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=-10.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 707EDC47425 for ; Fri, 25 Sep 2020 06:43:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DE79E23730 for ; Fri, 25 Sep 2020 06:43:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="gp4/PTjO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE79E23730 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BA95A6B005C; Fri, 25 Sep 2020 02:43:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B318B6B005D; Fri, 25 Sep 2020 02:43:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9D3216B0062; Fri, 25 Sep 2020 02:43:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0123.hostedemail.com [216.40.44.123]) by kanga.kvack.org (Postfix) with ESMTP id 826226B005C for ; Fri, 25 Sep 2020 02:43:16 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 3F69012F2 for ; Fri, 25 Sep 2020 06:43:16 +0000 (UTC) X-FDA: 77300641992.25.hook15_4d042c027165 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 16BC61804E3A0 for ; Fri, 25 Sep 2020 06:43:16 +0000 (UTC) X-HE-Tag: hook15_4d042c027165 X-Filterd-Recvd-Size: 4583 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Fri, 25 Sep 2020 06:43:15 +0000 (UTC) Received: from kernel.org (unknown [87.71.73.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 648B621D91; Fri, 25 Sep 2020 06:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601016194; bh=w9IKlZIfJMsHxegJ+VLXCONApnJkHjt/WLrJovIxo84=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gp4/PTjOTCt6wK+y6cBEuicvnrMX77A7MiRNbWPoUrNLDFWXc7dXI8MhLKiFWXqsv W10CVzH2Sh5bikH6aMEPT2GD6WMerz6IjUQAM+CvT/52Z2l6KeVLCZlvbVQ+NG092g JDBOaIbH10dUGBs84yFpT+eEft/TvzNhegpH41cU= Date: Fri, 25 Sep 2020 09:42:57 +0300 From: Mike Rapoport To: Andrew Morton Cc: Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , David Hildenbrand , Elena Reshetova , "H. Peter Anvin" , Idan Yaniv , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Thomas Gleixner , Shuah Khan , Tycho Andersen , Will Deacon , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org Subject: Re: [PATCH v6 0/6] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: <20200925064257.GX2142832@kernel.org> References: <20200924132904.1391-1-rppt@kernel.org> <20200924193428.6642e0cc3436bb67ddf8024a@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200924193428.6642e0cc3436bb67ddf8024a@linux-foundation.org> 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 Thu, Sep 24, 2020 at 07:34:28PM -0700, Andrew Morton wrote: > On Thu, 24 Sep 2020 16:28:58 +0300 Mike Rapoport wrote: > > > From: Mike Rapoport > > > > Hi, > > > > This is an implementation of "secret" mappings backed by a file descriptor. > > I've dropped the boot time reservation patch for now as it is not strictly > > required for the basic usage and can be easily added later either with or > > without CMA. > > > > ... > > > > The file descriptor backing secret memory mappings is created using a > > dedicated memfd_secret system call The desired protection mode for the > > memory is configured using flags parameter of the system call. The mmap() > > of the file descriptor created with memfd_secret() will create a "secret" > > memory mapping. The pages in that mapping will be marked as not present in > > the direct map and will have desired protection bits set in the user page > > table. For instance, current implementation allows uncached mappings. > > > > Although normally Linux userspace mappings are protected from other users, > > such secret mappings are useful for environments where a hostile tenant is > > trying to trick the kernel into giving them access to other tenants > > mappings. > > > > Additionally, the secret mappings may be used as a mean to protect guest > > memory in a virtual machine host. > > > > For demonstration of secret memory usage we've created a userspace library > > [1] that does two things: the first is act as a preloader for openssl to > > I can find no [1]. Oops, sorry. It's https://git.kernel.org/pub/scm/linux/kernel/git/jejb/secret-memory-preloader.git/ > I'm not a fan of the enumerated footnote thing. Why not inline the url > right here so readers don't need to jump around? > > -- Sincerely yours, Mike.