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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 962FBC433E3 for ; Wed, 13 May 2020 15:09:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B0DAB205ED for ; Wed, 13 May 2020 15:09:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389072AbgEMPJx (ORCPT ); Wed, 13 May 2020 11:09:53 -0400 Received: from mga02.intel.com ([134.134.136.20]:61998 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727778AbgEMPJw (ORCPT ); Wed, 13 May 2020 11:09:52 -0400 IronPort-SDR: Vh3ZEWqEMc8MhyMH+3O2clGkvjj3Y7a/vHqR7LFjTorT8aCi0gCBXBCYWgqBrVxz6ZeXg1AjF4 YXsN2yS2oo6w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 May 2020 08:09:52 -0700 IronPort-SDR: Ue669IgB67/dzfgU4jZaJf1QR3Z9iMh0oZJ7tuDrbILUTFCOm+fBok+1+8SRIGtU7YzElkBO4e h24E0SgN5TWA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,388,1583222400"; d="scan'208";a="265905695" Received: from cwward1-mobl.amr.corp.intel.com (HELO [10.254.205.248]) ([10.254.205.248]) by orsmga006.jf.intel.com with ESMTP; 13 May 2020 08:09:42 -0700 Subject: Re: [PATCH v4 1/3] arch/x86: Update config and kernel doc for MPK feature on AMD To: Babu Moger , corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, pbonzini@redhat.com, sean.j.christopherson@intel.com Cc: x86@kernel.org, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, mchehab+samsung@kernel.org, changbin.du@intel.com, namit@vmware.com, bigeasy@linutronix.de, yang.shi@linux.alibaba.com, asteinhauser@google.com, anshuman.khandual@arm.com, jan.kiszka@siemens.com, akpm@linux-foundation.org, steven.price@arm.com, rppt@linux.vnet.ibm.com, peterx@redhat.com, dan.j.williams@intel.com, arjunroy@google.com, logang@deltatee.com, thellstrom@vmware.com, aarcange@redhat.com, justin.he@arm.com, robin.murphy@arm.com, ira.weiny@intel.com, keescook@chromium.org, jgross@suse.com, andrew.cooper3@citrix.com, pawan.kumar.gupta@linux.intel.com, fenghua.yu@intel.com, vineela.tummalapalli@intel.com, yamada.masahiro@socionext.com, sam@ravnborg.org, acme@redhat.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <158932780954.44260.4292038705292213548.stgit@naples-babu.amd.com> <158932793646.44260.2629848287332937779.stgit@naples-babu.amd.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzShEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gPGRhdmVAc3I3MS5uZXQ+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAUCTo3k0QIZAQAKCRBoNZUwcMmSsMO2D/421Xg8pimb9mPzM5N7khT0 2MCnaGssU1T59YPE25kYdx2HntwdO0JA27Wn9xx5zYijOe6B21ufrvsyv42auCO85+oFJWfE K2R/IpLle09GDx5tcEmMAHX6KSxpHmGuJmUPibHVbfep2aCh9lKaDqQR07gXXWK5/yU1Dx0r VVFRaHTasp9fZ9AmY4K9/BSA3VkQ8v3OrxNty3OdsrmTTzO91YszpdbjjEFZK53zXy6tUD2d e1i0kBBS6NLAAsqEtneplz88T/v7MpLmpY30N9gQU3QyRC50jJ7LU9RazMjUQY1WohVsR56d ORqFxS8ChhyJs7BI34vQusYHDTp6PnZHUppb9WIzjeWlC7Jc8lSBDlEWodmqQQgp5+6AfhTD kDv1a+W5+ncq+Uo63WHRiCPuyt4di4/0zo28RVcjtzlGBZtmz2EIC3vUfmoZbO/Gn6EKbYAn rzz3iU/JWV8DwQ+sZSGu0HmvYMt6t5SmqWQo/hyHtA7uF5Wxtu1lCgolSQw4t49ZuOyOnQi5 f8R3nE7lpVCSF1TT+h8kMvFPv3VG7KunyjHr3sEptYxQs4VRxqeirSuyBv1TyxT+LdTm6j4a mulOWf+YtFRAgIYyyN5YOepDEBv4LUM8Tz98lZiNMlFyRMNrsLV6Pv6SxhrMxbT6TNVS5D+6 UorTLotDZKp5+M7BTQRUY85qARAAsgMW71BIXRgxjYNCYQ3Xs8k3TfAvQRbHccky50h99TUY sqdULbsb3KhmY29raw1bgmyM0a4DGS1YKN7qazCDsdQlxIJp9t2YYdBKXVRzPCCsfWe1dK/q 66UVhRPP8EGZ4CmFYuPTxqGY+dGRInxCeap/xzbKdvmPm01Iw3YFjAE4PQ4hTMr/H76KoDbD cq62U50oKC83ca/PRRh2QqEqACvIH4BR7jueAZSPEDnzwxvVgzyeuhwqHY05QRK/wsKuhq7s UuYtmN92Fasbxbw2tbVLZfoidklikvZAmotg0dwcFTjSRGEg0Gr3p/xBzJWNavFZZ95Rj7Et db0lCt0HDSY5q4GMR+SrFbH+jzUY/ZqfGdZCBqo0cdPPp58krVgtIGR+ja2Mkva6ah94/oQN lnCOw3udS+Eb/aRcM6detZr7XOngvxsWolBrhwTQFT9D2NH6ryAuvKd6yyAFt3/e7r+HHtkU kOy27D7IpjngqP+b4EumELI/NxPgIqT69PQmo9IZaI/oRaKorYnDaZrMXViqDrFdD37XELwQ gmLoSm2VfbOYY7fap/AhPOgOYOSqg3/Nxcapv71yoBzRRxOc4FxmZ65mn+q3rEM27yRztBW9 AnCKIc66T2i92HqXCw6AgoBJRjBkI3QnEkPgohQkZdAb8o9WGVKpfmZKbYBo4pEAEQEAAcLB XwQYAQIACQUCVGPOagIbDAAKCRBoNZUwcMmSsJeCEACCh7P/aaOLKWQxcnw47p4phIVR6pVL e4IEdR7Jf7ZL00s3vKSNT+nRqdl1ugJx9Ymsp8kXKMk9GSfmZpuMQB9c6io1qZc6nW/3TtvK pNGz7KPPtaDzvKA4S5tfrWPnDr7n15AU5vsIZvgMjU42gkbemkjJwP0B1RkifIK60yQqAAlT YZ14P0dIPdIPIlfEPiAWcg5BtLQU4Wg3cNQdpWrCJ1E3m/RIlXy/2Y3YOVVohfSy+4kvvYU3 lXUdPb04UPw4VWwjcVZPg7cgR7Izion61bGHqVqURgSALt2yvHl7cr68NYoFkzbNsGsye9ft M9ozM23JSgMkRylPSXTeh5JIK9pz2+etco3AfLCKtaRVysjvpysukmWMTrx8QnI5Nn5MOlJj 1Ov4/50JY9pXzgIDVSrgy6LYSMc4vKZ3QfCY7ipLRORyalFDF3j5AGCMRENJjHPD6O7bl3Xo 4DzMID+8eucbXxKiNEbs21IqBZbbKdY1GkcEGTE7AnkA3Y6YB7I/j9mQ3hCgm5muJuhM/2Fr OPsw5tV/LmQ5GXH0JQ/TZXWygyRFyyI2FqNTx4WHqUn3yFj8rwTAU1tluRUYyeLy0ayUlKBH ybj0N71vWO936MqP6haFERzuPAIpxj2ezwu0xb1GjTk4ynna6h5GjnKgdfOWoRtoWndMZxbA z5cecg== Message-ID: Date: Wed, 13 May 2020 08:09:41 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <158932793646.44260.2629848287332937779.stgit@naples-babu.amd.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/12/20 4:58 PM, Babu Moger wrote: > +config X86_MEMORY_PROTECTION_KEYS > + # Both Intel and AMD platforms support "Memory Protection Keys" > + # feature. So add a generic option X86_MEMORY_PROTECTION_KEYS > + # and set the option whenever X86_INTEL_MEMORY_PROTECTION_KEYS > + # is set. This is to avoid the confusion about the feature > + # availability on AMD platforms. Also renaming the old option > + # would cause the user an extra prompt during the kernel > + # configuration. So avoided changing the old config name. > + def_bool X86_INTEL_MEMORY_PROTECTION_KEYS Hi Babu, I made a request earlier for an end date (or version) to be included here. I believe that appeared in one of your earlier versions, but it was removed in later ones. Was there a reason for that? I'd really prefer to put some kind of expiration date on the config option. It will outlive us all otherwise. > Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature > which is found on Intel's Skylake "Scalable Processor" Server CPUs. > -It will be avalable in future non-server parts. > +It will be available in future non-server parts. Also, AMD64 > +Architecture Programmer’s Manual defines PKU feature in AMD processors. I actually worked pretty hard to make that sentence useful to Linux users. Instead of forcing them to imply that it will be available on future AMD CPUs, can we just come out and say it? Can we give any more information to our users? Naming the AMD manual in which the feature is defined doesn't really help our users. Let's not waste the bytes on it. How about: Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature which is found on Intel's Skylake (and later) "Scalable Processor" Server CPUs. It will be avalable in future non- server Intel parts and future AMD parts. Any clarity you can add, such as to say what AMD is doing for server vs. client would be nice. BTW, when I first submitted pkeys, I didn't have any statement like this in the changelog or documentation. Ingo, I think, asked for it and I worked with folks inside Intel to figure out how much we could say publicly about our plans. A similar effort from AMD would be much appreciated here.