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 X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 780C1C4363D for ; Wed, 7 Oct 2020 13:04:34 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E73AA206F4 for ; Wed, 7 Oct 2020 13:04:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Bb62M9Rf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E73AA206F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49276 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kQ97Q-0001O9-Sy for qemu-devel@archiver.kernel.org; Wed, 07 Oct 2020 09:04:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50358) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kQ95j-0008T5-SV for qemu-devel@nongnu.org; Wed, 07 Oct 2020 09:02:51 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:33486) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kQ95g-0001hL-Qc for qemu-devel@nongnu.org; Wed, 07 Oct 2020 09:02:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602075764; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YAC7NOB+gtz3eLsj/JsOKrn9rwcp50yoW4Q24mtEiaQ=; b=Bb62M9RfDzWHn3qI5kaYoxbCn9yjONVfOJ5H0WQVDP79cq3wtw8gW427Opq8MYrYb0vkjD 2mxyBDd4hDEyGYR0cQQj8bGtB3/W0LJoL3x2rXdzthuoIjXJYZbCNy2Xzr0FMpCwOMoNPh WBWa8ph+XoHzUf0sr6nmjNIKwIQjvP8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-535-6Tu-Sz0zO3ylFGAV9iP4mg-1; Wed, 07 Oct 2020 09:02:42 -0400 X-MC-Unique: 6Tu-Sz0zO3ylFGAV9iP4mg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 38B9A804013; Wed, 7 Oct 2020 13:02:41 +0000 (UTC) Received: from localhost (ovpn-119-102.rdu2.redhat.com [10.10.119.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id B33BC60BF1; Wed, 7 Oct 2020 13:02:40 +0000 (UTC) Date: Wed, 7 Oct 2020 09:02:40 -0400 From: Eduardo Habkost To: Paolo Bonzini Subject: Re: Purpose of QOM properties registered at realize time? Message-ID: <20201007130240.GU7303@habkost.net> References: <20201006220647.GR7303@habkost.net> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=ehabkost@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/07 00:54:30 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.742, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , qemu-riscv@nongnu.org, qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, "Daniel P. Berrange" , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Oct 07, 2020 at 02:04:23PM +0200, Paolo Bonzini wrote: > On 07/10/20 00:06, Eduardo Habkost wrote: > > Hi, > > > > While trying to understand how QOM properties are used in QEMU, I > > stumbled upon multiple cases where alias properties are added at > > realize time. > > > > Now, I don't understand why those properties exist. As the > > properties are added at realize time, I assume they aren't > > supposed to be touched by the user at all. If they are not > > supposed to be touched by the user, what exactly is the purpose > > of those QOM properties? > > In the case of GPIOs, I think they will be used by other devices that > are added afterwards. Do you know how exactly are they used? Is this always wrapped behind a specific API for GPIOs, or the devices can look for the properties directly? I'm concerned by the possibility of having QOM properties as an undocumented part of an internal API. > > The remaining ones are: > > > hw/arm/allwinner-h3.c=232=static void allwinner_h3_realize(DeviceState *dev, Error **errp) > > hw/arm/allwinner-h3.c:359: object_property_add_alias(OBJECT(s), "sd-bus", OBJECT(&s->mmc0), > > -- > > hw/arm/bcm2835_peripherals.c=128=static void bcm2835_peripherals_realize(DeviceState *dev, Error **errp) > > hw/arm/bcm2835_peripherals.c:322: object_property_add_alias(OBJECT(s), "sd-bus", OBJECT(&s->gpio), "sd-bus"); > > -- > > hw/arm/bcm2836.c=69=static void bcm2836_realize(DeviceState *dev, Error **errp) > > hw/arm/bcm2836.c:87: object_property_add_alias(OBJECT(s), "sd-bus", OBJECT(&s->peripherals), > > -- > > hw/arm/xlnx-zynqmp.c=276=static void xlnx_zynqmp_realize(DeviceState *dev, Error **errp) > > hw/arm/xlnx-zynqmp.c:522: object_property_add_alias(OBJECT(s), bus_name, sdhci, "sd-bus"); > > And this are probably usable with "bus=sd-bus" or something like that on > other devices, too. > > Paolo > -- Eduardo