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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF000C7EE23 for ; Thu, 8 Jun 2023 06:36:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234306AbjFHGg0 (ORCPT ); Thu, 8 Jun 2023 02:36:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233781AbjFHGgY (ORCPT ); Thu, 8 Jun 2023 02:36:24 -0400 Received: from mail-ed1-f50.google.com (mail-ed1-f50.google.com [209.85.208.50]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D53552113 for ; Wed, 7 Jun 2023 23:36:23 -0700 (PDT) Received: by mail-ed1-f50.google.com with SMTP id 4fb4d7f45d1cf-5148e4a2f17so393171a12.1 for ; Wed, 07 Jun 2023 23:36:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686206182; x=1688798182; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4WbslFANnmX2X7GcQx6MMGxO+lQs8WTrs7UKG6GJbTI=; b=NA/JruQT1ZObO5+KqwITOth7gRBJTLz4CvSZYEpDjTOko+Y1DO/MZl/KeQBhg5I9KY xn9eUStZFj4MBr5gzuGayHYeqcrrwbHKH+ibQhTf+EUfq9ImxrZM1cnzbFLTuySq1uS6 nXfRftn8kdc0S27YT7+GbZZ99Z0VfCvRDiz0A5s69QFGk/yc8BJPa1OqBb2E/dqEVVhe Yd3Z2HM4tiF9+B09GpzgRlg//iDaEDMqG/1tFrWI+xWWFnoP0u13XHhukMK79Fomfteg iddF/TPx/deGBUjfTjmMI+u8VX99e6P2fkwJf+ka/Eqi9uEDxBzi+PoeDCHhwpj89OJ+ L1CQ== X-Gm-Message-State: AC+VfDxQMaOXkW2gOSCJZbfePeZcmK72VyDoipZMPX3bA7SPvHS1XLd6 s8fjmPjuqc8+u0gzt+wDzBw= X-Google-Smtp-Source: ACHHUZ68ETqR4T7prVx7m7+jmSwcX9yKUQXmjC2V8i9yPOkTw8y9tW5XLPUGyOQ/wIOVDXimQIx/YA== X-Received: by 2002:a17:907:3d9f:b0:94e:8559:b5c5 with SMTP id he31-20020a1709073d9f00b0094e8559b5c5mr8819858ejc.64.1686206181971; Wed, 07 Jun 2023 23:36:21 -0700 (PDT) Received: from ?IPV6:2a0b:e7c0:0:107::aaaa:59? ([2a0b:e7c0:0:107::aaaa:59]) by smtp.gmail.com with ESMTPSA id cf20-20020a170906b2d400b00977d14d89fesm272586ejb.34.2023.06.07.23.36.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Jun 2023 23:36:21 -0700 (PDT) Message-ID: <98e85cf9-22db-9b1f-f486-fd5d57e58c4e@kernel.org> Date: Thu, 8 Jun 2023 08:36:20 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.2 Subject: Re: [PATCH 3/3] x86: Disable running 32bit processes if ia32_disabled is passed Content-Language: en-US From: Jiri Slaby To: Thomas Gleixner , Andrew Cooper , Nikolay Borisov , x86@kernel.org Cc: linux-kernel@vger.kernel.org, mhocko@suse.com References: <20230607072936.3766231-1-nik.borisov@suse.com> <20230607072936.3766231-4-nik.borisov@suse.com> <87legvjxat.ffs@tglx> <80f2045b-f276-e127-8e46-87fb6994fb41@suse.com> <87fs73juwa.ffs@tglx> <87a5xbjpk2.ffs@tglx> <875d0ab7-4470-25e2-6c01-72e231aae515@citrix.com> <874jnjj5z2.ffs@tglx> <278d7231-ee27-602f-4ba7-45d45d6772b3@citrix.com> <871qimkdft.ffs@tglx> <4217f682-f0e3-28de-1fb9-634c5df3581a@suse.cz> In-Reply-To: <4217f682-f0e3-28de-1fb9-634c5df3581a@suse.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08. 06. 23, 8:16, Jiri Slaby wrote: > On 08. 06. 23, 2:25, Thomas Gleixner wrote: >> I really wish that we could disable syscall32 reliably on AMD and make >> it raise #UD as it does on Intal. > > Sorry, I am likely missing something, but why is not #GP enough when we > set CSTAR = 0? Or rather to some hole (to avoid mappings when mmap_min_addr=0) or to something like entry_SYSCALL32_kill which you suggested elsewhere. But that is maybe what you consider not being "reliable". > It's of course not as good as Intel's *defined* #UD, but > why is not the above sufficient/reliable? > > thanks, -- js suse labs