This is the report about the first tutorial for the Linux Kernel development: Setting up a test environment for Linux Kernel Dev using QEMU and libvirt.

To develop the Linux Kernel, the first thing we need to do is setting up our test environment. This was done in several steps.

0. Installing dependencies

First, I needed to install all the required dependencies for it, through pacman, since I use the Manjaro distro.

sudo pacman -Syy && sudo pacman -S qemu-full libvirt virt-install guestfs-tools wget

QUEMU (Quick Emulator) will be used to run VMs and libvirt, as a toolkit to manage virtualization platforms, will provide tools to interact with VMs.

1. Testing environment directory and script

After that, I created a separated directoy and attributed it to the libvirt-qemu group.

sudo mkdir /home/lk_dev
sudo chown -R libvirt-qemu:libvirt-qemu /home/lk_dev
sudo chmod -R 2770 /home/lk_dev
sudo usermod -aG libvirt-qemu "$USER"

In this folder, I created the script that will be used to host environment variables and common functions for further developments.

touch '/home/lk_dev/activate.sh'
chmod +x '/home/lk_dev/activate.sh'

This is the initial content of the script.

#!/usr/bin/env bash

# environment variables
export LK_DEV_DIR='/home/lk_dev' # path to testing environment directory

# prompt preamble
prompt_preamble='(LK-DEV)'

# colors
GREEN="\e[32m"
PINK="\e[35m"
BOLD="\e[1m"
RESET="\e[0m"

# launch Bash shell session w/ env vars defined
echo -e "${GREEN}Entering shell session for Linux Kernel Dev${RESET}"
echo -e "${GREEN}To exit, type 'exit' or press Ctrl+D.${RESET}"
exec bash --rcfile <(echo "source ~/.bashrc; PS1=\"\[${BOLD}\]\[${PINK}\]${prompt_preamble}\[${RESET}\] \$PS1\"")

On a side note, I tried to modify the script to use the zsh shell instead of bash, that way I could use the autocomplete capabilities of it. However, I couldn’t make it work.

After that, I ran the script with /home/lk_dev/activate.sh and had it active for the following sections.

2. Configuring a VM

We need a virtual machine to test our modified kernel versions. Since the tutorial focuses in the IIO (Industrial I/O) subsystem, we chose a Debian image with ARM 64-bit architecture: http://cdimage.debian.org/cdimage/cloud/bookworm/daily/20250217-2026/debian-12-nocloud-arm64-daily-20250217-2026.qcow2.

Then I followed all the steps for configuring the VM, which consists of:

1. Downloading the disk image in a new folder;
2. Resizing the disk image rootfs;
3. Extracting the kernel and initrd images from the guest OS and launching the VM;
4. Using libvirt to make the VM management easier.

3. Configuring SSH access

After successfully booting the VM, we had to configure SSH access to make file transfer easier.

In this part I had some problems when setting up the SSH server, since the VM didn´t seem to have all the needed dependencies installed. Because of it, I had fix the firewall configurations, allowing the VM to connect to the internet and then install the needed dependencies.

4. Fetching the list of loaded modules

Then, with the SSH access configured, I fetched the list of loaded modules in the VM, which will be used in the following parts of the tutorial.

# @host
ssh root@<VM-IP-address>
# @VM
lsmod > vm_mod_list