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* QEMU live migration
* Copyright IBM, Corp. 2008
* Authors:
* Anthony Liguori <>
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
#include "exec/cpu-common.h"
#include "hw/qdev-core.h"
#include "qapi/qapi-types-migration.h"
#include "qemu/thread.h"
#include "qemu/coroutine_int.h"
#include "io/channel.h"
#include "net/announce.h"
struct PostcopyBlocktimeContext;
* 1<<6=64 pages -> 256K chunk when page size is 4K. This gives us
* the benefit that all the chunks are 64 pages aligned then the
* bitmaps are always aligned to LONG.
* 1<<18=256K pages -> 1G chunk when page size is 4K. This is the
* default value to use if no one specified.
* 1<<31=2G pages -> 8T chunk when page size is 4K. This should be
* big enough and make sure we won't overflow easily.
/* State for the incoming migration */
struct MigrationIncomingState {
QEMUFile *from_src_file;
* Free at the start of the main state load, set as the main thread finishes
* loading state.
QemuEvent main_thread_load_event;
/* For network announces */
AnnounceTimer announce_timer;
size_t largest_page_size;
bool have_fault_thread;
QemuThread fault_thread;
QemuSemaphore fault_thread_sem;
/* Set this when we want the fault thread to quit */
bool fault_thread_quit;
bool have_listen_thread;
QemuThread listen_thread;
QemuSemaphore listen_thread_sem;
/* For the kernel to send us notifications */
int userfault_fd;
/* To notify the fault_thread to wake, e.g., when need to quit */
int userfault_event_fd;
QEMUFile *to_src_file;
QemuMutex rp_mutex; /* We send replies from multiple threads */
/* RAMBlock of last request sent to source */
RAMBlock *last_rb;
void *postcopy_tmp_page;
void *postcopy_tmp_zero_page;
/* PostCopyFD's for external userfaultfds & handlers of shared memory */
GArray *postcopy_remote_fds;
int state;
bool have_colo_incoming_thread;
QemuThread colo_incoming_thread;
/* The coroutine we should enter (back) after failover */
Coroutine *migration_incoming_co;
QemuSemaphore colo_incoming_sem;
* PostcopyBlocktimeContext to keep information for postcopy
* live migration, to calculate vCPU block time
* */
struct PostcopyBlocktimeContext *blocktime_ctx;
/* notify PAUSED postcopy incoming migrations to try to continue */
bool postcopy_recover_triggered;
QemuSemaphore postcopy_pause_sem_dst;
QemuSemaphore postcopy_pause_sem_fault;
/* List of listening socket addresses */
SocketAddressList *socket_address_list;
MigrationIncomingState *migration_incoming_get_current(void);
void migration_incoming_state_destroy(void);
* Functions to work with blocktime context
void fill_destination_postcopy_migration_info(MigrationInfo *info);
#define TYPE_MIGRATION "migration"
#define MIGRATION_CLASS(klass) \
#define MIGRATION_OBJ(obj) \
#define MIGRATION_GET_CLASS(obj) \
typedef struct MigrationClass {
/*< private >*/
DeviceClass parent_class;
} MigrationClass;
struct MigrationState
/*< private >*/
DeviceState parent_obj;
/*< public >*/
QemuThread thread;
QEMUBH *cleanup_bh;
QEMUFile *to_dst_file;
* Protects to_dst_file pointer. We need to make sure we won't
* yield or hang during the critical section, since this lock will
* be used in OOB command handler.
QemuMutex qemu_file_lock;
* Used to allow urgent requests to override rate limiting.
QemuSemaphore rate_limit_sem;
/* pages already send at the beginning of current iteration */
uint64_t iteration_initial_pages;
/* pages transferred per second */
double pages_per_second;
/* bytes already send at the beginning of current iteration */
uint64_t iteration_initial_bytes;
/* time at the start of current iteration */
int64_t iteration_start_time;
* The final stage happens when the remaining data is smaller than
* this threshold; it's calculated from the requested downtime and
* measured bandwidth
int64_t threshold_size;
/* params from 'migrate-set-parameters' */
MigrationParameters parameters;
int state;
/* State related to return path */
struct {
QEMUFile *from_dst_file;
QemuThread rp_thread;
bool error;
QemuSemaphore rp_sem;
} rp_state;
double mbps;
/* Timestamp when recent migration starts (ms) */
int64_t start_time;
/* Total time used by latest migration (ms) */
int64_t total_time;
/* Timestamp when VM is down (ms) to migrate the last stuff */
int64_t downtime_start;
int64_t downtime;
int64_t expected_downtime;
bool enabled_capabilities[MIGRATION_CAPABILITY__MAX];
int64_t setup_time;
* Whether guest was running when we enter the completion stage.
