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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 75C1EC433E1 for ; Tue, 25 Aug 2020 21:28:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 521172074A for ; Tue, 25 Aug 2020 21:28:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="tOoYjJYv"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="oQR1S/0D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726374AbgHYV2d (ORCPT ); Tue, 25 Aug 2020 17:28:33 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:52524 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726149AbgHYV2c (ORCPT ); Tue, 25 Aug 2020 17:28:32 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1598390910; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DM8kbYiy7ZvYakB3fMHVSwg1j58bcLwh1sILIYH/AFI=; b=tOoYjJYvUPFZDmOguQPFJDhQeHuqRavvHi/bJrAyTkchveyhC+en4z3ohJa6FmPIHI2vow qc9HQ8/FTpaHEhGVpgURbiV1lVl+XKejxCXJmH2j3Sj2h8nwPHrrK3/Kb6Do9W3PTncSXY TOuqFSROfKTujH662yP4shxjPWBDkywHOauPnwUWRRiR+DHAaP2psLdtuzSJtmNFJD79PB hjeXftohGgS9rC9Xb2dZuw6mNwzd/d9QfmdUvlkZy88Ftt7fM3r9rWu4L7KrgJ8gocSx1K eGa2PZEjfsTIQ/LxJMcJsM3xNXGuHKDY89giMPP0/QzKHuUEf3bJ22fUusSPsg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1598390910; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DM8kbYiy7ZvYakB3fMHVSwg1j58bcLwh1sILIYH/AFI=; b=oQR1S/0DMHh75hr94qI0low3SKHVQ7r24k+kTQlDcy/nGiegnvAQmFWoo65Pv64XBO7xgV AXir3AUyBr42qvBg== To: Bjorn Helgaas Cc: LKML , x86@kernel.org, Bjorn Helgaas , linux-pci@vger.kernel.org, Joerg Roedel , iommu@lists.linux-foundation.org, linux-hyperv@vger.kernel.org, Haiyang Zhang , Jon Derrick , Lu Baolu , Wei Liu , "K. Y. Srinivasan" , Stephen Hemminger , Steve Wahl , Dimitri Sivanich , Russ Anderson , Lorenzo Pieralisi , Konrad Rzeszutek Wilk , xen-devel@lists.xenproject.org, Juergen Gross , Boris Ostrovsky , Stefano Stabellini , Marc Zyngier , Greg Kroah-Hartman , "Rafael J. Wysocki" , Megha Dey , Jason Gunthorpe , Dave Jiang , Alex Williamson , Jacob Pan , Baolu Lu , Kevin Tian , Dan Williams Subject: Re: [patch RFC 30/38] PCI/MSI: Allow to disable arch fallbacks In-Reply-To: <20200825200742.GA1924669@bjorn-Precision-5520> References: <20200825200742.GA1924669@bjorn-Precision-5520> Date: Tue, 25 Aug 2020 23:28:30 +0200 Message-ID: <87a6yixvnl.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Aug 25 2020 at 15:07, Bjorn Helgaas wrote: >> + * The arch hooks to setup up msi irqs. Default functions are implemented >> + * as weak symbols so that they /can/ be overriden by architecture specific >> + * code if needed. >> + * >> + * They can be replaced by stubs with warnings via >> + * CONFIG_PCI_MSI_DISABLE_ARCH_FALLBACKS when the architecture fully >> + * utilizes direct irqdomain based setup. > > Do you expect *all* arches to eventually use direct irqdomain setup? Ideally that happens some day. We have five left when x86 is converted: IA64, MIPS, POWERPC, S390, SPARC IA64 is unlikely to be fixed, but might be solved naturally by removal. For the others I don't know, but it's not on the horizon anytime soon I fear. > And in that case, to remove the config option? Yes, and all the code which depends on it. > If not, it seems like it'd be nicer to have the burden on the arches > that need/want to use arch-specific code instead of on the arches that > do things generically. Right, but they still share the common code there and some of them provide only parts of the weak callbacks. I'm not sure whether it's a good idea to copy all of this into each affected architecture. Or did you just mean that those architectures should select CONFIG_I_WANT_THE CRUFT instead of opting out on the fully irq domain based ones? Thanks, tglx