Build a Linux Distribution

Step 1

Compile linux kernel.

make menuconfig
make -j 8

The kernel image is the file project-root/arch/x86/boot/bzImage in my case. Use the file command to check its type:

# file /path/to/bzImage
bzImage: Linux kernel x86 boot executable bzImage, version 6.11.2 (root@yrd) #3 SMP PREEMPT_DYNAMIC Thu Oct 31 19:12:51 CST 2024, RO-rootFS, swap_dev 0X8, Normal VGA

Step 2

Create a directory named initramfs with the following layout:

bin
    prog1
    prog2
boot
    grub
        grub.cfg
    bzImage
    initramfs.cpio.gz
device
home
    README.txt

The grub.cfg configuation is for GNU grub(link). Write the following into it:

menuentry "linux-version" {
	linux /boot/bzImage
	initrd /boot/initramfs.cpio.gz
}

Step 3

Generate bootable image and boot it in qemu.

grub-mkrescue -o bootable.iso initramfs

Run qemu by qemu-system-x86_64 -cdrom bootable.iso.