migration/migration.h

   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 "qapi/qmp/json-writer.h"
  21 #include "qemu/thread.h"
  22 #include "qemu/coroutine_int.h"
  23 #include "io/channel.h"
  24 #include "io/channel-buffer.h"
  25 #include "net/announce.h"
  26 #include "qom/object.h"
  27 #include "postcopy-ram.h"
  28
  29 struct PostcopyBlocktimeContext;
  30
  31 #define  MIGRATION_RESUME_ACK_VALUE  (1)
  32
  33 /*
  34  * 1<<6=64 pages -> 256K chunk when page size is 4K.  This gives us
  35  * the benefit that all the chunks are 64 pages aligned then the
  36  * bitmaps are always aligned to LONG.
  37  */
  38 #define CLEAR_BITMAP_SHIFT_MIN             6
  39 /*
  40  * 1<<18=256K pages -> 1G chunk when page size is 4K.  This is the
  41  * default value to use if no one specified.
  42  */
  43 #define CLEAR_BITMAP_SHIFT_DEFAULT        18
  44 /*
  45  * 1<<31=2G pages -> 8T chunk when page size is 4K.  This should be
  46  * big enough and make sure we won't overflow easily.
  47  */
  48 #define CLEAR_BITMAP_SHIFT_MAX            31
  49
  50 /* This is an abstraction of a "temp huge page" for postcopy's purpose */
  51 typedef struct {
  52     /*
  53      * This points to a temporary huge page as a buffer for UFFDIO_COPY.  It's
  54      * mmap()ed and needs to be freed when cleanup.
  55      */
  56     void *tmp_huge_page;
  57     /*
  58      * This points to the host page we're going to install for this temp page.
  59      * It tells us after we've received the whole page, where we should put it.
  60      */
  61     void *host_addr;
  62     /* Number of small pages copied (in size of TARGET_PAGE_SIZE) */
  63     unsigned int target_pages;
  64     /* Whether this page contains all zeros */
  65     bool all_zero;
  66 } PostcopyTmpPage;
  67
  68 /* State for the incoming migration */
  69 struct MigrationIncomingState {
  70     QEMUFile *from_src_file;
  71     /* Previously received RAM's RAMBlock pointer */
  72     RAMBlock *last_recv_block[RAM_CHANNEL_MAX];
  73     /* A hook to allow cleanup at the end of incoming migration */
  74     void *transport_data;
  75     void (*transport_cleanup)(void *data);
  76     /*
  77      * Used to sync thread creations.  Note that we can't create threads in
  78      * parallel with this sem.
  79      */
  80     QemuSemaphore  thread_sync_sem;
  81     /*
  82      * Free at the start of the main state load, set as the main thread finishes
  83      * loading state.
  84      */
  85     QemuEvent main_thread_load_event;
  86
  87     /* For network announces */
  88     AnnounceTimer  announce_timer;
  89
  90     size_t         largest_page_size;
  91     bool           have_fault_thread;
  92     QemuThread     fault_thread;
  93     /* Set this when we want the fault thread to quit */
  94     bool           fault_thread_quit;
  95
  96     bool           have_listen_thread;
  97     QemuThread     listen_thread;
  98
  99     /* For the kernel to send us notifications */
 100     int       userfault_fd;
 101     /* To notify the fault_thread to wake, e.g., when need to quit */
 102     int       userfault_event_fd;
 103     QEMUFile *to_src_file;
 104     QemuMutex rp_mutex;    /* We send replies from multiple threads */
 105     /* RAMBlock of last request sent to source */
 106     RAMBlock *last_rb;
 107     /*
 108      * Number of postcopy channels including the default precopy channel, so
 109      * vanilla postcopy will only contain one channel which contain both
 110      * precopy and postcopy streams.
 111      *
 112      * This is calculated when the src requests to enable postcopy but before
 113      * it starts.  Its value can depend on e.g. whether postcopy preemption is
 114      * enabled.
 115      */
 116     unsigned int postcopy_channels;
 117     /* QEMUFile for postcopy only; it'll be handled by a separate thread */
 118     QEMUFile *postcopy_qemufile_dst;
 119     /*
 120      * When postcopy_qemufile_dst is properly setup, this sem is posted.
 121      * One can wait on this semaphore to wait until the preempt channel is
 122      * properly setup.
 123      */
 124     QemuSemaphore postcopy_qemufile_dst_done;
 125     /* Postcopy priority thread is used to receive postcopy requested pages */
 126     QemuThread postcopy_prio_thread;
 127     bool postcopy_prio_thread_created;
 128     /*
 129      * Used to sync between the ram load main thread and the fast ram load
 130      * thread.  It protects postcopy_qemufile_dst, which is the postcopy
 131      * fast channel.
