iommu/sva: Bind process address spaces to devices

hulk inclusion
category: feature
bugzilla: 14369
CVE: NA
-------------------

Add bind() and unbind() operations to the IOMMU API. Bind() returns a
PASID that drivers can program in hardware, to let their devices access an
mm. This patch only adds skeletons for the device driver API, most of the
implementation is still missing.

IOMMU groups with more than one device aren't supported for SVA at the
moment. There may be P2P traffic between devices within a group, which
cannot be seen by an IOMMU (note that supporting PASID doesn't add any
form of isolation with regard to P2P). Supporting groups would require
calling bind() for all bound processes every time a device is added to a
group, to perform sanity checks (e.g. ensure that new devices support
PASIDs at least as big as those already allocated in the group). It also
means making sure that reserved ranges (IOMMU_RESV_*) of all devices are
carved out of processes. This is already tricky with single devices, but
becomes very difficult with groups. Since SVA-capable devices are expected
to be cleanly isolated, and since we don't have any way to test groups or
hot-plug, we only allow singular groups for now.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Fang Lijun <fanglijun3@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>