From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Date: Sun, 5 Dec 2010 16:11:33 +0000 (+0900)
Subject: KVM: MMU: Avoid dropping accessed bit while removing write access
X-Git-Tag: v2.6.38-rc1~244^2~46
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=700e1b12196c4b01524ca10d89f8731418d72b6e;p=linux.git

KVM: MMU: Avoid dropping accessed bit while removing write access

One more "KVM: MMU: Don't drop accessed bit while updating an spte."

Sptes are accessed by both kvm and hardware.
This patch uses update_spte() to fix the way of removing write access.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d35950087e3d..482a5c0c48db 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3447,7 +3447,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
 		for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
 			/* avoid RMW */
 			if (is_writable_pte(pt[i]))
-				pt[i] &= ~PT_WRITABLE_MASK;
+				update_spte(&pt[i], pt[i] & ~PT_WRITABLE_MASK);
 	}
 	kvm_flush_remote_tlbs(kvm);
 }