* If migration is interrupted by any reason, we need to continue
* running the guest on source.
bool vm_was_running;
/* Flag set once the migration has been asked to enter postcopy */
bool start_postcopy;
/* Flag set after postcopy has sent the device state */
bool postcopy_after_devices;
/* Flag set once the migration thread is running (and needs joining) */
bool migration_thread_running;
/* Flag set once the migration thread called bdrv_inactivate_all */
bool block_inactive;
/* Migration is waiting for guest to unplug device */
QemuSemaphore wait_unplug_sem;
/* Migration is paused due to pause-before-switchover */
QemuSemaphore pause_sem;
/* The semaphore is used to notify COLO thread that failover is finished */
QemuSemaphore colo_exit_sem;
/* The semaphore is used to notify COLO thread to do checkpoint */
QemuSemaphore colo_checkpoint_sem;
int64_t colo_checkpoint_time;
QEMUTimer *colo_delay_timer;
/* The first error that has occurred.
We used the mutex to be able to return the 1st error message */
Error *error;
/* mutex to protect errp */
QemuMutex error_mutex;
/* Do we have to clean up -b/-i from old migrate parameters */
/* This feature is deprecated and will be removed */
bool must_remove_block_options;
* Global switch on whether we need to store the global state
* during migration.
bool store_global_state;
/* Whether we send QEMU_VM_CONFIGURATION during migration */
bool send_configuration;
/* Whether we send section footer during migration */
bool send_section_footer;
/* Needed by postcopy-pause state */
QemuSemaphore postcopy_pause_sem;
QemuSemaphore postcopy_pause_rp_sem;
* Whether we abort the migration if decompression errors are
* detected at the destination. It is left at false for qemu
* older than 3.0, since only newer qemu sends streams that
* do not trigger spurious decompression errors.
bool decompress_error_check;
* This decides the size of guest memory chunk that will be used
* to track dirty bitmap clearing. The size of memory chunk will
* be GUEST_PAGE_SIZE << N. Say, N=0 means we will clear dirty
* bitmap for each page to send (1<<0=1); N=10 means we will clear
* dirty bitmap only once for 1<<10=1K continuous guest pages
* (which is in 4M chunk).
uint8_t clear_bitmap_shift;
void migrate_set_state(int *state, int old_state, int new_state);
void migration_fd_process_incoming(QEMUFile *f, Error **errp);
void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
void migration_incoming_process(void);
bool migration_has_all_channels(void);
uint64_t migrate_max_downtime(void);
void migrate_set_error(MigrationState *s, const Error *error);
void migrate_fd_error(MigrationState *s, const Error *error);
void migrate_fd_connect(MigrationState *s, Error *error_in);
bool migration_is_setup_or_active(int state);
bool migration_is_running(int state);
void migrate_init(MigrationState *s);
bool migration_is_blocked(Error **errp);
/* True if outgoing migration has entered postcopy phase */
bool migration_in_postcopy(void);
MigrationState *migrate_get_current(void);
bool migrate_postcopy(void);
bool migrate_release_ram(void);
bool migrate_postcopy_ram(void);
bool migrate_zero_blocks(void);
bool migrate_dirty_bitmaps(void);
bool migrate_ignore_shared(void);
bool migrate_validate_uuid(void);
bool migrate_auto_converge(void);
bool migrate_use_multifd(void);
bool migrate_pause_before_switchover(void);
int migrate_multifd_channels(void);
MultiFDCompression migrate_multifd_compression(void);
int migrate_multifd_zlib_level(void);
int migrate_multifd_zstd_level(void);
int migrate_use_xbzrle(void);
int64_t migrate_xbzrle_cache_size(void);
bool migrate_colo_enabled(void);
bool migrate_use_block(void);
bool migrate_use_block_incremental(void);
int migrate_max_cpu_throttle(void);
bool migrate_use_return_path(void);
uint64_t ram_get_total_transferred_pages(void);
bool migrate_use_compression(void);
int migrate_compress_level(void);
int migrate_compress_threads(void);
int migrate_compress_wait_thread(void);
int migrate_decompress_threads(void);
bool migrate_use_events(void);
bool migrate_postcopy_blocktime(void);
/* Sending on the return path - generic and then for each message type */
void migrate_send_rp_shut(MigrationIncomingState *mis,
uint32_t value);
void migrate_send_rp_pong(MigrationIncomingState *mis,
uint32_t value);
int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char* rbname,
ram_addr_t start, size_t len);
void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
char *block_name);
void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value);
void dirty_bitmap_mig_before_vm_start(void);
void init_dirty_bitmap_incoming_migration(void);
void migrate_add_address(SocketAddress *address);
int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
#define qemu_ram_foreach_block \
#warning "Use foreach_not_ignored_block in migration code"
void migration_make_urgent_request(void);
void migration_consume_urgent_request(void);
bool migration_rate_limit(void);