CONFIG_KSEG_PADDR is not available for thedefaultarchitecture x86.
Result is shown for architecture xtensa

Physical address of the KSEG mapping


Linux Kernel Configuration
└─>Platform options
└─>Physical address of the KSEG mapping
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This is the physical address where KSEG is mapped. Please refer to
the chosen KSEG layout help for the required address alignment.
Unpacked kernel image (including vectors) must be located completely
within KSEG.
Physical memory below this address is not available to linux.

If unsure, leave the default value here.