[V2 PATCH 4/4] PVH xen tools: xenstored changes

[Mukesh Rathor <mukesh.rathor@oracle.com>]

 Allow map_interface in xenstored to revert to the
 xc_map_foreign_range if xc_gnttab_map_grant_ref is unable
 to map the mfn because grant is not yet setup for a PVH guest.
 PVH sets it up during boot via HVM mechanism.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 tools/xenstore/xenstored_domain.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index bf83d58..4a89831 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -168,13 +168,15 @@ static int readchn(struct connection *conn, void *data, unsigned int len)
 static void *map_interface(domid_t domid, unsigned long mfn)
 {
 	if (*xcg_handle != NULL) {
+		void *addr;
 		/* this is the preferred method */
-		return xc_gnttab_map_grant_ref(*xcg_handle, domid,
+		addr = xc_gnttab_map_grant_ref(*xcg_handle, domid,
 			GNTTAB_RESERVED_XENSTORE, PROT_READ|PROT_WRITE);
-	} else {
-		return xc_map_foreign_range(*xc_handle, domid,
-			getpagesize(), PROT_READ|PROT_WRITE, mfn);
+		if (addr)
+			return addr;
 	}
+	return xc_map_foreign_range(*xc_handle, domid,
+			getpagesize(), PROT_READ|PROT_WRITE, mfn);
 }
 
 static void unmap_interface(void *interface)
-- 
1.7.2.3