migration.h (16710B)
1 /* 2 * QEMU live migration 3 * 4 * Copyright IBM, Corp. 2008 5 * 6 * Authors: 7 * Anthony Liguori <aliguori@us.ibm.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2. See 10 * the COPYING file in the top-level directory. 11 * 12 */ 13 14 #ifndef QEMU_MIGRATION_H 15 #define QEMU_MIGRATION_H 16 17 #include "exec/cpu-common.h" 18 #include "hw/qdev-core.h" 19 #include "qapi/qapi-types-migration.h" 20 #include "qemu/thread.h" 21 #include "qemu/coroutine_int.h" 22 #include "io/channel.h" 23 #include "io/channel-buffer.h" 24 #include "net/announce.h" 25 #include "qom/object.h" 26 #include "postcopy-ram.h" 27 28 struct PostcopyBlocktimeContext; 29 30 #define MIGRATION_RESUME_ACK_VALUE (1) 31 32 /* 33 * 1<<6=64 pages -> 256K chunk when page size is 4K. This gives us 34 * the benefit that all the chunks are 64 pages aligned then the 35 * bitmaps are always aligned to LONG. 36 */ 37 #define CLEAR_BITMAP_SHIFT_MIN 6 38 /* 39 * 1<<18=256K pages -> 1G chunk when page size is 4K. This is the 40 * default value to use if no one specified. 41 */ 42 #define CLEAR_BITMAP_SHIFT_DEFAULT 18 43 /* 44 * 1<<31=2G pages -> 8T chunk when page size is 4K. This should be 45 * big enough and make sure we won't overflow easily. 46 */ 47 #define CLEAR_BITMAP_SHIFT_MAX 31 48 49 /* This is an abstraction of a "temp huge page" for postcopy's purpose */ 50 typedef struct { 51 /* 52 * This points to a temporary huge page as a buffer for UFFDIO_COPY. It's 53 * mmap()ed and needs to be freed when cleanup. 54 */ 55 void *tmp_huge_page; 56 /* 57 * This points to the host page we're going to install for this temp page. 58 * It tells us after we've received the whole page, where we should put it. 59 */ 60 void *host_addr; 61 /* Number of small pages copied (in size of TARGET_PAGE_SIZE) */ 62 unsigned int target_pages; 63 /* Whether this page contains all zeros */ 64 bool all_zero; 65 } PostcopyTmpPage; 66 67 /* State for the incoming migration */ 68 struct MigrationIncomingState { 69 QEMUFile *from_src_file; 70 /* Previously received RAM's RAMBlock pointer */ 71 RAMBlock *last_recv_block[RAM_CHANNEL_MAX]; 72 /* A hook to allow cleanup at the end of incoming migration */ 73 void *transport_data; 74 void (*transport_cleanup)(void *data); 75 /* 76 * Used to sync thread creations. Note that we can't create threads in 77 * parallel with this sem. 78 */ 79 QemuSemaphore thread_sync_sem; 80 /* 81 * Free at the start of the main state load, set as the main thread finishes 82 * loading state. 83 */ 84 QemuEvent main_thread_load_event; 85 86 /* For network announces */ 87 AnnounceTimer announce_timer; 88 89 size_t largest_page_size; 90 bool have_fault_thread; 91 QemuThread fault_thread; 92 /* Set this when we want the fault thread to quit */ 93 bool fault_thread_quit; 94 95 bool have_listen_thread; 96 QemuThread listen_thread; 97 98 /* For the kernel to send us notifications */ 99 int userfault_fd; 100 /* To notify the fault_thread to wake, e.g., when need to quit */ 101 int userfault_event_fd; 102 QEMUFile *to_src_file; 103 QemuMutex rp_mutex; /* We send replies from multiple threads */ 104 /* RAMBlock of last request sent to source */ 105 RAMBlock *last_rb; 106 /* 107 * Number of postcopy channels including the default precopy channel, so 108 * vanilla postcopy will only contain one channel which contain both 109 * precopy and postcopy streams. 110 * 111 * This is calculated when the src requests to enable postcopy but before 112 * it starts. Its value can depend on e.g. whether postcopy preemption is 113 * enabled. 114 */ 115 unsigned int postcopy_channels; 116 /* QEMUFile for postcopy only; it'll be handled by a separate thread */ 117 QEMUFile *postcopy_qemufile_dst; 118 /* Postcopy priority thread is used to receive postcopy requested pages */ 119 QemuThread postcopy_prio_thread; 120 bool postcopy_prio_thread_created; 121 /* 122 * Used to sync between the ram load main thread and the fast ram load 123 * thread. It protects postcopy_qemufile_dst, which is the postcopy 124 * fast channel. 125 * 126 * The ram fast load thread will take it mostly for the whole lifecycle 127 * because it needs to continuously read data from the channel, and 128 * it'll only release this mutex if postcopy is interrupted, so that 129 * the ram load main thread will take this mutex over and properly 130 * release the broken channel. 