Running Android VMs on ARM: Rebuilding the Minisforum MS-R1 Kernel for Cuttlefish

Part 1: Getting a kernel suitable for virtual machines

The author wanted a box capable of running multiple Android instances simultaneously, utilizing native arm64 Android on arm64 silicon without any translation layer. The Minisforum MS-R1 seemed ideal, featuring a 12-core ARMv9 SoC and ample memory. Google's Cuttlefish, an official Android virtual device, supports arm64 Android guests on arm64 hosts with KVM acceleration.

However, the vendor had disabled the entire vhost subsystem, which is necessary for Cuttlefish to function. The shipped kernel, 6.6.10-cix-build-generic, lacked the CONFIG_VHOST_VSOCK symbol, preventing the creation of /dev/vhost-vsock. This crucial issue caused two traps: the first involved virtualization support and the second centered around the choice of a source tree for the kernel.

Part 2: Restoring virtualization support and choosing a source tree

To resolve the virtualization problem, the author needed to enable the vhost subsystem in the kernel. After exploring three options - mainline, cixtech/cix-linux-main, and cixtech/cix_opensource_linux - the author decided to go with cixtech/cix_opensource_linux, branch cix_p1_k6.6_master. This branch provides a full bootloader source tree for the CIX P1 architecture and uses the same 6.6 lineage as the shipped kernel.

The key challenge lay in booting the system, as the MS-R1 does not have a bootloader package or an EFI partition mounted. After some investigation, the author found the GRUB bootloader in the ESP (EFI System Partition) at /mnt/esp/EFI/BOOT/BOOTAA64.EFI. With the bootloader in place, the author could successfully boot the kernel and start running virtual machines using Cuttlefish on the Minisforum MS-R1.