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, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 36BB2C4332B for ; Mon, 8 Feb 2021 11:00:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 003BE64E99 for ; Mon, 8 Feb 2021 11:00:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232347AbhBHK7x convert rfc822-to-8bit (ORCPT ); Mon, 8 Feb 2021 05:59:53 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2521 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231938AbhBHK50 (ORCPT ); Mon, 8 Feb 2021 05:57:26 -0500 Received: from fraeml734-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4DZ2rz6gNRz67lTf; Mon, 8 Feb 2021 18:51:47 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml734-chm.china.huawei.com (10.206.15.215) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Mon, 8 Feb 2021 11:56:38 +0100 Received: from localhost (10.47.30.32) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Mon, 8 Feb 2021 10:56:37 +0000 Date: Mon, 8 Feb 2021 10:55:51 +0000 From: Jonathan Cameron To: Chris Browy , CC: Ben Widawsky , , , , , , , , , , Subject: Re: [RFC PATCH v1 01/01] PCIe DOE for PCIe and CXL 2.0 Message-ID: <20210208105551.00005c12@Huawei.com> In-Reply-To: <593ADBD3-9A16-4875-AF5B-57E346A3460A@avery-design.com> References: <4F370DAB-1EFE-490B-B93F-312AC5081057@avery-design.com> <20210205160954.00006728@Huawei.com> <20210205171936.nx62hs4z4vr5g2er@intel.com> <20210205184942.00002233@Huawei.com> <593ADBD3-9A16-4875-AF5B-57E346A3460A@avery-design.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.47.30.32] X-ClientProxiedBy: lhreml719-chm.china.huawei.com (10.201.108.70) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org ... > > > > >> > >>>> > >>>> Just like you we feel what's most important is to have DOE supported so that > >>>> UEFI and Linux kernel and drivers can progress. We're also contributing to > >>>> writing compliance tests for the CXL Compliance Software Development WG. > >>> > >>> Great. > >> > >> Is anyone doing the kernel enabling for it? > > > > Planning to look at this but plenty of other things on my todo list if someone > > else gets to it first. > > > > Generic DOE support should be straight forward (the infrastructure). > > Parsing CDAT also straight forward. > > Doing something with the results is hard unless we just provide an interface for > > userspace to query them for a given device - or dump the table > > (I think we do want to be able to that). > > > > What I'm really not sure on is how to handle NUMA domains that are created late > > in the kernel boot sequence. The ACPI flow is set up with the assumption > > that we can get them from SRAT very early in boot. Need to figure out how to > > work around that. (e.g. preallocate a bunch of spare nodes for example though that's > > ugly). Note IIRC the kernel doesn't do runtime update of any of the ACPI > > performance parameters yet (_SLI, _HMA) so there probably isn't any infrastructure > > that we can reuse. > > > > There is also the firmware based enumeration and description option (OS not necessarily > > aware of CXL) in which this is all up to EDK2 and the kernel gets it all presented > > as standard tables. > > Do we know who’s on this as part of the EDK2 development? It would be great if they could > address the SRAT/HMAT generation from reading CDAT. EDK2 does address CXL 1.1 now. No idea who, if anyone, is looking at this currently. Perhaps ask on the EDK2 list? Jonathan > > > > > As you can perhaps tell from my half done reviews, this week disappeared in > > other things so bit of catch up for me to do next week. > > > > Thanks, > > > > Joanthan > > ...