docs, conf, schema: add support for shared memory mapping

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>

docs/formatdomain.html.in

@@ -1141,7 +1141,7 @@
     ...
     <numa>
       <cell id='0' cpus='0-3' memory='512000'/>
-      <cell id='1' cpus='4-7' memory='512000'/>
+      <cell id='1' cpus='4-7' memory='512000' memAccess='shared'/>
     </numa>
     ...
   </cpu>
@@ -1158,6 +1158,11 @@
       assigned <code>id</code>s in the increasing order starting from
       0.  Mixing cells with and without the <code>id</code> attribute
       is not recommended as it may result in unwanted behaviour.
+
+      <span class='since'>Since 1.2.9</span> the optional attribute
+      <code>memAccess</code> can control whether the memory is to be
+      mapped as "shared" or "private".  This is valid only for
+      hugepages-backed memory.
     </p>
 
     <p>

docs/schemas/domaincommon.rng

@@ -4030,6 +4030,14 @@
       <attribute name="memory">
         <ref name="memoryKB"/>
       </attribute>
+      <optional>
+        <attribute name="memAccess">
+          <choice>
+            <value>shared</value>
+            <value>private</value>
+          </choice>
+        </attribute>
+      </optional>
     </element>
   </define>