIG_CAP("x-rdma-pin-all", MIGRATION_CAPABILITY_RDMA_PIN_ALL),
4234 DEFINE_PROP_MIG_CAP("x-auto-converge", MIGRATION_CAPABILITY_AUTO_CONVERGE),
4235 DEFINE_PROP_MIG_CAP("x-zero-blocks", MIGRATION_CAPABILITY_ZERO_BLOCKS),
4236 DEFINE_PROP_MIG_CAP("x-compress", MIGRATION_CAPABILITY_COMPRESS),
4237 DEFINE_PROP_MIG_CAP("x-events", MIGRATION_CAPABILITY_EVENTS),
4238 DEFINE_PROP_MIG_CAP("x-postcopy-ram", MIGRATION_CAPABILITY_POSTCOPY_RAM),
4239 DEFINE_PROP_MIG_CAP("x-colo", MIGRATION_CAPABILITY_X_COLO),
4240 DEFINE_PROP_MIG_CAP("x-release-ram", MIGRATION_CAPABILITY_RELEASE_RAM),
4241 DEFINE_PROP_MIG_CAP("x-block", MIGRATION_CAPABILITY_BLOCK),
4242 DEFINE_PROP_MIG_CAP("x-return-path", MIGRATION_CAPABILITY_RETURN_PATH),
4243 DEFINE_PROP_MIG_CAP("x-multifd", MIGRATION_CAPABILITY_MULTIFD),
4244 DEFINE_PROP_MIG_CAP("x-background-snapshot",
4245 MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT),
4247 DEFINE_PROP_END_OF_LIST(),
4250 static void migration_class_init(ObjectClass *klass, void *data)
4252 DeviceClass *dc = DEVICE_CLASS(klass);
4254 dc->user_creatable = false;
4255 device_class_set_props(dc, migration_properties);
4258 static void migration_instance_finalize(Object *obj)
4260 MigrationState *ms = MIGRATION_OBJ(obj);
4261 MigrationParameters *params = &ms->parameters;
4263 qemu_mutex_destroy(&ms->error_mutex);
4264 qemu_mutex_destroy(&ms->qemu_file_lock);
4265 g_free(params->tls_hostname);
4266 g_free(params->tls_creds);
4267 qemu_sem_destroy(&ms->wait_unplug_sem);
4268 qemu_sem_destroy(&ms->rate_limit_sem);
4269 qemu_sem_destroy(&ms->pause_sem);
4270 qemu_sem_destroy(&ms->postcopy_pause_sem);
4271 qemu_sem_destroy(&ms->postcopy_pause_rp_sem);
4272 qemu_sem_destroy(&ms->rp_state.rp_sem);
4273 error_free(ms->error);
4276 static void migration_instance_init(Object *obj)
4278 MigrationState *ms = MIGRATION_OBJ(obj);
4279 MigrationParameters *params = &ms->parameters;
4281 ms->state = MIGRATION_STATUS_NONE;
4282 ms->mbps = -1;
4283 ms->pages_per_second = -1;
4284 qemu_sem_init(&ms->pause_sem, 0);
4285 qemu_mutex_init(&ms->error_mutex);
4287 params->tls_hostname = g_strdup("");
4288 params->tls_creds = g_strdup("");
4290 /* Set has_* up only for parameter checks */
4291 params->has_compress_level = true;
4292 params->has_compress_threads = true;
4293 params->has_decompress_threads = true;
4294 params->has_throttle_trigger_threshold = true;
4295 params->has_cpu_throttle_initial = true;
4296 params->has_cpu_throttle_increment = true;
4297 params->has_cpu_throttle_tailslow = true;
4298 params->has_max_bandwidth = true;
4299 params->has_downtime_limit = true;
4300 params->has_x_checkpoint_delay = true;
4301 params->has_block_incremental = true;
4302 params->has_multifd_channels = true;
4303 params->has_multifd_compression = true;
4304 params->has_multifd_zlib_level = true;
4305 params->has_multifd_zstd_level = true;
4306 params->has_xbzrle_cache_size = true;
4307 params->has_max_postcopy_bandwidth = true;
4308 params->has_max_cpu_throttle = true;
4309 params->has_announce_initial = true;
4310 params->has_announce_max = true;
4311 params->has_announce_rounds = true;
4312 params->has_announce_step = true;
4314 qemu_sem_init(&ms->postcopy_pause_sem, 0);
4315 qemu_sem_init(&ms->postcopy_pause_rp_sem, 0);
4316 qemu_sem_init(&ms->rp_state.rp_sem, 0);
4317 qemu_sem_init(&ms->rate_limit_sem, 0);
4318 qemu_sem_init(&ms->wait_unplug_sem, 0);
4319 qemu_mutex_init(&ms->qemu_file_lock);
4323 * Return true if check pass, false otherwise. Error will be put
4324 * inside errp if provided.
4326 static bool migration_object_check(MigrationState *ms, Error **errp)
4328 MigrationCapabilityStatusList *head = NULL;
4329 /* Assuming all off */
4330 bool cap_list[MIGRATION_CAPABILITY__MAX] = { 0 }, ret;
4331 int i;
4333 if (!migrate_params_check(&ms->parameters, errp)) {
4334 return false;
4337 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
4338 if (ms->enabled_capabilities[i]) {
4339 QAPI_LIST_PREPEND(head, migrate_cap_add(i, true));
4343 ret = migrate_caps_check(cap_list, head, errp);
4345 /* It works with head == NULL */
4346 qapi_free_MigrationCapabilityStatusList(head);
4348 return ret;
4351 static const TypeInfo migration_type = {
4352 .name = TYPE_MIGRATION,
4354 * NOTE: TYPE_MIGRATION is not really a device, as the object is
4355 * not created using qdev_new(), it is not attached to the qdev
4356 * device tree, and it is never realized.
4358 * TODO: Make this TYPE_OBJECT once QOM provides something like
4359 * TYPE_DEVICE's "-global" properties.
4361 .parent = TYPE_DEVICE,
4362 .class_init = migration_class_init,
4363 .class_size = sizeof(MigrationClass),
4364 .instance_size = sizeof(MigrationState),
4365 .instance_init = migration_instance_init,
4366 .instance_finalize = migration_instance_finalize,
4369 static void register_migration_types(void)
4371 type_register_static(&migration_type);
4374 type_init(register_migration_types);