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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 ADCC2C2D0EA for ; Wed, 8 Apr 2020 11:34:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C0B720747 for ; Wed, 8 Apr 2020 11:34:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RoRVKKv8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728502AbgDHLeC (ORCPT ); Wed, 8 Apr 2020 07:34:02 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:54358 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727902AbgDHLeC (ORCPT ); Wed, 8 Apr 2020 07:34:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586345641; 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=iMpv1Tcf8msq6CIz6hAZaaOwWt8dkcRjoWBRfrYNwKk=; b=RoRVKKv8OqqSmOdsNBjN+SXCfrC6dR9pT5+lcHua/Ex+qQDyNWTC0wvqN/+IE349BXb7rJ DCBWeZFn9iUKNIQDUzuUtaAMAA6z9vlh4Ms9L0viXFQDWQe+SJ8B+CXWwQ2YaPz53qEI2N eXIJPskYhxi9bTFUGZ8VFpj3Vk0JCfc= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-50-LJQTftwPM5KjlQlkob7pvg-1; Wed, 08 Apr 2020 07:33:59 -0400 X-MC-Unique: LJQTftwPM5KjlQlkob7pvg-1 Received: by mail-wr1-f70.google.com with SMTP id o10so3805931wrj.7 for ; Wed, 08 Apr 2020 04:33:59 -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=iMpv1Tcf8msq6CIz6hAZaaOwWt8dkcRjoWBRfrYNwKk=; b=DKmvBigkuLlNTY9IiGSUMqteaEQvjm73c8KR3NGQarPZKzDS0MKWab3Wv0VBu2tZsp 7xp3ldWCPKlBsqQ6ghs8ufH+0wi6DRsqgnrsIzVUr0+G4ckinUMemGKlRcVWJ7Zptz4B tkno2xTtzqHZitf3TAz4xQLP7IZW4XcI+ZmNqAMw3qogO7F0CTV5Bes5xFUSya/ngVxW ckYvPWoR+7DhC3ZsBoDf0dehonJOUG4f8vjqHMaakMULXVsypeTLEPoA36hK6GyKdNbv LO7fQ2BK7yiEKerCxXYlj/8gZvQlvAIM9I8Ta66yYSoNibvdFfZjaMQW2lTJv7lIqZfE YlOg== X-Gm-Message-State: AGi0PuYtRw0kqJfKOLObF6hJGq3hoGlLtbBWkpY39GUgjfbI/cAushlX +H1olVt1dFcfQ0MqZWAePPJ9UeQUCT4G+cLZ34HHkLt+3lEiO22zfSPH3UF/xu5qUP9BiDrmpYu WNZegaCfPw85wRo7pJDTUS74L X-Received: by 2002:a1c:3281:: with SMTP id y123mr4239285wmy.30.1586345637884; Wed, 08 Apr 2020 04:33:57 -0700 (PDT) X-Google-Smtp-Source: APiQypLT538fz8uSoawd2IFWIE2g4SRUOixPL/PauE1AvjtumpV89MF+Ihgn7usDfr2aRZ/BhKLoLQ== X-Received: by 2002:a1c:3281:: with SMTP id y123mr4239265wmy.30.1586345637681; Wed, 08 Apr 2020 04:33:57 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id f63sm3148639wma.47.2020.04.08.04.33.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Apr 2020 04:33:57 -0700 (PDT) Subject: Re: [PATCH 2/2] KVM: s390: Return last valid slot if approx index is out-of-bounds To: Claudio Imbrenda , Sean Christopherson Cc: Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+d889b59b2bb87d4047a2@syzkaller.appspotmail.com References: <20200408064059.8957-1-sean.j.christopherson@intel.com> <20200408064059.8957-3-sean.j.christopherson@intel.com> <20200408122138.71493308@p-imbrenda> From: Paolo Bonzini Message-ID: <40b325c7-ca24-3513-b2fa-1e9397c9e353@redhat.com> Date: Wed, 8 Apr 2020 13:33:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200408122138.71493308@p-imbrenda> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/04/20 12:21, Claudio Imbrenda wrote: > on s390 memory always starts at 0; you can't even boot a system missing > the first pages of physical memory, so this means this situation would > never happen in practice. > > of course, a malicious userspace program could create an (unbootable) VM > and trigger this bug, so the patch itself makes sense. > > Reviewed-by: Claudio Imbrenda What about using KVM just for isolation and not just to run a full-blown OS (that is, you might even only have the guest run in problem state)? Would that be feasible on s390? Thanks, Paolo