From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753411AbeBSRlZ (ORCPT ); Mon, 19 Feb 2018 12:41:25 -0500 Received: from mx2.suse.de ([195.135.220.15]:59562 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753279AbeBSRlY (ORCPT ); Mon, 19 Feb 2018 12:41:24 -0500 Subject: Re: [PATCH] x86: fix {pmd,pud}_{set,clear}_flags() To: Jan Beulich Cc: Ingo Molnar , Thomas Gleixner , Boris Ostrovsky , lkml , "H. Peter Anvin" References: <5A8AF1BB02000078001A91C3@suse.com> <44911e30-7d7a-14fd-1a70-ae3d92bfc771@suse.com> <5A8B119F02000078001A9412@suse.com> From: Juergen Gross Message-ID: Date: Mon, 19 Feb 2018 18:41:22 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <5A8B119F02000078001A9412@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/02/18 18:04, Jan Beulich wrote: >>>> On 19.02.18 at 17:23, wrote: >> On 19/02/18 15:48, Jan Beulich wrote: >>> Just like pte_{set,clear}_flags() their PMD and PUD counterparts should >>> not do any address translation. This was outright wrong under Xen >>> (causing a dead boot with no useful output on "suitable" systems), and >>> produced needlessly more complicated code (even if just slightly) when >>> paravirt was enabled. >>> >>> Signed-off-by: Jan Beulich >>> Cc: stable@vger.kernel.org >> >> While the changes look alright I'm really curious which kind of failure >> you are seeing, especially considering how long those functions haven't >> been changed (since more than 6 years). > > It's the new use of pmd_set_flags() in 2cc42bac1c ("x86-64/Xen: > eliminate W+X mappings"), and due to the (very odd afaic) identity > map handling the issue is invisible on most systems/setups. Aah, okay. This helps. Reviewed-by: Juergen Gross Juergen