Re: [Qemu-devel] RFC: usb redirection over the network, interesting outside of spice?

[François Revol]

>>> The idea here is that a usb device connected to machine a, will be
>>> available for use by the guest os running on host b (machine b).
>>> 
>>> I'm working on this because it is something which we want / need
>>> for spice. I'm wondering if there is interest in this outside
>>> of spice ?
>>> I'm asking because at this moment in time the redirection support
>>> can probably be written in a way which abstracts the transport channel
>>> quite easily, allowing use outside of spice.
[...]
>> Not me at the moment, but unless you tunnel it inside another
>> protocol, you'd really want to look at the existing USB-over-IP
>> protocols instead of reinventing the wheel:
>> http://usbip.sourceforge.net/ (some support in Linux already IIRC)
>> (and there are others which I don't recall)
> 
> Doesn't look very useful on a quick glance.
> 
> First: Yes, we wanna embed this into other protocol(s).
> 
> Second, seems usbip is implemented using special drivers in kernel space for 
> both sides.  We will not need special drivers on the qemu side (we just hook 
> up the devices to the emulated hci).  On the client side using libusb looks 
> alot more sensible than requiring kernel modules.

I recall seeing discussions about it on the libusb-devel list (CCing).

http://search.gmane.org/?query=usbip&group=gmane.comp.lib.libusb.devel.general

It's just one implementation of it, it should be possible to implement a subset 
of the features at least with libusb which should be enough for most devices 
(scanners/printers/mass storage). 

And it's better to use the same protocol anyway when possible.
This way the untunnelled version could be used from QEMU or a host using a stub 
driver connecting to a server using either the kernel driver or the libusb 
version regardless.

François.