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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 C8937C61DD8 for ; Sun, 15 Nov 2020 08:45:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 42B1C2415A for ; Sun, 15 Nov 2020 08:45:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="mvUrkC8D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42B1C2415A 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 5DBEB6B005C; Sun, 15 Nov 2020 03:45:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 58AE16B005D; Sun, 15 Nov 2020 03:45:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 452546B0068; Sun, 15 Nov 2020 03:45:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0180.hostedemail.com [216.40.44.180]) by kanga.kvack.org (Postfix) with ESMTP id 0D8CB6B005C for ; Sun, 15 Nov 2020 03:45:56 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 99D268249980 for ; Sun, 15 Nov 2020 08:45:56 +0000 (UTC) X-FDA: 77486019912.06.cub98_360f8072731e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id 72D4E10037CA8 for ; Sun, 15 Nov 2020 08:45:56 +0000 (UTC) X-HE-Tag: cub98_360f8072731e X-Filterd-Recvd-Size: 3856 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Sun, 15 Nov 2020 08:45:55 +0000 (UTC) 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 AC352223FB; Sun, 15 Nov 2020 08:45:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605429954; bh=I2e6oiG56Ipc+LYVEf48Tzpdu9e5X2SPeAjMkXGJ+FY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mvUrkC8DbWSBeGtX5LmBQbQw3erYKhs5cOaKJid6GDJMPM7nXXubIxoNcBB3oGNe7 rCwIs49LamtntTc1amgIjfXRya2sb8UfoqlV6jooN7E3J+NN/S80wRZL4M8ZXWanKD tXrCqT3L+M5TGE/FDZPfoLrZTF0AQQmH6gi3Hxpk= Date: Sun, 15 Nov 2020 10:45:39 +0200 From: Mike Rapoport To: Matthew Wilcox Cc: Andrew Morton , Alexander Viro , Andy Lutomirski , 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" , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Shuah Khan , Thomas Gleixner , 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, Hagen Paul Pfeifer Subject: Re: [PATCH v8 4/9] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: <20201115084539.GU4758@kernel.org> References: <20201110151444.20662-1-rppt@kernel.org> <20201110151444.20662-5-rppt@kernel.org> <20201113140656.GG17076@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201113140656.GG17076@casper.infradead.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 Fri, Nov 13, 2020 at 02:06:56PM +0000, Matthew Wilcox wrote: > On Tue, Nov 10, 2020 at 05:14:39PM +0200, Mike Rapoport wrote: > > diff --git a/mm/Kconfig b/mm/Kconfig > > index c89c5444924b..d8d170fa5210 100644 > > --- a/mm/Kconfig > > +++ b/mm/Kconfig > > @@ -884,4 +884,7 @@ config ARCH_HAS_HUGEPD > > config MAPPING_DIRTY_HELPERS > > bool > > > > +config SECRETMEM > > + def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED > > So I now have to build this in, whether I want it or not? Why wouldn't anybody want this nice feature? ;-) Now, seriously, I hesitated a lot about having a prompt here, but in the end I've decided to go without it. The added footprint is not so big, with x86 defconfig it's less than 8K and with distro (I've checked with Fedora) config the difference is less than 1k because they anyway have CMA=y. As this is "security" feature, disros most probably would have this enabled anyway, and I believe users that will see something like "Allow hiding memory from the kernel" will hit Y there. -- Sincerely yours, Mike.