[PATCH] public/gnttab: relax v2 recommendation

[Jan Beulich <jbeulich@xxxxxxxx>]

With there being a way to disable v2 support, telling new guests to use
v2 exclusively is not a good suggestion.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/include/public/grant_table.h
+++ b/xen/include/public/grant_table.h
@@ -121,8 +121,10 @@ typedef uint32_t grant_ref_t;
  */
 
 /*
- * Version 1 of the grant table entry structure is maintained purely
- * for backwards compatibility.  New guests should use version 2.
+ * Version 1 of the grant table entry structure is maintained largely for
+ * backwards compatibility.  New guests are recommended to support using
+ * version 2 to overcome version 1 limitations, but to be able to fall back
+ * to version 1.
  */
 #if __XEN_INTERFACE_VERSION__ < 0x0003020a
 #define grant_entry_v1 grant_entry