From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konstantin Khorenko <khorenko@virtuozzo.com>
Date: Tue, 25 Aug 2026 16:50:45 +0200
Subject: Re: [Devel] [PATCH vz10 v2] selftests/iommu: skip when the mock
 device is not there
In-Reply-To: <20260825115029.1074947-1-eva.kurchatova@virtuozzo.com>
References: <20260825115029.1074947-1-eva.kurchatova@virtuozzo.com>
Message-ID: <caf33f83-7e15-4022-b6b1-f7e2e2bf499e@virtuozzo.com>
List-Id: <devel.openvz.org>

ack

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 8/25/26 13:50, 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.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-142443
> Feature: fix selftests
> 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(-)
> 
> diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
> index de348d641279..5e0309a7ec67 100644
> --- a/tools/testing/selftests/iommu/iommufd.c
> +++ b/tools/testing/selftests/iommu/iommufd.c
> @@ -3523,4 +3523,17 @@ TEST_F(iommufd_device_pasid, pasid_attach)
>  	test_cmd_mock_domain_replace(self->stdev_id, self->ioas_id);
>  }
>  
> -TEST_HARNESS_MAIN
> +static bool iommufd_mock_available(void)
> +{
> +	return access("/sys/bus/iommufd_mock", F_OK) == 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	if (!iommufd_mock_available())
> +		ksft_exit_skip("no iommufd mock device, the tests need "
> +			       "CONFIG_IOMMUFD_TEST=y and the iommufd "
> +			       "module loaded\n");
> +
> +	return test_harness_run(argc, argv);
> +}
> diff --git a/tools/testing/selftests/iommu/iommufd_fail_nth.c b/tools/testing/selftests/iommu/iommufd_fail_nth.c
> index 45c14323a618..a76cd19970c0 100644
> --- a/tools/testing/selftests/iommu/iommufd_fail_nth.c
> +++ b/tools/testing/selftests/iommu/iommufd_fail_nth.c
> @@ -745,4 +745,17 @@ TEST_FAIL_NTH(basic_fail_nth, device)
>  	return 0;
>  }
>  
> -TEST_HARNESS_MAIN
> +static bool iommufd_mock_available(void)
> +{
> +	return access("/sys/bus/iommufd_mock", F_OK) == 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	if (!iommufd_mock_available())
> +		ksft_exit_skip("no iommufd mock device, the tests need "
> +			       "CONFIG_IOMMUFD_TEST=y and the iommufd "
> +			       "module loaded\n");
> +
> +	return test_harness_run(argc, argv);
> +}