From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751020AbdLGIDY (ORCPT ); Thu, 7 Dec 2017 03:03:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:60784 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750781AbdLGIDX (ORCPT ); Thu, 7 Dec 2017 03:03:23 -0500 Date: Thu, 7 Dec 2017 09:03:12 +0100 From: Borislav Petkov To: Ricardo Neri Cc: Peter Zijlstra , Thomas Gleixner , luto@kernel.org, adam.buchbinder@gmail.com, mst@redhat.com, mhiramat@kernel.org, dave.hansen@linux.intel.com, mingo@kernel.org, linux-kernel@vger.kernel.org, colin.king@canonical.com, jslaby@suse.cz, pbonzini@redhat.com, cmetcalf@mellanox.com, akpm@linux-foundation.org, vbabka@suse.cz, acme@redhat.com, brgerst@gmail.com, shuah@kernel.org, paul.gortmaker@windriver.com, lstoakes@gmail.com, hpa@zytor.com, thgarnie@google.com, keescook@chromium.org, adrian.hunter@intel.com, ray.huang@amd.com, dvyukov@google.com, ravi.v.shankar@intel.com, slaoub@gmail.com, corbet@lwn.net, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/mpx] x86/insn-eval: Add utility function to get segment descriptor Message-ID: <20171207080312.6izk3edr2ctng6sd@pd.tnic> References: <1509135945-13762-15-git-send-email-ricardo.neri-calderon@linux.intel.com> <20171205174844.GM3165@worktop.lehotels.local> <20171205181456.akycirziiuhb7crw@pd.tnic> <20171205183845.GO3165@worktop.lehotels.local> <20171205212933.amf4pkpzgrjpdssw@pd.tnic> <20171207072359.GA19428@voyager> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20171207072359.GA19428@voyager> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 06, 2017 at 11:23:59PM -0800, Ricardo Neri wrote: > In UMIP emulation we can potentially access the LDT twice. Once when > determining the base address of the code segment and again when determining > the base address and limit of the segment in which the result of the > emulation is written. I guess that mm->context.ldt_seq needs to not change > not only while decoding a particular linear address but across these two > linear address decodings. Yap, stuff which needs to see an *unchanged* LDT should use the cookie to verify that and the LDT code should change the cookie when the LDT is modified. > Sure, I will look into implementing this idea and post patches for it. Thanks! -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --