Just a quick update before we dive in: what we're actually doing here is running Raspberry Pi OS (64-bit) on a QEMU virtual ARM setup. This isn't full-blown hardware emulation of the Raspberry Pi 4, but more about creating a virtual environment for the OS. It doesn't mimic all the specific hardware features of the Pi 4, but it's pretty useful and great for general testing. I turned to this solution mainly to extract a modified sysroot from the Raspberry Pi OS, something not readily available in other resources. For those looking into detailed emulation of the actual Raspberry Pi 4's hardware in QEMU, check out this link for the latest updates: https://gitlab.com/qemu-project/qemu/-/issues/1208.
Hope it helps! :D
Shortcomings: No GUI yet, only console.
- Download Raspberry Pi OS (64-bit) from Raspberry Pi operating system images.
Here we downloaded Raspberry Pi OS (64-bit) with desktop, Kernel version: 6.1, Debian version: 11 (bullseye), Release date: May 3rd 2023, named2023-05-03-raspios-bullseye-arm64.img. We put it in/home/mydir. - Install the required packages on your host system:
$ # Cross compilers for arm64 $ sudo apt install gcc-aarch64-linux-gnu g++-aarch64-linux-gnu $ # Qemu itself $ sudo apt install qemu qemubuilder qemu-system-gui qemu-system-arm qemu-utils \ qemu-system-data qemu-system
- Build the Linux kernel for qemu arm64 (You can download the kernel from Kernel.org):
$ wget https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-6.1.34.tar.xz $ tar xvJf linux-6.1.34.tar.xz $ cd linux-6.1.34 $ # create a .config file $ ARCH=arm64 CROSS_COMPILE=/bin/aarch64-linux-gnu- make defconfig $ # Use the kvm_guest config as the base defconfig, which is suitable for qemu $ ARCH=arm64 CROSS_COMPILE=/bin/aarch64-linux-gnu- make kvm_guest.config $ # Build the kernel $ ARCH=arm64 CROSS_COMPILE=/bin/aarch64-linux-gnu- make -j8 $ cp arch/arm64/boot/Image /home/mydir
- Mount the image for enabling ssh and configuring username and password:
- Get the correct offset value with the help of
fdiskutility:As we can see, we have two partitions inside the downloaded image. The first device (partition) is the bootable partition, and the second one is the root filesystem. The first partition is what will be mounted as$ fdisk -l 2023-05-03-raspios-bullseye-arm64.img Disk 2023-05-03-raspios-bullseye-arm64.img: 4.11 GiB, 4412407808 bytes, 8617984 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x3e247b30 Device Boot Start End Sectors Size Id Type 2023-05-03-raspios-bullseye-arm64.img1 8192 532479 524288 256M c W95 FAT32 (LBA) 2023-05-03-raspios-bullseye-arm64.img2 532480 8617983 8085504 3.9G 83 Linux/bootin Raspberry Pi, and this is where we'll need to create some files.
Obtain the correct offset of the first device by multiplying the start of the first partition (here 8192) by the sector size (here 512). Here it will be calculated as 8192 * 512 = 4194304 - Mount the image in
/mnt/rpidirectory:$ sudo mkdir /mnt/rpi $ sudo mount -o loop,offset=4194304 2023-05-03-raspios-bullseye-arm64.img /mnt/rpi
- Create a file named
sshto enable ssh:$ cd /mnt/rpi $ sudo touch ssh - Additionally, create a file named
userconf.txtin the same directory and put your desired username and password there, like<username>:<hashed-password>(might be better to leave the username aspi). This will be your default credentials:$ openssl passwd -6 # Generate the <hashed-password> $ echo 'pi:<hashed-password>' | sudo tee userconf.txt # Put them inside `userconf.txt`
- Finally, unmount the image:
$ sudo umount /mnt/rpi
- Get the correct offset value with the help of
- Run qemu emulator:
This machine will be able to access the internet.
$ cd /home/mydir $ qemu-system-aarch64 -machine virt -cpu cortex-a72 -smp 6 -m 4G \ -kernel Image -append "root=/dev/vda2 rootfstype=ext4 rw panic=0 console=ttyAMA0" \ -drive format=raw,file=2023-05-03-raspios-bullseye-arm64.img,if=none,id=hd0,cache=writeback \ -device virtio-blk,drive=hd0,bootindex=0 \ -netdev user,id=mynet,hostfwd=tcp::2222-:22 \ -device virtio-net-pci,netdev=mynet \ -monitor telnet:127.0.0.1:5555,server,nowait
- After the machine is completely booted up, you can login to it from your computer by using ssh and the username and password you specified:
$ ssh -l pi localhost -p 2222
- Done!
- If you had any problem with connecting to internet, it might be because of bad DNS configurations, and you should consider adding
nameserver 8.8.8.8to top of the file/etc/resolv.confin the machine. - You can access the qemu monitor console with:
$ telnet localhost 5555
Emulating
raspi3bis a bit easier than the genericvirtbecause we can simply extract thekernel8.8.imgfrom the raspberry image, without having to compile the linux kernel manually.qemu-system-aarch64 \ -machine raspi3b \ -cpu cortex-a72 \ -m 1G \ -smp 4 \ -sd ${IMAGE_FILE} \ -kernel ${KERNEL} \ -dtb ${DEVICE_TREE_BLOB} \ -append "rw earlyprintk loglevel=8 console=ttyAMA0,115200 dwc_otg.lpm_enable=0 root=/dev/mmcblk0p2 rootdelay=1" \ -netdev user,id=net0,hostfwd=tcp::2264-:22 \ -device usb-net,netdev=net0 \ -device usb-mouse -device usb-kbd \ -msg timestamp=onThe above command will also give you graphics if:
apton Debian.That version has a bug which prevents it from creating
/dev/fb0framebuffer, and without that bad boy you have no graphics.I went on a wild goose chase trying to compile the kernel with
CONFIG_DRM_FBDEV_EMULATION=yand similar params, but that wasn't the problem; the defaults are ok.With qemu v6.2.0 we see this error during boot:
pi@raspberrypi:/dev$ dmesg | grep -i fb [ 1.501182] bcm2708_fb soc:fb: Unable to determine number of FBs. Disabling driver. [ 1.501286] bcm2708_fb: probe of soc:fb failed with error -2buster.2021-05-07-raspios-buster-arm64.img- graphics work2024-07-04-raspios-bullseye-arm64.img- the logo appears, but after that the graphics don't. don't know why2024-07-04-raspios-bookworm-arm64.img- bookworm is even more tricky to get to work thanbullseye, even the console won't workBoth of these points are also mentioned here.
If you want to use
-machine virt, the advantage is you can give it more cores and ram. But you will need to find the right flags to attach graphics, because otherwise you will get just the console, and you'll see that the/dev/fb0is not there.