From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7920AEB64D9 for ; Thu, 29 Jun 2023 13:42:10 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qErtn-0001Kt-Qo; Thu, 29 Jun 2023 09:41:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qErtm-0001Jm-Fy for qemu-devel@nongnu.org; Thu, 29 Jun 2023 09:41:26 -0400 Received: from mail-wr1-x42e.google.com ([2a00:1450:4864:20::42e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qErtk-0001oH-Kn for qemu-devel@nongnu.org; Thu, 29 Jun 2023 09:41:26 -0400 Received: by mail-wr1-x42e.google.com with SMTP id ffacd0b85a97d-3094910b150so772993f8f.0 for ; Thu, 29 Jun 2023 06:41:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1688046083; x=1690638083; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=dnZTPLoaZx8Nk2z2XqVUeu3zBMJ+VXgYU2pI3EyyALU=; b=lVVQRlI4e7t+vBB9rVzKojGN4kU25H1f+xQzkHR9TAFmif2DiOHOXPyqVsiWoO1grG erukjuPHPaOh4EWH25N2j9lcjBfjHAmTGYMaOn32lLyI4EeOkCnNddoDctNEnZfLPjEz NQ5uzh+na9ythm12pnYZGBIT6RnmsAxiQJDOu3VcQePwXgtCdCHOd2itFwxWVUbK3Gi/ L0sl/Lh3H3xkE3WUUudvcaW/EyIaeO8ewP4HjEqzzhnPGktTE6DrvfDiCuDUdYH3ilt0 WYalxOVLVkkqsmRlyuL/ZI0lxWMVq/M2k46TrUfQuuRY7L4NHU8jQJ2sI0YtkBl5IF8j jIjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688046083; x=1690638083; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=dnZTPLoaZx8Nk2z2XqVUeu3zBMJ+VXgYU2pI3EyyALU=; b=OvSc8B6VYDb9Bip4JnDJk+ijisr57qt+7A2VUeDEPQyhMNNGmFEJyETBSF3XGU6Z36 P1alzDJZlo9vPsBjE3fqg0zx/6Odv0TOmOh8NUHjWGT2yQpxzibcpTkEcfTO8hkp34ON In4M/nZw5ueJgV8jptNCf4s1S44DcdiUXApHsZbJaHIgzlyUKu7I5cHw2vN6AHXVz8E9 SGFlr2MtdDbYT1ge2nr4lcxlw/o5MTO7p1M1MSYgGX0kz5s8shD3/uCXC/fsGX/0aPpd Sid2R61ulj4fbAwJfdp0u7xZhdysRBYmNk7bhkQp6bUhNq4YBCvjC80aH1CEoHefuong 0WTw== X-Gm-Message-State: AC+VfDweKPuwOLIWGf9oOgTJqQFoOX+XaxLUn3tkkwwjujcMekTnEW7W ifDzZlsXoLU53etTqbmWw/l7aLqHlWo6ntmpNeM= X-Google-Smtp-Source: ACHHUZ4EYiDqc/h9ZzKwyQN4znT6jHnZB6a8dhdjX5fniQjgQL0MOXirXzXHuRRJTTqWV2h41tWu3g== X-Received: by 2002:adf:f98c:0:b0:313:f5fd:62af with SMTP id f12-20020adff98c000000b00313f5fd62afmr8204591wrr.18.1688046082791; Thu, 29 Jun 2023 06:41:22 -0700 (PDT) Received: from [192.168.69.115] ([176.176.166.242]) by smtp.gmail.com with ESMTPSA id v2-20020a5d6782000000b00313f5babb18sm9983596wru.9.2023.06.29.06.41.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 29 Jun 2023 06:41:22 -0700 (PDT) Message-ID: Date: Thu, 29 Jun 2023 15:41:18 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v3 25/36] docs/devel: introduce some key concepts for QOM development Content-Language: en-US To: =?UTF-8?Q?Alex_Benn=c3=a9e?= , qemu-devel@nongnu.org Cc: Wainer dos Santos Moschetta , Juan Quintela , Thomas Huth , Cleber Rosa , Leonardo Bras , Beraldo Leal , Peter Maydell , Bin Meng , Yanan Wang , Darren Kenny , Alexander Bulekov , Marcel Apfelbaum , Peter Xu , Radoslaw Biernacki , Laurent Vivier , Paolo Bonzini , Eduardo Habkost , qemu-arm@nongnu.org, Stefan Hajnoczi , Richard Henderson , Bandan Das , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , Alexandre Iooss , Marcin Juszkiewicz , Leif Lindholm , Laurent Vivier , Qiuhao Li , Mahmoud Mandour , Riku Voipio References: <20230627160943.2956928-1-alex.bennee@linaro.org> <20230627160943.2956928-26-alex.bennee@linaro.org> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= In-Reply-To: <20230627160943.2956928-26-alex.bennee@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::42e; envelope-from=philmd@linaro.org; helo=mail-wr1-x42e.google.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.093, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 27/6/23 18:09, Alex Bennée wrote: > Using QOM correctly is increasingly important to maintaining a modern > code base. However the current documentation skips some important > concepts before launching into a simple example. Lets: > > - at least mention properties > - mention TYPE_OBJECT and TYPE_DEVICE > - talk about why we have realize/unrealize > - mention the QOM tree > - lightly re-arrange the order we mention things > > Signed-off-by: Alex Bennée > Message-Id: <20230619171437.357374-6-alex.bennee@linaro.org> > > --- > v3 > - moved around as per Paolo's review > --- > docs/devel/qom.rst | 58 +++++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 52 insertions(+), 6 deletions(-) > +Creating a QOM class > +==================== > + > +A simple minimal device implementation may look something like bellow: > > .. code-block:: c > :caption: Creating a minimal type > @@ -48,6 +66,12 @@ In the above example, we create a simple type that is described by #TypeInfo. > #TypeInfo describes information about the type including what it inherits > from, the instance and class size, and constructor/destructor hooks. > > +The TYPE_DEVICE class is the parent class for all modern devices > +implemented in QEMU and adds some specific methods to handle QEMU > +device model. This includes managing the lifetime of devices from > +creation through to when they become visible to the guest and > +eventually unrealized. Good enough but we are mixing QOM vs QDev... > Alternatively several static types could be registered using helper macro > DEFINE_TYPES() > +.. _device-life-cycle: > + > +Device Life-cycle > +================= > + > +As class initialisation cannot fail devices have an two additional > +methods to handle the creation of dynamic devices. The ``realize`` > +function is called with ``Error **`` pointer which should be set if > +the device cannot complete its setup. Otherwise on successful > +completion of the ``realize`` method the device object is added to the > +QOM tree and made visible to the guest. > + > +The reverse function is ``unrealize`` and should be were clean-up > +code lives to tidy up after the system is done with the device. Worth mentioning hotplug devices must implement it? > +All devices can be instantiated by C code, however only some can > +created dynamically via the command line or monitor. > > +Likewise only some can be unplugged after creation and need an > +explicit ``unrealize`` implementation. Ah, here we go. > This is determined by the > +``user_creatable`` variable in the root ``DeviceClass`` structure. > +Devices can only be unplugged if their ``parent_bus`` has a registered > +``HotplugHandler``. TODO on top, mentions the reset() handlers are called after realize(), and can be called multiple times. > API Reference > -------------- > +============= > > See the :ref:`QOM API` and :ref:`QDEV API` > documents for the complete API description. Reviewed-by: Philippe Mathieu-Daudé