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 7DA7DC4332F for ; Fri, 3 Nov 2023 08:04:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qyp9l-0002ak-9z; Fri, 03 Nov 2023 04:03:53 -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 1qyp9h-0002Z1-RN for qemu-devel@nongnu.org; Fri, 03 Nov 2023 04:03:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qyp9f-00050Y-Bt for qemu-devel@nongnu.org; Fri, 03 Nov 2023 04:03:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698998626; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nClG9ccEZC0QF2L/MnX2qNfu1EoY9WKuPBTKGbzovao=; b=BnBjO6sSH+PjheQr25aKzyDJlOFihiiil5cCkh0qYe4UYCJtwmgrK4eSqgU0ETkhR/intW DLaAzfXpheIL16yiglif8HaCQ5XW1jcvKupqJJMDt/nQ6hGL0Ja5U+qdQGrlt30kZ5nAOC 51y99QaI6XAeAZsmkvDBOQFMNeNrPgo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-119-2uUoRCSRNcW0t7XyM7aNVw-1; Fri, 03 Nov 2023 04:03:42 -0400 X-MC-Unique: 2uUoRCSRNcW0t7XyM7aNVw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E24AB83B865; Fri, 3 Nov 2023 08:03:41 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.56]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A327EC1290F; Fri, 3 Nov 2023 08:03:41 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id ADD0221E6A1F; Fri, 3 Nov 2023 09:03:40 +0100 (CET) From: Markus Armbruster To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Cc: qemu-devel@nongnu.org, Peter Maydell , Luc Michel , Daniel Henrique Barboza , Alistair Francis , Paolo Bonzini , Eduardo Habkost , Mark Cave-Ayland , Bernhard Beschow , qemu-ppc@nongnu.org, "Edgar E . Iglesias" , "Daniel P . Berrange" , Thomas Huth Subject: Re: [RFC PATCH 5/5] hw/ppc/e500: Pass array of CPUs as array of canonical QOM paths References: <20231030143957.82988-1-philmd@linaro.org> <20231030143957.82988-6-philmd@linaro.org> Date: Fri, 03 Nov 2023 09:03:40 +0100 In-Reply-To: <20231030143957.82988-6-philmd@linaro.org> ("Philippe =?utf-8?Q?Mathieu-Daud=C3=A9=22's?= message of "Mon, 30 Oct 2023 15:39:56 +0100") Message-ID: <87wmuz1cwz.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.393, 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, 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 Philippe Mathieu-Daud=C3=A9 writes: > Devices should avoid calling qemu_get_cpu() because this call > doesn't work as expected with heterogeneous machines. Such > devices often iterate over a cluster of CPUs, which the device's > parent has direct access (when creating the child device). > > We can pass QOM as 'link' between objects, but we can't pass an > array of links. Here we exploits QAPI simplicity, by using Do you mean qdev simplicity? > DEFINE_PROP_ARRAY and a list of strings, each string being the > CPU canonical path in QOM tree (which is constant and unique). > When the device realizes itself, the original CPU pointer is > recovered via a object_resolve_path() call. We have link properties, see DEFINE_PROP_LINK() and qdev_prop_link. Would an array of link properties be feasible here? > Inspired-by: Peter Maydell > Inspired-by: Markus Armbruster > Signed-off-by: Philippe Mathieu-Daud=C3=A9 > --- > Tested with: > $ make check-qtest-ppc{,64} > $ make check-avocado AVOCADO_TAGS=3D'machine:ppce500 machine:mpc8544ds' > > RFC: See cover > > FIXME: Should we free spin_cpu_list using g_autoptr(QList)?