From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 60FB77D048 for ; Mon, 18 Jun 2018 21:55:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755357AbeFRVzH convert rfc822-to-8bit (ORCPT ); Mon, 18 Jun 2018 17:55:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56110 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754628AbeFRVzG (ORCPT ); Mon, 18 Jun 2018 17:55:06 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4E2643082A2E; Mon, 18 Jun 2018 21:55:06 +0000 (UTC) Received: from t450s.home (ovpn-116-135.phx2.redhat.com [10.3.116.135]) by smtp.corp.redhat.com (Postfix) with ESMTP id F176F4507; Mon, 18 Jun 2018 21:55:04 +0000 (UTC) Date: Mon, 18 Jun 2018 15:55:04 -0600 From: Alex Williamson To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, Stephen Bates , Christoph Hellwig , Bjorn Helgaas , Jonathan Corbet , Ingo Molnar , Thomas Gleixner , "Paul E. McKenney" , Marc Zyngier , Kai-Heng Feng , Frederic Weisbecker , Dan Williams , =?UTF-8?B?SsOpcsO0bWU=?= Glisse , Benjamin Herrenschmidt , Christian =?UTF-8?B?S8O2bmln?= Subject: Re: [PATCH v3 2/3] PCI: Allow specifying devices using a base bus and path of devfns Message-ID: <20180618155504.68e56358@t450s.home> In-Reply-To: <20180618193636.16210-3-logang@deltatee.com> References: <20180618193636.16210-1-logang@deltatee.com> <20180618193636.16210-3-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 18 Jun 2018 21:55:06 +0000 (UTC) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, 18 Jun 2018 13:36:35 -0600 Logan Gunthorpe wrote: > When specifying PCI devices on the kernel command line using a > BDF, the bus numbers can change when adding or replacing a device, > changing motherboard firmware, or applying kernel parameters like > pci=assign-buses. When this happens, it is usually undesirable to > apply whatever command line tweak to the wrong device. > > Therefore, it is useful to be able to specify devices with a base > bus number and the path of devfns needed to get to it. (Similar to > the "device scope" structure in the Intel VT-d spec, Section 8.3.1.) > > Thus, we add an option to specify devices in the following format: > > [:]:.[/.][/ ...] > > The path can be any segment within the PCI hierarchy of any length and > determined through the use of 'lspci -t'. When specified this way, it is > less likely that a renumbered bus will result in a valid device specification > and the tweak won't be applied to the wrong device. > > Signed-off-by: Logan Gunthorpe > Reviewed-by: Stephen Bates > Acked-by: Christian König > --- > Documentation/admin-guide/kernel-parameters.txt | 8 +- > drivers/pci/pci.c | 120 ++++++++++++++++++++---- > 2 files changed, 106 insertions(+), 22 deletions(-) Reviewed-by: Alex Williamson -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html