migration: Add multifd capability

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

--

Use new DEFINE_PROP

migration/migration.c

@@ -1449,6 +1449,15 @@ bool migrate_use_events(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
 }
 
+bool migrate_use_multifd(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_X_MULTIFD];
+}
+
 int migrate_use_xbzrle(void)
 {
     MigrationState *s;
@@ -2227,6 +2236,7 @@ static Property migration_properties[] = {
     DEFINE_PROP_MIG_CAP("x-release-ram", MIGRATION_CAPABILITY_RELEASE_RAM),
     DEFINE_PROP_MIG_CAP("x-block", MIGRATION_CAPABILITY_BLOCK),
     DEFINE_PROP_MIG_CAP("x-return-path", MIGRATION_CAPABILITY_RETURN_PATH),
+    DEFINE_PROP_MIG_CAP("x-multifd", MIGRATION_CAPABILITY_X_MULTIFD),
 
     DEFINE_PROP_END_OF_LIST(),
 };

migration/migration.h

@@ -174,6 +174,7 @@ bool migrate_postcopy_ram(void);
 bool migrate_zero_blocks(void);
 
 bool migrate_auto_converge(void);
+bool migrate_use_multifd(void);
 
 int migrate_use_xbzrle(void);
 int64_t migrate_xbzrle_cache_size(void);

qapi/migration.json

@@ -341,12 +341,14 @@
 # @return-path: If enabled, migration will use the return path even
 #               for precopy. (since 2.10)
 #
+# @x-multifd: Use more than one fd for migration (since 2.11)
+#
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
   'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
            'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
-           'block', 'return-path' ] }
+           'block', 'return-path', 'x-multifd' ] }
 
 ##
 # @MigrationCapabilityStatus: