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 typedef enum {
  69     PREEMPT_THREAD_NONE = 0,
  70     PREEMPT_THREAD_CREATED,
  71     PREEMPT_THREAD_QUIT,
  72 } PreemptThreadStatus;
  73
  74 /* State for the incoming migration */
  75 struct MigrationIncomingState {
  76     QEMUFile *from_src_file;
  77     /* Previously received RAM's RAMBlock pointer */
  78     RAMBlock *last_recv_block[RAM_CHANNEL_MAX];
  79     /* A hook to allow cleanup at the end of incoming migration */
  80     void *transport_data;
  81     void (*transport_cleanup)(void *data);
  82     /*
  83      * Used to sync thread creations.  Note that we can't create threads in
  84      * parallel with this sem.
  85      */
  86     QemuSemaphore  thread_sync_sem;
  87     /*
  88      * Free at the start of the main state load, set as the main thread finishes
  89      * loading state.
  90      */
  91     QemuEvent main_thread_load_event;
  92
  93     /* For network announces */
  94     AnnounceTimer  announce_timer;
  95
  96     size_t         largest_page_size;
  97     bool           have_fault_thread;
  98     QemuThread     fault_thread;
  99     /* Set this when we want the fault thread to quit */
 100     bool           fault_thread_quit;
 101
 102     bool           have_listen_thread;
 103     QemuThread     listen_thread;
 104
 105     /* For the kernel to send us notifications */
 106     int       userfault_fd;
 107     /* To notify the fault_thread to wake, e.g., when need to quit */
 108     int       userfault_event_fd;
 109     QEMUFile *to_src_file;
 110     QemuMutex rp_mutex;    /* We send replies from multiple threads */
 111     /* RAMBlock of last request sent to source */
 112     RAMBlock *last_rb;
 113     /*
 114      * Number of postcopy channels including the default precopy channel, so
 115      * vanilla postcopy will only contain one channel which contain both
 116      * precopy and postcopy streams.
 117      *
 118      * This is calculated when the src requests to enable postcopy but before
 119      * it starts.  Its value can depend on e.g. whether postcopy preemption is
 120      * enabled.
 121      */
 122     unsigned int postcopy_channels;
 123     /* QEMUFile for postcopy only; it'll be handled by a separate thread */
 124     QEMUFile *postcopy_qemufile_dst;
 125     /*
 126      * When postcopy_qemufile_dst is properly setup, this sem is posted.
 127      * One can wait on this semaphore to wait until the preempt channel is
 128      * properly setup.
 129      */
 130     QemuSemaphore postcopy_qemufile_dst_done;
 131     /* Postcopy priority thread is used to receive postcopy requested pages */
 132     QemuThread postcopy_prio_thread;
 133     /*
 134      * Always set by the main vm load thread only, but can be read by the
 135      * postcopy preempt thread.  "volatile" makes sure all reads will be
 136      * uptodate across cores.
 137      */
 138     volatile PreemptThreadStatus preempt_thread_status;
 139     /*
 140      * Used to sync between the ram load main thread and the fast ram load
 141      * thread.  It protects postcopy_qemufile_dst, which is the postcopy
 142      * fast channel.
 143      *
 144      * The ram fast load thread will take it mostly for the whole lifecycle
 145      * because it needs to continuously read data from the channel, and
 146      * it'll only release this mutex if postcopy is interrupted, so that
 147      * the ram load main thread will take this mutex over and properly
 148      * release the broken channel.
 149      */
 150     QemuMutex postcopy_prio_thread_mutex;
 151     /*
 152      * An array of temp host huge pages to be used, one for each postcopy
 153      * channel.
 154      */
 155     PostcopyTmpPage *postcopy_tmp_pages;
 156     /* This is shared for all postcopy channels */
 157     void     *postcopy_tmp_zero_page;
 158     /* PostCopyFD's for external userfaultfds & handlers of shared memory */
 159     GArray   *postcopy_remote_fds;
 160
 161     QEMUBH *bh;
 162
 163     int state;
 164
 165     bool have_colo_incoming_thread;
 166     QemuThread colo_incoming_thread;
 167     /* The coroutine we should enter (back) after failover */
 168     Coroutine *migration_incoming_co;
 169     QemuSemaphore colo_incoming_sem;
 170
 171     /*
 172      * PostcopyBlocktimeContext to keep information for postcopy
 173      * live migration, to calculate vCPU block time
 174      * */
 175     struct PostcopyBlocktimeContext *blocktime_ctx;
 176
 177     /* notify PAUSED postcopy incoming migrations to try to continue */
 178     QemuSemaphore postcopy_pause_sem_dst;
 179     QemuSemaphore postcopy_pause_sem_fault;
 180     /*
 181      * This semaphore is used to allow the ram fast load thread (only when
 182      * postcopy preempt is enabled) fall into sleep when there's network
 183      * interruption detected.  When the recovery is done, the main load
 184      * thread will kick the fast ram load thread using this semaphore.
