Throughout this post, I will document the process that was taken to run Ubuntu 22.04 on a Pixel Fold running Android 14 as an extension of the previous post. I leveraged an x86_64 Ubuntu 22.04 machine for this work. $ will be commands to run on your technician machine. # will be commands to run with su on the Android phone using a tool like adb shell or termux.

The primary goal of this is to be able to run the VM on the device without adb connected. LIkewise, we aim to be able to ssh into the device. Finally, the VM should be able to run docker.

Mount Directories

$ sudo mount kvm/vm-host.ext4 vm-host
$ sudo mount ./vm-host/ubuntu-rootfs.ext4 ubuntu-rootfs

Install Linux Kernel Modules

$ cp -r linux ./ubuntu-rootfs
$ chroot ./ubuntu-rootfs /bin/bash
$ apt install build-essential
$ cd /linux
$ make install
$ cd /
$ apt remove build-essential
$ rm -rf /linux
$ exit

Start VM Network Proxy at Boot

$ sudo vim ./ubuntu-rootfs/lib/systemd/system/gvisor-network-proxy.service

Set the value to the following

[Unit]
Description=gvisor network proxy
After=network.target

[Service]
ExecStart=/gvisor-tap-vsock/gvforwarder
Restart=on-failure

[Install]
WantedBy=multi-user.target

$ sudo chroot ./ubuntu-rootfs /bin/bash
$ systemctl enable gvisor-network-proxy
$ exit

Creating Android Scripts

Download curl-aarch64 from https://github.com/moparisthebest/static-curl and place it into the vm-host directory.

$ cd ./vm-host
$ sudo chmod +x ./curl-aarch64
$ sudo vim ./start-network.sh

Set the value to the following

#! /system/bin/sh

/storage/emulated/0/kvm/vm-host/gvisor-tap-vsock/gvproxy -listen vsock://:1024 -listen unix:///storage/emulated/0/kvm/vm-host/network.sock &
sleep 1
./curl-aarch64  --unix-socket /storage/emulated/0/kvm/vm-host/network.sock http:/unix/services/forwarder/expose -X POST -d '{"local":":22","remote":"192.168.127.2:22"}'

$ sudo chmod +x ./start-network.sh
$ sudo vim ./start-vm.sh

Set the value to the following

#! /system/bin/sh

/apex/com.android.virt/bin/crosvm run --disable-sandbox -p 'init=/sbin/init' --rwroot /storage/emulated/0/kvm/vm-host/ubuntu-rootfs.ext4 /storage/emulated/0/kvm/Image --vsock 3 --mem 10240 --cpus 10

$ sudo chmod +x ./start-vm.sh

Unmount Directories

$ umount ./ubuntu-rootfs $ umount ./vm-host

Prep the package for the phone

$ tar -cvf kvm.tar.gz ./kvm -I "pigz -9"

Prep the phone

$ adb push kvm.tar.gz /storage/emulated/0
# cd /storage/emulated/0
# tar -xvf kvm.tar.gz
# cd /storage/emulated/0/kvm
# mount vm-host.ext4 vm-host
# ./start-network.sh

Disconnect the phone from usb. Install Termux from F-Droid. In Termux:

# cd /storage/emulated/0/kvm/vm-host
# ./start-vm.sh

SSH into the Phone

Grab the IP Address of the phone from its setting page.

On your technician machine, ssh <user>@<phone IP>. You should be connected to a machine with the hostname android-vm.