iommu: Introduce Shared Virtual Addressing API

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

Shared Virtual Addressing (SVA) provides a way for device drivers to bind
process address spaces to devices. This requires the IOMMU to support page
table format and features compatible with the CPUs, and usually requires
the system to support I/O Page Faults (IOPF) and Process Address Space ID
(PASID). When all of these are available, DMA can access virtual addresses
of a process. A PASID is allocated for each process, and the device driver
programs it into the device in an implementation-specific way.

Add a new API for sharing process page tables with devices. Introduce two
IOMMU operations, sva_device_init() and sva_device_shutdown(), that
prepare the IOMMU driver for SVA. For example allocate PASID tables and
fault queues. Subsequent patches will implement the bind() and unbind()
operations.

Support for I/O Page Faults will be added in a later patch using a new
feature bit (IOMMU_SVA_FEAT_IOPF). With the current API users must pin
down all shared mappings. Other feature bits that may be added in the
future are IOMMU_SVA_FEAT_PRIVATE, to support private PASID address
spaces, and IOMMU_SVA_FEAT_NO_PASID, to bind the whole device address
space to a process.

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>