The iommu driver doesn't know whether the bit width of a PCI
device is sufficient for access to the whole system memory.
Hence, the driver checks this when the driver calls into the
dma APIs. If a device is using an identity domain, but the
bit width is less than the system requirement, we need to use
a dma domain instead. This also applies after we delegated
the domain life cycle management to the upper layer.
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>