[PATCH 3.19.y-ckt 043/155] x86/xen: Do not clip xen_e820_map to xen_e820_map_entries when sanitizing map

From: Kamal Mostafa
Date: Thu Nov 12 2015 - 19:00:50 EST


3.19.8-ckt10 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>

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@xxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
[ kamal: backport to 3.19-stable: context ]
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
arch/x86/xen/setup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 865e56c..8b9240b 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -621,7 +621,7 @@ 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)
--
1.9.1

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