KVM: x86 emulator: cleanup for BitOp instruction emulation

Commit Message

Wei Yongjun Aug. 4, 2010, 9:01 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index eba5a67..c05a5d7 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2545,6 +2545,10 @@  done_prefixes:
 		break;
 	}
 
+	/* Only subword offset for BitOp: bt/bts/btr/btc. */
+	if (c->d & BitOp)
+		c->src.val &= (c->op_bytes << 3) - 1;
+
 	/*
 	 * Decode and fetch the second source operand: register, memory
 	 * or immediate.
@@ -3303,8 +3307,6 @@  twobyte_insn:
 	case 0xa3:
 	      bt:		/* bt */
 		c->dst.type = OP_NONE;
-		/* only subword offset */
-		c->src.val &= (c->dst.bytes << 3) - 1;
 		emulate_2op_SrcV_nobyte("bt", c->src, c->dst, ctxt->eflags);
 		break;
 	case 0xa4: /* shld imm8, r, r/m */
@@ -3321,8 +3323,6 @@  twobyte_insn:
 		break;
 	case 0xab:
 	      bts:		/* bts */
-		/* only subword offset */
-		c->src.val &= (c->dst.bytes << 3) - 1;
 		emulate_2op_SrcV_nobyte("bts", c->src, c->dst, ctxt->eflags);
 		break;
 	case 0xac: /* shrd imm8, r, r/m */
@@ -3350,8 +3350,6 @@  twobyte_insn:
 		break;
 	case 0xb3:
 	      btr:		/* btr */
-		/* only subword offset */
-		c->src.val &= (c->dst.bytes << 3) - 1;
 		emulate_2op_SrcV_nobyte("btr", c->src, c->dst, ctxt->eflags);
 		break;
 	case 0xb6 ... 0xb7:	/* movzx */
@@ -3373,8 +3371,6 @@  twobyte_insn:
 		break;
 	case 0xbb:
 	      btc:		/* btc */
-		/* only subword offset */
-		c->src.val &= (c->dst.bytes << 3) - 1;
 		emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);
 		break;
 	case 0xbe ... 0xbf:	/* movsx */