For small bitmaps that aren't PAGE_SIZE aligned *and* that are less than
512 pages in bitmap length, use an extra page to be able to cover the
entire range e.g. [1M..3G] which would be iterated more efficiently in a
single iteration, rather than two.
Fixes: b058ea3ab5 ("vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries")
Link: https://lore.kernel.org/r/20240202133415.23819-10-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Tested-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
IOVA bitmap is a zero-copy scheme of recording dirty bits that iterate the
different bitmap user pages at chunks of a maximum of
PAGE_SIZE/sizeof(struct page*) pages.
When the iterations are split up into 64G, the end of the range may be
broken up in a way that's aligned with a non base page PTE size. This
leads to only part of the huge page being recorded in the bitmap. Note
that in pratice this is only a problem for IOMMU dirty tracking i.e. when
the backing PTEs are in IOMMU hugepages and the bitmap is in base page
granularity. So far this not something that affects VF dirty trackers
(which reports and records at the same granularity).
To fix that, if there is a remainder of bits left to set in which the
current IOVA bitmap doesn't cover, make a copy of the bitmap structure and
iterate-and-set the rest of the bits remaining. Finally, when advancing
the iterator, skip all the bits that were set ahead.
Link: https://lore.kernel.org/r/20240202133415.23819-5-joao.m.martins@oracle.com
Reported-by: Avihai Horon <avihaih@nvidia.com>
Fixes: f35f22cc76 ("iommu/vt-d: Access/Dirty bit support for SS domains")
Fixes: 421a511a29 ("iommu/amd: Access/Dirty bit support in IOPTEs")
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Tested-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
iova_bitmap_mapped_length() don't deal correctly with the small bitmaps
(< 2M bitmaps) when the starting address isn't u64 aligned, leading to
skipping a tiny part of the IOVA range. This is materialized as not
marking data dirty that should otherwise have been.
Fix that by using a u8 * in the internal state of IOVA bitmap. Most of the
data structures use the type of the bitmap to adjust its indexes, thus
changing the type of the bitmap decreases the granularity of the bitmap
indexes.
Fixes: b058ea3ab5 ("vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries")
Link: https://lore.kernel.org/r/20240202133415.23819-3-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Tested-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Dirty IOMMU hugepages reported on a base page page-size granularity can
lead to an attempt to set dirty pages in the bitmap beyond the limits that
are pinned.
Bounds check the page index of the array we are trying to access is within
the limits before we kmap() and return otherwise.
While it is also a defensive check, this is also in preparation to defer
setting bits (outside the mapped range) to the next iteration(s) when the
pages become available.
Fixes: b058ea3ab5 ("vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries")
Link: https://lore.kernel.org/r/20240202133415.23819-2-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Tested-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Both VFIO and IOMMUFD will need iova bitmap for storing dirties and walking
the user bitmaps, so move to the common dependency into IOMMUFD. In doing
so, create the symbol IOMMUFD_DRIVER which designates the builtin code that
will be used by drivers when selected. Today this means MLX5_VFIO_PCI and
PDS_VFIO_PCI. IOMMU drivers will do the same (in future patches) when
supporting dirty tracking and select IOMMUFD_DRIVER accordingly.
Given that the symbol maybe be disabled, add header definitions in
iova_bitmap.h for when IOMMUFD_DRIVER=n
Link: https://lore.kernel.org/r/20231024135109.73787-3-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
