IOMMU Userspace API Test support

configname: CONFIG_IOMMUFD_TEST

Linux Kernel Configuration
└─>Device Drivers
└─>IOMMU Hardware Support
└─>IOMMU Userspace API Test support
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
This is dangerous, do not enable unless running
tools/testing/selftests/iommu