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>
[ luis: backported to 3.16:
  - use 'map' instead of 'xen_e820_map_entries' ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 2e555163c2fe4f0b44f37289887539ab274adc1c..dca94c650d6a45854bf315569f680fdfb0f9158e 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -385,7 +385,7 @@ 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)