On Thu, Nov 24, 2016 at 10:45:18AM +0100, Christian König wrote:
Am 24.11.2016 um 00:25 schrieb Jason Gunthorpe:
>There is certainly nothing about the hardware that cares
>about ZONE_DEVICE vs System memory.
Well that is clearly not so simple. When your ZONE_DEVICE pages describe a
PCI BAR and another PCI device initiates a DMA to this address the DMA
subsystem must be able to check if the interconnection really works.
I said the hardware doesn't care.. You are right, we still have an
outstanding problem in Linux of how to generically DMA map a P2P
address - which is a different issue from getting the P2P address from
a __user pointer...