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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A3CA9C48BDF for ; Tue, 15 Jun 2021 07:55:40 +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 1932560E09 for ; Tue, 15 Jun 2021 07:55:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1932560E09 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]:47684 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lt3v9-00028P-Ae for qemu-devel@archiver.kernel.org; Tue, 15 Jun 2021 03:55:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36168) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lt3pY-0008Ly-KL for qemu-devel@nongnu.org; Tue, 15 Jun 2021 03:49:53 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:48520) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lt3pP-0008Dm-SR for qemu-devel@nongnu.org; Tue, 15 Jun 2021 03:49:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623743381; 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=AiWMQZ0RX44C5YEGAZc6sMqw8vMDy4dDPF9k3Jbrv+s=; b=RPidSxGkvF1+ZtNqpjk6NgV4qtmhnp5kVb2m4WAFuR8WCE7RIvf8L3X1rUP/CgGPUI7Ho+ KkQsJHm/k2e0FJ8LX1OgGpp1w8Wxn04D24NR5WS76X14ptpzKaay4qEpeMFgMRQXjiMfFm Pb8tRk5NhJn/n5s5e8ohLkGWGqW95Zo= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-51-pkcHlQZ2PCGmQfxll1xTMg-1; Tue, 15 Jun 2021 03:49:38 -0400 X-MC-Unique: pkcHlQZ2PCGmQfxll1xTMg-1 Received: by mail-wm1-f72.google.com with SMTP id o14-20020a1c4d0e0000b029019a2085ba40so3054072wmh.1 for ; Tue, 15 Jun 2021 00:49:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=AiWMQZ0RX44C5YEGAZc6sMqw8vMDy4dDPF9k3Jbrv+s=; b=slGm16l0d9GrwEWk7WSN9FNhWtS9sfvsHEs2HlJVt9JFjaiG3k0SzvsA0kn5pR3/PJ JKdJ9PUGPz9SnKJ4s023dDuUZMl3sVGtBsnWYiK6S2YoYGnCsqWrh1kw+doCmH0x6sgk 53Vsu7iZDN0Xixj8k9D2I1gcj7DJ2l27wdiiwuDkL521UyxOTZXA02Swcj999AyNlJIU QGikD7LLTjl2Gk2VxR/FVMZdDE3Ns+XuexKdiWr8ytR/DYvNW5pwb6f1JQC5lbPary4r Do1Sz0VeI5+KgnrwXX0D8LcF1gyJMQGlPCQxZ/Ym9FMSbbLLu0oYVRxooDVXIireVmyT jZMw== X-Gm-Message-State: AOAM533vGxydkjtRp7plCh0NhmEnUX+K6JPBdB7Pc+Jc24pwO8PbGRD9 KTs91ICu9VTQ/1OjlrnHBwJQc9j+Xrxxx1+LQHEbXHXt4XrAUk8NvRW+xQ1EUi/bkeIVFungb5j wprOJnsK5ioB7Cps= X-Received: by 2002:a1c:35c2:: with SMTP id c185mr2357762wma.126.1623743377132; Tue, 15 Jun 2021 00:49:37 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyM/FGnF3Fx4IRGVIhRUUi+rbPvAeBZY7RhcJggb3WFQ7OHn/XIeqpc9+oLaK+DIRHZcsbMMg== X-Received: by 2002:a1c:35c2:: with SMTP id c185mr2357744wma.126.1623743376934; Tue, 15 Jun 2021 00:49:36 -0700 (PDT) Received: from [192.168.3.132] (p5b0c6136.dip0.t-ipconnect.de. [91.12.97.54]) by smtp.gmail.com with ESMTPSA id z19sm1434259wmf.31.2021.06.15.00.49.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Jun 2021 00:49:36 -0700 (PDT) Subject: Re: [PATCH 2/5] target/s390x: Do not modify cpu state in s390_cpu_get_psw_mask To: Richard Henderson , qemu-devel@nongnu.org References: <20210615030744.1252385-1-richard.henderson@linaro.org> <20210615030744.1252385-3-richard.henderson@linaro.org> From: David Hildenbrand Organization: Red Hat Message-ID: Date: Tue, 15 Jun 2021 09:49:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210615030744.1252385-3-richard.henderson@linaro.org> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.2, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.489, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: ruixin.bao@ibm.com, jonathan.albrecht@linux.vnet.ibm.com, cohuck@redhat.com, qemu-s390x@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 15.06.21 05:07, Richard Henderson wrote: > We want to use this function for debugging, and debug should > not modify cpu state (even non-architectural cpu state) lest > we introduce heisenbugs. > > Signed-off-by: Richard Henderson > --- > target/s390x/helper.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/target/s390x/helper.c b/target/s390x/helper.c > index d311903b94..559fc3573f 100644 > --- a/target/s390x/helper.c > +++ b/target/s390x/helper.c > @@ -321,12 +321,12 @@ uint64_t s390_cpu_get_psw_mask(CPUS390XState *env) > uint64_t r = env->psw.mask; > > if (tcg_enabled()) { > - env->cc_op = calc_cc(env, env->cc_op, env->cc_src, env->cc_dst, > - env->cc_vr); > + uint64_t cc = calc_cc(env, env->cc_op, env->cc_src, > + env->cc_dst, env->cc_vr); > > + assert(cc <= 3); > r &= ~PSW_MASK_CC; > - assert(!(env->cc_op & ~3)); > - r |= (uint64_t)env->cc_op << 44; > + r |= cc << 44; > } > > return r; > I wonder if this can actually suboptimal performance-wise, because we might be recomputing the same thing. However, I guess it's rather a corner case Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb