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