 132      *
 133      * The ram fast load thread will take it mostly for the whole lifecycle
 134      * because it needs to continuously read data from the channel, and
 135      * it'll only release this mutex if postcopy is interrupted, so that
 136      * the ram load main thread will take this mutex over and properly
 137      * release the broken channel.
 138      */
 139     QemuMutex postcopy_prio_thread_mutex;
 140     /*
 141      * An array of temp host huge pages to be used, one for each postcopy
 142      * channel.
 143      */
 144     PostcopyTmpPage *postcopy_tmp_pages;
 145     /* This is shared for all postcopy channels */
 146     void     *postcopy_tmp_zero_page;
 147     /* PostCopyFD's for external userfaultfds & handlers of shared memory */
 148     GArray   *postcopy_remote_fds;
 149
 150     QEMUBH *bh;
 151
 152     int state;
 153
 154     bool have_colo_incoming_thread;
 155     QemuThread colo_incoming_thread;
 156     /* The coroutine we should enter (back) after failover */
 157     Coroutine *migration_incoming_co;
 158     QemuSemaphore colo_incoming_sem;
 159
 160     /*
 161      * PostcopyBlocktimeContext to keep information for postcopy
 162      * live migration, to calculate vCPU block time
 163      * */
 164     struct PostcopyBlocktimeContext *blocktime_ctx;
 165
 166     /* notify PAUSED postcopy incoming migrations to try to continue */
 167     QemuSemaphore postcopy_pause_sem_dst;
 168     QemuSemaphore postcopy_pause_sem_fault;
 169     /*
 170      * This semaphore is used to allow the ram fast load thread (only when
 171      * postcopy preempt is enabled) fall into sleep when there's network
 172      * interruption detected.  When the recovery is done, the main load
 173      * thread will kick the fast ram load thread using this semaphore.
 174      */
 175     QemuSemaphore postcopy_pause_sem_fast_load;
 176
 177     /* List of listening socket addresses  */
 178     SocketAddressList *socket_address_list;
 179
 180     /* A tree of pages that we requested to the source VM */
 181     GTree *page_requested;
 182     /* For debugging purpose only, but would be nice to keep */
 183     int page_requested_count;
 184     /*
 185      * The mutex helps to maintain the requested pages that we sent to the
 186      * source, IOW, to guarantee coherent between the page_requests tree and
 187      * the per-ramblock receivedmap.  Note! This does not guarantee consistency
 188      * of the real page copy procedures (using UFFDIO_[ZERO]COPY).  E.g., even
 189      * if one bit in receivedmap is cleared, UFFDIO_COPY could have happened
 190      * for that page already.  This is intended so that the mutex won't
 191      * serialize and blocked by slow operations like UFFDIO_* ioctls.  However
 192      * this should be enough to make sure the page_requested tree always
 193      * contains valid information.
 194      */
 195     QemuMutex page_request_mutex;
 196 };
 197
 198 MigrationIncomingState *migration_incoming_get_current(void);
 199 void migration_incoming_state_destroy(void);
 200 void migration_incoming_transport_cleanup(MigrationIncomingState *mis);
 201 /*
 202  * Functions to work with blocktime context
 203  */
 204 void fill_destination_postcopy_migration_info(MigrationInfo *info);
 205
 206 #define TYPE_MIGRATION "migration"
 207
 208 typedef struct MigrationClass MigrationClass;
 209 DECLARE_OBJ_CHECKERS(MigrationState, MigrationClass,
 210                      MIGRATION_OBJ, TYPE_MIGRATION)
 211
 212 struct MigrationClass {
 213     /*< private >*/
 214     DeviceClass parent_class;
 215 };
 216
 217 struct MigrationState {
 218     /*< private >*/
 219     DeviceState parent_obj;
 220
 221     /*< public >*/
 222     QemuThread thread;
 223     QEMUBH *vm_start_bh;
 224     QEMUBH *cleanup_bh;
 225     /* Protected by qemu_file_lock */
 226     QEMUFile *to_dst_file;
 227     /* Postcopy specific transfer channel */
 228     QEMUFile *postcopy_qemufile_src;
 229     /*
 230      * It is posted when the preempt channel is established.  Note: this is
 231      * used for both the start or recover of a postcopy migration.  We'll
 232      * post to this sem every time a new preempt channel is created in the
 233      * main thread, and we keep post() and wait() in pair.
 234      */
 235     QemuSemaphore postcopy_qemufile_src_sem;
 236     QIOChannelBuffer *bioc;
 237     /*
 238      * Protects to_dst_file/from_dst_file pointers.  We need to make sure we
 239      * won't yield or hang during the critical section, since this lock will be
 240      * used in OOB command handler.
 241      */
 242     QemuMutex qemu_file_lock;
 243
 244     /*
 245      * Used to allow urgent requests to override rate limiting.
