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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64725C7EE2A for ; Thu, 1 Jun 2023 16:20:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231241AbjFAQUS (ORCPT ); Thu, 1 Jun 2023 12:20:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230174AbjFAQUR (ORCPT ); Thu, 1 Jun 2023 12:20:17 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78ADF12C; Thu, 1 Jun 2023 09:20:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1685636416; x=1717172416; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=66IbxJcu+ERP7iDReAuuseWeSYepw+/LOPDcQLh6/HQ=; b=cQMgBE2wPwabOoxsqdvdV0HK9JzB/E25Aiz2JnLsAHxW301ib0A0g0Ws JLipOHlD4uKXnpvr/NaWWsBq6qnjpi8d3q908UMbSvFC4uVOcHdiTfW7+ 89i6XwssIWsRqZVQ4LfO1IEjUPAY2si1OIyOpoAzGICsdYN2aXzV/C8CV ivVr0kpBwofVYYfuTART+fK8nI7UrTBgOnIzgLhjO3Ff8cYHAoSVcaVdc iD+QStK4AlHcepQ3TWONa4pAjzZuAdJf+F9q6LP89FUilPy6JI1kVlttI 00exzl1ZDTsDLMMeF7BU/IjJQkoET7NDi9AdavlZupquxvV9TvhWtXyYK w==; X-IronPort-AV: E=McAfee;i="6600,9927,10728"; a="383879560" X-IronPort-AV: E=Sophos;i="6.00,210,1681196400"; d="scan'208";a="383879560" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2023 09:16:04 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10728"; a="737160337" X-IronPort-AV: E=Sophos;i="6.00,210,1681196400"; d="scan'208";a="737160337" Received: from jdboswor-mobl.amr.corp.intel.com (HELO [10.212.227.45]) ([10.212.227.45]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2023 09:16:03 -0700 Message-ID: Date: Thu, 1 Jun 2023 09:16:03 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1 Content-Language: en-US To: Jeff Xu Cc: Jeff Xu , =?UTF-8?Q?Stephen_R=c3=b6ttger?= , luto@kernel.org, jorgelo@chromium.org, keescook@chromium.org, groeck@chromium.org, jannh@google.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-hardening@vger.kernel.org References: <20230515130553.2311248-1-jeffxu@chromium.org> <2bcffc9f-9244-0362-2da9-ece230055320@intel.com> <2b14036e-aed8-4212-bc0f-51ec4fe5a5c1@intel.com> <9d64c949-6d5f-06c0-47ef-caade67477e5@intel.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On 5/31/23 18:39, Jeff Xu wrote: > I think this solution should work. By "work" I think you mean that if laser-focused on this one use case, without a full implementation, it looks like it can work. I'll give you a "maybe" on that. But that leaves out the bigger picture. How many other things will we regress doing this? What's the opportunity cost? What other things will get neglected because we did _this_ one? Are there more users out there? Looking at the big picture, I'm not convinced those tradeoffs are good ones (and you're not going to find anyone that's a bigger fan of pkeys than me).