From: Dr. David Alan Gilbert <dgilbert@redhat.com>
Date: Fri, 20 Oct 2017 09:05:50 +0000 (+0100)
Subject: migration: Add 'pause-before-switchover' capability
X-Git-Tag: v2.11.0-rc0~28^2~15
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=93fbd0314ec060ffaf90169a06d5737fa97ffb25;p=thirdparty%2Fqemu.git

migration: Add 'pause-before-switchover' capability

When 'pause-before-switchover' is enabled, the outgoing migration
will pause before invalidating the block devices and serializing
the device state.
At this point the management layer gets the chance to clean up any
device jobs or other device users before the migration completes.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---

diff --git a/migration/migration.c b/migration/migration.c
index 3feffb5e265..c041ec7aedf 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1511,6 +1511,16 @@ bool migrate_use_multifd(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_X_MULTIFD];
 }
 
+bool migrate_pause_before_switchover(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[
+        MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER];
+}
+
 int migrate_multifd_channels(void)
 {
     MigrationState *s;
diff --git a/migration/migration.h b/migration/migration.h
index b83cceadc44..969866303e1 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -177,6 +177,7 @@ bool migrate_zero_blocks(void);
 
 bool migrate_auto_converge(void);
 bool migrate_use_multifd(void);
+bool migrate_pause_before_switchover(void);
 int migrate_multifd_channels(void);
 int migrate_multifd_page_count(void);
 
diff --git a/qapi/migration.json b/qapi/migration.json
index f8b365e3f51..4960231ba2b 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -341,6 +341,9 @@
 # @return-path: If enabled, migration will use the return path even
 #               for precopy. (since 2.10)
 #
+# @pause-before-switchover: Pause outgoing migration before serialising device
+#          state and before disabling block IO (since 2.11)
+#
 # @x-multifd: Use more than one fd for migration (since 2.11)
 #
 # Since: 1.2
@@ -348,7 +351,7 @@
 { 'enum': 'MigrationCapability',
   'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
            'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
-           'block', 'return-path', 'x-multifd' ] }
+           'block', 'return-path', 'pause-before-switchover', 'x-multifd' ] }
 
 ##
 # @MigrationCapabilityStatus: