diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 17ad86b907960a709c87345a483129ce1731531d..2beb035035f9d4a92849639462ee5764bf6cd8f5 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -1188,11 +1188,32 @@
       <ref name="genericName"/>
     </attribute>
     <optional>
-      <attribute name="type">
-        <ref name="genericName"/>
+      <attribute name='type'>
+        <choice>
+          <ref name='diskFormat'/>
+          <value>aio</value> <!-- back-compat for 'raw' -->
+        </choice>
       </attribute>
     </optional>
   </define>
+  <define name='diskFormat'>
+    <choice>
+      <value>raw</value>
+      <value>dir</value>
+      <value>bochs</value>
+      <value>cloop</value>
+      <value>cow</value>
+      <value>dmg</value>
+      <value>iso</value>
+      <value>qcow</value>
+      <value>qcow2</value>
+      <value>qed</value>
+      <value>vmdk</value>
+      <value>vpc</value>
+      <value>fat</value>
+      <value>vhd</value>
+    </choice>
+  </define>
   <define name="driverCache">
     <attribute name="cache">
       <choice>
@@ -3356,7 +3377,7 @@
       </attribute>
       <optional>
         <attribute name='format'>
-          <ref name="genericName"/>
+          <ref name='diskFormat'/>
         </attribute>
       </optional>
       <optional>
diff --git a/docs/schemas/domainsnapshot.rng b/docs/schemas/domainsnapshot.rng
index 0ef0631246c003952023675f306fc8857fc90957..ecaafe9baeafb4d44081de69545c586f80f8ce05 100644
--- a/docs/schemas/domainsnapshot.rng
+++ b/docs/schemas/domainsnapshot.rng
@@ -105,7 +105,7 @@
               <element name='driver'>
                 <optional>
                   <attribute name='type'>
-                    <ref name='genericName'/>
+                    <ref name='diskFormat'/>
                   </attribute>
                 </optional>
                 <empty/>