Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932701AbbBBQW3 (ORCPT ); Mon, 2 Feb 2015 11:22:29 -0500 Received: from mail-qc0-f173.google.com ([209.85.216.173]:35043 "EHLO mail-qc0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932559AbbBBQW1 (ORCPT ); Mon, 2 Feb 2015 11:22:27 -0500 MIME-Version: 1.0 In-Reply-To: <54CFA29B.9000200@arm.com> References: <1422456683-797-1-git-send-email-marc.zyngier@arm.com> <54C8FE61.1030304@linux.intel.com> <54C8FFE0.3030007@arm.com> <54CFA29B.9000200@arm.com> From: Bjorn Helgaas Date: Mon, 2 Feb 2015 10:22:06 -0600 Message-ID: Subject: Re: [PATCH] PCI: Fix pcibios_update_irq misuse of irq number To: Marc Zyngier Cc: Jiang Liu , Thomas Gleixner , Lorenzo Pieralisi , Andre Przywara , "linux-pci@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3749 Lines: 94 On Mon, Feb 2, 2015 at 10:15 AM, Marc Zyngier wrote: > On 28/01/15 15:43, Bjorn Helgaas wrote: >> On Wed, Jan 28, 2015 at 9:27 AM, Marc Zyngier wrote: >>> Hi Gerry, >>> >>> On 28/01/15 15:21, Jiang Liu wrote: >>>> >>>> >>>> On 2015/1/28 22:51, Marc Zyngier wrote: >>>>> pcibios_update_irq writes an irq number into the config space >>>>> of a given PCI device, but ignores the fact that this number >>>>> is a virtual interrupt number, which might be a very different >>>>> value from what the underlying hardware is using. >>>>> >>>>> The obvious fix is to fetch the HW interrupt number from the >>>>> corresponding irq_data structure. This is slightly complicated >>>>> by the fact that this interrupt might be services by a stacked >>>>> domain. >>>>> >>>>> This has been tested on KVM with kvmtool. >>>>> >>>>> Reported-by: Lorenzo Pieralisi >>>>> Tested-by: Andre Przywara >>>>> Signed-off-by: Marc Zyngier >>>>> --- >>>>> drivers/pci/setup-irq.c | 12 ++++++++++-- >>>>> 1 file changed, 10 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/drivers/pci/setup-irq.c b/drivers/pci/setup-irq.c >>>>> index 4e2d595..828cbc9 100644 >>>>> --- a/drivers/pci/setup-irq.c >>>>> +++ b/drivers/pci/setup-irq.c >>>>> @@ -15,11 +15,19 @@ >>>>> #include >>>>> #include >>>>> #include >>>>> +#include >>>>> >>>>> void __weak pcibios_update_irq(struct pci_dev *dev, int irq) >>>>> { >>>>> - dev_dbg(&dev->dev, "assigning IRQ %02d\n", irq); >>>>> - pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq); >>>>> + struct irq_data *d; >>>>> + >>>>> + d = irq_get_irq_data(irq); >>>>> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY >>>>> + while (d->parent_data) >>>>> + d = d->parent_data; >>>>> +#endif >>>>> + dev_dbg(&dev->dev, "assigning IRQ %02ld\n", d->hwirq); >>>>> + pci_write_config_byte(dev, PCI_INTERRUPT_LINE, d->hwirq); >>>>> } >>>> Hi Mark, >>>> Instead of modifying the common version, how about >>>> implementing an arch specific version? Arch may have different >>>> way to determine the irq number. Above implementation doesn't >>>> work with x86, for example. >>> >>> If you look at the Makefile, this file is used on: >>> >>> obj-$(CONFIG_ALPHA) += setup-irq.o >>> obj-$(CONFIG_ARM) += setup-irq.o >>> obj-$(CONFIG_UNICORE32) += setup-irq.o >>> obj-$(CONFIG_SUPERH) += setup-irq.o >>> obj-$(CONFIG_MIPS) += setup-irq.o >>> obj-$(CONFIG_TILE) += setup-irq.o >>> obj-$(CONFIG_SPARC_LEON) += setup-irq.o >>> obj-$(CONFIG_M68K) += setup-irq.o >>> >>> x86 doesn't use that at all. >> >> Since you're looking at this, Marc, do you see a nice way to get rid >> of these arch dependencies in the Makefile and unify this a bit? We >> still have this pci_fixup_irqs() ugliness -- it's not really >> arch-specific at all, but it's called from arch code, and it uses >> for_each_pci_dev(), which obviously only works for things present at >> boot and not for things hot-added later. > > I can have a look at this in the next cycle - I'm a bit strapped for > time just now. > > As for for_each_pci_dev(), I'm not completely clear about what it should > be replaced for. Do we have some form of notifier for this? I think this should be done somewhere in the enumeration path, e.g., maybe in pci_device_add(). Then we shouldn't need a for_each_pci_dev() loop or a notifier at all. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/