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			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>
		
			
				
	
	
		
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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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| 
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| #ifndef QEMU_MIGRATION_SNAPSHOT_H
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| #define QEMU_MIGRATION_SNAPSHOT_H
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| 
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| #include "qapi/qapi-builtin-types.h"
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| #include "qapi/qapi-types-run-state.h"
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| 
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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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|  * @overwrite: replace existing snapshot with @name
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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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|  * @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 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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| 
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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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|  * @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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|  * @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 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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| 
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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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| 
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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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| 
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| #endif
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