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

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Nov 07, 2022 at 08:49:08PM -0400, 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.

This patch crossed 100k so it was bounced from the vger lists.

If anyone didn't get it and would like to see it lore has it:

https://lore.kernel.org/linux-iommu/15-v4-0de2f6c78ed0+9d1-iommufd_jgg@nvidia.com/

For the eventual v5 I will split the nth test into its own patch

Jason