Add 'auto-converge' migration capability

The auto-converge migration capability allows the user to specify if they
choose live migration seqeunce to automatically detect and force convergence.

Signed-off-by: Chegu Vinod <chegu_vinod@hp.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

include/migration/migration.h

@@ -125,6 +125,8 @@ void migrate_del_blocker(Error *reason);
 
 bool migrate_rdma_pin_all(void);
 
+bool migrate_auto_converge(void);
+
 int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
                          uint8_t *dst, int dlen);
 int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen);

migration.c

@@ -484,6 +484,15 @@ bool migrate_rdma_pin_all(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_X_RDMA_PIN_ALL];
 }
 
+bool migrate_auto_converge(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
+}
+
 int migrate_use_xbzrle(void)
 {
     MigrationState *s;

qapi-schema.json

@@ -616,7 +616,7 @@
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
-  'data': ['xbzrle', 'x-rdma-pin-all'] }
+  'data': ['xbzrle', 'x-rdma-pin-all', 'auto-converge'] }
 
 ##
 # @MigrationCapabilityStatus