On 11/7/22 7:49 PM, Jason Gunthorpe wrote:

Cover the essential functionality of the iommufd with a directed test. This aims to achieve reasonable functional coverage using the in-kernel self test framework.

It provides a mock kernel module for the iommu_domain that allows it to run without any HW and the mocking provides a way to directly validate that the PFNs loaded into the iommu_domain are correct.

The mock also simulates the rare case of PAGE_SIZE > iommu page size as the mock will operate at a 2K iommu page size. This allows exercising all of the calculations to support this mismatch.

This allows achieving high coverage of the corner cases in the iopt_pages.

However, it is an unusually invasive config option to enable all of this. The config option should not be enabled in a production kernel.

Tested-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com

Ran the selftests on s390 in both LPAR (z16) and a QEMU kvm guest using 1M hugepages, all tests are passing.

Tested-by: Matthew Rosato mjrosato@linux.ibm.com # s390