1 files changed, 52 insertions, 46 deletions

diff --git a/kvm/kernel/x86_emulate.c b/kvm/kernel/x86_emulate.c
index be70795b4..7513cddb9 100644
--- a/kvm/kernel/x86_emulate.c
+++ b/kvm/kernel/x86_emulate.c
@@ -61,6 +61,7 @@
 #define ModRM       (1<<6)
 /* Destination is only written; never read. */
 #define Mov         (1<<7)
+#define BitOp       (1<<8)
 
 static u8 opcode_table[256] = {
 	/* 0x00 - 0x07 */
@@ -148,7 +149,7 @@ static u8 opcode_table[256] = {
 	0, 0, ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM
 };
 
-static u8 twobyte_table[256] = {
+static u16 twobyte_table[256] = {
 	/* 0x00 - 0x0F */
 	0, SrcMem | ModRM | DstReg, 0, 0, 0, 0, ImplicitOps, 0,
 	0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0,
@@ -180,16 +181,16 @@ static u8 twobyte_table[256] = {
 	/* 0x90 - 0x9F */
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	/* 0xA0 - 0xA7 */
-	0, 0, 0, DstMem | SrcReg | ModRM, 0, 0, 0, 0,
+	0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
 	/* 0xA8 - 0xAF */
-	0, 0, 0, DstMem | SrcReg | ModRM, 0, 0, 0, 0,
+	0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
 	/* 0xB0 - 0xB7 */
 	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,
-	    DstMem | SrcReg | ModRM,
+	    DstMem | SrcReg | ModRM | BitOp,
 	0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
 	    DstReg | SrcMem16 | ModRM | Mov,
 	/* 0xB8 - 0xBF */
-	0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM,
+	0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM | BitOp,
 	0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
 	    DstReg | SrcMem16 | ModRM | Mov,
 	/* 0xC0 - 0xCF */
@@ -469,7 +470,8 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
 int
 x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 {
-	u8 b, d, sib, twobyte = 0, rex_prefix = 0;
+	unsigned d;
+	u8 b, sib, twobyte = 0, rex_prefix = 0;
 	u8 modrm, modrm_mod = 0, modrm_reg = 0, modrm_rm = 0;
 	unsigned long *override_base = NULL;
 	unsigned int op_bytes, ad_bytes, lock_prefix = 0, rep_prefix = 0, i;
@@ -726,46 +728,6 @@ done_prefixes:
 		;
 	}
 
-	/* Decode and fetch the destination operand: register or memory. */
-	switch (d & DstMask) {
-	case ImplicitOps:
-		/* Special instructions do their own operand decoding. */
-		goto special_insn;
-	case DstReg:
-		dst.type = OP_REG;
-		if ((d & ByteOp)
-		    && !(twobyte_table && (b == 0xb6 || b == 0xb7))) {
-			dst.ptr = decode_register(modrm_reg, _regs,
-						  (rex_prefix == 0));
-			dst.val = *(u8 *) dst.ptr;
-			dst.bytes = 1;
-		} else {
-			dst.ptr = decode_register(modrm_reg, _regs, 0);
-			switch ((dst.bytes = op_bytes)) {
-			case 2:
-				dst.val = *(u16 *)dst.ptr;
-				break;
-			case 4:
-				dst.val = *(u32 *)dst.ptr;
-				break;
-			case 8:
-				dst.val = *(u64 *)dst.ptr;
-				break;
-			}
-		}
-		break;
-	case DstMem:
-		dst.type = OP_MEM;
-		dst.ptr = (unsigned long *)cr2;
-		dst.bytes = (d & ByteOp) ? 1 : op_bytes;
-		if (!(d & Mov) && /* optimisation - avoid slow emulated read */
-		    ((rc = ops->read_emulated((unsigned long)dst.ptr,
-					      &dst.val, dst.bytes, ctxt)) != 0))
-			goto done;
-		break;
-	}
-	dst.orig_val = dst.val;
-
 	/*
 	 * Decode and fetch the source operand: register, memory
 	 * or immediate.
@@ -838,6 +800,50 @@ done_prefixes:
 		break;
 	}
 
+	/* Decode and fetch the destination operand: register or memory. */
+	switch (d & DstMask) {
+	case ImplicitOps:
+		/* Special instructions do their own operand decoding. */
+		goto special_insn;
+	case DstReg:
+		dst.type = OP_REG;
+		if ((d & ByteOp)
+		    && !(twobyte_table && (b == 0xb6 || b == 0xb7))) {
+			dst.ptr = decode_register(modrm_reg, _regs,
+						  (rex_prefix == 0));
+			dst.val = *(u8 *) dst.ptr;
+			dst.bytes = 1;
+		} else {
+			dst.ptr = decode_register(modrm_reg, _regs, 0);
+			switch ((dst.bytes = op_bytes)) {
+			case 2:
+				dst.val = *(u16 *)dst.ptr;
+				break;
+			case 4:
+				dst.val = *(u32 *)dst.ptr;
+				break;
+			case 8:
+				dst.val = *(u64 *)dst.ptr;
+				break;
+			}
+		}
+		break;
+	case DstMem:
+		dst.type = OP_MEM;
+		dst.ptr = (unsigned long *)cr2;
+		dst.bytes = (d & ByteOp) ? 1 : op_bytes;
+		if (d & BitOp) {
+			dst.ptr += src.val / BITS_PER_LONG;
+			dst.bytes = sizeof(long);
+		}
+		if (!(d & Mov) && /* optimisation - avoid slow emulated read */
+		    ((rc = ops->read_emulated((unsigned long)dst.ptr,
+					      &dst.val, dst.bytes, ctxt)) != 0))
+			goto done;
+		break;
+	}
+	dst.orig_val = dst.val;
+
 	if (twobyte)
 		goto twobyte_insn;