Re: [Xen-devel] Realtime access to PCI NIC

[Simon Martin <furryfuttock@xxxxxxxxx>]

Thanks Ian,

Tuesday, July 8, 2014, 3:46:25 PM, you wrote:


> Only PCI cfg reads/writes go via the backend, I think. Any MMIO space
> (i.e. described in the PCI BARS) can be directly mapped, likewise for
> the IO port spaces associated with the device.

> I think PCI cfg space is only generally used during probing/setup etc.
> Hopefully you don't need to poke it at runtime?

You have confirmed the conclusion that I was coming to!

> Right, VT-d allows the MMIO stuff to be mapped to an HVM guest (PV
> doesn't even need that), but unfortunately there are bits in the pci cfg
> space which even a guest with the device passed to it shouldn't be able
> to mess with (I don't know the details though).

Perfect.

-- 
Best regards,
 Simon                            mailto:furryfuttock@xxxxxxxxx


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