Re: [PATCH 2/2] selftests: iommu: skip when the mock device is not there

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Sep 09, 2026 at 12:48:12AM +0300, Eva Kurchatova wrote:
> Both iommufd tests need the mock device the iommufd module registers
> under CONFIG_IOMMUFD_TEST, and they open /dev/iommu in every fixture
> without checking, so on a kernel that does not provide it every case
> fails on the open.
> 
> Checking the open is not enough on its own. /dev/iommu appears as soon
> as the iommufd module is loaded, which says nothing about the mock
> device: the release config here is CONFIG_IOMMUFD=m with
> CONFIG_IOMMUFD_TEST unset, so the open succeeds and the tests fail later
> in the ioctls that drive the mock device instead. Only the debug config
> sets CONFIG_IOMMUFD_TEST.
> 
> /sys/bus/iommufd_mock covers both, it exists only once the module is
> loaded and the kernel was built with CONFIG_IOMMUFD_TEST. Check for it
> once before handing over to the harness, rather than in each of the
> fixtures, and report a skip. test_harness_run() is what TEST_HARNESS_MAIN
> calls anyway, so the tests still run exactly as they did.
> 
> Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
> ---
>  tools/testing/selftests/iommu/iommufd.c          | 15 ++++++++++++++-
>  tools/testing/selftests/iommu/iommufd_fail_nth.c | 15 ++++++++++++++-
>  2 files changed, 28 insertions(+), 2 deletions(-)

Applied thanks

Jason