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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 624CFC83011 for ; Mon, 30 Nov 2020 20:21:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0ED362074A for ; Mon, 30 Nov 2020 20:21:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="14GJ1kfJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729103AbgK3UVE (ORCPT ); Mon, 30 Nov 2020 15:21:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:57784 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728839AbgK3UVD (ORCPT ); Mon, 30 Nov 2020 15:21:03 -0500 Received: from localhost (129.sub-72-107-112.myvzw.com [72.107.112.129]) (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 B61002074A; Mon, 30 Nov 2020 20:20:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606767623; bh=Hpw2PczhkHKDUohGu9XA63kRRhtANavoFBG2MTLhVsc=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=14GJ1kfJP79EuRWnEWpkjplbRdQEr2yEuwUFqoeMhBuFu/pZOoZlnmhFB+2AiV0Ox 0Yx5w3Ul1+9cvDZuK0cUf4/SHE8pZKmS3dezRIDuV+Eonv0fk4sal360j9EwH7bFZC YRnclvcW+amj9EQzbXlXBgyuuhTrzOiiqItWZzbM= Date: Mon, 30 Nov 2020 14:20:21 -0600 From: Bjorn Helgaas To: Guilherme Piccoli Cc: "Eric W. Biederman" , Thomas Gleixner , lukas@wunner.de, linux-pci@vger.kernel.org, Pingfan Liu , andi@firstfloor.org, "H. Peter Anvin" , Baoquan He , x86@kernel.org, Sinan Kaya , Ingo Molnar , Jay Vosburgh , Dave Young , Gavin Guo , Borislav Petkov , Bjorn Helgaas , Guowen Shan , "Rafael J. Wysocki" , "Guilherme G. Piccoli" , kexec mailing list , LKML , Dan Streetman , Vivek Goyal Subject: Re: [PATCH 1/3] x86/quirks: Scan all busses for early PCI quirks Message-ID: <20201130202021.GA1106292@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Nov 18, 2020 at 07:36:08PM -0300, Guilherme Piccoli wrote: > Thanks a lot Bjorn! I confess except for PPC64 Server machines, I > never saw other "domains" or segments. Is it common in x86 to have > that? The early_quirks() are restricted to the first segment, no > matter how many host bridges we have in segment 0000? I don't know whether it's *common* to have multiple domains on x86, but they're definitely used on large systems. This includes some lspci info from an HPE Superdome Flex system: https://lore.kernel.org/lkml/5350E02A-6457-41A8-8F33-AF67BFDAEE3E@fb.com/ The early quirks in arch/x86/kernel/early-quirks.c (not the DECLARE_PCI_FIXUP_EARLY quirks in drivers/pci/quirks.c) are restricted to segment 0, no matter how many host bridges there are. This is because they use read_pci_config_16(), which uses a config access mechanism that has no provision for a segment number. Bjorn