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 65AC4C433B4 for ; Thu, 8 Apr 2021 10:56:48 +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 E4B71610A2 for ; Thu, 8 Apr 2021 10:56:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4B71610A2 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]:42922 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lUSL8-0002md-Oz for qemu-devel@archiver.kernel.org; Thu, 08 Apr 2021 06:56:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48742) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUSKS-0002IM-Em for qemu-devel@nongnu.org; Thu, 08 Apr 2021 06:56:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:57394) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUSKQ-0008J6-P7 for qemu-devel@nongnu.org; Thu, 08 Apr 2021 06:56:04 -0400 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 13BAEB01E; Thu, 8 Apr 2021 10:56:01 +0000 (UTC) Subject: Re: [RFC v12 31/65] target/arm: move exception code out of tcg/helper.c To: Richard Henderson , Peter Maydell , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , =?UTF-8?Q?Alex_Benn=c3=a9e?= References: <20210326193701.5981-1-cfontana@suse.de> <20210326193701.5981-32-cfontana@suse.de> From: Claudio Fontana Message-ID: <2e19f3f4-f8cf-645e-1d9d-13e3b208438d@suse.de> Date: Thu, 8 Apr 2021 12:56:00 +0200 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: 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: Paolo Bonzini , Roman Bolshakov , qemu-devel@nongnu.org, Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 3/28/21 6:40 PM, Richard Henderson wrote: > On 3/26/21 1:36 PM, Claudio Fontana wrote: >> +#ifdef CONFIG_TCG >> + arm_rebuild_hflags(env); >> +#endif /* CONFIG_TCG */ > > No functional changes during code movement. > Really. > I cannot emphasize this enough. we are asserting "not reached" for arm_rebuild_hflags in KVM-only, but the KVM-only build is not "active" yet at this point, so will add separately ok. > > Also, why is this an ifdef and not tcg_enabled()? right, will change. > >> + aarch64_restore_sp(env, new_el); >> +#ifdef CONFIG_TCG >> + arm_rebuild_hflags(env); >> +#endif /* CONFIG_TCG */ > > Likewise. Yes, will change. > >> +#ifdef CONFIG_TCG >> + if (tcg_enabled()) { > > Likewise. And, why in the world do you need both? Here both are needed because the prototypes of other functions in the block are not visile for non-tcg builds. It is a struggle to balance making TCG-only symbols "invisible" to kvm-builds, so one developing for KVM only can forget about them, and keeping TCG things contained, and on the other side opening up the ability to use tcg_enabled(), which requires those prototypes to be visible. Where do you see that balance? Should I make arm_is_psci_call, arm_handle_psci_call, tcg_handle_semihosting visible as well? Or can we give a meaningful name to this operation: + if (tcg_enabled()) { + if (arm_is_psci_call(cpu, cs->exception_index)) { + arm_handle_psci_call(cpu); + qemu_log_mask(CPU_LOG_INT, "...handled as PSCI call\n"); + return; + } + /* + * Semihosting semantics depend on the register width of the code + * that caused the exception, not the target exception level, so + * must be handled here. + */ + if (cs->exception_index == EXCP_SEMIHOST) { + tcg_handle_semihosting(cs); + return; + } + } and store it in a single tcg-specific function, whole prototype we could make visible? Thanks, Claudio > > > r~ >