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
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