From af4ef2e88e3eae7012aa85febd2df6410c4d723b Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@redhat.com>
Date: Wed, 3 Feb 2010 16:11:03 -0500
Subject: [PATCH] --- yaml --- r: 186052 b: refs/heads/master c:
 6316e1c8c6af6ccb55ff8564231710660608f46c h: refs/heads/master v: v3

---
 [refs]                   |  2 +-
 trunk/arch/x86/kvm/mmu.c | 10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 0d76b41ef74b..85bf499a3904 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8f0b1ab6fb045a1324d9435ba00c2940783b0041
+refs/heads/master: 6316e1c8c6af6ccb55ff8564231710660608f46c
diff --git a/trunk/arch/x86/kvm/mmu.c b/trunk/arch/x86/kvm/mmu.c
index 913ef4b7939a..b8da6715d08b 100644
--- a/trunk/arch/x86/kvm/mmu.c
+++ b/trunk/arch/x86/kvm/mmu.c
@@ -838,9 +838,15 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 	u64 *spte;
 	int young = 0;
 
-	/* always return old for EPT */
+	/*
+	 * Emulate the accessed bit for EPT, by checking if this page has
+	 * an EPT mapping, and clearing it if it does. On the next access,
+	 * a new EPT mapping will be established.
+	 * This has some overhead, but not as much as the cost of swapping
+	 * out actively used pages or breaking up actively used hugepages.
+	 */
 	if (!shadow_accessed_mask)
-		return 0;
+		return kvm_unmap_rmapp(kvm, rmapp, data);
 
 	spte = rmap_next(kvm, rmapp, NULL);
 	while (spte) {