From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date: Sat, 17 Nov 2012 03:39:05 +0000 (-0800)
Subject: x86, mm: Add pointer about Xen mmu requirement for alloc_low_pages
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=ddd3509df8f8d4f1cf4784f559d702ce00dc8846;p=deliverable%2Flinux.git

x86, mm: Add pointer about Xen mmu requirement for alloc_low_pages

Add link for more information
	279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve

-v2: updated to commets from hpa to include commit name.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-29-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 02cea14c6d0c..cb4f8ba70ecc 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -25,6 +25,15 @@ unsigned long __meminitdata pgt_buf_top;
 
 static unsigned long min_pfn_mapped;
 
+/*
+ * Pages returned are already directly mapped.
+ *
+ * Changing that is likely to break Xen, see commit:
+ *
+ *    279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
+ *
+ * for detailed information.
+ */
 __ref void *alloc_low_pages(unsigned int num)
 {
 	unsigned long pfn;