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=-8.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 AE45FC3E8C5 for ; Fri, 27 Nov 2020 18:35:26 +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 3FB2B21534 for ; Fri, 27 Nov 2020 18:35:26 +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="bOkK9VAp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FB2B21534 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]:33308 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kiiaa-00022A-SH for qemu-devel@archiver.kernel.org; Fri, 27 Nov 2020 13:35:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45324) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kiiZT-0001XT-ED for qemu-devel@nongnu.org; Fri, 27 Nov 2020 13:34:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22528) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kiiZR-0000GO-HQ for qemu-devel@nongnu.org; Fri, 27 Nov 2020 13:34:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606502052; 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=iICL1agcEiygQzI8eSHuKQaqoZngT06q/7fMESG2MQY=; b=bOkK9VApMlCdfS7vpzY28hj+Xzgn54l2iY4ZunUayNmaziEnE/H1ZCgEgL4CS1fcUT0VSZ OHIoGlov+7vzOJfIavs0SeYTBmF2+Z0gaCBgN6aSCSeuyrzrgaRKTi0Gj58OOC9bdx2Jid v6ikzfj2bP4rkldIrs/3MBUVbw8XvKo= 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-141-8mHOjEHoOjqd5juRQAuAuw-1; Fri, 27 Nov 2020 13:34:10 -0500 X-MC-Unique: 8mHOjEHoOjqd5juRQAuAuw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5F59B107ACF7; Fri, 27 Nov 2020 18:34:08 +0000 (UTC) Received: from localhost (unknown [10.10.67.2]) by smtp.corp.redhat.com (Postfix) with ESMTP id CE35510023B1; Fri, 27 Nov 2020 18:34:04 +0000 (UTC) Date: Fri, 27 Nov 2020 13:33:58 -0500 From: Eduardo Habkost To: Claudio Fontana Subject: Re: [RFC v6 11/11] i386: split cpu accelerators from cpu.c, using AccelCPUClass Message-ID: <20201127183358.GG2271382@habkost.net> References: <20201126223218.31480-1-cfontana@suse.de> <20201126223218.31480-12-cfontana@suse.de> <20201127174121.GC2271382@habkost.net> <81e97089-9c8a-d9f3-58cf-c26fa78a9a70@suse.de> <20201127180953.GD2271382@habkost.net> <588c357c-da76-25bd-61f4-c28da0982639@suse.de> MIME-Version: 1.0 In-Reply-To: <588c357c-da76-25bd-61f4-c28da0982639@suse.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_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: Paul Durrant , Jason Wang , qemu-devel@nongnu.org, Peter Xu , haxm-team@intel.com, Colin Xu , Olaf Hering , Stefano Stabellini , Bruce Rogers , "Emilio G . Cota" , Anthony Perard , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Laurent Vivier , Thomas Huth , Richard Henderson , Cameron Esfahani , Dario Faggioli , Roman Bolshakov , Sunil Muthuswamy , Marcelo Tosatti , Wenchao Wang , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Nov 27, 2020 at 07:16:25PM +0100, Claudio Fontana wrote: > On 11/27/20 7:09 PM, Eduardo Habkost wrote: > > On Fri, Nov 27, 2020 at 06:53:23PM +0100, Claudio Fontana wrote: > >> On 11/27/20 6:41 PM, Eduardo Habkost wrote: > >>> On Thu, Nov 26, 2020 at 11:32:18PM +0100, Claudio Fontana wrote: > >>>> i386 is the first user of AccelCPUClass, allowing to split > >>>> cpu.c into: > >>>> > >>>> cpu.c cpuid and common x86 cpu functionality > >>>> host-cpu.c host x86 cpu functions and "host" cpu type > >>>> kvm/cpu.c KVM x86 AccelCPUClass > >>>> hvf/cpu.c HVF x86 AccelCPUClass > >>>> tcg/cpu.c TCG x86 AccelCPUClass > >>>> > >>>> Signed-off-by: Claudio Fontana > >>>> --- > >>> [...] > >>>> +static void tcg_cpu_class_init(CPUClass *cc) > >>> > >>> Is this the only case where we need to provide an > >>> AccelCPUClass.cpu_class_init method? > >>> > >>> > >>>> +{ > >>>> + cc->do_interrupt = x86_cpu_do_interrupt; > >>>> + cc->cpu_exec_interrupt = x86_cpu_exec_interrupt; > >>>> + cc->synchronize_from_tb = x86_cpu_synchronize_from_tb; > >>>> + cc->cpu_exec_enter = x86_cpu_exec_enter; > >>>> + cc->cpu_exec_exit = x86_cpu_exec_exit; > >>>> + cc->tcg_initialize = tcg_x86_init; > >>>> + cc->tlb_fill = x86_cpu_tlb_fill; > >>>> +#ifndef CONFIG_USER_ONLY > >>>> + cc->debug_excp_handler = breakpoint_handler; > >>>> +#endif /* !CONFIG_USER_ONLY */ > >>> > >>> I find the need for these method overrides suspicious. > >> > >> These mechanisms are preexistent. My refactoring only makes them more visible. > >> > >>> > >>> Comparing this with the code on qemu.git master: > >>> > >>> static void x86_cpu_common_class_init(ObjectClass *oc, void *data) > >>> { > >>> [...] > >>> #ifdef CONFIG_TCG > >>> cc->do_interrupt = x86_cpu_do_interrupt; > >>> cc->cpu_exec_interrupt = x86_cpu_exec_interrupt; > >>> #endif > >>> [...] > >>> cc->synchronize_from_tb = x86_cpu_synchronize_from_tb; > >>> [...] > >>> #if defined(CONFIG_TCG) && !defined(CONFIG_USER_ONLY) > >>> cc->debug_excp_handler = breakpoint_handler; > >>> #endif > >>> cc->cpu_exec_enter = x86_cpu_exec_enter; > >>> cc->cpu_exec_exit = x86_cpu_exec_exit; > >>> #ifdef CONFIG_TCG > >>> cc->tcg_initialize = tcg_x86_init; > >>> cc->tlb_fill = x86_cpu_tlb_fill; > >>> #endif > >>> [...] > >>> } > >>> > >>> So, we have two kinds of CPUClass fields above: > >>> * Code that was never conditional on CONFIG_TCG, and now is > >>> conditional (synchronize_from_tb, cpu_exec_enter, > >>> cpu_exec_exit). > >> > >> > >> > >> synchronize_from_tb, cpu_exec_enter and cpu_exec_exit only makes sense for TCG, > >> and their code should not be compiled in for non-TCG. > >> > >> This is part of the effort to separate away non-pertinent code into accelerator-specific builds (and in the future modules). > >> > >> The fact that they were unconditionally compiled in before was a mistake, or at least this is the assumption I am making when changing this. > > > > Can you clarify why that was a mistake? Patch 07/11 makes > > existing functions TCG-specific, but doesn't explain why. > > > > They are functions called only for TCG. You don't need translation blocks and cpu_exec() for other accelerators. > I can add this information in the commit message. Thanks! I believe we can clarify in patch 07/11 why some methods that were not conditional on CONFIG_TCG were moved to tcg_cpu_common_class_init(). Do you think it would be too complicated to move those methods from CPUClass to CpusAccel? If they are really accel-specific, CPUClass looks like the wrong place for them. > [...] -- Eduardo