conf: Hoist validation of memory size into the post parse callback

Later patches will need to access the full definition to do check the
memory size and thus the checking needs to be done after the whole
definition including devices is known.

src/conf/domain_conf.c

@@ -3172,6 +3172,26 @@ virDomainDefPostParseInternal(virDomainDefPtr def,
         return -1;
     }
 
+    if (def->mem.cur_balloon > def->mem.max_balloon) {
+        /* Older libvirt could get into this situation due to
+         * rounding; if the discrepancy is less than 4MiB, we silently
+         * round down, otherwise we flag the issue.  */
+        if (VIR_DIV_UP(def->mem.cur_balloon, 4096) >
+            VIR_DIV_UP(def->mem.max_balloon, 4096)) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("current memory '%lluk' exceeds "
+                             "maximum '%lluk'"),
+                           def->mem.cur_balloon, def->mem.max_balloon);
+            return -1;
+        } else {
+            VIR_DEBUG("Truncating current %lluk to maximum %lluk",
+                      def->mem.cur_balloon, def->mem.max_balloon);
+            def->mem.cur_balloon = def->mem.max_balloon;
+        }
+    } else if (def->mem.cur_balloon == 0) {
+        def->mem.cur_balloon = def->mem.max_balloon;
+    }
+
     /*
      * Some really crazy backcompat stuff for consoles
      *
@@ -13036,27 +13056,6 @@ virDomainDefParseXML(xmlDocPtr xml,
     }
     VIR_FREE(tmp);
 
-    if (def->mem.cur_balloon > def->mem.max_balloon) {
-        /* Older libvirt could get into this situation due to
-         * rounding; if the discrepancy is less than 4MiB, we silently
-         * round down, otherwise we flag the issue.  */
-        if (VIR_DIV_UP(def->mem.cur_balloon, 4096) >
-            VIR_DIV_UP(def->mem.max_balloon, 4096)) {
-            virReportError(VIR_ERR_XML_ERROR,
-                           _("current memory '%lluk' exceeds "
-                             "maximum '%lluk'"),
-                           def->mem.cur_balloon, def->mem.max_balloon);
-            goto error;
-        } else {
-            VIR_DEBUG("Truncating current %lluk to maximum %lluk",
-                      def->mem.cur_balloon, def->mem.max_balloon);
-            def->mem.cur_balloon = def->mem.max_balloon;
-        }
-    } else if (def->mem.cur_balloon == 0) {
-        def->mem.cur_balloon = def->mem.max_balloon;
-    }
-
-
     if ((n = virXPathNodeSet("./memoryBacking/hugepages/page", ctxt, &nodes)) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("cannot extract hugepages nodes"));