CONFIG_S390_GUEST is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT or s390
s390 guest support (EXPERIMENTAL)
configname: CONFIG_S390_GUEST
Linux Kernel Configuration
└─>Base setup
└─>s390 guest support (EXPERIMENTAL)
In linux kernel since version 2.6.26 (release Date: 2008-07-13)
Select this option if you want to run the kernel under s390 linux