# qemu-rpi-kernel

Ready-made kernels that can be used to emulate a Raspberry Pi using QEMU.

They are compiled from the same [kernel sources] used for official Raspian
images, with tweaks to make them suitable for use with QEMU, and are supposed
to be used along with official Raspbian images.

## Obtaining Raspbian

Before starting, you should download a [Raspbian image] from the Raspberry Pi
website and extract the `.zip` archive to obtain an `.img` file.

## Choosing a kernel image

This repository contains three types of kernel images:

* `kernel-qemu-4.*.*-buster` are the most recent images, which are compatible
  with Raspbian Buster and Stretch. To use these images, you'll need the
  `versatile-pb.dtb` file which is also contained in this repository. Unless
  you are positive you need a different kernel, the most recent of these images
  is probably what you want.

* `kernel-qemu-4.*.*-stretch` are compatible with Raspbian Stretch and Jessie.
  To use these images, you'll need the `versatile-pb.dtb` file which is also
  contained in this repository. Unless you are positive you need a different
  kernel, the most recent of these images is probably what you want.

* `kernel-qemu-4.4.*-jessie` are images compatible with Raspbian Jessie and
  Wheezy.

* `kernel-qemu-3.10.25-wheezy` is the original image from [xecdesign.com],
  which is compatible with Raspbian Wheezy only.

## Using kernel images with QEMU

The QEMU command line will look like

    $ qemu-system-arm \
      -M versatilepb \
      -cpu arm1176 \
      -m 256 \
      -hda /.../2018-11-13-raspbian-stretch-lite.img \
      -net nic \
      -net user,hostfwd=tcp::5022-:22 \
      -dtb /.../versatile-pb.dtb \
      -kernel /.../kernel-qemu-4.14.79-stretch \
      -append 'root=/dev/sda2 panic=1' \
      -no-reboot

with the paths to the disk image, `.dtb` file and kernel image adjusted
appropriately.

## Using kernel images with libvirt

Assuming your libvirt version is at least 5.0.0, you can use something like

    $ virt-install \
      --name pi \
      --arch armv6l \
      --machine versatilepb \
      --cpu arm1176 \
      --vcpus 1 \
      --memory 256 \
      --import \
      --disk /.../2018-11-13-raspbian-stretch-lite.img,format=raw,bus=virtio \
      --network user,model=virtio \
      --video vga \
      --graphics spice \
      --rng device=/dev/urandom,model=virtio \
      --boot 'dtb=/.../versatile-pb.dtb,kernel=/.../kernel-qemu-4.14.79-stretch,kernel_args=root=/dev/vda2 panic=1' \
      --events on_reboot=destroy

to create a new libvirt guest called `pi`. You'll be able to manage the guest
with all the usual tools, such as `virsh` and `virt-manager`.

## Building your own kernel image

See the contents of the `tools/` directory, where the build scripts and
instructions on how to use them are stored.

## Origin of this repository

While searching the Internet for information on emulating a Raspberry Pi using
QEMU in Jun 2015, most of the guides pointed to kernel images hosted on
[xecdesign.com]; however, at the time the resource was no longer online, and
that's still the case as of Feb 2019.

This repository was initially created as a way to make those kernel images
available once again, and has since been expanded to provide improved and
up-to-date images.

## Further information

Additional documentation can be found on the [wiki].

[Raspbian image]: https://www.raspberrypi.org/downloads/raspbian/
[kernel sources]: https://github.com/raspberrypi/linux/
[xecdesign.com]: https://xecdesign.com/downloads/linux-qemu/kernel-qemu
[wiki]: https://github.com/dhruvvyas90/qemu-rpi-kernel/wiki