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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 CFFE7C4361B for ; Fri, 18 Dec 2020 22:33:00 +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 4EF4D23B5D for ; Fri, 18 Dec 2020 22:32:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4EF4D23B5D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60410 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kqOJ1-0003Xb-10 for qemu-devel@archiver.kernel.org; Fri, 18 Dec 2020 17:32:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45636) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kqOH7-00034N-1n for qemu-devel@nongnu.org; Fri, 18 Dec 2020 17:31:01 -0500 Received: from mx2.suse.de ([195.135.220.15]:45430) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kqOH4-0003BP-Ej for qemu-devel@nongnu.org; Fri, 18 Dec 2020 17:31:00 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AF440AC7B; Fri, 18 Dec 2020 22:30:56 +0000 (UTC) Subject: Re: [RFC v6 10/11] accel: introduce AccelCPUClass extending CPUClass From: Claudio Fontana To: Paolo Bonzini , Thomas Huth , Richard Henderson , Stefano Stabellini , Wenchao Wang , Roman Bolshakov , Sunil Muthuswamy , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= References: <20201126223218.31480-1-cfontana@suse.de> <20201126223218.31480-11-cfontana@suse.de> <6cbd508c-b24b-3219-3302-196dfefaa8f7@redhat.com> <51838c6c-8a44-afef-1acf-b8acb3eada19@redhat.com> <050bc10b-861c-f463-18e1-c4d1aa0c301e@suse.de> <4bca1b60-ceeb-4b99-dd92-77dac07e9064@suse.de> Message-ID: <343846ce-12ba-23d6-4832-4aa16cb22f9d@suse.de> Date: Fri, 18 Dec 2020 23:30:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <4bca1b60-ceeb-4b99-dd92-77dac07e9064@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=195.135.220.15; envelope-from=cfontana@suse.de; helo=mx2.suse.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: Laurent Vivier , Eduardo Habkost , Paul Durrant , Jason Wang , Marcelo Tosatti , qemu-devel@nongnu.org, Peter Xu , Dario Faggioli , Cameron Esfahani , haxm-team@intel.com, Colin Xu , Anthony Perard , Bruce Rogers , Olaf Hering , "Emilio G . Cota" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/18/20 10:55 PM, Claudio Fontana wrote: > On 12/18/20 7:04 PM, Claudio Fontana wrote: >> On 12/18/20 7:01 PM, Paolo Bonzini wrote: >>> On 18/12/20 18:51, Claudio Fontana wrote: >>>> But with things like cris/ for example, >>>> the tcg functions to use are actually versioned per each subclass of TYPE_CRIS_CPU. >>>> >>>> Different tcg_ops need to be used for different subclasses of the CPU_RESOLVING_TYPE. >>> >>> CRIS is not that bad since it's TCG only. You can just make it a field >>> in CRISCPUClass and copy it over to tcg_ops. >>> >>> I think ARM had something similar though, with different do_interrupt >>> implementations for M and A processors. Somebody from Linaro was >>> cleaning it up as part of some BQL work, but it was never merged. But >>> even in that case, do_interrupt is somewhat special for ARM so making it >>> an xxxCPUClass field makes sense. >>> >>> Paolo >> >> Ok that's a good alternative, >> >>> >>>> So in order to avoid code in the class initialization like this: >>>> >>>> if (version1) { then set the tcg ops for version 1; } >>>> if (version2) { then set the tcg ops for version 2; ...} etc, >>>> >>>> we could define the right tcg op variants corresponding to the cpu variants, so that everything can be matched automatically. >>>> >>>> But I think we'd need to pass explicitly the cpu type in accel_init_cpu_interfaces for this to work.. >>>> we could still in the future call accel_init_cpu_interfaces multiple times, once for each cpu model we want to use. >>>> >>>> Or, we could do something else: we could delay the accel cpu interface initialization and call it in cpu_create(const char *typename), >>>> where typename needs to be known for sure. >> >> >> I take you don't like this idea to initialize the accel cpu interface in cpu_create()? >> It seems to make sense to me, but any drawbacks? >> >> Ciao thanks! >> >> Claudio >> >> >>>> >>>> This last option seems kinda attractive, but any ideas? >> >> > > Oh I see, sadly, only user mode code seem to be guaranteed to go through cpu_create(), so there is probably no single code point, > where we are guaranteed to see the creation of a cpu, everything is duplicated with explict calls to object_new in multiple places. > > Hmm... Well we can actually do it in the right place, that is in cpu_common_intfn, by calling accel_init_cpu_intefaces there, which kinda makes sense anyway... wdyt? Ciao, CLaudio