 246      */
 247     QemuSemaphore rate_limit_sem;
 248
 249     /* pages already send at the beginning of current iteration */
 250     uint64_t iteration_initial_pages;
 251
 252     /* pages transferred per second */
 253     double pages_per_second;
 254
 255     /* bytes already send at the beginning of current iteration */
 256     uint64_t iteration_initial_bytes;
 257     /* time at the start of current iteration */
 258     int64_t iteration_start_time;
 259     /*
 260      * The final stage happens when the remaining data is smaller than
 261      * this threshold; it's calculated from the requested downtime and
 262      * measured bandwidth
 263      */
 264     int64_t threshold_size;
 265
 266     /* params from 'migrate-set-parameters' */
 267     MigrationParameters parameters;
 268
 269     int state;
 270
 271     /* State related to return path */
 272     struct {
 273         /* Protected by qemu_file_lock */
 274         QEMUFile     *from_dst_file;
 275         QemuThread    rp_thread;
 276         bool          error;
 277         /*
 278          * We can also check non-zero of rp_thread, but there's no "official"
 279          * way to do this, so this bool makes it slightly more elegant.
 280          * Checking from_dst_file for this is racy because from_dst_file will
 281          * be cleared in the rp_thread!
 282          */
 283         bool          rp_thread_created;
 284         QemuSemaphore rp_sem;
 285         /*
 286          * We post to this when we got one PONG from dest. So far it's an
 287          * easy way to know the main channel has successfully established
 288          * on dest QEMU.
 289          */
 290         QemuSemaphore rp_pong_acks;
 291     } rp_state;
 292
 293     double mbps;
 294     /* Timestamp when recent migration starts (ms) */
 295     int64_t start_time;
 296     /* Total time used by latest migration (ms) */
 297     int64_t total_time;
 298     /* Timestamp when VM is down (ms) to migrate the last stuff */
 299     int64_t downtime_start;
 300     int64_t downtime;
 301     int64_t expected_downtime;
 302     bool enabled_capabilities[MIGRATION_CAPABILITY__MAX];
 303     int64_t setup_time;
 304     /*
 305      * Whether guest was running when we enter the completion stage.
 306      * If migration is interrupted by any reason, we need to continue
 307      * running the guest on source.
 308      */
 309     bool vm_was_running;
 310
 311     /* Flag set once the migration has been asked to enter postcopy */
 312     bool start_postcopy;
 313     /* Flag set after postcopy has sent the device state */
 314     bool postcopy_after_devices;
 315
 316     /* Flag set once the migration thread is running (and needs joining) */
 317     bool migration_thread_running;
 318
 319     /* Flag set once the migration thread called bdrv_inactivate_all */
 320     bool block_inactive;
 321
 322     /* Migration is waiting for guest to unplug device */
 323     QemuSemaphore wait_unplug_sem;
 324
 325     /* Migration is paused due to pause-before-switchover */
 326     QemuSemaphore pause_sem;
 327
 328     /* The semaphore is used to notify COLO thread that failover is finished */
 329     QemuSemaphore colo_exit_sem;
 330
 331     /* The event is used to notify COLO thread to do checkpoint */
 332     QemuEvent colo_checkpoint_event;
 333     int64_t colo_checkpoint_time;
 334     QEMUTimer *colo_delay_timer;
 335
 336     /* The first error that has occurred.
 337        We used the mutex to be able to return the 1st error message */
 338     Error *error;
 339     /* mutex to protect errp */
 340     QemuMutex error_mutex;
 341
 342     /* Do we have to clean up -b/-i from old migrate parameters */
 343     /* This feature is deprecated and will be removed */
 344     bool must_remove_block_options;
 345
 346     /*
 347      * Global switch on whether we need to store the global state
 348      * during migration.
 349      */
 350     bool store_global_state;
 351
 352     /* Whether we send QEMU_VM_CONFIGURATION during migration */
 353     bool send_configuration;
 354     /* Whether we send section footer during migration */
 355     bool send_section_footer;
 356
 357     /* Needed by postcopy-pause state */
 358     QemuSemaphore postcopy_pause_sem;
 359     QemuSemaphore postcopy_pause_rp_sem;
 360     /*
 361      * Whether we abort the migration if decompression errors are
 362      * detected at the destination. It is left at false for qemu
 363      * older than 3.0, since only newer qemu sends streams that
 364      * do not trigger spurious decompression errors.
 365      */
 366     bool decompress_error_check;
 367
 368     /*
 369      * This decides the size of guest memory chunk that will be used
 370      * to track dirty bitmap clearing.  The size of memory chunk will
 371      * be GUEST_PAGE_SIZE << N.  Say, N=0 means we will clear dirty
 372      * bitmap for each page to send (1<<0=1); N=10 means we will clear
 373      * dirty bitmap only once for 1<<10=1K continuous guest pages
 374      * (which is in 4M chunk).
