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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 E311FC4320A for ; Thu, 12 Aug 2021 15:41:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9DFB60D07 for ; Thu, 12 Aug 2021 15:41:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238121AbhHLPly (ORCPT ); Thu, 12 Aug 2021 11:41:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:36183 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237413AbhHLPlx (ORCPT ); Thu, 12 Aug 2021 11:41:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628782887; 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=wVAySSNkRIQjjk+QH2YkijF+uGWoxw5I4DLvZClTw1U=; b=D134bOSUHTTA0PBGBrfxeua3cjVaITA/aBeygqqG9zTT1sBhyUKi2w0KPInxk3bKwqOzda u1EV3dEohJvWbbo8vwT6klqVzAk0hvI/pwYaAxSyJm/zBxIB/ODa88m6P0j4NYOD9d2vrb uM+rN2JHSIrzqz2iA+75RisxeW/qbCg= Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-86-wZL33MRCOdiRFLiRosI_kw-1; Thu, 12 Aug 2021 11:41:26 -0400 X-MC-Unique: wZL33MRCOdiRFLiRosI_kw-1 Received: by mail-ed1-f71.google.com with SMTP id z4-20020a05640240c4b02903be90a10a52so3211032edb.19 for ; Thu, 12 Aug 2021 08:41:25 -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:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=wVAySSNkRIQjjk+QH2YkijF+uGWoxw5I4DLvZClTw1U=; b=rV6J6AogI5miqXfyfLDz1Z1+PJunU2QE84mMz/sFPg8W0QBUEDxrM8/GfQ6D3hNZxi sShg6+FQKeHOBL8VVNSiHg7HL483QMWsCMSrByj9ODvaWJ+2HoQlMG8SkvTcqwR5hqLq LwoUyvcmJ0g8f4KUmtMrzotrJwk1CW5BYxQbEI9p5qG6pPGvQ/8t2x2W6TLJgmNHZnXM SJlfx+Y9X40HViihiK71XqWbB8XuluvpNvwEWLYRVX/hPf3tKfcjH8jrBCB6SG17X0HU xt0mudKOVHPODjmNIdjiPR/lO7XlJiTe/hQda8hUezzM3Tqv1xeNmhb1ak4ksT7CTMF6 h1Rw== X-Gm-Message-State: AOAM532GqyYFQTj67KgQRI6J/qes4WARf+U4ad76BIgodmklM7u/A2jY h6CRCpqzVcS8EvTO8oT6Qp07BxDpQLWvRY17BvWurW3XYReyc/xTShrscw46teiKV4DOw4xUqUG YbMdRbCM+dFrDhdE+EarfA/sR X-Received: by 2002:a50:ef11:: with SMTP id m17mr6095912eds.233.1628782885025; Thu, 12 Aug 2021 08:41:25 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzbkauFimraFjcUcxW/s5naeDzEHblJnwTGW5kN8SFMxVNVXXtWI2AkXQ1TgeG7maJbDTkRTw== X-Received: by 2002:a50:ef11:: with SMTP id m17mr6095860eds.233.1628782884809; Thu, 12 Aug 2021 08:41:24 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id s18sm988134ejh.12.2021.08.12.08.41.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Aug 2021 08:41:24 -0700 (PDT) Subject: Re: [PATCH v2 1/2] KVM: Refactor kvm_arch_vcpu_fault() to return a struct page pointer To: David Hildenbrand , Hou Wenlong , kvm@vger.kernel.org Cc: Sean Christopherson , Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Huacai Chen , Aleksandar Markovic , Thomas Bogendoerfer , Paul Mackerras , Michael Ellerman , Benjamin Herrenschmidt , Christian Borntraeger , Janosch Frank , Cornelia Huck , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org References: <1c510b24fc1d7cbae8aa4b69c0799ebd32e65b82.1628739116.git.houwenlong93@linux.alibaba.com> <98adbd3c-ec6f-5689-1686-2a8a7909951a@redhat.com> From: Paolo Bonzini Message-ID: Date: Thu, 12 Aug 2021 17:41:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <98adbd3c-ec6f-5689-1686-2a8a7909951a@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/08/21 11:04, David Hildenbrand wrote: > > Reviewed-by: David Hildenbrand > > But at the same time I wonder if we should just get rid of > CONFIG_KVM_S390_UCONTROL and consequently kvm_arch_vcpu_fault(). > > In practice CONFIG_KVM_S390_UCONTROL, is never enabled in any reasonable > kernel build and consequently it's never tested; further, exposing the > sie_block to user space allows user space to generate random SIE > validity intercepts. > > CONFIG_KVM_S390_UCONTROL feels like something that should just be > maintained out of tree by someone who really needs to hack deep into hw > virtualization for testing purposes etc. I have no preference either way. It should definitely have selftests, but in x86 land there are some features that are not covered by QEMU and were nevertheless accepted upstream with selftests. Paolo