KVM: x86 emulator: add bsf/bsr instruction emulation

Commit Message

Wei Yongjun Aug. 9, 2010, 10 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index fb4ac8c..831aa6e 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2342,8 +2342,8 @@  static struct opcode twobyte_table[256] = {
 	/* 0xB8 - 0xBF */
 	N, N,
 	G(BitOp, group8), D(DstMem | SrcReg | ModRM | BitOp | Lock),
-	N, N, D(ByteOp | DstReg | SrcMem | ModRM | Mov),
-	    D(DstReg | SrcMem16 | ModRM | Mov),
+	D(DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),
+	D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
 	/* 0xC0 - 0xCF */
 	N, N, N, D(DstMem | SrcReg | ModRM | Mov),
 	N, N, N, GD(0, &group9),
@@ -3464,6 +3464,30 @@  twobyte_insn:
 	      btc:		/* btc */
 		emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);
 		break;
+	case 0xbc: {		/* bsf */
+		int zf;
+		__asm__ ("bsf %2, %0; setz %b1"
+			 : "=r"(c->dst.val), "=q"(zf)
+			 : "r"(c->src.val), "1" (0));
+		ctxt->eflags &= ~X86_EFLAGS_ZF;
+		if (zf) {
+			ctxt->eflags |= X86_EFLAGS_ZF;
+			c->dst.type = OP_NONE;	/* Disable writeback. */
+		}
+		break;
+	}
+	case 0xbd: {		/* bsr */
+		int zf;
+		__asm__ ("bsr %2, %0; setz %b1"
+			 : "=r"(c->dst.val), "=q"(zf)
+			 : "r"(c->src.val), "1" (0));
+		ctxt->eflags &= ~X86_EFLAGS_ZF;
+		if (zf) {
+			ctxt->eflags |= X86_EFLAGS_ZF;
+			c->dst.type = OP_NONE;	/* Disable writeback. */
+		}
+		break;
+	}
 	case 0xbe ... 0xbf:	/* movsx */
 		c->dst.bytes = c->op_bytes;
 		c->dst.val = (c->d & ByteOp) ? (s8) c->src.val :