Re: q35 in xen? vfio in xen?

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, Feb 21, 2014 at 09:41:39PM +0000, Zhang, Eniac wrote:
> Hi all,
> 
> I am playing with q35 chipset in qemu (1.6.1).  It seems we can't enable q35 machine under xen yet.  I made a few quick hacks which all fail miserably (linux kernel oops and window BSOD).  I was wondering why this hasn't been done (q35 was introduced into qemu in 2009).
> 
> Next question, vfio works very well for me in standalone qemu (with Linux host handling iommu), but is that supported under xen?  I haven't tried anything there yet because my gut-feeling is that it won't work.  Because passing vfio device to qemu can only be done on qemu commandline, and xen is not aware of this passing through device, thus not able to make iommu arrangement for this device.  Am I on the right track here?

Yes and no. VFIO won't work - but QEMU does do PCI passthrough under Xen. It uses
a different mechanism (and you need to bind the device to pciback).

> 
> I am interested in implementing both these two features.  I'd like to connect with anyone who's already on this so we don't duplicate the efforts.

What do you need Q35 for?

> 
> Regards/Eniac

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