Re: PCI Passthrough, error: The driver 'pci-stub' is occupying your device 0000:08:06.2

James Neave
2011-02-25T23:10:09Z

On Fri, Feb 25, 2011 at 11:02 PM, James Neave <roboj1m@gmail.com> wrote:
> On Fri, Feb 25, 2011 at 10:47 PM, James Neave <roboj1m@gmail.com> wrote:
>> On Fri, Feb 25, 2011 at 12:06 AM, Chris Wright <chrisw@sous-sol.org> wrote:
>>> * James Neave (roboj1m@gmail.com) wrote:
>>>> OK, here's my latest dmesg with amd_iommu_dump and debug with no quiet
>>>> http://pastebin.com/JxEwvqRA
>>>
>>> Yeah, that's what I expected:
>>>
>>> [    0.724403] AMD-Vi:   DEV_ALIAS_RANGE                 devid: 08:00.0 flags: 00 devid_to: 00:14.4
>>> [    0.724439] AMD-Vi:   DEV_RANGE_END           devid: 08:1f.7
>>>
>>> That basically says 08:00.0 - 08:1f.7 will show up as 00:14.4 (and
>>> should all go into same iommu domain).
>>>
>>>> I've just figured out a sequence of "echo DEV > PATH" commands to call
>>>> for 14.4 gets me past the "claimed by pci-stub" error and gets me to
>>>> the "failed to assign IRQ" error.
>>>> I'm going to narrow down the required sequence and then post it.
>>>
>>> Kind of afraid to ask, but does it include:
>>>
>>> (assuming 1002 4384 is the pci to pci bridge)
>>> echo 1002 4384 > /sys/bus/pci/drivers/pci-stub/new_id
>>> echo 0000:00:14.4 > /sys/bus/pci/drivers/pci-stub/unbind
>>>
>>> (this has the side effect of detaching the bridge from its domain)
>>>
>>> thanks,
>>> -chris
>>>
>>
>> Exact sequence is:
>>
>> echo "1002 4384" > /sys/bus/pci/drivers/pci-stub/new_id
>> echo "0000:00:14.4" > /sys/bus/pci/devices/0000:00:14.4/driver/unbind
>>
>> I take it this is a bad thing then?
>>
>>> I assume this means that 00:14.4 is still left claimed by pci-stub?
>>
>> Yes
>>
>>> How are you determining this?  The lspci paste above has pci-stub for all
>>> of them.  The easiest thing might be to start with manually disabling
>>> host driver and reassigning pci-stub to: 00:14.4, 08: 06.2,3 and 0e.0
>>> Then giving the guest only 08:06.1.
>>
>> I determined it by being half asleep and not reading it properly... >.<
>> You're right, all 5 devices were using pci-stub
>>
>>>> libvirtError: this function is not supported by the connection driver:
>>>> Unable to reset PCI device 0000:00:14.4: no FLR, PM reset or bus reset
>>>> available
>>
>>> Right, libvirt is more restrictive than qemu-kvm (forgot you were using
>>> libvirt here).
>>
>> What does that libvirt error mean? I can't find a definition.
>> Am I limiting myself by using libvirt? Would not using it help and how
>> would I go about not using it?
>>
>>> Trouble now is that
>>> with shared IRQ we don't have a good way to handle that right now.
>>
>> Game over then?
>> I've tried assigning the USB devices before, I couldn't do it because
>> qemu doesn't support USB2 devices.
>> I don't really understand where this IRQ conflict is, the firewire and
>> the USB2 device share IRQ22 but I'm assigning them both to the VM?
>> Is that still a problem?
>> I don't suppose there's any way to change which IRQ they use in the
>> BIOS or with a command is there?
>>
>> I don't know if it means anything but this page:
>>
>> http://linuxtv.org/wiki/index.php/Hauppauge_WinTV-HVR-2200
>>
>> Has the lspci output for the HVR-2200 which mentions MSI and IRQ255.
>> My knowledge it very limited on this subject so I don't know if that's
>> meaningless looking at the output from another person's lspci.
>>
>> Anything left to try?
>>
>> Regardless, many thanks for your help,
>>
>> James.
>>
>
> On the off chance I tried disabling the firewire in the BIOS, which
> leaves only my tuner card using IRQ 20, 21 and 22.
> No difference, still complains about IRQs:
>
> Using raw in/out ioport access (sysfs - Input/output error)
> Failed to assign irq for "hostdev0": Operation not permitted
> Perhaps you are assigning a device that shares an IRQ with another device?
>
> It does say "Operation not permitted" and that only "perhaps" I am
> assigning a device that shares an IRQ.
> Perhaps IRQ conflict it not the problem? They really are sitting on
> their own. Another permissions problem perhaps?
>
> Regards,
>
> James.
>

I'm reading something about this error message being related to
libvirt and CAP_SYS_RAWIO?

http://www.mail-archive.com/kvm@vger.kernel.org/msg34338.html
http://www.google.co.uk/#hl=en&xhr=t&q=libvirt+CAP_SYS_RAWIO&cp=21&pf=p&sclient=psy&aq=f&aqi=&aql=&oq=libvirt+CAP_SYS_RAWIO&pbx=1&fp=2d8e3f69fec095f4

"When I patch libvirt to not drop the capabilities, everything works
as expected."

Regards,

James.