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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 03AC5C32789 for ; Fri, 2 Nov 2018 23:30:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEC8E2081F for ; Fri, 2 Nov 2018 23:30:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEC8E2081F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-pci-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728221AbeKCIjM (ORCPT ); Sat, 3 Nov 2018 04:39:12 -0400 Received: from mail.skyhub.de ([5.9.137.197]:50664 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726778AbeKCIjL (ORCPT ); Sat, 3 Nov 2018 04:39:11 -0400 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id pzsfQp6ePQH9; Sat, 3 Nov 2018 00:30:00 +0100 (CET) Received: from zn.tnic (p200300EC2BCD3B00329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2bcd:3b00:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id E428E1EC0A67; Sat, 3 Nov 2018 00:29:59 +0100 (CET) Date: Sat, 3 Nov 2018 00:29:48 +0100 From: Borislav Petkov To: Bjorn Helgaas Cc: "Woods, Brian" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "x86@kernel.org" , Clemens Ladisch , Jean Delvare , Guenter Roeck , Pu Wen , Jia Zhang , "linux-kernel@vger.kernel.org" , "linux-hwmon@vger.kernel.org" , "linux-pci@vger.kernel.org" Subject: Re: [PATCH 2/4] x86/amd_nb: add support for newer PCI topologies Message-ID: <20181102232948.GC26770@zn.tnic> References: <20181102181055.130531-1-brian.woods@amd.com> <20181102181055.130531-3-brian.woods@amd.com> <20181102195925.GB160487@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181102195925.GB160487@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Fri, Nov 02, 2018 at 02:59:25PM -0500, Bjorn Helgaas wrote: > This isn't my code, and I'm not really objecting to these changes, but > from where I sit, the fact that you need this sort of vendor-specific > topology discovery is a little bit ugly and seems like something of a > maintenance issue. You could argue that this is sort of an "AMD CPU > driver", which is entitled to be device-specific, and that does make > some sense. It is a bunch of glue code which enumerates the PCI devices a CPU has and other in-kernel users can use that instead of doing the discovery/enumeration themselves. > But device-specific code is typically packaged as a driver that uses > driver registration interfaces like acpi_bus_register_driver(), > pci_register_driver(), etc. That gives you a consistent structure > and, more importantly, a framework for dealing with hotplug. It > doesn't look like amd_nb.c would deal well with hot-add of CPUs. If you mean physical hotadd, then that's a non-issue as, AFAIK, AMD doesn't support that. Now, TBH I've never tried soft-offlining the cores of a node and then check whether using the PCI devices of that node would work. Now, I don't mind this getting converted to a proper PCI driver as long as it is not a module as it has to be present at all times. Other than that, I'm a happy camper. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.