From: Keir Fraser <keir.fraser@citrix.com>
Date: Fri, 7 Aug 2009 09:53:22 +0000 (+0100)
Subject: x86_emulate: Fixes for 'mov rm16,sreg'
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~13506
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=b1b6362f10c95343eec1be30c346593df89adf9f;p=xen.git

x86_emulate: Fixes for 'mov rm16,sreg'

1. Memory reads should be 16 bits only
2. Attempt to load %cs should result in #UD

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
---

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c
index 8fa5fd400b..dc6e624995 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -113,7 +113,7 @@ static uint8_t opcode_table[256] = {
     ByteOp|DstMem|SrcReg|ModRM|Mov, DstMem|SrcReg|ModRM|Mov,
     ByteOp|DstReg|SrcMem|ModRM|Mov, DstReg|SrcMem|ModRM|Mov,
     DstMem|SrcReg|ModRM|Mov, DstReg|SrcNone|ModRM,
-    DstReg|SrcMem|ModRM|Mov, DstMem|SrcNone|ModRM|Mov,
+    DstReg|SrcMem16|ModRM|Mov, DstMem|SrcNone|ModRM|Mov,
     /* 0x90 - 0x97 */
     ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
     ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
@@ -2042,6 +2042,7 @@ x86_emulate(
     case 0x8e: /* mov r/m,Sreg */ {
         enum x86_segment seg = decode_segment(modrm_reg);
         generate_exception_if(seg == decode_segment_failed, EXC_UD, -1);
+        generate_exception_if(seg == x86_seg_cs, EXC_UD, -1);
         if ( (rc = load_seg(seg, (uint16_t)src.val, ctxt, ops)) != 0 )
             goto done;
         if ( seg == x86_seg_ss )