This patch adds some hooks to let PCI devices and busses use the new IOMMU
infrastructure. When IOMMU support is enabled, each PCI device now
contains a DMAContext * which is used by the pci_dma_*() wrapper functions.
By default, the contexts are initialized to NULL, assuming no IOMMU.
However the platform or host bridge code which sets up the PCI bus can use
pci_setup_iommu() to set a function which will determine the correct
DMAContext for a given PCI device.
Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Richard Henderson <rth@twiddle.net> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>