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=-5.2 required=3.0 tests=BAYES_00, 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 028F6C47420 for ; Thu, 1 Oct 2020 08:55:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADD2420B1F for ; Thu, 1 Oct 2020 08:55:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731725AbgJAIzv (ORCPT ); Thu, 1 Oct 2020 04:55:51 -0400 Received: from foss.arm.com ([217.140.110.172]:56276 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbgJAIzq (ORCPT ); Thu, 1 Oct 2020 04:55:46 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 35BF8D6E; Thu, 1 Oct 2020 01:55:45 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4B29D3F70D; Thu, 1 Oct 2020 01:55:44 -0700 (PDT) Date: Thu, 1 Oct 2020 09:55:38 +0100 From: Lorenzo Pieralisi To: Baolin Wang Cc: Will Deacon , catalin.marinas@arm.com, baolin.wang7@gmail.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: PCI: Validate the node before setting node id for root bus Message-ID: <20201001085538.GA5142@e121166-lin.cambridge.arm.com> References: <1600770804-116365-1-git-send-email-baolin.wang@linux.alibaba.com> <20200928140054.GA11500@willie-the-truck> <20200928144957.GA90366@VM20190228-100.tbsite.net> <20200928152326.GA15640@e121166-lin.cambridge.arm.com> <26284ca5-ea05-0496-629d-9951f49dda8f@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <26284ca5-ea05-0496-629d-9951f49dda8f@linux.alibaba.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 29, 2020 at 11:41:29PM +0800, Baolin Wang wrote: > Hi, > > 锟斤拷 2020/9/28 23:23, Lorenzo Pieralisi 写锟斤拷: > > On Mon, Sep 28, 2020 at 10:49:57PM +0800, Baolin Wang wrote: > > > On Mon, Sep 28, 2020 at 03:00:55PM +0100, Will Deacon wrote: > > > > [+ Lorenzo] > > > > > > > > On Tue, Sep 22, 2020 at 06:33:24PM +0800, Baolin Wang wrote: > > > > > If the BIOS disabled the NUMA configuration, but did not change the > > > > > proximity domain description in the SRAT table, so the PCI root bus > > > > > device may get a incorrect node id by acpi_get_node(). > > > > > > > > How "incorrect" are we talking here? What actually goes wrong? At some > > > > point, we have to trust what the firmware is telling us. > > > > > > What I mean is, if we disable the NUMA from BIOS > > > > Please define what this means ie are you removing SRAT from ACPI static > > tables ? > > Yes. > > > > > > but we did not change the PXM for the PCI devices, > > > > If a _PXM maps to a proximity domain that is not described in the SRAT > > your firmware is buggy. > > Sorry for confusing, that's not what I mean. When the BIOS disable the NUMA > (remove the SRAT table), but the PCI devices' _PXM description is still > available, which means we can still get the pxm from acpi_evaluate_integer() > in this case. There should not be a _PXM object if the SRAT is not available, that's a firmware bug. > So we can get below inconsistent log on ARM platform: > "No NUMA configuration found > PCI_bus 0000:00 on NUMA node 0 > ... > PCI_bus 0000:e3 on NUMA node 1" > > On X86, the pci_acpi_root_get_node() will validate the node before setting > the node id for root bus. So I think we can add this validation for ARM > platform. Or anything else I missed? We are not adding checks because x86 does it, it is certainly to paper over a firmware bug that you hopefully still have a chance to fix, let's do that instead of adding code that is not necessary. Lorenzo