Re: [PATCH] KVM: x86 emulator: emulate RETF imm

[Gleb Natapov <gleb@redhat.com>]

On Tue, Sep 03, 2013 at 01:42:09PM -0600, Bruce Rogers wrote:
> Opcode CA
> 
> This gets used by a DOS based NetWare guest.
> 
> Signed-off-by: Bruce Rogers <brogers@suse.com>
> ---
>  arch/x86/kvm/emulate.c |   23 ++++++++++++++++++++++-
>  1 files changed, 22 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 2bc1e81..aee238a 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -2025,6 +2025,26 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
>  	return rc;
>  }
>  
> +static int em_ret_far_imm(struct x86_emulate_ctxt *ctxt)
> +{
> +        int rc;
> +        unsigned long cs;
> +
> +        rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes);
> +        if (rc != X86EMUL_CONTINUE)
> +                return rc;
> +        if (ctxt->op_bytes == 4)
> +                ctxt->_eip = (u32)ctxt->_eip;
> +        rc = emulate_pop(ctxt, &cs, ctxt->op_bytes);
> +        if (rc != X86EMUL_CONTINUE)
> +                return rc;
> +        rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS);
> +        if (rc != X86EMUL_CONTINUE)
> +                return rc;
> +        rsp_increment(ctxt, ctxt->src.val);
> +        return X86EMUL_CONTINUE;
> +}
> +
Why not:

static int em_ret_far_imm(struct x86_emulate_ctxt *ctxt)
{
	int rc;
	rc = em_ret_far(struct x86_emulate_ctxt *ctxt);
	if (rc != X86EMUL_CONTINUE)
		return rc;
	rsp_increment(ctxt, ctxt->src.val);
	return X86EMUL_CONTINUE;
}

--
			Gleb.