default or selected kernelversion does not have config value CONFIG_S390_CCW_IOMMU.
Result is shown for kernelversion 6.9.9

S390 CCW IOMMU Support

configname: CONFIG_S390_CCW_IOMMU

Linux Kernel Configuration
└─>Device Drivers
└─>IOMMU Hardware Support
└─>S390 CCW IOMMU Support
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Enables bits of IOMMU API required by VFIO. The iommu_ops
is not implemented as it is not necessary for VFIO.


depends
CONFIG_IOMMU_SUPPORT
CONFIG_COMPILE_TEST or CONFIG_CCW
CONFIG_S390