include/migration/register.h

   1 /*
   2  * QEMU migration vmstate registration
   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 MIGRATION_REGISTER_H
  15 #define MIGRATION_REGISTER_H
  16
  17 #include "hw/vmstate-if.h"
  18
  19 typedef struct SaveVMHandlers {
  20     /* This runs inside the BQL.  */
  21     void (*save_state)(QEMUFile *f, void *opaque);
  22
  23     /*
  24      * save_prepare is called early, even before migration starts, and can be
  25      * used to perform early checks.
  26      */
  27     int (*save_prepare)(void *opaque, Error **errp);
  28     int (*save_setup)(QEMUFile *f, void *opaque);
  29     void (*save_cleanup)(void *opaque);
  30     int (*save_live_complete_postcopy)(QEMUFile *f, void *opaque);
  31     int (*save_live_complete_precopy)(QEMUFile *f, void *opaque);
  32
  33     /* This runs both outside and inside the BQL.  */
  34     bool (*is_active)(void *opaque);
  35     bool (*has_postcopy)(void *opaque);
  36
  37     /* is_active_iterate
  38      * If it is not NULL then qemu_savevm_state_iterate will skip iteration if
  39      * it returns false. For example, it is needed for only-postcopy-states,
  40      * which needs to be handled by qemu_savevm_state_setup and
  41      * qemu_savevm_state_pending, but do not need iterations until not in
  42      * postcopy stage.
  43      */
  44     bool (*is_active_iterate)(void *opaque);
  45
  46     /* This runs outside the BQL in the migration case, and
  47      * within the lock in the savevm case.  The callback had better only
  48      * use data that is local to the migration thread or protected
  49      * by other locks.
  50      */
  51     int (*save_live_iterate)(QEMUFile *f, void *opaque);
  52
  53     /* This runs outside the BQL!  */
  54     /* Note for save_live_pending:
  55      * must_precopy:
  56      * - must be migrated in precopy or in stopped state
  57      * - i.e. must be migrated before target start
  58      *
  59      * can_postcopy:
  60      * - can migrate in postcopy or in stopped state
  61      * - i.e. can migrate after target start
  62      * - some can also be migrated during precopy (RAM)
  63      * - some must be migrated after source stops (block-dirty-bitmap)
  64      *
  65      * Sum of can_postcopy and must_postcopy is the whole amount of
  66      * pending data.
  67      */
  68     /* This estimates the remaining data to transfer */
  69     void (*state_pending_estimate)(void *opaque, uint64_t *must_precopy,
  70                                    uint64_t *can_postcopy);
  71     /* This calculate the exact remaining data to transfer */
  72     void (*state_pending_exact)(void *opaque, uint64_t *must_precopy,
  73                                 uint64_t *can_postcopy);
  74     int (*load_state)(QEMUFile *f, void *opaque, int version_id);
  75     int (*load_setup)(QEMUFile *f, void *opaque);
  76     int (*load_cleanup)(void *opaque);
  77     /* Called when postcopy migration wants to resume from failure */
  78     int (*resume_prepare)(MigrationState *s, void *opaque);
  79     /* Checks if switchover ack should be used. Called only in dest */
  80     bool (*switchover_ack_needed)(void *opaque);
  81 } SaveVMHandlers;
  82
  83 int register_savevm_live(const char *idstr,
  84                          uint32_t instance_id,
  85                          int version_id,
  86                          const SaveVMHandlers *ops,
  87                          void *opaque);
  88
  89 void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque);
  90
  91 #endif