From: Jan Beulich <JBeulich@suse.com>
Date: Thu, 6 Mar 2014 11:32:48 +0000 (+0000)
Subject: x86/shadow: add a clarifying assertion
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~5510
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks://%22Dat/%22http:/www.example.com/cgi/%22https:/%22bookmarks:/%22Dat?a=commitdiff_plain;h=4888ac5891f3daa37bdb3059893db084b50f497b;p=xen.git

x86/shadow: add a clarifying assertion

... documenting that we don't have to worry about merging guest
provided flags with the ones we want to enforce ourselves.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tim Deegan <tim@xen.org>
---

diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 5c7a7ace6b..3c1b25b998 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -592,6 +592,8 @@ _sh_propagate(struct vcpu *v,
     {
         unsigned int type;
 
+        ASSERT(!(sflags & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)));
+
         /* compute the PAT index for shadow page entry when VT-d is enabled
          * and device assigned. 
          * 1) direct MMIO: compute the PAT index with gMTRR=UC and gPAT.