From 7cb31b752c71e0bd405c1139e1907c3335877dff Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 27 Jan 2011 10:13:25 -0500 Subject: 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 Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Michael A Young --- arch/x86/xen/setup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index b5a7f92..75bdf2a 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); -- cgit v1.1