Re: [Xen-users] usb passthrough

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Fri, Feb 26, 2010 at 05:34:14PM -0500, chris wrote:
> I would be curious to see benchmarks comparing usb device passthrough
> with vt-d passthrough of a usb controller + device. Would be
> interesting to see what differences if any there are. If I get some
> time I will try to test this.
> 

See here for benchmark results:
http://www.xen.org/files/xensummit_intel09/PVUSBStatusUpdate.pdf

pvusb performance seems to be pretty close to dom0 native usb performance.

If using the normal qemu-dm usb passthrough it is limited to emulated usb 1.1,
so that'll be slow.

-- Pasi

>  - chris
> 
> On Fri, Feb 26, 2010 at 5:00 PM, James Harper
> <james.harper@xxxxxxxxxxxxxxxx> wrote:
> > Pvusb should work for most things. You might be thinking of the USB frontend
> > in gplpv which only works with a very limited number of storage devices (and
> > probably not at all since the last update)
> >
> > James
> >
> > Sent from my iPhone
> >
> > On 27/02/2010, at 5:25, "chris" <tknchris@xxxxxxxxx> wrote:
> >
> >> Pasi,
> >>
> >> I know, my understanding was that pvusb was simply for exposing usb
> >> mass storage as a block device to the domain. I've never actually used
> >> it but I believe you can do this with a hvm domain without anything
> >> special. If anyone can actually confirm this it would be good to know
> >> :)
> >>
> >> As far as his original question, he needs vt-d to passthrough any
> >> physical device to a hvm domain.
> >>
> >> - chris
> >>
> >> On Fri, Feb 26, 2010 at 10:03 AM, Pasi Kärkkäinen <pasik@xxxxxx> wrote:
> >>>
> >>> On Fri, Feb 26, 2010 at 10:00:34AM -0500, chris wrote:
> >>>>
> >>>> He said it was a HVM guest. I don't think you can passthrough to a hvm
> >>>> domain anything except usb storage with pvusb, correct?
> >>>>
> >>>
> >>> pvusb is different from the 'normal' usb=1 / usbdevice = [] stuff..
> >>>
> >>> I'm not totally sure what devices are supported with pvusb and with the
> >>> normal usb passthrough.
> >>>
> >>> -- Pasi
> >>>
> >>>> On Fri, Feb 26, 2010 at 9:49 AM, Pasi Kärkkäinen <pasik@xxxxxx> wrote:
> >>>>>
> >>>>> On Fri, Feb 26, 2010 at 09:49:38AM -0300, Sergio Charpinel Jr. wrote:
> >>>>>>
> >>>>>> Hi,
> >>>>>>
> >>>>>> I want to use a webcam in a HVM guest, but my dom0 doesnt support VT-d
> >>>>>> (just VT).
> >>>>>>
> >>>>>
> >>>>> USB passthrough doesn't require VT-d, it's only required for PCI device
> >>>>> passthrough to HVM guests.
> >>>>>
> >>>>>> I tried passing the parameters usb=1 and usbdevice = [ '..' ] and I
> >>>>>> could see an usb device in domU. But it does not know which device is.
> >>>>>>
> >>>>>> Which are the possibilites to do that? I prefer to use hvm machines,
> >>>>>> but if it is not possible, with PV machines it can work?
> >>>>>>
> >>>>>
> >>>>> With PV guest you could passthrough the whole USB controller (the PCI
> >>>>> device)..
> >>>>>
> >>>>> -- Pasi
> >>>>>
> >>>>>
> >>>>> _______________________________________________
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> >>>>> Xen-users@xxxxxxxxxxxxxxxxxxx
> >>>>> http://lists.xensource.com/xen-users
> >>>>>
> >>>
> >>
> >> _______________________________________________
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> >> http://lists.xensource.com/xen-users
> >

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