How to Emulate Raspberry Pi Raspbian with Qemu

How to emulate Raspberry Pi Raspbian with QEMU?

You should expand the Raspbian Image file before starting

Mount the Raspbian Image file with kpartx (might have to install kpartx)

$ sudo kpartx -av your-image.img
add map loop0p1 (252:5): 0 117187 linear /dev/loop0 1
add map loop0p2 (252:6): 0 3493888 linear /dev/loop0 118784

$ sudo mount /dev/mapper/loop0p2 /mnt/img1
$ cd /mnt/img1

Modify the /etc/fstab and comment out the MMCBLK mounts

$ sudo nano etc/fstab

proc            /proc           proc    defaults          0       0
#/dev/mmcblk0p1  /boot           vfat    defaults          0       2
#/dev/mmcblk0p2  /               ext4    defaults,noatime  0       1
# a swapfile is not a swap partition, no line here
#   use  dphys-swapfile swap[on|off]  for that

Modify /etc/ld.so.preload and comment out lines ...

$ sudo nano etc/ld.so.preload

#/usr/lib/arm-linux-gnueabihf/libarmmem.so

Unmount and destroy loops from kpartx

$ sudo umount /mnt/img1
$ sudo kpartx -d your-image.img

Get the Qemu kernel matching the Raspbian image here...

https://github.com/dhruvvyas90/qemu-rpi-kernel

I used this command to successfully emulate Raspbian Jessie

qemu-system-arm -kernel kernel-qemu-4.4.12-jessie -cpu arm1176 -m 256 -M versatilepb \
-no-reboot -serial stdio -append "root=/dev/sda2 panic=1 rootfstype=ext4 rw" \
-redir tcp:5022::22 \
-hda 2016-05-27-raspbian-jessie-lite.img

How to emulate the Raspberry Pi 2 on QEMU?

If you're comfortable building qemu, you can find support for pi2 system emulation here: https://github.com/0xabu/qemu. It's not particularly speedy, and the device emulations are incomplete, but you can resize the RAM and framebuffer.

There are brief instructions for booting Raspbian at the end of https://github.com/0xabu/qemu/wiki

Is there a Raspberry Pi hardware emulator that supports custom ISOs?

For most of the complex hardware (i.e. CPU, GPU, RAM, network cards, disks and so on), qemu has you covered, there also seem to be a --machine raspi3b flag that's supposed to be close to a Raspberry Pi 3B but I can't find any information about what is included exactly.

If you want to emulate some other raspi, you can use qemu-system-aarch64 --machine help to list all 64bits ARM devices that can be emulated by qemu (note that as of writing this, qemu has no support for the raspi4).

If the emulation offered by qemu doesn't include some hardware you want, a lot of things can be emulated using dummy kernel modules such as the GPIO mockup driver as explained here and the mac80211_hwsim module. It's probably not as close to the hardware as you'd like though, if you prefer a more hands on approach you could create qemu "hardware" to be a perfect replica of the pi.

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