iommufd/selftest: Test u64 unaligned bitmaps

Exercise the dirty tracking bitmaps with byte unaligned addresses in
addition to the PAGE_SIZE unaligned bitmaps, using a address towards the
end of the page boundary.

In doing so, increase the tailroom we allocate for the bitmap from
MOCK_PAGE_SIZE(2K) into PAGE_SIZE(4K), such that we can test end of bitmap
boundary.

Link: https://lore.kernel.org/r/20240202133415.23819-4-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

tools/testing/selftests/iommu/iommufd.c

@@ -1741,9 +1741,9 @@ FIXTURE_SETUP(iommufd_dirty_tracking)
 	self->bitmap_size =
 		variant->buffer_size / self->page_size / BITS_PER_BYTE;
 
-	/* Provision with an extra (MOCK_PAGE_SIZE) for the unaligned case */
+	/* Provision with an extra (PAGE_SIZE) for the unaligned case */
 	rc = posix_memalign(&self->bitmap, PAGE_SIZE,
-			    self->bitmap_size + MOCK_PAGE_SIZE);
+			    self->bitmap_size + PAGE_SIZE);
 	assert(!rc);
 	assert(self->bitmap);
 	assert((uintptr_t)self->bitmap % PAGE_SIZE == 0);
@@ -1873,6 +1873,13 @@ TEST_F(iommufd_dirty_tracking, get_dirty_bitmap)
 				self->bitmap + MOCK_PAGE_SIZE,
 				self->bitmap_size, 0, _metadata);
 
+	/* u64 unaligned bitmap */
+	test_mock_dirty_bitmaps(hwpt_id, variant->buffer_size,
+				MOCK_APERTURE_START, self->page_size,
+				self->bitmap + 0xff1,
+				self->bitmap_size, 0, _metadata);
+
+
 	test_ioctl_destroy(stddev_id);
 	test_ioctl_destroy(hwpt_id);
 }
@@ -1907,6 +1914,14 @@ TEST_F(iommufd_dirty_tracking, get_dirty_bitmap_no_clear)
 				IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR,
 				_metadata);
 
+	/* u64 unaligned bitmap */
+	test_mock_dirty_bitmaps(hwpt_id, variant->buffer_size,
+				MOCK_APERTURE_START, self->page_size,
+				self->bitmap + 0xff1,
+				self->bitmap_size,
+				IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR,
+				_metadata);
+
 	test_ioctl_destroy(stddev_id);
 	test_ioctl_destroy(hwpt_id);
 }