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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2011-01-27 10:13:25 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-01-27 10:49:35 -0500
commit7cb31b752c71e0bd405c1139e1907c3335877dff (patch)
treefb867bd74a89ddff24075907080faa41b33797f2
parentcf04d120d9413de581437cf9a29f138ec1178f65 (diff)
xen/e820: Guard against E820_RAM not having page-aligned size or start.
Under Dell Inspiron 1525, and Intel SandyBridge SDP's the BIOS e820 RAM is not page-aligned: [ 0.000000] Xen: 0000000000100000 - 00000000df66d800 (usable) We were not handling that and ended up setting up a pagetable that included up to df66e000 with the disastrous effect that when memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t)); tried to clear the page it would crash at the 2K mark. Initially reported by Michael Young @ http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00108.html The fix is to page-align the size and also take into consideration the start of the E820 (in case that is not page-aligned either). This fixes the bootup failure on those affected machines. This patch is a rework of the Micheal A Young initial patch and considers the case if the start is not page-aligned. Reported-by: Michael A Young <m.a.young@durham.ac.uk> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Michael A Young <m.a.young@durham.ac.uk>
-rw-r--r--arch/x86/xen/setup.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index b5a7f928234b..75bdf2ab3d7c 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -179,8 +179,13 @@ char * __init xen_memory_setup(void)
e820.nr_map = 0;
xen_extra_mem_start = mem_end;
for (i = 0; i < memmap.nr_entries; i++) {
- unsigned long long end = map[i].addr + map[i].size;
+ unsigned long long end;
+ /* Guard against non-page aligned E820 entries. */
+ if (map[i].type == E820_RAM)
+ map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
+
+ end = map[i].addr + map[i].size;
if (map[i].type == E820_RAM && end > mem_end) {
/* RAM off the end - may be partially included */
u64 delta = min(map[i].size, end - mem_end);