131 */ 132 QemuMutex postcopy_prio_thread_mutex; 133 /* 134 * An array of temp host huge pages to be used, one for each postcopy 135 * channel. 136 */ 137 PostcopyTmpPage *postcopy_tmp_pages; 138 /* This is shared for all postcopy channels */ 139 void *postcopy_tmp_zero_page; 140 /* PostCopyFD's for external userfaultfds & handlers of shared memory */ 141 GArray *postcopy_remote_fds; 142 143 QEMUBH *bh; 144 145 int state; 146 147 bool have_colo_incoming_thread; 148 QemuThread colo_incoming_thread; 149 /* The coroutine we should enter (back) after failover */ 150 Coroutine *migration_incoming_co; 151 QemuSemaphore colo_incoming_sem; 152 153 /* 154 * PostcopyBlocktimeContext to keep information for postcopy 155 * live migration, to calculate vCPU block time 156 * */ 157 struct PostcopyBlocktimeContext *blocktime_ctx; 158 159 /* notify PAUSED postcopy incoming migrations to try to continue */ 160 QemuSemaphore postcopy_pause_sem_dst; 161 QemuSemaphore postcopy_pause_sem_fault; 162 /* 163 * This semaphore is used to allow the ram fast load thread (only when 164 * postcopy preempt is enabled) fall into sleep when there's network 165 * interruption detected. When the recovery is done, the main load 166 * thread will kick the fast ram load thread using this semaphore. 167 */ 168 QemuSemaphore postcopy_pause_sem_fast_load; 169 170 /* List of listening socket addresses */ 171 SocketAddressList *socket_address_list; 172 173 /* A tree of pages that we requested to the source VM */ 174 GTree *page_requested; 175 /* For debugging purpose only, but would be nice to keep */ 176 int page_requested_count; 177 /* 178 * The mutex helps to maintain the requested pages that we sent to the 179 * source, IOW, to guarantee coherent between the page_requests tree and 180 * the per-ramblock receivedmap. Note! This does not guarantee consistency 181 * of the real page copy procedures (using UFFDIO_[ZERO]COPY). E.g., even 182 * if one bit in receivedmap is cleared, UFFDIO_COPY could have happened 183 * for that page already. This is intended so that the mutex won't 184 * serialize and blocked by slow operations like UFFDIO_* ioctls. However 185 * this should be enough to make sure the page_requested tree always 186 * contains valid information. 187 */ 188 QemuMutex page_request_mutex; 189 }; 190 191 MigrationIncomingState *migration_incoming_get_current(void); 192 void migration_incoming_state_destroy(void); 193 void migration_incoming_transport_cleanup(MigrationIncomingState *mis); 194 /* 195 * Functions to work with blocktime context 196 */ 197 void fill_destination_postcopy_migration_info(MigrationInfo *info); 198 199 #define TYPE_MIGRATION "migration" 200 201 typedef struct MigrationClass MigrationClass; 202 DECLARE_OBJ_CHECKERS(MigrationState, MigrationClass, 203 MIGRATION_OBJ, TYPE_MIGRATION) 204 205 struct MigrationClass { 206 /*< private >*/ 207 DeviceClass parent_class; 208 }; 209 210 struct MigrationState { 211 /*< private >*/ 212 DeviceState parent_obj; 213 214 /*< public >*/ 215 QemuThread thread; 216 QEMUBH *vm_start_bh; 217 QEMUBH *cleanup_bh; 218 /* Protected by qemu_file_lock */ 219 QEMUFile *to_dst_file; 220 /* Postcopy specific transfer channel */ 221 QEMUFile *postcopy_qemufile_src; 222 /* 223 * It is posted when the preempt channel is established. Note: this is 224 * used for both the start or recover of a postcopy migration. We'll 225 * post to this sem every time a new preempt channel is created in the 226 * main thread, and we keep post() and wait() in pair. 227 */ 228 QemuSemaphore postcopy_qemufile_src_sem; 229 QIOChannelBuffer *bioc; 230 /* 231 * Protects to_dst_file/from_dst_file pointers. We need to make sure we 232 * won't yield or hang during the critical section, since this lock will be 233 * used in OOB command handler. 234 */ 235 QemuMutex qemu_file_lock; 236 237 /* 238 * Used to allow urgent requests to override rate limiting. 