iommu/vt-d: Report page request faults for guest SVA

iommu/vt-d: Report page request faults for guest SVA

A pasid might be bound to a page table from a VM guest via the iommu
ops.sva_bind_gpasid. In this case, when a DMA page fault is detected
on the physical IOMMU, we need to inject the page fault request into
the guest. After the guest completes handling the page fault, a page
response need to be sent back via the iommu ops.page_response().

This adds support to report a page request fault. Any external module
which is interested in handling this fault should regiester a notifier
with iommu_register_device_fault_handler().

Co-developed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Co-developed-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20200724014925.15523-11-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>