From: Alex Williamson <alex.williamson@redhat.com>
To: Jiang Liu <jiang.liu@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Thomas Gleixner <tglx@linutronix.de>,
Bjorn Helgaas <bhelgaas@google.com>,
Yinghai Lu <yinghai@kernel.org>, Borislav Petkov <bp@alien8.de>,
Lv Zheng <lv.zheng@intel.com>, Ingo Molnar <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Len Brown <lenb@kernel.org>,
Tony Luck <tony.luck@intel.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-acpi@vger.kernel.org
Subject: Re: [Patch v4 21/23] x86/PCI: Refine the way to release PCI IRQ resources
Date: Wed, 04 Mar 2015 16:48:43 -0700 [thread overview]
Message-ID: <1425512923.5200.318.camel@redhat.com> (raw)
In-Reply-To: <1425485213.5200.230.camel@redhat.com>
On Wed, 2015-03-04 at 09:06 -0700, Alex Williamson wrote:
> Hi,
>
> I'm getting a regression from this patch when using VFIO for device
> assignment to a QEMU VM. I have a device initially bound to the nouveau
> driver, which is unbound from that driver and bound to vfio-pci for use
> by userspace. vfio-pci calls pci_enable_device, but when userspace
> attempts to setup the legacy INTx interrupt, pci_dev->irq is zero and
> vfio-pci errors with -ENODEV.
>
> Where is pci_dev->irq supposed to be getting re-initialized in this
> case? Am I missing an important initialization step in vfio-pci? I
> certainly don't think I should be calling request_irq(pci_dev->irq, ...
> when pci_dev->irq is zero. Thanks,
It looks like the imbalance is in pci_dev->enable_cnt. Any call to
pci_disable_device() will clear pci_dev->irq, but pci_enable_device()
does effectively nothing unless it's called with enable_cnt == zero. So
I'm at the mercy of the previous driver behaving relatively sanely in
order to re-enable legacy interrupts for a device :-\ Maybe the unbound
notifier needs to do some sanitizing of the device? Thanks,
Alex
next prev parent reply other threads:[~2015-03-04 23:48 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-05 5:44 [Patch v4 00/23] Improve ACPI resource parsing interfaces and enable IOAPIC hotplug Jiang Liu
2015-02-05 5:44 ` [Patch v4 01/23] ACPICA: Resources: Provide common part for struct acpi_resource_address structures Jiang Liu
2015-02-05 5:44 ` Jiang Liu
2015-02-05 5:44 ` Jiang Liu
2015-02-05 5:44 ` Jiang Liu
2015-02-05 10:05 ` [Xen-devel] " David Vrabel
2015-02-05 10:05 ` [Xen-devel] [Patch v4 01/23] ACPICA: Resources: Provide common part for struct acpi_resource_add David Vrabel
2015-02-05 10:05 ` [Xen-devel] [Patch v4 01/23] ACPICA: Resources: Provide common part for struct acpi_resource_address structures David Vrabel
2015-02-05 10:05 ` David Vrabel
2015-02-05 15:49 ` KY Srinivasan
2015-02-05 15:49 ` KY Srinivasan
2015-02-05 15:49 ` [Patch v4 01/23] ACPICA: Resources: Provide common part for struct acpi_resource_address structu KY Srinivasan
2015-02-05 15:49 ` [Patch v4 01/23] ACPICA: Resources: Provide common part for struct acpi_resource_address structures KY Srinivasan
2015-02-05 5:44 ` [Patch v4 02/23] ACPI: Remove redundant check in function acpi_dev_resource_address_space() Jiang Liu
2015-02-05 5:44 ` [Patch v4 03/23] ACPI: Implement proper length checks for mem resources Jiang Liu
2015-02-05 5:44 ` [Patch v4 04/23] ACPI: Use the length check for io resources as well Jiang Liu
2015-02-05 5:44 ` [Patch v4 05/23] ACPI: Let the parser return false for disabled resources Jiang Liu
2015-02-05 5:44 ` [Patch v4 06/23] ACPI: Unify the parsing of address_space and ext_address_space Jiang Liu
2015-02-05 5:44 ` [Patch v4 07/23] ACPI: Move the window flag logic to the combined parser Jiang Liu
2015-02-05 5:44 ` [Patch v4 08/23] ACPI: Add prefetch decoding to the address space parser Jiang Liu
2015-02-05 5:44 ` [Patch v4 09/23] ACPI: Fix a bug in parsing ACPI Memory24 resource Jiang Liu
2015-02-05 5:44 ` [Patch v4 10/23] ACPI: Normalize return value of resource parser functions Jiang Liu
2015-02-05 5:44 ` [Patch v4 11/23] ACPI: Set flag IORESOURCE_UNSET for unassigned resources Jiang Liu
2015-02-05 5:44 ` [Patch v4 12/23] ACPI: Enforce stricter checks for address space descriptors Jiang Liu
2015-02-05 5:44 ` [Patch v4 13/23] ACPI: Return translation offset when parsing ACPI address space resources Jiang Liu
2015-02-05 5:44 ` [Patch v4 14/23] ACPI: Translate resource into master side address for bridge window resources Jiang Liu
2015-02-05 5:44 ` [Patch v4 15/23] ACPI: Add field offset to struct resource_list_entry Jiang Liu
2015-02-05 5:44 ` [Patch v4 16/23] ACPI: Introduce helper function acpi_dev_filter_resource_type() Jiang Liu
2015-02-05 5:44 ` [Patch v4 17/23] resources: Move struct resource_list_entry from ACPI into resource core Jiang Liu
2015-02-05 5:44 ` [Patch v4 18/23] PCI: Use common resource list management code instead of private implementation Jiang Liu
2015-02-05 5:44 ` Jiang Liu
2015-02-05 5:44 ` [Patch v4 19/23] x86/PCI: Fix the range check for IO resources Jiang Liu
2015-02-05 5:44 ` [Patch v4 20/23] x86/PCI/ACPI: Use common ACPI resource interfaces to simplify implementation Jiang Liu
2015-02-05 5:44 ` [Patch v4 21/23] x86/PCI: Refine the way to release PCI IRQ resources Jiang Liu
2015-03-04 16:06 ` Alex Williamson
2015-03-04 23:48 ` Alex Williamson [this message]
2015-02-05 5:44 ` [Patch v4 22/23] ACPI: Add interfaces to parse IOAPIC ID for IOAPIC hotplug Jiang Liu
2015-02-05 5:44 ` [Patch v4 23/23] x86/irq, ACPI: Implement ACPI driver to support " Jiang Liu
2015-02-05 15:16 ` [Patch v4 00/23] Improve ACPI resource parsing interfaces and enable " Rafael J. Wysocki
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