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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 533F5C64E7A for ; Tue, 24 Nov 2020 09:29:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F164520782 for ; Tue, 24 Nov 2020 09:29:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="P3bKeuXg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731188AbgKXJ3j (ORCPT ); Tue, 24 Nov 2020 04:29:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:38102 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727901AbgKXJ3i (ORCPT ); Tue, 24 Nov 2020 04:29:38 -0500 Received: from kernel.org (unknown [77.125.7.142]) (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 08D202073C; Tue, 24 Nov 2020 09:29:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606210177; bh=iTkMZLIpRtTWQfDGIB3Vl3mRtp/b8gkTxfVBLDleW2s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=P3bKeuXgUqKvyJMqI2t3WocMqVtq5rV80ChLv9RkXZobErCnfHPcZXypQS/ff8OIc k9Yt6nSUwbnDnaqXryHrQQDoC3ltsZJwF2Txq8wR9gdzisTN7cFmPk0qphW+f2nwAw 8OtVd4ZVVbsESt0E2Fi0gLuo0Co6IDESghVXVkF8= Date: Tue, 24 Nov 2020 11:29:19 +0200 From: Mike Rapoport To: Andy Lutomirski Cc: Andrew Morton , Alexander Viro , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , David Hildenbrand , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , Linux API , linux-arch , linux-arm-kernel , Linux FS Devel , Linux-MM , LKML , "open list:KERNEL SELFTEST FRAMEWORK" , linux-nvdimm , linux-riscv@lists.infradead.org, X86 ML Subject: Re: [PATCH v10 0/9] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: <20201124092919.GI8537@kernel.org> References: <20201123095432.5860-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 23, 2020 at 07:28:22AM -0800, Andy Lutomirski wrote: > On Mon, Nov 23, 2020 at 1:54 AM Mike Rapoport wrote: > > > > From: Mike Rapoport > > > > Hi, > > > > This is an implementation of "secret" mappings backed by a file descriptor. > > > > 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. > > I'm still not ready to ACK uncached mappings on x86. I'm fine with > the concept of allowing privileged users to create UC memory on x86 > for testing and experimentation, but it's a big can of worms in > general. Ok, let's move forward without UC. -- Sincerely yours, Mike.