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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 8E6B8C433E0 for ; Tue, 16 Feb 2021 16:34:57 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 51AA464DF0 for ; Tue, 16 Feb 2021 16:34:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 51AA464DF0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=U9gDnr0Y+F28syniksBL0iOhdKRlLpCwaUeaMuHvKpk=; b=t6piFj4vJvhgXXfg2AjFi0D7J FiqUFt6G8S41tiNJXU9Y1Ua5xzC5sxFotk0XcTffSLc9wfP2KVtZhiz2ltrQXJy6vk93mEz5eu/sH 2aV4cfmQOr4bBku7HZuGnPDbmaznrkOYciM8VwQHmsHn9jQVBiZDarOoKJCojaAKWS5OwUgFiLNcq ToHIZlDL3UoHhtqWfQdORrH6CZjhKDQPF5//l/KQ4HYnDPJOTKdUU2KKWc5hyr6PrPy2LFiktERAD SL15KGiQzx6GD7he9HMFvOlqav51QFyFdcGq+LdwXajfjyqHkvUrPz2dSplwbgtxo66bOBAOxeMJ0 28n/whP/w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lC3JB-0003ZC-Om; Tue, 16 Feb 2021 16:34:41 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lC3J7-0003Wb-M4 for linux-riscv@lists.infradead.org; Tue, 16 Feb 2021 16:34:39 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613493275; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KysYIYMpQ7qMwmL/JUOCOKvLfXo3jE4QCyxH618MYzE=; b=YOYDTf7Trq50U2iN2ri3ebMVB/pbjAdiqZeHv8At2BKNYOswrJirI8kB1TbesObe/kJwF6 sukwNjy6F1RB/9+0tlMP1KGSx/zseuyNpexWV/eJO+LThf4778H+Ky3IqPklNjMTAR11hm BzKTUuH/MWO2whGJTBQMTTFkLiHUdW4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-12-p1-EOjkyMC-fthVSXfK3rw-1; Tue, 16 Feb 2021 11:34:33 -0500 X-MC-Unique: p1-EOjkyMC-fthVSXfK3rw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8B1051E561; Tue, 16 Feb 2021 16:34:28 +0000 (UTC) Received: from [10.36.114.70] (ovpn-114-70.ams2.redhat.com [10.36.114.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id BF8E31970A; Tue, 16 Feb 2021 16:34:18 +0000 (UTC) Subject: Re: [PATCH v17 07/10] mm: introduce memfd_secret system call to create "secret" memory areas To: jejb@linux.ibm.com, Michal Hocko References: <20210214091954.GM242749@kernel.org> <052DACE9-986B-424C-AF8E-D6A4277DE635@redhat.com> <244f86cba227fa49ca30cd595c4e5538fe2f7c2b.camel@linux.ibm.com> <12c3890b233c8ec8e3967352001a7b72a8e0bfd0.camel@linux.ibm.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Tue, 16 Feb 2021 17:34:17 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <12c3890b233c8ec8e3967352001a7b72a8e0bfd0.camel@linux.ibm.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210216_113437_999274_F9C1932E X-CRM114-Status: GOOD ( 21.24 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Palmer Dabbelt , Arnd Bergmann , Hagen Paul Pfeifer , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin , Mike Rapoport Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 16.02.21 17:25, James Bottomley wrote: > On Mon, 2021-02-15 at 20:20 +0100, Michal Hocko wrote: > [...] >>>> What kind of flags are we talking about and why would that be a >>>> problem with memfd_create interface? Could you be more specific >>>> please? >>> >>> You mean what were the ioctl flags in the patch series linked >>> above? They were SECRETMEM_EXCLUSIVE and SECRETMEM_UNCACHED in >>> patch 3/5. >> >> OK I see. How many potential modes are we talking about? A few or >> potentially many? > > Well I initially thought there were two (uncached or not) until you > came up with the migratable or non-migratable, which affects the > security properties. But now there's also potential for hardware > backing, like mktme, described by flags as well. I suppose you could > also use RDT to restrict which cache the data goes into: say L1 but not > L2 on to lessen the impact of fully uncached (although the big thrust > of uncached was to blunt hyperthread side channels). So there is > potential for quite a large expansion even though I'd be willing to bet > that a lot of the modes people have thought about turn out not to be > very effective in the field. Thanks for the insight. I remember that even the "uncached" parts was effectively nacked by x86 maintainers (I might be wrong). For the other parts, the question is what we actually want to let user space configure. Being able to specify "Very secure" "maximum secure" "average secure" all doesn't really make sense to me. The discussion regarding migratability only really popped up because this is a user-visible thing and not being able to migrate can be a real problem (fragmentation, ZONE_MOVABLE, ...). -- Thanks, David / dhildenb _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv