[Qemu-devel] [PATCH 1/7] target-i386: avoid repeated calls to the bnd_jmp helper

[Richard Henderson <rth@twiddle.net>]

From: Paolo Bonzini <pbonzini@redhat.com>

Two flags were tested the wrong way.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1456845145-18891-1-git-send-email-pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
[rth: Fixed enable test as well.]
---
 target-i386/translate.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/target-i386/translate.c b/target-i386/translate.c
index 53dee79..cd214a6 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -2409,12 +2409,12 @@ static void gen_reset_hflag(DisasContext *s, uint32_t mask)
 /* Clear BND registers during legacy branches.  */
 static void gen_bnd_jmp(DisasContext *s)
 {
-    /* Do nothing if BND prefix present, MPX is disabled, or if the
-       BNDREGs are known to be in INIT state already.  The helper
-       itself will check BNDPRESERVE at runtime.  */
+    /* Clear the registers only if BND prefix is missing, MPX is enabled,
+       and if the BNDREGs are known to be in use (non-zero) already.
+       The helper itself will check BNDPRESERVE at runtime.  */
     if ((s->prefix & PREFIX_REPNZ) == 0
-        && (s->flags & HF_MPX_EN_MASK) == 0
-        && (s->flags & HF_MPX_IU_MASK) == 0) {
+        && (s->flags & HF_MPX_EN_MASK) != 0
+        && (s->flags & HF_MPX_IU_MASK) != 0) {
         gen_helper_bnd_jmp(cpu_env);
     }
 }
-- 
2.5.0