From e96d277ba252f785d1146520b794c4e159e34680 Mon Sep 17 00:00:00 2001
From: Stefan Bader <stefan.bader@canonical.com>
Date: Thu, 20 Jan 2011 15:38:23 +0100
Subject: [PATCH] --- yaml --- r: 232095 b: refs/heads/master c:
 8e1b4cf2108488ccfb9a3e7ed7cd85a435e01d4b h: refs/heads/master i:   232093:
 4732ca7273a502d338653ce440082eaa13cefbdd   232091:
 ac0e7f527fbce359caccd71eceb816c4c5b691da   232087:
 1b0e84b301d2a99b72794dbf70b1bca1cdb56352   232079:
 898ec8b75bcaf2bfdd6fb914cbce72cb5da7acec   232063:
 3d391049d6884d8809c8920b083746ce062d9f16 v: v3

---
 [refs]                   |  2 +-
 trunk/arch/x86/xen/p2m.c | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 394b4164e6d5..d34c95b6844c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7d81c3b9e2e5057c52256e154205143ad4e6e919
+refs/heads/master: 8e1b4cf2108488ccfb9a3e7ed7cd85a435e01d4b
diff --git a/trunk/arch/x86/xen/p2m.c b/trunk/arch/x86/xen/p2m.c
index 8f2251d2a3f8..ddc81a06edb9 100644
--- a/trunk/arch/x86/xen/p2m.c
+++ b/trunk/arch/x86/xen/p2m.c
@@ -237,7 +237,25 @@ void __init xen_build_dynamic_phys_to_machine(void)
 			p2m_top[topidx] = mid;
 		}
 
-		p2m_top[topidx][mididx] = &mfn_list[pfn];
+		/*
+		 * As long as the mfn_list has enough entries to completely
+		 * fill a p2m page, pointing into the array is ok. But if
+		 * not the entries beyond the last pfn will be undefined.
+		 * And guessing that the 'what-ever-there-is' does not take it
+		 * too kindly when changing it to invalid markers, a new page
+		 * is allocated, initialized and filled with the valid part.
+		 */
+		if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) {
+			unsigned long p2midx;
+			unsigned long *p2m = extend_brk(PAGE_SIZE, PAGE_SIZE);
+			p2m_init(p2m);
+
+			for (p2midx = 0; pfn + p2midx < max_pfn; p2midx++) {
+				p2m[p2midx] = mfn_list[pfn + p2midx];
+			}
+			p2m_top[topidx][mididx] = p2m;
+		} else
+			p2m_top[topidx][mididx] = &mfn_list[pfn];
 	}
 
 	m2p_override_init();