 185      */
 186     QemuSemaphore postcopy_pause_sem_fast_load;
 187
 188     /* List of listening socket addresses  */
 189     SocketAddressList *socket_address_list;
 190
 191     /* A tree of pages that we requested to the source VM */
 192     GTree *page_requested;
 193     /* For debugging purpose only, but would be nice to keep */
 194     int page_requested_count;
 195     /*
 196      * The mutex helps to maintain the requested pages that we sent to the
 197      * source, IOW, to guarantee coherent between the page_requests tree and
 198      * the per-ramblock receivedmap.  Note! This does not guarantee consistency
 199      * of the real page copy procedures (using UFFDIO_[ZERO]COPY).  E.g., even
 200      * if one bit in receivedmap is cleared, UFFDIO_COPY could have happened
 201      * for that page already.  This is intended so that the mutex won't
 202      * serialize and blocked by slow operations like UFFDIO_* ioctls.  However
 203      * this should be enough to make sure the page_requested tree always
 204      * contains valid information.
 205      */
 206     QemuMutex page_request_mutex;
 207 };
 208
 209 MigrationIncomingState *migration_incoming_get_current(void);
 210 void migration_incoming_state_destroy(void);
 211 void migration_incoming_transport_cleanup(MigrationIncomingState *mis);
 212 /*
 213  * Functions to work with blocktime context
 214  */
 215 void fill_destination_postcopy_migration_info(MigrationInfo *info);
 216
 217 #define TYPE_MIGRATION "migration"
 218
 219 typedef struct MigrationClass MigrationClass;
 220 DECLARE_OBJ_CHECKERS(MigrationState, MigrationClass,
 221                      MIGRATION_OBJ, TYPE_MIGRATION)
 222
 223 struct MigrationClass {
 224     /*< private >*/
 225     DeviceClass parent_class;
 226 };
 227
 228 struct MigrationState {
 229     /*< private >*/
 230     DeviceState parent_obj;
 231
 232     /*< public >*/
 233     QemuThread thread;
 234     QEMUBH *vm_start_bh;
 235     QEMUBH *cleanup_bh;
 236     /* Protected by qemu_file_lock */
 237     QEMUFile *to_dst_file;
 238     /* Postcopy specific transfer channel */
 239     QEMUFile *postcopy_qemufile_src;
 240     /*
 241      * It is posted when the preempt channel is established.  Note: this is
 242      * used for both the start or recover of a postcopy migration.  We'll
 243      * post to this sem every time a new preempt channel is created in the
 244      * main thread, and we keep post() and wait() in pair.
 245      */
 246     QemuSemaphore postcopy_qemufile_src_sem;
 247     QIOChannelBuffer *bioc;
 248     /*
 249      * Protects to_dst_file/from_dst_file pointers.  We need to make sure we
 250      * won't yield or hang during the critical section, since this lock will be
 251      * used in OOB command handler.
 252      */
 253     QemuMutex qemu_file_lock;
 254
 255     /*
 256      * Used to allow urgent requests to override rate limiting.
 257      */
 258     QemuSemaphore rate_limit_sem;
 259
 260     /* pages already send at the beginning of current iteration */
 261     uint64_t iteration_initial_pages;
 262
 263     /* pages transferred per second */
 264     double pages_per_second;
 265
 266     /* bytes already send at the beginning of current iteration */
 267     uint64_t iteration_initial_bytes;
 268     /* time at the start of current iteration */
 269     int64_t iteration_start_time;
 270     /*
 271      * The final stage happens when the remaining data is smaller than
 272      * this threshold; it's calculated from the requested downtime and
 273      * measured bandwidth
 274      */
 275     int64_t threshold_size;
 276
 277     /* params from 'migrate-set-parameters' */
 278     MigrationParameters parameters;
 279
 280     int state;
 281
 282     /* State related to return path */
 283     struct {
 284         /* Protected by qemu_file_lock */
 285         QEMUFile     *from_dst_file;
 286         QemuThread    rp_thread;
 287         bool          error;
 288         /*
 289          * We can also check non-zero of rp_thread, but there's no "official"
 290          * way to do this, so this bool makes it slightly more elegant.
