From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:54030)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1XTKui-0004wU-3r
	for qemu-devel@nongnu.org; Sun, 14 Sep 2014 21:17:12 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1XTKuV-0001kB-Dy
	for qemu-devel@nongnu.org; Sun, 14 Sep 2014 21:17:08 -0400
Received: from mail-la0-f46.google.com ([209.85.215.46]:52416)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1XTKuV-0001jx-6b
	for qemu-devel@nongnu.org; Sun, 14 Sep 2014 21:16:55 -0400
Received: by mail-la0-f46.google.com with SMTP id el20so3723668lab.19
	for <qemu-devel@nongnu.org>; Sun, 14 Sep 2014 18:16:54 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <878ulmoumw.fsf@linaro.org>
References: <1410626734-3804-1-git-send-email-rth@twiddle.net>
	<1410626734-3804-6-git-send-email-rth@twiddle.net>
	<878ulmoumw.fsf@linaro.org>
From: Peter Maydell <peter.maydell@linaro.org>
Date: Sun, 14 Sep 2014 18:16:33 -0700
Message-ID: <CAFEAcA9Nj7UzgNfGRNccoE-=2G_OR1wx5yC7gpnzHpAmvnNLgw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH 05/23] target-ppc: Use cpu_exec_enter qom
	hook
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: =?UTF-8?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>
Cc: Anthony Liguori <aliguori@amazon.com>, "qemu-ppc@nongnu.org" <qemu-ppc@nongnu.org>, QEMU Developers <qemu-devel@nongnu.org>, =?UTF-8?Q?Andreas_F=C3=A4rber?= <afaerber@suse.de>, Richard Henderson <rth@twiddle.net>

On 14 September 2014 12:43, Alex Benn=C3=A9e <alex.bennee@linaro.org> wrote=
:
>
> Richard Henderson writes:
>
>> Cc: qemu-ppc@nongnu.org
>> Signed-off-by: Richard Henderson <rth@twiddle.net>
> <snip>
>> +static void ppc_cpu_exec_enter(CPUState *cs)
>> +{
>> +    PowerPCCPU *cpu =3D POWERPC_CPU(cs);
>> +    CPUPPCState *env =3D &cpu->env;
>> +
>
> Ok the naming of those structures and the order to traverse them gets
> confusing - is it really CPUState -> ${ARCH}CPU -> ${ARCH}CPUState?

CPUState is the QOM base class name. The
subclass names are ${ARCH}CPU. CPU${ARCH}State
is the name of the "env struct" which is embedded
within the ${ARCH}CPU struct (but not at the start of it).

The available conversions are:
 ${ARCH}CPU to CPUState : CPU(x)
 CPUState to ${ARCH}CPU : ${ARCH}_CPU(cs)
(these are just the stock QOM casting macros)

 ${ARCH}CPU to env: &cpu->env
 env to ${ARCH}CPU: ${arch}_env_get_cpu(env)
(the latter is just a container_of operation)

 env to CPUState: ENV_GET_CPU(env)
 CPUState to env: convert via ${ARCH}_CPU
(and actually ENV_GET_CPU is just sugar for
a conversion via ${ARCH}_CPU)

As a method on the base QOM CPU class, this
family of functions is correctly taking CPUState*
as the argument.

-- PMM