Re: USB mini-summit at LinuxCon Vancouver

[Greg KH <greg@kroah.com>]

On Mon, Jun 13, 2011 at 12:44:57PM +0200, Alexander Graf wrote:
> 
> Am 10.06.2011 um 22:50 schrieb Greg KH <greg@kroah.com>:
> 
> > On Fri, Jun 10, 2011 at 12:48:15PM -0700, Sarah Sharp wrote:
> >> On Thu, Jun 09, 2011 at 08:18:05PM -0700, Greg KH wrote:
> >>> On Thu, Jun 09, 2011 at 05:21:03PM -0700, Sarah Sharp wrote:
> >>>> Topic 1
> >>>> -------
> >>>> 
> >>>> The KVM folks suggested that it would be good to get USB and
> >>>> virtualization developers together to talk about how to virtualize the
> >>>> xHCI host controller.  The xHCI spec architect worked closely with
> >>>> VMWare to get some extra goodies in the spec to help virtualization, and
> >>>> I'd like to see the other virtualization developers take advantage of
> >>>> that.  I'd also like us to hash out any issues they have been finding in
> >>>> the USB core or xHCI driver during the virtualization effort.
> >>> 
> >>> Do people really want to virtualize the whole xHCI controller, or just
> >>> specific ports or devices to the guest operating system?
> >> 
> >> A host OS could chose to virtualize the whole xHCI controller if it
> >> wanted to.  That's part of the reason why xHCI does all the bandwidth
> >> checking in hardware, not in software.
> > 
> > And here I thought it did that so it would be "correct" :)
> > 
> >> 
> >>> If just specific ports, would something like usbip be better for virtual
> >>> machines, with the USB traffic going over the network connection between
> >>> the guest/host?
> >> 
> >> It could be done that way too.  But that doesn't help if you're trying
> >> to run Windows under Linux, right?  Only if all the guest OSes use the
> >> same USB IP protocol then it would work.
> > 
> > usbip works on Windows as well as Linux.
> 
> Do you have a reliable, working usbip solution at hand that work on
> Windows and Linux and doesn't require real network access, which can
> be a no-go for some scenarios?

What do you mean by "real network access"?  A virtual network connection
to the guest and host should be sufficient, right?

> > But how could you run Windows with a xHCI controller in a guest, as
> > Windows has no xHCI driver?  What would it expect to see?
> 
> There are drivers for xhci adapters on Windows.

Not well-working ones, see the windows driver mailing list as well as
the libusb mailing list for problems that people are having due to there
not being any "official" Microsoft xhci drivers shipping yet.

> Also, this whole discussion is pretty much future oriented - which
> most likely means built-in xhci drivers anywhere.

Agreed.

thanks,

greg k-h