This page attempts to document running NetBSD/evbarm under the QEMU open source processor emulator. This can be extremely useful for development and testing.

Requirements

• qemu 4.1.0 or higher
• disk image
  • NetBSD 9.x armv7
  • NetBSD 9.x arm64
• Tianocore EDK2 firmware
  • QEMU_EFI.fd for armv7
  • QEMU_EFI.fd for arm64

Installing QEMU on NetBSD

You can install latest qemu with the following commands. It is assumed that your pkgsrc tree is in /usr/pkgsrc directory.

# cd /usr/pkgsrc/emulators/qemu
# make install

Preparing the disk image

The disk image (armv7.img.gz or arm64.img.gz) must first be uncompressed. The qemu-img tool can then resize the image to the desired size. On first boot, NetBSD will grow the root file-system to match the size of the disk.

$ gunzip arm64.img.gz
$ qemu-img resize arm64.img 20g

Booting the system (arm64)

$ qemu-system-aarch64 -M virt -cpu cortex-a53 -smp 4 -m 4g \
      -drive if=none,file=arm64.img,id=hd0 -device virtio-blk-device,drive=hd0 \
      -netdev type=user,id=net0 -device virtio-net-device,netdev=net0,mac=00:11:22:33:44:55 \
      -bios QEMU_EFI.fd -nographic

Booting the system (arm64) directly into the kernel with hardware accelerated virtualization on a Linux host

$ qemu-system-aarch64 -M virt,accel=kvm -cpu host -m 256 \
      -drive if=none,file=arm64.img,id=hd0 -device virtio-blk-device,drive=hd0 \
      -device virtio-rng-pci -kernel netbsd-GENERIC64.img -append "root=NAME=netbsd-root" \
      -netdev type=user,id=net0 -device virtio-net-device,netdev=net0,mac=00:11:22:33:44:55 \
      -display none -serial stdio

• As of today, a regular ELF kernel won't boot, use netbsd-GENERIC64.img (.img suffix)
• -device virtio-rng-pci is needed for the boot not to hang on Waiting for entropy...

Booting the system (armv7)

$ qemu-system-arm -M virt -cpu cortex-a15 -smp 4 -m 2g \
      -drive if=none,file=armv7.img,id=hd0 -device virtio-blk-device,drive=hd0 \
      -netdev type=user,id=net0 -device virtio-net-device,netdev=net0,mac=00:11:22:33:44:55 \
      -bios QEMU_EFI.fd -nographic

Enabling graphics support

To enable graphics support, remove the following command-line argument:

-nographic

and replace it with:

-display sdl,gl=on -device ramfb -device usb-ehci,id=ehci \
-device usb-mouse,bus=ehci.0 -device usb-kbd,bus=ehci.0

Bridged networking

To bridge a QEMU guest to your network, you need to create a tap(4) interface for your VM, then connect it to a physical interface with a bridge(4) interface.

The following example assumes NetBSD as a host OS, and a physical interface named bge0.

descr "LAN VM bridge" up
!brconfig bridge0 add bge0

link f2:0b:a4:d1:f2:69 descr "NetBSD Arm64 VM" up
!brconfig bridge0 add tap0

Then replace the -netdev part of the qemu command with:

-net nic -net tap,ifname=tap0,script=no