Re: [PATCH v2 5/5] KVM: selftests: List the known IOMMU modes in irq_test's help output

[Sean Christopherson <seanjc@google.com>]

On Wed, Nov 04, 2026, David Matlack wrote:
> On 2026-11-04 06:53 AM, Sean Christopherson wrote:
> > const char *iommu_mode_names(void)
> > {
> > 	return __iommu_mode_names(false);
> > }
> 
> How about listing both? That keeps -h consistent with how other KVM
> selftests list the options for their arguments (e.g. backing_src_help()
> lists every backing src type), while also showing which modes can
> actually be used. e.g. on a system with only the legacy VFIO container:
> 
>   # ./irq_test -h
>   ...
>   -t	Override the IOMMU mode to use
>   	Options: iommufd, vfio_type1v2_iommu, vfio_type1_iommu, iommufd_compat_type1v2, iommufd_compat_type1
>   	Available: vfio_type1v2_iommu, vfio_type1_iommu

That'd be awesome!

> The available modes also get printed when the requested mode is not
> available, i.e. when the __TEST_REQUIRE() fails:
> 
>   # ./irq_test -d 0000:01:00.0 -t iommufd
>   1..0 # SKIP - IOMMU mode 'iommufd' is not available.  Available modes: vfio_type1v2_iommu, vfio_type1_iommu.
> 
> libvfio exposes iommu_mode_names_all() and iommu_mode_names_available()
> for this, built on your helper for juggling all vs. available.