default or selected kernelversion does not have config value CONFIG_HAVE_KVM_GMEM_PREPARE.
Result is shown for kernelversion 6.11-rc1

CONFIG_HAVE_KVM_GMEM_PREPARE (not configurable)

configname: CONFIG_HAVE_KVM_GMEM_PREPARE

Linux Kernel Configuration
└─>HAVE_KVM_GMEM_PREPARE