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 80C4DC4361B for ; Fri, 18 Dec 2020 17:52:51 +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 0A17923B51 for ; Fri, 18 Dec 2020 17:52:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A17923B51 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]:55116 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kqJvt-00010A-P4 for qemu-devel@archiver.kernel.org; Fri, 18 Dec 2020 12:52:49 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40912) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kqJuJ-0007kB-Nh for qemu-devel@nongnu.org; Fri, 18 Dec 2020 12:51:11 -0500 Received: from mx2.suse.de ([195.135.220.15]:34870) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kqJuH-00061s-Nz for qemu-devel@nongnu.org; Fri, 18 Dec 2020 12:51:11 -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 97E38ACC4; Fri, 18 Dec 2020 17:51:06 +0000 (UTC) Subject: Re: [RFC v6 10/11] accel: introduce AccelCPUClass extending CPUClass 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> From: Claudio Fontana Message-ID: Date: Fri, 18 Dec 2020 18:51:03 +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: <6cbd508c-b24b-3219-3302-196dfefaa8f7@redhat.com> 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 11/27/20 7:21 AM, Paolo Bonzini wrote: > On 26/11/20 23:32, Claudio Fontana wrote: >> + if (acc) { >> + object_class_foreach(accel_init_cpu_int_aux, cpu_type, false, acc); >> + } > > Any reason to do it for cpu_type only, rather than for all subclasses of > CPU_RESOLVING_TYPE? This would remove the cpu_type argument to > accel_init_cpu_interfaces and accel_init_interfaces. > > Otherwise I haven't done a careful review yet but it looks very nice, > thanks! > > Paolo > Hi Paolo, going back to this topic: while doing some experiments in applying the ACCEL_CPU_TYPE classes for all targets (TCG for now, not KVM or other hw accels), and merging all tcg cpu ops, I did encounter some issue. For the simplest of targets like hppa for example, it works just fine, we can do: static void hppa_tcg_cpu_class_init(CPUClass *cc) { cc->tcg_ops.initialize = hppa_translate_init; cc->tcg_ops.do_interrupt = hppa_cpu_do_interrupt; cc->tcg_ops.cpu_exec_interrupt = hppa_cpu_exec_interrupt; cc->tcg_ops.synchronize_from_tb = hppa_cpu_synchronize_from_tb; cc->tcg_ops.tlb_fill = hppa_cpu_tlb_fill; #ifndef CONFIG_USER_ONLY cc->tcg_ops.do_unaligned_access = hppa_cpu_do_unaligned_access; #endif } *(later on I will try to change the cc->tcg_ops thing to something that ends up in cc->accel_cpu->tcg_ops->initialize, as I try to merge tcg_ops with accel_cpu, but this is spoiler of the future)* static void hppa_tcg_cpu_accel_class_init(ObjectClass *oc, void *data) { AccelCPUClass *acc = ACCEL_CPU_CLASS(oc); acc->cpu_class_init = hppa_tcg_cpu_class_init; } static const TypeInfo hppa_tcg_cpu_accel_type = { .name = ACCEL_CPU_NAME("tcg"), .parent = TYPE_ACCEL_CPU, .class_init = hppa_tcg_cpu_accel_class_init, }; static void hppa_cpu_register_types(void) { type_register_static(&hppa_cpu_type_info); type_register_static(&hppa_tcg_cpu_accel_type); } type_init(hppa_cpu_register_types) So this is good. 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. 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. This last option seems kinda attractive, but any ideas? Thanks, ciao, Claudio