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=-9.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 081D6C433DF for ; Mon, 24 Aug 2020 05:09:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E16B220706 for ; Mon, 24 Aug 2020 05:09:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727813AbgHXFJi (ORCPT ); Mon, 24 Aug 2020 01:09:38 -0400 Received: from mx2.suse.de ([195.135.220.15]:44020 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725817AbgHXFJi (ORCPT ); Mon, 24 Aug 2020 01:09:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 36A65AD71; Mon, 24 Aug 2020 05:10:06 +0000 (UTC) Subject: Re: [patch RFC 23/38] x86/xen: Rework MSI teardown To: Thomas Gleixner , LKML Cc: x86@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 , linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Konrad Rzeszutek Wilk , xen-devel@lists.xenproject.org, 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 References: <20200821002424.119492231@linutronix.de> <20200821002947.575838946@linutronix.de> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Mon, 24 Aug 2020 07:09:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200821002947.575838946@linutronix.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 21.08.20 02:24, Thomas Gleixner wrote: > X86 cannot store the irq domain pointer in struct device without breaking > XEN because the irq domain pointer takes precedence over arch_*_msi_irqs() > fallbacks. > > XENs MSI teardown relies on default_teardown_msi_irqs() which invokes > arch_teardown_msi_irq(). default_teardown_msi_irqs() is a trivial iterator > over the msi entries associated to a device. > > Implement this loop in xen_teardown_msi_irqs() to prepare for removal of > the fallbacks for X86. > > This is a preparatory step to wrap XEN MSI alloc/free into a irq domain > which in turn allows to store the irq domain pointer in struct device and > to use the irq domain functions directly. > > Signed-off-by: Thomas Gleixner > --- > arch/x86/pci/xen.c | 23 ++++++++++++++++++----- > 1 file changed, 18 insertions(+), 5 deletions(-) > > --- a/arch/x86/pci/xen.c > +++ b/arch/x86/pci/xen.c > @@ -376,20 +376,31 @@ static void xen_initdom_restore_msi_irqs > static void xen_teardown_msi_irqs(struct pci_dev *dev) > { > struct msi_desc *msidesc; > + int i; > + > + for_each_pci_msi_entry(msidesc, dev) { > + if (msidesc->irq) { > + for (i = 0; i < msidesc->nvec_used; i++) > + xen_destroy_irq(msidesc->irq + i); > + } > + } > +} > + > +static void xen_pv_teardown_msi_irqs(struct pci_dev *dev) > +{ > + struct msi_desc *msidesc = first_pci_msi_entry(dev); > > - msidesc = first_pci_msi_entry(dev); > if (msidesc->msi_attrib.is_msix) > xen_pci_frontend_disable_msix(dev); > else > xen_pci_frontend_disable_msi(dev); > > - /* Free the IRQ's and the msidesc using the generic code. */ > - default_teardown_msi_irqs(dev); > + xen_teardown_msi_irqs(dev); > } > > static void xen_teardown_msi_irq(unsigned int irq) > { > - xen_destroy_irq(irq); > + WARN_ON_ONCE(1); > } > > #endif > @@ -412,7 +423,7 @@ int __init pci_xen_init(void) > #ifdef CONFIG_PCI_MSI > x86_msi.setup_msi_irqs = xen_setup_msi_irqs; > x86_msi.teardown_msi_irq = xen_teardown_msi_irq; > - x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs; > + x86_msi.teardown_msi_irqs = xen_pv_teardown_msi_irqs; > pci_msi_ignore_mask = 1; > #endif > return 0; > @@ -436,6 +447,7 @@ static void __init xen_hvm_msi_init(void > } > > x86_msi.setup_msi_irqs = xen_hvm_setup_msi_irqs; > + x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs; > x86_msi.teardown_msi_irq = xen_teardown_msi_irq; > } > #endif > @@ -472,6 +484,7 @@ int __init pci_xen_initial_domain(void) > #ifdef CONFIG_PCI_MSI > x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs; > x86_msi.teardown_msi_irq = xen_teardown_msi_irq; > + x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs; This should be xen_pv_teardown_msi_irqs, as pci_xen_initial_domain() is called only for the pv initial domain case today. > x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs; > pci_msi_ignore_mask = 1; > #endif > Juergen