Unsupported configuration error when creating vagrant VM libvirt provider - arm

Question

I am creating an Ubuntu 20.04 server vagrant base box for libvirt provider for arm64 platform. I already created a base box from a qcow2 image file.
When trying to create the vagrant box with vagrant up command I get the error at the end of the output:
Bringing machine 'ubuntu-vm' up with 'libvirt' provider...
==> ubuntu-vm: Creating image (snapshot of base box volume).
==> ubuntu-vm: Creating domain with the following settings...
==> ubuntu-vm: -- Name: vagrant-vm_ubuntu-vm
==> ubuntu-vm: -- Domain type: kvm
==> ubuntu-vm: -- Cpus: 1
==> ubuntu-vm: -- Memory: 512M
==> ubuntu-vm: -- Management MAC:
==> ubuntu-vm: -- Loader:
==> ubuntu-vm: -- Nvram:
==> ubuntu-vm: -- Base box: ubuntu20.04-arm64
==> ubuntu-vm: -- Storage pool: default
==> ubuntu-vm: -- Image: /var/lib/libvirt/images/vagrant-vm_ubuntu-vm.img (10G)
==> ubuntu-vm: -- Volume Cache: default
==> ubuntu-vm: -- Kernel:
==> ubuntu-vm: -- Initrd:
==> ubuntu-vm: -- Graphics Type: vnc
==> ubuntu-vm: -- Graphics Port: -1
==> ubuntu-vm: -- Graphics IP: 127.0.0.1
==> ubuntu-vm: -- Graphics Password: Not defined
==> ubuntu-vm: -- Video Type: cirrus
==> ubuntu-vm: -- Video VRAM: 9216
==> ubuntu-vm: -- Sound Type:
==> ubuntu-vm: -- Keymap: en-us
==> ubuntu-vm: -- TPM Path:
==> ubuntu-vm: -- INPUT: type=mouse, bus=ps2
==> ubuntu-vm: Creating shared folders metadata...
==> ubuntu-vm: Starting domain.
There was an error talking to Libvirt. The error message is shown below:
Call to virDomainCreateWithFlags failed: unsupported configuration: CPU mode 'host-model' for aarch64 kvm domain on aarch64 host is not supported by hypervisor
My Vagrantfile is:
UbuARM = "ubuntu20.04-arm64"
Vagrant.configure("2") do |config|
config.vm.define "ubuntu-vm" do |nodeconfig|
nodeconfig.vm.box = UbuARM
nodeconfig.vm.hostname = "ubuntu-vm"
nodeconfig.vm.network :public_network,
bridge: "br0",
dev: "br0",
mode: "bridge",
type: "bridge"
nodeconfig.vm.provider :libvirt do |libvirt|
libvirt.uri="qemu:///system"
libvirt.storage_pool_name = "default"
libvirt.storage_pool_path = "/var/lib/libvirt/images"
libvirt.features = [] # had to put this to solve some error
end
end
end

Answer 1

In most cases, qemu for ARM64 does not support vagrant's default options.
In this case default value for cpu_mode is 'host-model', which is not supported in the architecture. You may use 'host-passthrough'.
TIP: for anyone trying to virtualize using vagrant-libvirt in ARM64 I recommend dumping libvirt XML domain definition and replicate it with vagrant-libvirt plugin options.
These options were useful to me:
libvirt.features = ["apic", "gic version='2'"]
libvirt.machine_type = "virt-5.2"
libvirt.machine_arch = "aarch64"
libvirt.loader = "/usr/share/AAVMF/AAVMF_CODE.fd"
libvirt.cpu_mode = "host-passthrough"
libvirt.input :type => "mouse", :bus => "usb"
libvirt.input :type => "keyboard", :bus => "usb"
libvirt.usb_controller :model => "qemu-xhci"
libvirt.video_type = "vga"
libvirt.channel :type => 'unix', :target_type => 'virtio', :target_name => 'org.qemu.guest_agent.0', :target_port => '1', :source_path => '/var/lib/libvirt/qemu/channel/target/domain-1-ubuntu20.04/org.qemu.guest_agent.0', :source_mode => 'bind'