Minos - A lightweight open source Type 1 Hypervisor for mobile and embedded systems

Minos - Type 1 Hypervisor for ARMv8-A

Minos is a lightweight open source Type 1 Hypervisor for mobile and embedded systems that runs directly in bare metal environments. Minos implements a complete virtualization framework that can run multiple VMs (Linux or RTOS) on one hardware platform. Minos provides CPU virtualization; interrupt virtualization; memory virtualization; Timer virtual ; and the virtualization of some common peripherals.

Minos provides an application “mvm” running on VM0 to support the management of the Guest VM. At the same time, mvm provides a viviro-based paravirtualization solution that supports virtio-console, virtio-blk (in testing), virtio-net (in testing) and other devices.

Minos is suitable for mobile and embedded platforms and currently only supports the ARMv8-A architecture. Marvell’s Esspressobin development board is supported, and the hardware platform of the ARMv8-A + GICV3 combination can theoretically be supported. The software debugging platform supports ARM’s official Fix Virtual Platform (FVP), and developers can use ARM DS5 tools for simulation and debugging.

All the code is placed in https://github.com/minos-project. Welcome friends who are interested in virtualization to help support more development boards and modules. :grinning:

Download Source Code And Tools for Minos

  1. Create a working directory

     # mkdir ~/minos-workspace
     # cd ~/minos-workspace
  2. Install aarch64 gcc cross compilation tool

     # wget https://releases.linaro.org/components/toolchain/binaries/latest/aarch64-linux-gnu/gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu.tar.xz
     # tar xjf gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu.tar.xz
     # sudo mv gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu /opt
     # echo "export PATH=/opt/gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu/bin:$PATH" >> ~/.bashrc
     # source ~/.bashrc
  3. Install abootimg android image tool

     # sudo apt-get install abootimg

    The abootimg tool is used to make the bootimge of the Linux VM. mvm uses this format image to load the linux kernel, ramdisk and dtb files.

  4. Install devicetree tool

     # sudo apt-get install device-tree-compiler
  5. Download Minos sample

     # git clone https://github.com/minos-project/minos-samples.git

    The minos-sample provides the dts/dtb file of the Guest VM and the created Guest VM boot.img file.

  6. Download Minos hypervisor source code

     # git clone https://github.com/minos-project/minos-hypervisor.git
  7. Download Linux Kernel source code

     # git clone https://github.com/minos-project/linux-marvell.git
     # cd linux-marvell
     # git checkout -b minos origin/minos

    The default download is the Marvell linux kernel source which added the Minos kernel driver. If you are using another hardware platform, just add the Minos driver. The following command can get the Minos driver and the necessary Kernel Patch.

     # git clone  https://github.com/minos-project/minos-linux-driver.git
  8. Download the ATF source code

     # git clone https://github.com/ARM-software/arm-trusted-firmware.git

    Will be used when testing Minos on the ARM FVP

Run Minos on Marvell Esspressobin

  1. Compile Minos

     # cd ~/minos-workspace/minos
     # make

    The default platform for Minos is Marvel Esspressobin. After the compilation is completed, minos.bin will be generated in the hypervisor/out directory and the mvm application will be generated in the mvm directory.

  2. Compile Marvell Linux Kernel

     # cd ~/minos-workspace/linux-marvell
     # export ARCH=arm64
     # export CROSS_COMPILE=aarch64-linux-gnu-
     # make mvebu_v8_lsp_defconfig
     # make -j4

    After the compilation is complete, the kernel binary image will be generated in the arch/arm64/boot directory.

  3. The default kernel of Esspressobin is stored in the /boot directory of the development board. Copy the minos.bin and the new Kernel Image to the /boot directory, and copy the mvm application to the user root directory of the development board.

  4. Update Uboot boot settings of the development board

    Start the development board to the command line environment, execute the following command to update the Uboot startup settings (here is the example of the EMMC version of the Esspressobin).

     # setenv bootcmd “mmc dev 1; ext4load mmc 1:1 0x3c000000 boot/minos.bin; ext4load mmc 1:1 0x280000 boot/Image; ext4load mmc 1:1 0xfe00000 boot/armada-3720-community-v5.dtb; setenv bootargs console=ttyMV0,115200 earlycon=ar3700_uart,0xd0012000 root=PARTUUID=89708921-01 rw rootwait net.ifnames=0 biosdevname=0; booti 0x3c000000 - 0xfe00000”
     # saveenv
  5. After the setup is complete, restart the development board, then every time the board startup, it will first jump to the Minos to execute virtualization related settings, and then start VM0.

    Tip: If the system cannot be started because of the Minos code error, just start the non-virtualized environment with the original startup parameters, and then replace the right minos.bin to the /boot directory.

     # mmc dev 1; ext4load mmc 1:1 $kernel_addr $image_name; ext4load mmc 1:1 $fdt_addr $fdt_name; setenv bootargs $console root=PARTUUID=89708921-01 rw rootwait net.ifnames=0 biosdevname=0; booti $kernel_addr - $fdt_addr

Run Minos on ARM FVP

  1. Download ARM FVP and create a working directory

     # mkdir ~/minos-workspace/arm-fvp

    FVP can be downloaded from ARM’s official website. Minos supports FVP_Base_AEMv8A and FVP_Base_Cortex-A57x2-A53x4. Here we use FVP_Base_AEMv8A to do the testing. In addition, if you want to do related development based on Minos, you can also directly install the ARM DS5 debugging tool, and bring the above two FVPs after installation. The following is a tutorial on installing and using DS5.

