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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 8A289C3A5A2 for ; Tue, 3 Sep 2019 08:22:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D9582053B for ; Tue, 3 Sep 2019 08:22:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567498930; bh=3/JPGZ4D3hGv1VMXcX2nDpmVDwHoIw8Nh10e4io2B8Y=; h=Subject:To:Cc:References:From:Date:In-Reply-To:List-ID:From; b=x5LiBeUhILtfYY9GEDgN3IfoVR8+iISzyeaV/UGFH8pgWOutKIb23FX1xMAMrNjHN KMhq2qZ8ko4fI52ShGz20Bzbd0++HQEbU4x3pQsYAXPNjL1xKK+IapQVwCPmtOn1O6 a+Cb9XjVQ3dX+PXy44NUQPKONvTZcpL/g8/xlIy4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726557AbfICIWK (ORCPT ); Tue, 3 Sep 2019 04:22:10 -0400 Received: from foss.arm.com ([217.140.110.172]:33864 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726452AbfICIWJ (ORCPT ); Tue, 3 Sep 2019 04:22:09 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0694028; Tue, 3 Sep 2019 01:22:09 -0700 (PDT) Received: from [10.1.197.61] (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F12E03F246; Tue, 3 Sep 2019 01:22:03 -0700 (PDT) Subject: Re: [PATCH] irqdomain: Add the missing assignment of domain->fwnode for named fwnode To: Dexuan Cui , Thomas Gleixner Cc: KY Srinivasan , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Lorenzo Pieralisi , Bjorn Helgaas , "linux-kernel@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , Michael Kelley , "Lili Deng (Wicresoft North America Ltd)" References: From: Marc Zyngier Organization: Approximate Message-ID: <4acd6871-ca66-b45d-50b8-8609eee0e488@kernel.org> Date: Tue, 3 Sep 2019 09:22:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org Hi Dexuan, On 03/09/2019 00:14, Dexuan Cui wrote: > > Recently device pass-through stops working for Linux VM running on Hyper-V. > > git-bisect shows the regression is caused by the recent commit > 467a3bb97432 ("PCI: hv: Allocate a named fwnode ..."), but the root cause > is that the commit d59f6617eef0 forgets to set the domain->fwnode for > IRQCHIP_FWNODE_NAMED*, and as a result: > > 1. The domain->fwnode remains to be NULL. > > 2. irq_find_matching_fwspec() returns NULL since "h->fwnode == fwnode" is > false, and pci_set_bus_msi_domain() sets the Hyper-V PCI root bus's > msi_domain to NULL. > > 3. When the device is added onto the root bus, the device's dev->msi_domain > is set to NULL in pci_set_msi_domain(). > > 4. When a device driver tries to enable MSI-X, pci_msi_setup_msi_irqs() > calls arch_setup_msi_irqs(), which uses the native MSI chip (i.e. > arch/x86/kernel/apic/msi.c: pci_msi_controller) to set up the irqs, but > actually pci_msi_setup_msi_irqs() is supposed to call > msi_domain_alloc_irqs() with the hbus->irq_domain, which is created in > hv_pcie_init_irq_domain() and is associated with the Hyper-V chip > hv_msi_irq_chip. Consequently, the irq line is not properly set up, and > the device driver can not receive any interrupt. > > Fixes: d59f6617eef0 ("genirq: Allow fwnode to carry name information only") > Fixes: 467a3bb97432 ("PCI: hv: Allocate a named fwnode instead of an address-based one") > Reported-by: Lili Deng > Signed-off-by: Dexuan Cui > --- > > Note: the commit 467a3bb97432 ("PCI: hv: Allocate a named fwnode ...") has not > gone in Linus's tree yet (the commit is in linux-next for a while), so the commit ID > in the changelog can change when it goes in Linus's tree. This branch is supposed to be stable, and I try to only apply fixes to it. This normally ensures that commit IDs are the same once they land in Linus' tree. > This patch works in my test, but I'm not 100% sure this is the right fix. > > Looking forward to your comment! > > kernel/irq/irqdomain.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c > index e7bbab149750..132672b74e4b 100644 > --- a/kernel/irq/irqdomain.c > +++ b/kernel/irq/irqdomain.c > @@ -149,6 +149,7 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size, > switch (fwid->type) { > case IRQCHIP_FWNODE_NAMED: > case IRQCHIP_FWNODE_NAMED_ID: > + domain->fwnode = fwnode; > domain->name = kstrdup(fwid->name, GFP_KERNEL); > if (!domain->name) { > kfree(domain); > Looks absolutely correct to me, thanks for fixing it. I've applied it on top of irqchip-next. Thanks, M. -- Jazz is not dead, it just smells funny...