Re: [PATCH v4 15/17] iommufd: Add a selftest

Matthew Rosato
2022-11-09T23:52:06Z

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