[3.16.y-ckt stable] Patch "x86/xen: Do not clip xen_e820_map to xen_e820_map_entries when sanitizing map" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

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

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt21.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 77d90149203cbadc6a935116eafb380908d243f1 Mon Sep 17 00:00:00 2001
From: Malcolm Crossley <malcolm.crossley at citrix.com>
Date: Mon, 28 Sep 2015 11:36:52 +0100
Subject: 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 at citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky at oracle.com>
Signed-off-by: David Vrabel <david.vrabel at citrix.com>
[ luis: backported to 3.16:
  - use 'map' instead of 'xen_e820_map_entries' ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 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 2e555163c2fe..dca94c650d6a 100644
--- 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)