From: Eduardo Habkost <ehabkost@redhat.com>
Date: Wed, 7 Oct 2015 20:19:18 +0000 (-0300)
Subject: target-i386: Ensure always-1 bits on DR6 can't be cleared
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=462f8ed1f1eac189ef50d9586eae8af90dbe426f;p=qemu.git

target-i386: Ensure always-1 bits on DR6 can't be cleared

Bits 4-11 and 16-31 on DR6 are documented as always 1, so ensure they
can't be cleared by software.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---

diff --git a/target-i386/bpt_helper.c b/target-i386/bpt_helper.c
index 144cfd43fc..dac1b1a360 100644
--- a/target-i386/bpt_helper.c
+++ b/target-i386/bpt_helper.c
@@ -262,7 +262,7 @@ void helper_set_dr(CPUX86State *env, int reg, target_ulong t0)
         }
         /* fallthru */
     case 6:
-        env->dr[6] = t0;
+        env->dr[6] = t0 | DR6_FIXED_1;
         return;
     case 5:
         if (env->cr[4] & CR4_DE_MASK) {