Re: [Qemu-devel] USB passthrough in qemu

[Michal Suchanek <hramrach@gmail.com>]

On 12 June 2014 12:26, Gerd Hoffmann <kraxel@redhat.com> wrote:
>   Hi,
>
>> However, for the piix4 which is the default platform and is desirable
>> due to driver issues in many cases no simple way to instantiate the
>> companion setup and have qemu automagically attach the devices
>> correctly exists.
>
> We havn't added shortcuts like this to qemu for a while.  There are a
> bunch of other new things which don't have a shorthand command line
> switch too.  I suspect -usb2 wouldn't be very welcome @ qemu-devel.  You
> can try sending a patch though, shouldn't be hard, code is there as q35
> uses it.
>
> There is also the option to stick things into a config file (see
> docs/q35-chipset.cfg for an example), then do "-readconfig usb2.cfg".

Maybe such config file or a pc-usb2 machine specification would work then.

>
>> > If the guest is new enough that it has drivers you can also simply use
>> > xhci.
>>
>> What xhci hub is emulated?
>
> nec.

That seems to work with Windows 7, at least the real hardware.

However,
-device nec-usb-xhci -usbdevice host:0b95:772b -usbdevice tablet
gives empy xhci bus and both devices attached to uhci bus which does not work.

The example in usb2.txt only shows how to manually specify to which
bus the usb devices are to be attached but there is no example of
making usb devices just work.

Thanks

Michal