RE: [PATCH v5 10/15] iommupt: Add a mock pagetable format for iommufd selftest to use

From: Jason Gunthorpe jgg@nvidia.com Sent: Thursday, September 4, 2025 1:47 AM

The iommufd self test uses an xarray to store the pfns and their orders to emulate a page table. Slightly modify the amdv1 page table to create a real page table that has similar properties:

• 2k base granule to simulate something like a 4k page table on a 64K PAGE_SIZE ARM system
• Contiguous page support for every PFN order
• Dirty tracking

AMDv1 is the closest format, as it is the only one that already supports every page size. Tweak it to have only 5 levels and an 11 bit base granule and compile it separately as a format variant.

Tested-by: Alejandro Jimenez alejandro.j.jimenez@oracle.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com

Reviewed-by: Kevin Tian kevin.tian@intel.com