CONFIG_CIO_INJECT is not available for thedefaultarchitecture x86.
Result is shown for architecture s390

CIO Inject interfaces

modulename: cio_inject.ko

configname: CONFIG_CIO_INJECT

Linux Kernel Configuration
└─>CIO Inject interfaces
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
This option provides a debugging facility to inject certain artificial events
and instruction responses to the CIO layer of Linux kernel. The newly created
debugfs user-interfaces will be at /sys/kernel/debug/s390/cio/*

source code: