Re: [Xen-devel] [PATCH 3/4] usb: Introduce Xen pvUSB backend

[Juergen Gross <jgross@xxxxxxxx>]

On 03/04/2015 04:27 PM, Greg KH wrote:
> On Wed, Mar 04, 2015 at 02:31:08PM +0100, Juergen Gross wrote:
> > On 03/02/2015 12:39 PM, David Vrabel wrote:
> > > On 26/02/15 13:35, Juergen Gross wrote:
> > > > Introduces the Xen pvUSB backend. With pvUSB it is possible for a Xen
> > > > domU to communicate with a USB device assigned to that domU. The
> > > > communication is all done via the pvUSB backend in a driver domain
> > > > (usually Dom0) which is owner of the physical device.
> > > Why do we need a kernel usb backend instead of a user-space one using
> > > libusb?
> > Good question. At a first glance libusb seems to offer most/all needed
> > interfaces. The main question is whether performance with libusb will
> > be okay. There will be one additional copy of the I/O data needed if
> > I've read the code in drivers/usb/core/devio.c correctly.
> You can drive USB devices at line speed using libusb just fine.  Try it
> out and see please, processors copy data _very_ fast these days.
Okay, thanks for the information.

I'll take this as a hint to try the user space variant. :-)


Juergen


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel