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

James Neave
2011-02-23T19:44:39Z

On Wed, Feb 23, 2011 at 12:11 AM, Chris Wright <chrisw@sous-sol.org> wrote:
> * James Neave (roboj1m@gmail.com) wrote:
>> On Tue, Feb 22, 2011 at 1:51 AM, Chris Wright <chrisw@sous-sol.org> wrote:
>> > * James Neave (roboj1m@gmail.com) wrote:
>> >> Does anybody know the debug kernel switches for iommu?
>> >
>> > Two helpful kernel commandline options are:
>> >
>> > amd_iommu_dump debug (and drop "quiet")
>> >
>> > The problem is when you attach the device (function) you're getting
>> > stuck up in conflicts with the existing domain for that function.
>> >
>> > My guess is that all the functions are behind a PCI to PCI bridge, so the alias
>> > lookup is finding a conflict.
>>
>> Yes, it's behind a PCI-PCI bridge I think, here's the blurb from an
>> earlier email:
>
> Sorry, I missed that in your original mail, thanks for reposting.
>
>> cat /proc/interruts
>> http://pastebin.com/LQdB3hms
>>
>> lspci -vvv
>> http://pastebin.com/GJDkC8B4
>
>  00:14.4 PCI bridge: ATI Technologies Inc SBx00 PCI to PCI Bridge (rev 40)
>
>> lspci -t -v
>> http://pastebin.com/Ftx8Hfjt
>
> Yup, that's what I expected:
>
>  +-14.4-[08]--+-06.0  VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller
>  |            +-06.1  VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller
>  |            +-06.2  VIA Technologies, Inc. USB 2.0
>  |            \-0e.0  Texas Instruments TSB43AB23 IEEE-1394a-2000 Controller
>
> I'd now expect to see (if you boot with amd_iommu_dump) some IVRS
> details showing an alias range entry basically showing 08:* pointing
> back to 00:14.4.  This means that from the point of view of the IOMMU the
> devices 08:06.0, 08:06.1, 08:06.2, 08:0e.0 will all show up as if they
> are 00:14.4.
>
> When you assign a device to a guest, the guest VM gets an IOMMU domain
> (a context to manage IOMMU page table mappings) and the device is put
> into that guest's IOMMU domain.  However, if the device is behind a
> PCI-PCI bridge it will appear as an alias for the bridge itself.  The
> bridge is a PCI device with an IOMMU domain.  When trying to assign a
> device to a guest there's some sanity checking to verify that the device
> (or its alias) aren't already under some IOMMU domain other than the
> guest VM's IOMMU domain.
>
> I suspect this is what you are hitting.  You could test this theory by
> adding 2 more devices to your guest -- the firewire device (08:0e.0)
> and the PCI-PCI bridge itself (00:14.4).
>
> thanks,
> -chris
>

Hi,

OK, here we go again!

Right, I've diabled apparmor (I think) with this:

sudo invoke-rc.d apparmor stop
sudo update-rc.d -f apparmor remove

After a reboot I'm back to getting the error about pci-stub claiming the device.
Apparmor being off made no difference to that (except there are no
apparmor messages in dmesg)

Then I try adding 08:0e.0 and 00:14.4 to the VM and I get this error message:

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

There is nothing written to test.log when you try to start the VM with
00:14.4 attached.

At this point libvirt goes screwy and I have to restart it before I
can remove 00:14.4 from the VM.

However, once I've done THAT, starting the VM gets the different error
message in test.log and a new dmesg:

