Re: [Xen-users] hardware driver question

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> If you have no driver for a hardware-device for the OS running in dom0,
> but you have a driver for this hardware-device for the OS running in
> domU,
> is it possible to use this hardware-device in domU?

Yes, sometimes.

If it's a PCI device:

If domU is a PV guest then you can use PCI passthrough to pass the guest but 
this means the guest is as privileged and trusted as dom0 is.

If the domU is an HVM guest *and* you have Intel VT-d hardware, then it's 
possible to pass PCI devices through without making the guest as highly 
privileged as dom0.  I don't know if there's an AMD solution for this in Xen 
yet.

If it's a USB device:

Then the only way you can pass it to a PV guest is by using PCI passthrough to 
pass through an entire USB controller.  Guest is privileged.

For an HVM guest, you can modify the domain's config file to passthrough an 
individual USB device although some functionality (e.g. isochronous transfer 
used by webcams, etc) is not available.

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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