Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754090AbdCHQ4W (ORCPT ); Wed, 8 Mar 2017 11:56:22 -0500 Received: from smtp51.i.mail.ru ([94.100.177.111]:48806 "EHLO smtp51.i.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752177AbdCHQzD (ORCPT ); Wed, 8 Mar 2017 11:55:03 -0500 X-Greylist: delayed 9888 seconds by postgrey-1.27 at vger.kernel.org; Wed, 08 Mar 2017 11:55:02 EST Subject: Re: [v6 PATCH 00/21] x86: Enable User-Mode Instruction Prevention To: Andy Lutomirski References: <20170308003254.27833-1-ricardo.neri-calderon@linux.intel.com> <79ba0fff-4c01-2bfa-06cb-5cfc98dd710c@list.ru> <997ba581-ecfa-b773-a48e-85b92a439836@list.ru> Cc: Ricardo Neri , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Andy Lutomirski , Borislav Petkov , Peter Zijlstra , Andrew Morton , Brian Gerst , Chris Metcalf , Dave Hansen , Paolo Bonzini , Liang Z Li , Masami Hiramatsu , Huang Rui , Jiri Slaby , Jonathan Corbet , "Michael S. Tsirkin" , Paul Gortmaker , Vlastimil Babka , Chen Yucong , Alexandre Julliard , Fenghua Yu , "Ravi V. Shankar" , Shuah Khan , "linux-kernel@vger.kernel.org" , X86 ML , linux-msdos@vger.kernel.org, wine-devel@winehq.org From: Stas Sergeev Message-ID: Date: Wed, 8 Mar 2017 19:53:58 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Authentication-Results: smtp51.i.mail.ru; auth=pass smtp.auth=stsp@list.ru smtp.mailfrom=stsp@list.ru X-7FA49CB5: 0D63561A33F958A5F20C187F198EB8183167B6E84F270CC4AC00E3FDB1B1686E9F18ECD7E95F35E929AFE063DF4C541CCC7870F90177EF80CF48B855B8D54CED0BF2EBBBDD9D6B0F700B7D52D678FF46 X-Mailru-Sender: F1845AB6CCC9920DF7838D61D4D05C4280B753E73855438BE48E0D98424B72F2AC90A8F9D9BFD8A81653177920737CA72999BEE114A20FF4278B2D54D4112F244F0A872F021F905956A8FB0C6EBA5FCCEAB4BC95F72C04283CDA0F3B3F5B9367 X-Mras: OK Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 821 Lines: 17 08.03.2017 19:46, Andy Lutomirski пишет: >> No no, since I meant prot mode, this is not what I need. >> I would never need to disable UMIP as to allow the >> prot mode apps to do SLDT. Instead it would be good >> to have an ability to provide a replacement for the dummy >> emulation that is currently being proposed for kernel. >> All is needed for this, is just to deliver a SIGSEGV. > That's what I meant. Turning off FIXUP_UMIP would leave UMIP on but > turn off the fixup, so you'd get a SIGSEGV indicating #GP (or a vm86 > GP exit). But then I am confused with the word "compat" in your "COMPAT_MASK0_X86_UMIP_FIXUP" and "sys_adjust_compat_mask(int op, int word, u32 mask);" Leaving UMIP on and only disabling a fixup doesn't sound like a compat option to me. I would expect compat to disable it completely.