iommufd: Add IOMMU_HWPT_GET_DIRTY_BITMAP

mainline inclusion
from mainline-v6.7-rc1
commit b9a60d6f850e4470017b60f731220a58cda199aa
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I8Y6AM
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?b9a60d6f850e4470017b60f731220a58cda199aa

--------------------------------

Connect a hw_pagetable to the IOMMU core dirty tracking
read_and_clear_dirty iommu domain op. It exposes all of the functionality
for the UAPI that read the dirtied IOVAs while clearing the Dirty bits from
the PTEs.

In doing so, add an IO pagetable API iopt_read_and_clear_dirty_data() that
performs the reading of dirty IOPTEs for a given IOVA range and then
copying back to userspace bitmap.

Underneath it uses the IOMMU domain kernel API which will read the dirty
bits, as well as atomically clearing the IOPTE dirty bit and flushing the
IOTLB at the end. The IOVA bitmaps usage takes care of the iteration of the
bitmaps user pages efficiently and without copies. Within the iterator
function we iterate over io-pagetable contigous areas that have been
mapped.

Contrary to past incantation of a similar interface in VFIO the IOVA range
to be scanned is tied in to the bitmap size, thus the application needs to
pass a appropriately sized bitmap address taking into account the iova
range being passed *and* page size ... as opposed to allowing bitmap-iova
!= iova.

Intel-SIG: b9a60d6f850e iommufd: Add IOMMU_HWPT_GET_DIRTY_BITMAP
Backport IOMMUFD Dirty Tracking

Link: https://lore.kernel.org/r/20231024135109.73787-8-joao.m.martins@oracle.com


Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
[ jz: amend commit log ]
Signed-off-by: Jason Zeng <jason.zeng@intel.com>