[Qemu-devel] [PATCH] migration: Issue 'cont' only on successful incoming migration

[Amit Shah <amit.shah@redhat.com>]

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.

Reported-by: Laine Stump <laine@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 migration.c |    3 +++
 monitor.c   |    4 ++++
 sysemu.h    |    1 +
 vl.c        |    3 +++
 4 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/migration.c b/migration.c
index 650eb78..84d7e4a 100644
--- a/migration.c
+++ b/migration.c
@@ -67,6 +67,9 @@ void process_incoming_migration(QEMUFile *f)
     qemu_announce_self();
     DPRINTF("successfully loaded vm state\n");
 
+    incoming_expected = false;
+    incoming_done = true;
+
     if (autostart)
         vm_start();
 }
diff --git a/monitor.c b/monitor.c
index 45fd482..d12a7b5 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1056,6 +1056,10 @@ static int do_cont(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     struct bdrv_iterate_context context = { mon, 0 };
 
+    if (incoming_expected && !incoming_done) {
+        autostart = 1;
+        return 1; /* Waiting for incoming migration */
+    }
     bdrv_iterate(encrypted_bdrv_it, &context);
     /* only resume the vm if all keys are set and valid */
     if (!context.err) {
diff --git a/sysemu.h b/sysemu.h
index 9c988bb..f9c1962 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -99,6 +99,7 @@ typedef enum DisplayType
 } DisplayType;
 
 extern int autostart;
+extern int incoming_expected, incoming_done;
 extern int bios_size;
 
 typedef enum {
diff --git a/vl.c b/vl.c
index ba6ee11..b69c11b 100644
--- a/vl.c
+++ b/vl.c
@@ -182,6 +182,8 @@ int nb_nics;
 NICInfo nd_table[MAX_NICS];
 int vm_running;
 int autostart;
+int incoming_expected; /* Started with -incoming and waiting for incoming */
+int incoming_done; /* Incoming migration successful */
 static int rtc_utc = 1;
 static int rtc_date_offset = -1; /* -1 means no change */
 QEMUClock *rtc_clock;
@@ -2557,6 +2559,7 @@ int main(int argc, char **argv, char **envp)
                 break;
             case QEMU_OPTION_incoming:
                 incoming = optarg;
+                incoming_expected = true;
                 break;
             case QEMU_OPTION_nodefaults:
                 default_serial = 0;
-- 
1.7.1.1