migration: Accept 'cont' only after successful incoming migration

When a 'cont' is issued on a VM that's just waiting for an incoming
migration, the VM reboots and boots into the guest, possibly corrupting
its storage since it could be shared with another VM running elsewhere.

Ensure that a VM started with '-incoming' is only run when an incoming
migration successfully completes.

A new qerror, QERR_MIGRATION_EXPECTED, is added to signal that 'cont'
failed due to no incoming migration has been attempted yet.

Reported-by: Laine Stump <laine@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/sysemu.h b/sysemu.h
index 9c988bb2a3..a1f6466ac2 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -99,6 +99,7 @@ typedef enum DisplayType
 } DisplayType;
 
 extern int autostart;
+extern int incoming_expected;
 extern int bios_size;
 
 typedef enum {