From: Greg KH <gregkh@linuxfoundation.org>
To: Juergen Gross <jgross@suse.com>
Cc: David Vrabel <david.vrabel@citrix.com>,
linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com,
konrad.wilk@oracle.com, boris.ostrovsky@oracle.com,
linux-usb@vger.kernel.org, cyliu@suse.com
Subject: Re: [Xen-devel] [PATCH 3/4] usb: Introduce Xen pvUSB backend
Date: Wed, 4 Mar 2015 07:27:22 -0800 [thread overview]
Message-ID: <20150304152722.GA11839@kroah.com> (raw)
In-Reply-To: <54F7091C.1050001@suse.com>
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.
thanks,
greg k-h
next prev parent reply other threads:[~2015-03-04 15:27 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-26 13:35 [PATCH 0/4] xen, usb: support pvUSB drivers Juergen Gross
2015-02-26 13:35 ` [PATCH 1/4] usb: Add Xen pvUSB protocol description Juergen Gross
2015-02-26 13:35 ` [PATCH 2/4] usb: Introduce Xen pvUSB frontend Juergen Gross
2015-02-26 14:09 ` Oliver Neukum
2015-02-26 13:35 ` [PATCH 3/4] usb: Introduce Xen pvUSB backend Juergen Gross
2015-03-02 11:39 ` [Xen-devel] " David Vrabel
2015-03-02 11:39 ` David Vrabel
2015-03-04 13:31 ` Juergen Gross
2015-03-04 13:41 ` Ian Campbell
2015-03-04 13:41 ` Ian Campbell
2015-03-04 13:45 ` Juergen Gross
2015-03-04 13:53 ` David Vrabel
2015-03-04 13:53 ` David Vrabel
2015-03-04 14:09 ` Juergen Gross
2015-03-04 14:09 ` Juergen Gross
2015-03-04 14:19 ` David Vrabel
2015-03-04 14:19 ` David Vrabel
2015-03-04 14:29 ` Ian Campbell
2015-03-04 14:29 ` Ian Campbell
2015-03-04 14:41 ` Juergen Gross
2015-03-04 14:43 ` Peter Stuge
2015-03-04 14:43 ` Peter Stuge
2015-03-04 14:46 ` Ian Campbell
2015-03-04 14:46 ` Ian Campbell
2015-03-06 10:59 ` Pasi Kärkkäinen
2015-03-06 10:59 ` Pasi Kärkkäinen
2015-03-06 12:52 ` [Xen-devel] " Austin S Hemmelgarn
2015-03-04 15:27 ` Greg KH [this message]
2015-03-04 15:31 ` Juergen Gross
2015-02-26 13:35 ` [PATCH 4/4] xen: add Xen pvUSB maintainer Juergen Gross
2015-02-26 17:25 ` Konrad Rzeszutek Wilk
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