diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 0c7e69c12e..89f444b967 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -28926,7 +28926,8 @@ virDomainDefCompatibleDevice(virDomainDefPtr def,
         if ((virDomainDefGetMemoryTotal(def) + sz) > def->mem.max_memory) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("Attaching memory device with size '%llu' would "
-                             "exceed domain's maxMemory config"), sz);
+                             "exceed domain's maxMemory config size '%llu'"),
+                           sz, def->mem.max_memory);
             return -1;
         }
     }