From: Razvan Cojocaru <rcojocaru@bitdefender.com>
Date: Fri, 7 Oct 2016 09:35:58 +0000 (+0200)
Subject: x86/hvm: remove emulation context setting from hvmemul_cmpxchg()
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~196
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=84c1e7d8017c773c41d6e8b79384f37a67be1479;p=xen.git

x86/hvm: remove emulation context setting from hvmemul_cmpxchg()

hvmemul_cmpxchg() sets the read emulation context in p_new instead
of p_old, which is inconsistent (and wrong). Since p_old is
unused in any case and cmpxchg() semantics would be altered even
if it wasn't, remove the emulation context setting code.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
---

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index d759d3f7d1..6ed74866de 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1026,17 +1026,6 @@ static int hvmemul_cmpxchg(
     unsigned int bytes,
     struct x86_emulate_ctxt *ctxt)
 {
-    struct hvm_emulate_ctxt *hvmemul_ctxt =
-        container_of(ctxt, struct hvm_emulate_ctxt, ctxt);
-
-    if ( unlikely(hvmemul_ctxt->set_context) )
-    {
-        int rc = set_context_data(p_new, bytes);
-
-        if ( rc != X86EMUL_OKAY )
-            return rc;
-    }
-
     /* Fix this in case the guest is really relying on r-m-w atomicity. */
     return hvmemul_write(seg, offset, p_new, bytes, ctxt);
 }