Prerequisities

GNU

• nproc @ coreutils

QEMU

• qemu-x86_64 @ qemu

EFI

• edk2-ovmf

Buildroot

• submodule buildroot/buildroot

Build

EFI

cd buildroot \
&& make BR2_EXTERNAL=../external defconfig BR2_DEFCONFIG=../efi-defconfig \
&& make BR2_EXTERNAL=../external \
&& cd ..

MBR

cd buildroot \
&& make BR2_EXTERNAL="../external" defconfig BR2_DEFCONFIG=../mbr-defconfig \
&& make BR2_EXTERNAL=../external \
&& cd ..

Run

EFI

declare -i CPU_COUNT=$(nproc) \
&& qemu-system-x86_64 -smp ${CPU_COUNT} -m $(( ${CPU_COUNT} * 128 )) \
-enable-kvm -cpu max,hv-runtime \
-drive file=buildroot/output/images/disk.img,format=raw \
-bios /usr/share/OVMF/x64/OVMF.fd

MBR

declare -i CPU_COUNT=$(nproc) \
&& qemu-system-x86_64 -smp ${CPU_COUNT} -m $(( ${CPU_COUNT} * 128 )) \
-enable-kvm -cpu max,hv-runtime \
-cdrom buildroot/output/images/rootfs.iso9660

Command-line

• Run twice number of CPUs

declare -i CPU_COUNT=$(( $(nproc) * 2 )) \
&& qemu-system-x86_64 -smp ${CPU_COUNT} -m $(( ${CPU_COUNT} * 128 )) \
-enable-kvm -cpu max,hv-runtime \
-drive file=buildroot/output/images/disk.img,format=raw \
-kernel buildroot/output/images/bzImage \
-append "nr_cpus=${CPU_COUNT} root=/dev/sda2 rootwait console=tty1 quiet"

Example