From: Jan Beulich <jbeulich@suse.com>
Date: Wed, 20 Dec 2017 09:12:11 +0000 (+0100)
Subject: x86/shadow: make 1-bit-disable match 1-bit-enable
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~887
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=ca39b45bd2a2a394bdb81cc1b3240bab9aece92e;p=xen.git

x86/shadow: make 1-bit-disable match 1-bit-enable

shadow_one_bit_enable() sets PG_SH_enable (if not already set of course)
in addition to the bit being requested. Make shadow_one_bit_disable()
behave similarly - clear PG_SH_enable if that's the only bit remaining.

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

diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 600df0cedc..0e9e1912ca 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -3377,7 +3377,10 @@ static int shadow_one_bit_disable(struct domain *d, u32 mode)
     }
 
     /* Update the bits */
-    sh_new_mode(d, d->arch.paging.mode & ~mode);
+    mode = d->arch.paging.mode & ~mode;
+    if ( mode == PG_SH_enable )
+        mode = 0;
+    sh_new_mode(d, mode);
     if ( d->arch.paging.mode == 0 )
     {
         /* Get this domain off shadows */