iommufd/selftest: Fix page-size check in iommufd_test_dirty()

iommufd_test_dirty()/IOMMU_TEST_OP_DIRTY sets the dirty bits in the mock
domain implementation that the userspace side validates against what it
obtains via the UAPI.

However in introducing iommufd_test_dirty() it forgot to validate page_size
being 0 leading to two possible divide-by-zero problems: one at the
beginning when calculating @max and while calculating the IOVA in the
XArray PFN tracking list.

While at it, validate the length to require non-zero value as well, as we
can't be allocating a 0-sized bitmap.

Link: https://lore.kernel.org/r/[email protected]
Reported-by: [email protected]
Closes: https://lore.kernel.org/linux-iommu/[email protected]/
Fixes: a9af47e382a4 ("iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP")
Signed-off-by: Joao Martins <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

0 files changed, 0 insertions, 0 deletions