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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 D6177C433E3 for ; Fri, 17 Jul 2020 09:25:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9454F20691 for ; Fri, 17 Jul 2020 09:25:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="kazs8KzU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9454F20691 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 323908D002A; Fri, 17 Jul 2020 05:25:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2D4378D0028; Fri, 17 Jul 2020 05:25:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 210078D002A; Fri, 17 Jul 2020 05:25:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0155.hostedemail.com [216.40.44.155]) by kanga.kvack.org (Postfix) with ESMTP id 0A9A28D0028 for ; Fri, 17 Jul 2020 05:25:16 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 87564250A1 for ; Fri, 17 Jul 2020 09:25:15 +0000 (UTC) X-FDA: 77047034190.25.soup71_0704a9f26f09 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 2085E180E97D7 for ; Fri, 17 Jul 2020 09:25:15 +0000 (UTC) X-HE-Tag: soup71_0704a9f26f09 X-Filterd-Recvd-Size: 3302 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Fri, 17 Jul 2020 09:25:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=oh4+QZoZC7XJ5liIvD/prbetozs/+rcdlSei8EeQx8I=; b=kazs8KzUqKOCO/2D6mprbyvEnU +fzslg8lr95LXVXM9aFdR5oVu7YU+jtZjZuUuNhtdMoijq35pApqNb0Kjpu2+qVjYJPMxBkMxwxwt zJhrNYgoG+hopYMkGXql6VsXOH/lcfSxf6ew9w8rrvlgWZWbac4aHyF3rLfDTz9Z9EaOC5qqudxmp MPUw2W8cUivp9Wp2v/EKMhTIHSccGcg5LfOOnbnhGaWNlBaW4Nt73aFJHO/KOx+DjkatJQ183jtX+ +ShtbR2b2ELtr1q+XxcZs8EPUhEs/rKmpIBEOk0TS2IxU4449Zsd/jtbWwQvb1sB85UrR0QJJ9Ss7 A65td5HQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jwMc8-00048L-Pk; Fri, 17 Jul 2020 09:25:08 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 6906F300130; Fri, 17 Jul 2020 11:25:07 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5316B29CF6F53; Fri, 17 Jul 2020 11:25:07 +0200 (CEST) Date: Fri, 17 Jul 2020 11:25:07 +0200 From: Peter Zijlstra To: ira.weiny@intel.com Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , x86@kernel.org, Dave Hansen , Dan Williams , Vishal Verma , Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH RFC V2 16/17] [dax|pmem]: Enable stray write protection Message-ID: <20200717092507.GE10769@hirez.programming.kicks-ass.net> References: <20200717072056.73134-1-ira.weiny@intel.com> <20200717072056.73134-17-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200717072056.73134-17-ira.weiny@intel.com> X-Rspamd-Queue-Id: 2085E180E97D7 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jul 17, 2020 at 12:20:55AM -0700, ira.weiny@intel.com wrote: > From: Ira Weiny > > Protecting against stray writes is particularly important for PMEM > because, unlike writes to anonymous memory, writes to PMEM persists > across a reboot. Thus data corruption could result in permanent loss of > data. Therefore, there is no option presented to the user. > > Enable stray write protection by setting the flag in pgmap which > requests it. Note if Zone Device Access Protection not be supported > this flag will have no affect. The actual implementation is stray-access-protection, as noted ealier. This inconsisteny is throughout.