 291          * Checking from_dst_file for this is racy because from_dst_file will
 292          * be cleared in the rp_thread!
 293          */
 294         bool          rp_thread_created;
 295         QemuSemaphore rp_sem;
 296         /*
 297          * We post to this when we got one PONG from dest. So far it's an
 298          * easy way to know the main channel has successfully established
 299          * on dest QEMU.
 300          */
 301         QemuSemaphore rp_pong_acks;
 302     } rp_state;
 303
 304     double mbps;
 305     /* Timestamp when recent migration starts (ms) */
 306     int64_t start_time;
 307     /* Total time used by latest migration (ms) */
 308     int64_t total_time;
 309     /* Timestamp when VM is down (ms) to migrate the last stuff */
 310     int64_t downtime_start;
 311     int64_t downtime;
 312     int64_t expected_downtime;
 313     bool capabilities[MIGRATION_CAPABILITY__MAX];
 314     int64_t setup_time;
 315     /*
 316      * Whether guest was running when we enter the completion stage.
 317      * If migration is interrupted by any reason, we need to continue
 318      * running the guest on source.
 319      */
 320     bool vm_was_running;
 321
 322     /* Flag set once the migration has been asked to enter postcopy */
 323     bool start_postcopy;
 324     /* Flag set after postcopy has sent the device state */
 325     bool postcopy_after_devices;
 326
 327     /* Flag set once the migration thread is running (and needs joining) */
 328     bool migration_thread_running;
 329
 330     /* Flag set once the migration thread called bdrv_inactivate_all */
 331     bool block_inactive;
 332
 333     /* Migration is waiting for guest to unplug device */
 334     QemuSemaphore wait_unplug_sem;
 335
 336     /* Migration is paused due to pause-before-switchover */
 337     QemuSemaphore pause_sem;
 338
 339     /* The semaphore is used to notify COLO thread that failover is finished */
 340     QemuSemaphore colo_exit_sem;
 341
 342     /* The event is used to notify COLO thread to do checkpoint */
 343     QemuEvent colo_checkpoint_event;
 344     int64_t colo_checkpoint_time;
 345     QEMUTimer *colo_delay_timer;
 346
 347     /* The first error that has occurred.
 348        We used the mutex to be able to return the 1st error message */
 349     Error *error;
 350     /* mutex to protect errp */
 351     QemuMutex error_mutex;
 352
 353     /* Do we have to clean up -b/-i from old migrate parameters */
 354     /* This feature is deprecated and will be removed */
 355     bool must_remove_block_options;
 356
 357     /*
 358      * Global switch on whether we need to store the global state
 359      * during migration.
 360      */
 361     bool store_global_state;
 362
 363     /* Whether we send QEMU_VM_CONFIGURATION during migration */
 364     bool send_configuration;
 365     /* Whether we send section footer during migration */
 366     bool send_section_footer;
 367
 368     /* Needed by postcopy-pause state */
 369     QemuSemaphore postcopy_pause_sem;
 370     QemuSemaphore postcopy_pause_rp_sem;
 371     /*
 372      * Whether we abort the migration if decompression errors are
 373      * detected at the destination. It is left at false for qemu
 374      * older than 3.0, since only newer qemu sends streams that
 375      * do not trigger spurious decompression errors.
 376      */
 377     bool decompress_error_check;
 378     /*
 379      * This variable only affects behavior when postcopy preempt mode is
 380      * enabled.
 381      *
 382      * When set:
 383      *
 384      * - postcopy preempt src QEMU instance will generate an EOS message at
 385      *   the end of migration to shut the preempt channel on dest side.
 386      *
 387      * - postcopy preempt channel will be created at the setup phase on src
 388          QEMU.
 389      *
 390      * When clear:
 391      *
 392      * - postcopy preempt src QEMU instance will _not_ generate an EOS
 393      *   message at the end of migration, the dest qemu will shutdown the
 394      *   channel itself.
