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

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

[Hans de Goede]

Hi All,

Now that I have usb-1.1 passthrough  / local redirection support
working reliably (see my patch sets for this), I'm going to start
working on doing usb redirection support over the network.

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.

Regards,

Hans

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

[Gerd Hoffmann]

   Hi,

> 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 ?

Sure.  The idea to support usb forwarding over vnc comes up now and 
then.  Also having a standalone app is probably useful for testing and 
development and maybe logging the communication between guest OS and device.

> 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.

Yes, I think we certainly want to do that.  I think on the qemu side we 
want plumbing into chardev and spice, maybe also vnc.  On the client 
side a library (building on top of libusb?), a standalone app and 
support in spice client and maybe gtk-vnc would be good I think.

cheers,
   Gerd

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

[Jan Kiszka]

Am 29.11.2010 11:11, Hans de Goede wrote:
> Hi All,
> 
> Now that I have usb-1.1 passthrough  / local redirection support
> working reliably (see my patch sets for this), I'm going to start
> working on doing usb redirection support over the network.
> 
> 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.

Do you know usbip [1]? I haven't looked at any details, but maybe there
is room for synergies.

Jan

[1] http://usbip.sourceforge.net/

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

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

[François Revol]

> 
> Hi All,
> 
> Now that I have usb-1.1 passthrough  / local redirection support
> working reliably (see my patch sets for this), I'm going to start
> working on doing usb redirection support over the network.
> 
> 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 ?

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)

> 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.

Yeah it'd be nice to avoid code duplication.

Does RDP have such feature ?
I'd think it should be possible to add this to VNC somehow, since it has provisions for extensions.

François.

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

[Gerd Hoffmann]

   Hi,

> 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.

cheers,
   Gerd

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.

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

[Paul Brook]

>    Hi,
> 
> > 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 don't know how good the usp/ip stuff is, but I'd be very reluctant to invent 
yet annother remote-usb protocol.  USB is very hairy, so there's good reason 
to go with something that has already been tested.

IMO the ability to interact with the native kernel support is a feature in its 
own right.  If we end up with a libusb implementation of the usb/ip device 
end, then that only seems like a good thing - you potentialy get testing 
coverage from both qemu users and native vhci-hcd users.

Paul