On Thu, Mar 05, 2015 at 11:12:22AM +0100, Paolo Bonzini wrote:

On 04/03/2015 18:28, Catalin Marinas wrote:

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Can you add that property to the device tree for PCI devices too?

Yes but not with mainline yet:

http://thread.gmane.org/gmane.linux.kernel.iommu/8935

We can add the property at the PCI host bridge level (with the drawback
that it covers all the PCI devices), like here:

Even covering all PCI devices is not enough if we want to support device
assignment of PCI host devices. 

Can we not have another PCI bridge node in the DT for the host device
assignments?

I'd rather not spend effort on a solution that we know will only
half-work a few months down the road.

Which of the solutions are you referring to? On the Applied Micro
boards, for example, the PCIe is coherent. If you do device assignment,
the guest must be aware of the coherency property of the physical device
and behave accordingly, there isn't much the host can do about it.

-- 
Catalin