x86/xen: Do not clip xen_e820_map to xen_e820_map_entries when sanitizing map

commit 64c98e7f49100b637cd20a6c63508caed6bbba7a upstream.

Sanitizing the e820 map may produce extra E820 entries which would result in
the topmost E820 entries being removed. The removed entries would typically
include the top E820 usable RAM region and thus result in the domain having
signicantly less RAM available to it.

Fix by allowing sanitize_e820_map to use the full size of the allocated E820
array.

Signed-off-by: Malcolm Crossley <malcolm.crossley@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[bwh: Backported to 3.2:
 s/xen_e820_map_entries/memmap.nr_entries/; s/xen_e820_map/map/g]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 4d54b38e310c78ef2a367c55c0f4a38a37a3ad29..3c7b70deb7453cbac2e030ccf5bbdd4d817a696c 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -273,7 +273,7 @@ char * __init xen_memory_setup(void)
                xen_ignore_unusable(map, memmap.nr_entries);
 
        /* Make sure the Xen-supplied memory map is well-ordered. */
-       sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
+       sanitize_e820_map(map, ARRAY_SIZE(map), &memmap.nr_entries);
 
        max_pages = xen_get_max_pages();
        if (max_pages > max_pfn)