Building a Debian Stretch QEMU image for AARCH64

Introduction

After releasing my QEMU images and then publishing a post on how to build a QEMU image for Debian MIPSel, I still received many demands for information on building more VMs, and among those, the most popular one was AARCH64 (or ARM64).

If you’re just interested in downloading the ready-to-use AARCH64 image, just go to the Mega repository.

Pre-requisite

Just like we did earlier in the former post, we will proceed with the Debian Net Installer, so you will require:

an Internet connection
a recent QEMU (generally {apt,dnf} install qemu will suffice)
the initrd of the Debian installer

$ wget http://ftp.debian.org/debian/dists/Debian9.13/main/installer-arm64/current/images/netboot/debian-installer/arm64/initrd.gz

the kernel to boot on for the installation:

$ wget http://ftp.debian.org/debian/dists/Debian9.13/main/installer-arm64/current/images/netboot/debian-installer/arm64/linux

You also need a hard drive to install the OS on:

$ qemu-img create -f qcow2 disk.qcow2 20G

Installation steps

Note

since most steps are similar with the ones described in the post before, I’ll simply show the commands I’ve used so they can be copy/pasted for reproduction.

Start with running the installer (with 2 vCPUs and 1GB Ram):

$ qemu-system-aarch64 -smp 2 -M virt -cpu cortex-a57 -m 1G \
    -initrd initrd.gz \
    -kernel linux -append "root=/dev/ram console=ttyAMA0" \
    -global virtio-blk-device.scsi=off \
    -device virtio-scsi-device,id=scsi \
    -drive file=disk.qcow2,id=rootimg,cache=unsafe,if=none \
    -device scsi-hd,drive=rootimg \
    -netdev user,id=unet -device virtio-net-device,netdev=unet \
    -net user \
    -nographic

Then, go grab a coffee while the installer does its magic:

And finally:

Now we must shutdown the VM, and extract the initrd and kernel from the image, as follow:

$ sudo apt install nbd-client
$ sudo modprobe nbd max_part=8
$ sudo qemu-nbd --connect=/dev/nbd0 disk.qcow2
$ mkdir mnt
$ sudo mount /dev/nbd0p1 mnt
$ cp mnt/initrd.img-4.9.0-4-arm64 mnt/vmlinuz-4.9.0-4-arm64 .
$ sync
$ sudo umount /dev/nbd0p1
$ sudo nbd-client -d /dev/nbd0

And run your VM with the kernel and initrd copied from installer:

$ qemu-system-aarch64 -smp 2 -M virt -cpu cortex-a57 -m 1G \
    -initrd initrd.img-4.9.0-4-arm64 \
    -kernel vmlinuz-4.9.0-4-arm64 \
    -append "root=/dev/sda2 console=ttyAMA0" \
    -global virtio-blk-device.scsi=off \
    -device virtio-scsi-device,id=scsi \
    -drive file=disk.qcow2,id=rootimg,cache=unsafe,if=none \
    -device scsi-hd,drive=rootimg \
    -device e1000,netdev=net0 \
    -net nic \
    -netdev user,hostfwd=tcp:127.0.0.1:2222-:22,id=net0 \
    -nographic

And that’s it!

The ready-to-use image (with gcc, gdb, gef, etc.) is available here.

Adios ☕