Commit a77ab5ea authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: x86 emulator: implement 'ret far' instruction (opcode 0xcb) 



Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 8b3079a5

arch/x86/kvm/x86_emulate.c

+25 −1
Original line number Diff line number Diff line
@@ -178,7 +178,7 @@ static u32 opcode_table[256] = { 
	0, ImplicitOps | Stack, 0, 0,

	ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov,

	/* 0xC8 - 0xCF */

	0, 0, 0, 0, 0, 0, 0, 0,

	0, 0, 0, ImplicitOps | Stack, 0, 0, 0, 0,

	/* 0xD0 - 0xD7 */

	ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,

	ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
@@ -1278,6 +1278,25 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt, 
	return 0;

}



static int emulate_ret_far(struct x86_emulate_ctxt *ctxt,

			   struct x86_emulate_ops *ops)

{

	struct decode_cache *c = &ctxt->decode;

	int rc;

	unsigned long cs;



	rc = emulate_pop(ctxt, ops, &c->eip, c->op_bytes);

	if (rc)

		return rc;

	if (c->op_bytes == 4)

		c->eip = (u32)c->eip;

	rc = emulate_pop(ctxt, ops, &cs, c->op_bytes);

	if (rc)

		return rc;

	rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)cs, 1, VCPU_SREG_CS);

	return rc;

}



static inline int writeback(struct x86_emulate_ctxt *ctxt,

			    struct x86_emulate_ops *ops)

{
@@ -1735,6 +1754,11 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	mov:

		c->dst.val = c->src.val;

		break;

	case 0xcb:		/* ret far */

		rc = emulate_ret_far(ctxt, ops);

		if (rc)

			goto done;

		break;

	case 0xd0 ... 0xd1:	/* Grp2 */

		c->src.val = 1;

		emulate_grp2(ctxt);