239 */ 240 QemuSemaphore rate_limit_sem; 241 242 /* pages already send at the beginning of current iteration */ 243 uint64_t iteration_initial_pages; 244 245 /* pages transferred per second */ 246 double pages_per_second; 247 248 /* bytes already send at the beginning of current iteration */ 249 uint64_t iteration_initial_bytes; 250 /* time at the start of current iteration */ 251 int64_t iteration_start_time; 252 /* 253 * The final stage happens when the remaining data is smaller than 254 * this threshold; it's calculated from the requested downtime and 255 * measured bandwidth 256 */ 257 int64_t threshold_size; 258 259 /* params from 'migrate-set-parameters' */ 260 MigrationParameters parameters; 261 262 int state; 263 264 /* State related to return path */ 265 struct { 266 /* Protected by qemu_file_lock */ 267 QEMUFile *from_dst_file; 268 QemuThread rp_thread; 269 bool error; 270 /* 271 * We can also check non-zero of rp_thread, but there's no "official" 272 * way to do this, so this bool makes it slightly more elegant. 273 * Checking from_dst_file for this is racy because from_dst_file will 274 * be cleared in the rp_thread! 275 */ 276 bool rp_thread_created; 277 QemuSemaphore rp_sem; 278 } rp_state; 279 280 double mbps; 281 /* Timestamp when recent migration starts (ms) */ 282 int64_t start_time; 283 /* Total time used by latest migration (ms) */ 284 int64_t total_time; 285 /* Timestamp when VM is down (ms) to migrate the last stuff */ 286 int64_t downtime_start; 287 int64_t downtime; 288 int64_t expected_downtime; 289 bool enabled_capabilities[MIGRATION_CAPABILITY__MAX]; 290 int64_t setup_time; 291 /* 292 * Whether guest was running when we enter the completion stage. 293 * If migration is interrupted by any reason, we need to continue 294 * running the guest on source. 295 */ 296 bool vm_was_running; 297 298 /* Flag set once the migration has been asked to enter postcopy */ 299 bool start_postcopy; 300 /* Flag set after postcopy has sent the device state */ 301 bool postcopy_after_devices; 302 303 /* Flag set once the migration thread is running (and needs joining) */ 304 bool migration_thread_running; 305 306 /* Flag set once the migration thread called bdrv_inactivate_all */ 307 bool block_inactive; 308 309 /* Migration is waiting for guest to unplug device */ 310 QemuSemaphore wait_unplug_sem; 311 312 /* Migration is paused due to pause-before-switchover */ 313 QemuSemaphore pause_sem; 314 315 /* The semaphore is used to notify COLO thread that failover is finished */ 316 QemuSemaphore colo_exit_sem; 317 318 /* The event is used to notify COLO thread to do checkpoint */ 319 QemuEvent colo_checkpoint_event; 320 int64_t colo_checkpoint_time; 321 QEMUTimer *colo_delay_timer; 322 323 /* The first error that has occurred. 324 We used the mutex to be able to return the 1st error message */ 325 Error *error; 326 /* mutex to protect errp */ 327 QemuMutex error_mutex; 328 329 /* Do we have to clean up -b/-i from old migrate parameters */ 330 /* This feature is deprecated and will be removed */ 331 bool must_remove_block_options; 332 333 /* 334 * Global switch on whether we need to store the global state 335 * during migration. 336 */ 337 bool store_global_state; 338 339 /* Whether we send QEMU_VM_CONFIGURATION during migration */ 340 bool send_configuration; 341 /* Whether we send section footer during migration */ 342 bool send_section_footer; 343 /* 344 * Whether we allow break sending huge pages when postcopy preempt is 345 * enabled. When disabled, we won't interrupt precopy within sending a 346 * host huge page, which is the old behavior of vanilla postcopy. 347 * NOTE: this parameter is ignored if postcopy preempt is not enabled. 348 */ 349 bool postcopy_preempt_break_huge; 350 351 /* Needed by postcopy-pause state */ 352 QemuSemaphore postcopy_pause_sem; 353 QemuSemaphore postcopy_pause_rp_sem; 354 /* 355 * Whether we abort the migration if decompression errors are 356 * detected at the destination. It is left at false for qemu 357 * older than 3.0, since only newer qemu sends streams that 358 * do not trigger spurious decompression errors. 359 */ 360 bool decompress_error_check; 361 362 /* 363 * This decides the size of guest memory chunk that will be used 364 * to track dirty bitmap clearing. The size of memory chunk will 365 * be GUEST_PAGE_SIZE << N. Say, N=0 means we will clear dirty 366 * bitmap for each page to send (1<<0=1); N=10 means we will clear 367 * dirty bitmap only once for 1<<10=1K continuous guest pages 368 * (which is in 4M chunk). 