#!/bin/bash -e

function ask_yn() {
    local ans

    printf "$1 (Y/n) " >&2
    read -r ans
    case "${ans,,}" in
        y*|'') return 0 ;;
        *)     return 1 ;;
    esac
}

RAM="$(free -g | awk '/^Mem:/{print $2 - 2}')"

if   [ "$RAM" -le  2 ]; then  RAM=2
elif [ "$RAM" -gt 32 ]; then RAM=32; fi

RAM="${RAM}G"

CMD=(
    qemu-system-x86_64
        -accel kvm
        -M q35
        -cpu host
        -m "2G,maxmem=$RAM"
        -vga virtio
        -drive if=virtio,file=hda.qcow2
        # usb
        -device qemu-xhci
        # shared memory
        -object memory-backend-ram,id=mem,size=2G,share=on
        -numa node,memdev=mem
)