reproduce (this is a W=1 build):
        git remote add awilliam-vfio https://github.com/awilliam/linux-vfio.git
        git fetch awilliam-vfio next
        git checkout awilliam-vfio/next
        b4 shazam https://lore.kernel.org/r/a371fbe1c68e891a38f9cc8eadf2e93d4921e246.1736550979.git.nicolinc@nvidia.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/iommu/