Re: EHCI / USB2.0 for USB passthrough, or how to pass USB host device

[Jan Kiszka <jan.kiszka@web.de>]

[-- Attachment #1: Type: text/plain, Size: 1960 bytes --]

Tom Lanyon wrote:
> Hi list,
> 
> I've been playing with some KVM guests on KVM 83 on a RedHat 2.6.18 kernel (2.6.18-164.15.1.el5).
> 
> I tried to pass through a USB TV tuner device with a hostdev option in the guest's configuration. The guest can see the device but the driver (dvb_usb_dib0700) refuses to initialise it since it detected QEMU emulating a USB 1.1 host and needs USB 2.0:
> 	
> 	dvb-usb: This USB2.0 device cannot be run on a USB1.1 port. (it lacks a hardware PID filter)
> 
> Instead, and as this is the only USB device on the host, I tried to pass through the whole USB host controller to the guest via PCI pass through.
> 
> There's three functions provided by the USB controller's PCI device:
> 	01:08.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 62)
> 	01:08.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 62)
> 	01:08.2 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 65)
> 
> so I tried to pass the USB 2.0 (01:08.2) function to the guest but received an error when trying to start the guest:
> 
> 	error: this function is not supported by the hypervisor: No PCI reset capability available for 0000:01:08.2
> 
> I figured this was because I was only trying to pass one function of a multi-function device, so I tried passing all three functions concurrently but received the same 'PCI reset capability' error.
> 
> So, is there a way to emulate a USB 2.0 / EHCI controller in a guest and pass my USB device through? or alternatively, can anyone suggest how to get the PCI device(s) passed through for the physical USB controller?

There is ongoing work by David Ahern et al. to add EHCI emulation. I'm
hosting the QEMU tree that carries the patches:

git://git.kiszka.org/qemu.git ehci

As KVM is usable in upstream QEMU, you should be able to test it this
way (append -enable-kvm). Feedback welcome (to qemu-devel please).

Jan


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 257 bytes --]