2017-04-20 14:25:55 +02:00
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/*
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* QEMU snapshots
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*
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* Copyright (c) 2004-2008 Fabrice Bellard
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* Copyright (c) 2009-2015 Red Hat Inc
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*
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* Authors:
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* Juan Quintela <quintela@redhat.com>
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*
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#ifndef QEMU_MIGRATION_SNAPSHOT_H
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#define QEMU_MIGRATION_SNAPSHOT_H
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2021-02-04 13:48:30 +01:00
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#include "qapi/qapi-builtin-types.h"
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migration: preserve suspended for snapshot
Restoring a snapshot can break a suspended guest. Snapshots suffer from
the same suspended-state issues that affect live migration, plus they must
handle an additional problematic scenario, which is that a running vm must
remain running if it loads a suspended snapshot.
To save, the existing vm_stop call now completely stops the suspended
state. Finish with vm_resume to leave the vm in the state it had prior
to the save, correctly restoring the suspended state.
To load, if the snapshot is not suspended, then vm_stop + vm_resume
correctly handles all states, and leaves the vm in the state it had prior
to the load. However, if the snapshot is suspended, restoration is
trickier. First, call vm_resume to restore the state to suspended so the
current state matches the saved state. Then, if the pre-load state is
running, call wakeup to resume running.
Prior to these changes, the vm_stop to RUN_STATE_SAVE_VM and
RUN_STATE_RESTORE_VM did not change runstate if the current state was
suspended, but now it does, so allow these transitions.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-8-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-03 21:05:36 +01:00
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#include "qapi/qapi-types-run-state.h"
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2021-02-04 13:48:30 +01:00
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2021-02-04 13:48:24 +01:00
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/**
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* save_snapshot: Save an internal snapshot.
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* @name: name of internal snapshot
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2021-02-04 13:48:29 +01:00
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* @overwrite: replace existing snapshot with @name
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2021-02-04 13:48:30 +01:00
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* @vmstate: blockdev node name to store VM state in
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* @has_devices: whether to use explicit device list
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* @devices: explicit device list to snapshot
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2021-02-04 13:48:24 +01:00
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* @errp: pointer to error object
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* On success, return %true.
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* On failure, store an error through @errp and return %false.
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*/
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2021-02-04 13:48:30 +01:00
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bool save_snapshot(const char *name, bool overwrite,
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const char *vmstate,
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bool has_devices, strList *devices,
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Error **errp);
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2021-02-04 13:48:25 +01:00
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/**
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* load_snapshot: Load an internal snapshot.
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* @name: name of internal snapshot
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2021-02-04 13:48:30 +01:00
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* @vmstate: blockdev node name to load VM state from
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* @has_devices: whether to use explicit device list
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* @devices: explicit device list to snapshot
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2021-02-04 13:48:25 +01:00
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* @errp: pointer to error object
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* On success, return %true.
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* On failure, store an error through @errp and return %false.
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*/
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2021-02-04 13:48:30 +01:00
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bool load_snapshot(const char *name,
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const char *vmstate,
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bool has_devices, strList *devices,
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Error **errp);
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2017-04-20 14:25:55 +02:00
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2021-02-04 13:48:31 +01:00
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/**
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* delete_snapshot: Delete a snapshot.
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* @name: path to snapshot
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* @has_devices: whether to use explicit device list
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* @devices: explicit device list to snapshot
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* @errp: pointer to error object
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* On success, return %true.
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* On failure, store an error through @errp and return %false.
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*/
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bool delete_snapshot(const char *name,
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bool has_devices, strList *devices,
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Error **errp);
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migration: preserve suspended for snapshot
Restoring a snapshot can break a suspended guest. Snapshots suffer from
the same suspended-state issues that affect live migration, plus they must
handle an additional problematic scenario, which is that a running vm must
remain running if it loads a suspended snapshot.
To save, the existing vm_stop call now completely stops the suspended
state. Finish with vm_resume to leave the vm in the state it had prior
to the save, correctly restoring the suspended state.
To load, if the snapshot is not suspended, then vm_stop + vm_resume
correctly handles all states, and leaves the vm in the state it had prior
to the load. However, if the snapshot is suspended, restoration is
trickier. First, call vm_resume to restore the state to suspended so the
current state matches the saved state. Then, if the pre-load state is
running, call wakeup to resume running.
Prior to these changes, the vm_stop to RUN_STATE_SAVE_VM and
RUN_STATE_RESTORE_VM did not change runstate if the current state was
suspended, but now it does, so allow these transitions.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-8-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-01-03 21:05:36 +01:00
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/**
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* load_snapshot_resume: Restore runstate after loading snapshot.
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* @state: state to restore
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*/
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void load_snapshot_resume(RunState state);
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2017-04-20 14:25:55 +02:00
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#endif
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