CONFIG_ARCH_VIRT is not available for the selected architecture x86.
Result is shown for architecture riscv
QEMU Virt Machine
configname: CONFIG_ARCH_VIRT
Linux Kernel Configuration
└─>SoC selection
└─>QEMU Virt Machine
In linux kernel since version 3.1 (release Date: 2011-10-24)
This enables support for QEMU Virt Machine.