2011-02-23 19:21:13.483: starting up
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin
QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.14 -enable-kvm -m 512 -smp
3,sockets=3,cores=1,threads=1 -name test -uuid
307bfcd2-9dec-29b7-1b4d-c46cd9d7cdbc -nodefconfig -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/test.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=readline -rtc base=utc -boot
order=cd,menu=off -drive
file=/var/lib/libvirt/images/test.img,if=none,id=drive-virtio-disk0,boot=on,format=raw
-device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0
-drive if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw
-device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0
-netdev tap,fd=57,id=hostnet0 -device
virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:7d:32:7c,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:0 -vga
cirrus -device pci-assign,host=08:06.0,id=hostdev0,configfd=58,bus=pci.0,addr=0x6
-device pci-assign,host=08:06.1,id=hostdev1,configfd=59,bus=pci.0,addr=0x7
-device pci-assign,host=08:06.2,id=hostdev2,configfd=60,bus=pci.0,addr=0x8
-device pci-assign,host=08:0e.0,id=hostdev3,configfd=61,bus=pci.0,addr=0xa
-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5
char device redirected to /dev/pts/1
kvm: -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:7d:32:7c,bus=pci.0,addr=0x3:
pci_add_option_rom: failed to find romfile "pxe-virtio.bin"
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?
kvm: -device pci-assign,host=08:06.0,id=hostdev0,configfd=58,bus=pci.0,addr=0x6:
Device 'pci-assign' could not be initialized
2011-02-23 19:21:13.958: shutting down

dmesg:
http://pastebin.com/70D26xp4

This bit is different:

[ 201.625221] uhci_hcd 0000:08:06.0: remove, state 4
[ 201.625237] usb usb4: USB disconnect, address 1
[ 201.625514] uhci_hcd 0000:08:06.0: USB bus 4 deregistered
[ 201.625595] uhci_hcd 0000:08:06.0: PCI INT A disabled
[ 201.626028] pci-stub 0000:08:06.0: claimed by stub
[ 201.631922] uhci_hcd 0000:08:06.1: remove, state 4
[ 201.631937] usb usb9: USB disconnect, address 1
[ 201.632195] uhci_hcd 0000:08:06.1: USB bus 9 deregistered
[ 201.632274] uhci_hcd 0000:08:06.1: PCI INT B disabled
[ 201.632419] pci-stub 0000:08:06.1: claimed by stub
[ 201.638160] ehci_hcd 0000:08:06.2: remove, state 1
[ 201.638172] usb usb10: USB disconnect, address 1
[ 201.638178] usb 10-1: USB disconnect, address 2
[ 201.721626] dvb-usb: Hauppauge Nova-T 500 Dual DVB-T successfully
deinitialized and disconnected.
[ 201.721990] ehci_hcd 0000:08:06.2: USB bus 10 deregistered
[ 201.722126] ehci_hcd 0000:08:06.2: PCI INT C disabled
[ 201.725042] pci-stub 0000:08:06.2: claimed by stub
[ 201.731830] firewire_ohci 0000:08:0e.0: PCI INT A disabled
[ 201.731838] firewire_ohci: Removed fw-ohci device.
[ 201.732536] pci-stub 0000:08:0e.0: claimed by stub
[ 202.303880] device vnet0 entered promiscuous mode
[ 202.305184] virbr0: topology change detected, propagating
[ 202.305193] virbr0: port 1(vnet0) entering forwarding state
[ 202.305199] virbr0: port 1(vnet0) entering forwarding state
[ 202.433007] pci-stub 0000:08:06.0: PCI INT A -> GSI 20 (level, low) -> IRQ 20
[ 202.470076] pci-stub 0000:08:06.0: restoring config space at offset
0x1 (was 0x2100000, writing 0x2100001)
[ 202.697270] assign device 0:8:6.0
[ 202.697325] deassign device 0:8:6.0
[ 202.730080] pci-stub 0000:08:06.0: restoring config space at offset
0x1 (was 0x2100000, writing 0x2100001)
[ 202.730107] pci-stub 0000:08:06.0: PCI INT A disabled

This time the pci-stub claimed lines are not all bunched up and there
is only one per device, rather than three per device.
Also for the first time it says "assign device 0:8:6.0" rather than
"assign device 0:8:6.0 failed"
It them immediately deassigns the device and stops.

test.log shows:

Failed to assign irq for "hostdev0": Operation not permitted
Perhaps you are assigning a device that shares an IRQ with another device?

lspsci -vv for the relevant devices shows:
http://pastebin.com/EUtUMj8x

00:14.4 now appears to be using pci-stub as it's driver, as well as
08:06.1, 2, 3 but not 0e.0

Anyway, that's all for now.
I think I'll try 'amd_iommu_dump' next, does it write to dmesg?

Many Thanks,

James.