 375      */
 376     uint8_t clear_bitmap_shift;
 377
 378     /*
 379      * This save hostname when out-going migration starts
 380      */
 381     char *hostname;
 382
 383     /* QEMU_VM_VMDESCRIPTION content filled for all non-iterable devices. */
 384     JSONWriter *vmdesc;
 385 };
 386
 387 void migrate_set_state(int *state, int old_state, int new_state);
 388
 389 void migration_fd_process_incoming(QEMUFile *f, Error **errp);
 390 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
 391 void migration_incoming_process(void);
 392
 393 bool  migration_has_all_channels(void);
 394
 395 uint64_t migrate_max_downtime(void);
 396
 397 void migrate_set_error(MigrationState *s, const Error *error);
 398 void migrate_fd_error(MigrationState *s, const Error *error);
 399
 400 void migrate_fd_connect(MigrationState *s, Error *error_in);
 401
 402 bool migration_is_setup_or_active(int state);
 403 bool migration_is_running(int state);
 404
 405 void migrate_init(MigrationState *s);
 406 bool migration_is_blocked(Error **errp);
 407 /* True if outgoing migration has entered postcopy phase */
 408 bool migration_in_postcopy(void);
 409 MigrationState *migrate_get_current(void);
 410
 411 bool migrate_postcopy(void);
 412
 413 bool migrate_release_ram(void);
 414 bool migrate_postcopy_ram(void);
 415 bool migrate_zero_blocks(void);
 416 bool migrate_dirty_bitmaps(void);
 417 bool migrate_ignore_shared(void);
 418 bool migrate_validate_uuid(void);
 419
 420 bool migrate_auto_converge(void);
 421 bool migrate_use_multifd(void);
 422 bool migrate_pause_before_switchover(void);
 423 int migrate_multifd_channels(void);
 424 MultiFDCompression migrate_multifd_compression(void);
 425 int migrate_multifd_zlib_level(void);
 426 int migrate_multifd_zstd_level(void);
 427
 428 #ifdef CONFIG_LINUX
 429 bool migrate_use_zero_copy_send(void);
 430 #else
 431 #define migrate_use_zero_copy_send() (false)
 432 #endif
 433 int migrate_use_tls(void);
 434 int migrate_use_xbzrle(void);
 435 uint64_t migrate_xbzrle_cache_size(void);
 436 bool migrate_colo_enabled(void);
 437
 438 bool migrate_use_block(void);
 439 bool migrate_use_block_incremental(void);
 440 int migrate_max_cpu_throttle(void);
 441 bool migrate_use_return_path(void);
 442
 443 uint64_t ram_get_total_transferred_pages(void);
 444
 445 bool migrate_use_compression(void);
 446 int migrate_compress_level(void);
 447 int migrate_compress_threads(void);
 448 int migrate_compress_wait_thread(void);
 449 int migrate_decompress_threads(void);
 450 bool migrate_use_events(void);
 451 bool migrate_postcopy_blocktime(void);
 452 bool migrate_background_snapshot(void);
 453 bool migrate_postcopy_preempt(void);
 454
 455 /* Sending on the return path - generic and then for each message type */
 456 void migrate_send_rp_shut(MigrationIncomingState *mis,
 457                           uint32_t value);
 458 void migrate_send_rp_pong(MigrationIncomingState *mis,
 459                           uint32_t value);
 460 int migrate_send_rp_req_pages(MigrationIncomingState *mis, RAMBlock *rb,
 461                               ram_addr_t start, uint64_t haddr);
 462 int migrate_send_rp_message_req_pages(MigrationIncomingState *mis,
 463                                       RAMBlock *rb, ram_addr_t start);
 464 void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
 465                                  char *block_name);
 466 void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value);
 467
 468 void dirty_bitmap_mig_before_vm_start(void);
 469 void dirty_bitmap_mig_cancel_outgoing(void);
 470 void dirty_bitmap_mig_cancel_incoming(void);
 471 bool check_dirty_bitmap_mig_alias_map(const BitmapMigrationNodeAliasList *bbm,
 472                                       Error **errp);
 473
 474 void migrate_add_address(SocketAddress *address);
 475
 476 int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
 477
 478 #define qemu_ram_foreach_block \
 479   #warning "Use foreach_not_ignored_block in migration code"
 480
 481 void migration_make_urgent_request(void);
 482 void migration_consume_urgent_request(void);
 483 bool migration_rate_limit(void);
 484 void migration_cancel(const Error *error);
 485
 486 void populate_vfio_info(MigrationInfo *info);
 487 void postcopy_temp_page_reset(PostcopyTmpPage *tmp_page);
 488
 489 #endif