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Commit 612e89f0 authored by Avi Kivity's avatar Avi Kivity
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KVM: x86 emulator: implement ENTER



Opcode C8.

Only ENTER with lexical nesting depth 0 is implemented, since others are
very rare.  We'll fail emulation if nonzero lexical depth is used so data
is not corrupted.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 51ddff50
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+27 −1
Original line number Original line Diff line number Diff line
@@ -454,6 +454,11 @@ static ulong stack_mask(struct x86_emulate_ctxt *ctxt)
	return ~0U >> ((ss.d ^ 1) * 16);  /* d=0: 0xffff; d=1: 0xffffffff */
	return ~0U >> ((ss.d ^ 1) * 16);  /* d=0: 0xffff; d=1: 0xffffffff */
}
}


static int stack_size(struct x86_emulate_ctxt *ctxt)
{
	return (__fls(stack_mask(ctxt)) + 1) >> 3;
}

/* Access/update address held in a register, based on addressing mode. */
/* Access/update address held in a register, based on addressing mode. */
static inline unsigned long
static inline unsigned long
address_mask(struct x86_emulate_ctxt *ctxt, unsigned long reg)
address_mask(struct x86_emulate_ctxt *ctxt, unsigned long reg)
@@ -1592,6 +1597,26 @@ static int em_popf(struct x86_emulate_ctxt *ctxt)
	return emulate_popf(ctxt, &ctxt->dst.val, ctxt->op_bytes);
	return emulate_popf(ctxt, &ctxt->dst.val, ctxt->op_bytes);
}
}


static int em_enter(struct x86_emulate_ctxt *ctxt)
{
	int rc;
	unsigned frame_size = ctxt->src.val;
	unsigned nesting_level = ctxt->src2.val & 31;

	if (nesting_level)
		return X86EMUL_UNHANDLEABLE;

	rc = push(ctxt, &ctxt->regs[VCPU_REGS_RBP], stack_size(ctxt));
	if (rc != X86EMUL_CONTINUE)
		return rc;
	assign_masked(&ctxt->regs[VCPU_REGS_RBP], ctxt->regs[VCPU_REGS_RSP],
		      stack_mask(ctxt));
	assign_masked(&ctxt->regs[VCPU_REGS_RSP],
		      ctxt->regs[VCPU_REGS_RSP] - frame_size,
		      stack_mask(ctxt));
	return X86EMUL_CONTINUE;
}

static int em_leave(struct x86_emulate_ctxt *ctxt)
static int em_leave(struct x86_emulate_ctxt *ctxt)
{
{
	assign_masked(&ctxt->regs[VCPU_REGS_RSP], ctxt->regs[VCPU_REGS_RBP],
	assign_masked(&ctxt->regs[VCPU_REGS_RSP], ctxt->regs[VCPU_REGS_RBP],
@@ -3657,7 +3682,8 @@ static struct opcode opcode_table[256] = {
	I(DstReg | SrcMemFAddr | ModRM | No64 | Src2DS, em_lseg),
	I(DstReg | SrcMemFAddr | ModRM | No64 | Src2DS, em_lseg),
	G(ByteOp, group11), G(0, group11),
	G(ByteOp, group11), G(0, group11),
	/* 0xC8 - 0xCF */
	/* 0xC8 - 0xCF */
	N, I(Stack, em_leave), N, I(ImplicitOps | Stack, em_ret_far),
	I(Stack | SrcImmU16 | Src2ImmByte, em_enter), I(Stack, em_leave),
	N, I(ImplicitOps | Stack, em_ret_far),
	D(ImplicitOps), DI(SrcImmByte, intn),
	D(ImplicitOps), DI(SrcImmByte, intn),
	D(ImplicitOps | No64), II(ImplicitOps, em_iret, iret),
	D(ImplicitOps | No64), II(ImplicitOps, em_iret, iret),
	/* 0xD0 - 0xD7 */
	/* 0xD0 - 0xD7 */