USB 2.0 device passthrough

[Roman Vrublevskiy]

Dear all,

tell me please is it possible to passthrough usb 2.0 device in ganeti?
If I understand correctly, we need to emulate usb EHCI host controller but all my attempts ended without success.
Any help greatly appreciated.

[Helga Velroyen]

Hi!

what hypervisor do you use? And did you try it with a VM that not managed by Ganeti but using the same hypervisor version? (To see if it is a hypervisor issue or a Ganeti issue)

Cheers,

Helga

[Roman Vrublevskiy]

Hi!

I use KVM and was pretty sure that it's possible to emulate usb ehci with it. At least it was possible with qemu-kvm which as far as I know merged in qemu-system-x86-64.

Now I'm trying to make it without ganeti. Will post results here.

[Roman Vrublevskiy]

Yep, it works on the same machine with the following parameters:

qemu-system-x86_64 -enable-kvm -hda vdisk.img -boot d -m 2048 --vnc :7154 -usbdevice tablet \
-device usb-ehci \
-device usb-host,vendorid=0x8564,productid=0x1000

[Helga Velroyen]

What is the commandline that you used with ganeti to achieve this?

The man page of gnt-instance says about usb_devices. It seems ganeti only supports the passthrough of the parameters to "-usbdevice" and not "-device".

usb_devices

    Valid for the KVM hypervisor.

    Space separated list of usb devices. These can be emulated devices

    or passthrough ones, and each one gets passed to kvm with its own

    ``-usbdevice`` option. See the **qemu**\(1) manpage for the syntax

    of the possible components. Note that values set with this 

    parameter are split on a space character and currently don't support

    quoting. For backwards compatibility reasons, the RAPI interface keeps

    accepting comma separated lists too. 

Unfortunately, I currently don't have a KVM cluster at hand to test it, so I hope someone else on this list can way in.

Cheers,

Helga

[Thomas Ott]

Hi,

I use KVM as Hypervisor und Ganeti 2.12.
For passing a USB Dongle I modified the "kvm:usb_devices" with "host:<vendorid>:<productid>". After restarting the Instance the Dongle appears. And if I drop the dongle and reinsert it, it reappears. So I'm happy :-)

Greetz,
Thomas

[Roman Vrublevskiy]

If we use usb_devices=host:XXXX:YYYY ganeti emulates USB 1.0 (UHCI) controller. USB 2.0 devices don't work with it.
That's where the questiion "is it possible to passthrough USB 2.0 devices with ganeti" arose.
As we could see we can do it with KVM itself.

[Roman Vrublevskiy]

I managed to do that.

We need to use kvm_extra parameters. It works with the following:
gnt-instance modify -H kvm_extra="-device usb-ehci\,id=ehci\,bus=pci.0\,addr=0x10 -device usb-host\,vendorid=0x8564\,productid=0x1000\,bus=ehci.0" bcalfa

Without bus=pci.0,addr=0x10 I got an errors such as this:
gnt-instance start bcalfa
Waiting for job 155917 for bcalfa ...
Job 155917 for bcalfa has failed: Failure: command execution error:
Could not start instance 'bcalfa': Hypervisor error: Failed to start instance bcalfa: exited with exit code 1 (qemu-system-x86_64: -device virtio-blk-pci,drive=hotdisk-4897a639-pci-4,id=hotdisk-4897a639-pci-4,bus=pci.0,addr=0x4: PCI: slot 4 function 0 not available for virtio-blk-pci, in use by usb-ehci
qemu-system-x86_64: -device virtio-blk-pci,drive=hotdisk-4897a639-pci-4,id=hotdisk-4897a639-pci-4,bus=pci.0,addr=0x4: Device initialization failed.
qemu-system-x86_64: -device virtio-blk-pci,drive=hotdisk-4897a639-pci-4,id=hotdisk-4897a639-pci-4,bus=pci.0,addr=0x4: Device 'virtio-blk-pci' could not be initialized
)