x86: add movnti emulation

Linux added the use of movnti for copying from user to kernel space in
certain cases, and as per reports we got this may happen with the
destination being in MMIO.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c
index 8a6202b934c35b7f21cdcd9c6ad4966d65dcd1d5..c68bac53a84547a85e5f874dd3022d89d368f254 100644 (file)
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -236,7 +236,8 @@ static uint8_t twobyte_table[256] = {
     DstReg|SrcMem|ModRM, DstReg|SrcMem|ModRM,
     ByteOp|DstReg|SrcMem|ModRM|Mov, DstReg|SrcMem16|ModRM|Mov,
     /* 0xC0 - 0xC7 */
-    ByteOp|DstMem|SrcReg|ModRM, DstMem|SrcReg|ModRM, 0, 0,
+    ByteOp|DstMem|SrcReg|ModRM, DstMem|SrcReg|ModRM,
+    0, DstMem|SrcReg|ModRM|Mov,
     0, 0, 0, ImplicitOps|ModRM,
     /* 0xC8 - 0xCF */
     ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
@@ -3910,6 +3911,12 @@ x86_emulate(
         }
         goto add;
 
+    case 0xc3: /* movnti */
+        /* Ignore the non-temporal hint for now. */
+        generate_exception_if(dst.bytes <= 2, EXC_UD, -1);
+        dst.val = src.val;
+        break;
+
     case 0xc7: /* Grp9 (cmpxchg8b/cmpxchg16b) */ {
         unsigned long old[2], exp[2], new[2];
         unsigned int i;