369 */ 370 uint8_t clear_bitmap_shift; 371 372 /* 373 * This save hostname when out-going migration starts 374 */ 375 char *hostname; 376 }; 377 378 void migrate_set_state(int *state, int old_state, int new_state); 379 380 void migration_fd_process_incoming(QEMUFile *f, Error **errp); 381 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp); 382 void migration_incoming_process(void); 383 384 bool migration_has_all_channels(void); 385 386 uint64_t migrate_max_downtime(void); 387 388 void migrate_set_error(MigrationState *s, const Error *error); 389 void migrate_fd_error(MigrationState *s, const Error *error); 390 391 void migrate_fd_connect(MigrationState *s, Error *error_in); 392 393 bool migration_is_setup_or_active(int state); 394 bool migration_is_running(int state); 395 396 void migrate_init(MigrationState *s); 397 bool migration_is_blocked(Error **errp); 398 /* True if outgoing migration has entered postcopy phase */ 399 bool migration_in_postcopy(void); 400 MigrationState *migrate_get_current(void); 401 402 bool migrate_postcopy(void); 403 404 bool migrate_release_ram(void); 405 bool migrate_postcopy_ram(void); 406 bool migrate_zero_blocks(void); 407 bool migrate_dirty_bitmaps(void); 408 bool migrate_ignore_shared(void); 409 bool migrate_validate_uuid(void); 410 411 bool migrate_auto_converge(void); 412 bool migrate_use_multifd(void); 413 bool migrate_pause_before_switchover(void); 414 int migrate_multifd_channels(void); 415 MultiFDCompression migrate_multifd_compression(void); 416 int migrate_multifd_zlib_level(void); 417 int migrate_multifd_zstd_level(void); 418 419 #ifdef CONFIG_LINUX 420 bool migrate_use_zero_copy_send(void); 421 #else 422 #define migrate_use_zero_copy_send() (false) 423 #endif 424 int migrate_use_tls(void); 425 int migrate_use_xbzrle(void); 426 uint64_t migrate_xbzrle_cache_size(void); 427 bool migrate_colo_enabled(void); 428 429 bool migrate_use_block(void); 430 bool migrate_use_block_incremental(void); 431 int migrate_max_cpu_throttle(void); 432 bool migrate_use_return_path(void); 433 434 uint64_t ram_get_total_transferred_pages(void); 435 436 bool migrate_use_compression(void); 437 int migrate_compress_level(void); 438 int migrate_compress_threads(void); 439 int migrate_compress_wait_thread(void); 440 int migrate_decompress_threads(void); 441 bool migrate_use_events(void); 442 bool migrate_postcopy_blocktime(void); 443 bool migrate_background_snapshot(void); 444 bool migrate_postcopy_preempt(void); 445 446 /* Sending on the return path - generic and then for each message type */ 447 void migrate_send_rp_shut(MigrationIncomingState *mis, 448 uint32_t value); 449 void migrate_send_rp_pong(MigrationIncomingState *mis, 450 uint32_t value); 451 int migrate_send_rp_req_pages(MigrationIncomingState *mis, RAMBlock *rb, 452 ram_addr_t start, uint64_t haddr); 453 int migrate_send_rp_message_req_pages(MigrationIncomingState *mis, 454 RAMBlock *rb, ram_addr_t start); 455 void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis, 456 char *block_name); 457 void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value); 458 459 void dirty_bitmap_mig_before_vm_start(void); 460 void dirty_bitmap_mig_cancel_outgoing(void); 461 void dirty_bitmap_mig_cancel_incoming(void); 462 bool check_dirty_bitmap_mig_alias_map(const BitmapMigrationNodeAliasList *bbm, 463 Error **errp); 464 465 void migrate_add_address(SocketAddress *address); 466 467 int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque); 468 469 #define qemu_ram_foreach_block \ 470 #warning "Use foreach_not_ignored_block in migration code" 471 472 void migration_make_urgent_request(void); 473 void migration_consume_urgent_request(void); 474 bool migration_rate_limit(void); 475 void migration_cancel(const Error *error); 476 477 void populate_vfio_info(MigrationInfo *info); 478 void postcopy_temp_page_reset(PostcopyTmpPage *tmp_page); 479 480 bool migrate_multi_channels_is_allowed(void); 481 void migrate_protocol_allow_multi_channels(bool allow); 482 483 #endif