CONFIG_ARC_KVADDR_SIZE is not available for thedefaultarchitecture x86.
Result is shown for architecture arc

Kernel Virtual Address Space size (MB)


Linux Kernel Configuration
└─>ARC Architecture Configuration
└─>Kernel Virtual Address Space size (MB)
In linux kernel since version 4.1 (release Date: 2015-06-21)  
The kernel address space is carved out of 256MB of translated address
space for catering to vmalloc, modules, pkmap, fixmap. This however may
not suffice vmalloc requirements of a 4K CPU EZChip system. So allow
this to be stretched to 512 MB (by extending into the reserved
kernel-user gutter)