 395      *
 396      * - postcopy preempt channel will be created at the switching phase
 397      *   from precopy -> postcopy (to avoid race condtion of misordered
 398      *   creation of channels).
 399      *
 400      * NOTE: See message-id <ZBoShWArKDPpX/D7@work-vm> on qemu-devel
 401      * mailing list for more information on the possible race.  Everyone
 402      * should probably just keep this value untouched after set by the
 403      * machine type (or the default).
 404      */
 405     bool preempt_pre_7_2;
 406
 407     /*
 408      * flush every channel after each section sent.
 409      *
 410      * This assures that we can't mix pages from one iteration through
 411      * ram pages with pages for the following iteration.  We really
 412      * only need to do this flush after we have go through all the
 413      * dirty pages.  For historical reasons, we do that after each
 414      * section.  This is suboptimal (we flush too many times).
 415      * Default value is false.  Setting this property has no effect
 416      * until the patch that removes this comment.  (since 8.1)
 417      */
 418     bool multifd_flush_after_each_section;
 419     /*
 420      * This decides the size of guest memory chunk that will be used
 421      * to track dirty bitmap clearing.  The size of memory chunk will
 422      * be GUEST_PAGE_SIZE << N.  Say, N=0 means we will clear dirty
 423      * bitmap for each page to send (1<<0=1); N=10 means we will clear
 424      * dirty bitmap only once for 1<<10=1K continuous guest pages
 425      * (which is in 4M chunk).
 426      */
 427     uint8_t clear_bitmap_shift;
 428
 429     /*
 430      * This save hostname when out-going migration starts
 431      */
 432     char *hostname;
 433
 434     /* QEMU_VM_VMDESCRIPTION content filled for all non-iterable devices. */
 435     JSONWriter *vmdesc;
 436 };
 437
 438 void migrate_set_state(int *state, int old_state, int new_state);
 439
 440 void migration_fd_process_incoming(QEMUFile *f, Error **errp);
 441 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
 442 void migration_incoming_process(void);
 443
 444 bool  migration_has_all_channels(void);
 445
 446 uint64_t migrate_max_downtime(void);
 447
 448 void migrate_set_error(MigrationState *s, const Error *error);
 449 void migrate_fd_error(MigrationState *s, const Error *error);
 450
 451 void migrate_fd_connect(MigrationState *s, Error *error_in);
 452
 453 bool migration_is_setup_or_active(int state);
 454 bool migration_is_running(int state);
 455
 456 void migrate_init(MigrationState *s);
 457 bool migration_is_blocked(Error **errp);
 458 /* True if outgoing migration has entered postcopy phase */
 459 bool migration_in_postcopy(void);
 460 MigrationState *migrate_get_current(void);
 461
 462 uint64_t ram_get_total_transferred_pages(void);
 463
 464 /* Sending on the return path - generic and then for each message type */
 465 void migrate_send_rp_shut(MigrationIncomingState *mis,
 466                           uint32_t value);
 467 void migrate_send_rp_pong(MigrationIncomingState *mis,
 468                           uint32_t value);
 469 int migrate_send_rp_req_pages(MigrationIncomingState *mis, RAMBlock *rb,
 470                               ram_addr_t start, uint64_t haddr);
 471 int migrate_send_rp_message_req_pages(MigrationIncomingState *mis,
 472                                       RAMBlock *rb, ram_addr_t start);
 473 void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
 474                                  char *block_name);
 475 void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value);
 476
 477 void dirty_bitmap_mig_before_vm_start(void);
 478 void dirty_bitmap_mig_cancel_outgoing(void);
 479 void dirty_bitmap_mig_cancel_incoming(void);
 480 bool check_dirty_bitmap_mig_alias_map(const BitmapMigrationNodeAliasList *bbm,
 481                                       Error **errp);
 482
 483 void migrate_add_address(SocketAddress *address);
 484
 485 int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
 486
 487 #define qemu_ram_foreach_block \
 488   #warning "Use foreach_not_ignored_block in migration code"
 489
 490 void migration_make_urgent_request(void);
 491 void migration_consume_urgent_request(void);
 492 bool migration_rate_limit(void);
 493 void migration_cancel(const Error *error);
 494
 495 void populate_vfio_info(MigrationInfo *info);
 496 void postcopy_temp_page_reset(PostcopyTmpPage *tmp_page);
 497
 498 #endif