Tip on FW features

Adding a tip on FW features

xml/libvirt_guest_installation.xml

@@ -598,7 +598,13 @@ network=vnet_nated</screen>
         must be explicitly specified. Users can reference the JSON descriptor
         files to find a firmware that satisfies their requirements. 
       </para>
-
+      <tip>
+        <para>
+          The directory <filename>/usr/share/qemu/firmware</filename> contains all the json files
+          used by &libvirt;. This file give you all firmwares's information including
+          the fetaures capabilities.
+        </para>
+      </tip>
       <para>
         When using <command>virt-install</command>, automatic firmware selection
         is enabled by specifying the <emphasis>firmware=efi</emphasis> parameter