  1. Compile Minos

     # cd ~/minos-workspace/minos
     # make distclean  (Need to execute before changing the compile target)
     # make PLATFORM=fvp
  2. Compile FVP Kernel

     # cd ~/minos-workspace/minos
     # make ARCH=arm64 defconfig && make ARCH=arm64 -j8 Image
  3. Compile ARM Trusted Firmware

     # cd ~/minos-workspace/arm-trusted-firmware
  4. Download ARM64 virtio-block image

     # cd ~/minos-workspace
     # wget https://releases.linaro.org/archive/14.07/openembedded/aarch64/vexpress64-openembedded_minimal-armv8-gcc-4.9_20140727-682.img.gz
     # gunzip vexpress64-openembedded_minimal-armv8-gcc-4.9_20140727-682.img.gz
     # mv vexpress64-openembedded_minimal-armv8-gcc-4.9_20140727-682.img sd.img
  5. Run FVP with Minos

     # cd ~/minos-workspace/arm-fvp
     # ln -s ~/minos-workspace/sd.img sd.img
     # ln -s ~/minos-workspace/arm-trusted-firmware/build/fvp/release/bl31.bin bl31.bin
     # ln -s ~/minos-workspace/linux-marvell/arch/arm64/boot/Image Image
     # ln -s ~/minos-workspace/minos-sample/foundation-v8-gicv3.dtb fdt.dtb
     # ln -s ~/minos-workspace/minos/hypervisor/out/minos.bin minos.bin
     # /usr/local/DS-5_v5.27.0/bin/FVP_Base_AEMv8A               \
     -C pctl.startup=                                     \
     -C bp.secure_memory=0                                       \
     -C cluster0.NUM_CORES=4                                     \
     -C cache_state_modelled=1                                   \
     -C cluster0.cpu0.RVBAR=0x04020000                           \
     -C cluster0.cpu1.RVBAR=0x04020000                           \
     -C cluster0.cpu2.RVBAR=0x04020000                           \
     -C cluster0.cpu3.RVBAR=0x04020000                           \
     -C bp.hostbridge.userNetPorts="8022=22"                     \
     -C bp.hostbridge.userNetworking=true                        \
     -C bp.dram_size=8                                           \
     -C bp.smsc_91c111.enabled=true                              \
     -C bp.virtioblockdevice.image_path=sd.img                   \
     --data cluster0.cpu0=bl31.bin@0x04020000                    \
     --data cluster0.cpu0=fdt.dtb@0x83e00000                     \
     --data cluster0.cpu0=Image@0x80080000                       \
     --data cluster0.cpu0=minos.bin@0xc0000000
  6. After starting FVP, you can run the following command on the host to log in to FVP through ssh.

     # ssh -p 8022 root@

MVM usage

Minos provides two ways to create a VM. One is to use the JSON file under the Minos source (for example, hypervisor/config/fvp/fvp.json.cc) to create a corresponding VM by creating a json member of the vmtag. VM memory, IRQ and other hardware resources are managed by the corresponding json file. This method is suitable for creating VMs with real hardware permissions in embedded systems. Minos supports assigning specific hardware devices to specific VMs. VMs created this way are currently not managed by mvm.

#include "fvp_config.h"
	"version": "0.0.1",
	"platform": "armv8-fvp",

	"vmtags": [
			"vmid": 0,
			"name": "linux-01",
			"type": "linux",
			"nr_vcpu": 1,
			"entry": "0x80080000",
			"setup_data": "0x83e00000",
			"vcpu0_affinity": 0,
			"vcpu1_affinity": 1,
			"vcpu2_affinity": 2,
			"vcpu3_affinity": 3,
			"cmdline": "",
			"bit64": 1
	#include "fvp_irq.json.cc"
	#include "fvp_mem.json.cc"

	"others" : {
		"comments": "minos virtualization config json data"

Another way is to use the VM management tool mvm provided by Minos. Currently mvm already supports VM creation, destruction, restart and shutdown operations.

    Usage: mvm [options]

    -c <vcpu_count>            (set the vcpu numbers of the vm)
    -m <mem_size_in_MB>        (set the memsize of the vm - 2M align)
    -i <boot or kernel image>  (the kernel or bootimage to use)
    -s <mem_start>             (set the membase of the vm if not a boot.img)
    -n <vm name>               (the name of the vm)
    -t <vm type>               (the os type of the vm )
    -b <32 or 64>              (32bit or 64 bit )
    -r                         (do not load ramdisk image)
    -v                         (verbose print debug information)
    -d                         (run as a daemon process)
    -D                         (device argument)
    -C                         (set the cmdline for the os)

For example, the following command is used to create a Linux virtual machine with 2 vcpu, 84M memory, bootimage as boot.img, and 64-bit (current Minos only supports 64-bit VM) with virtio-console device.

    #./mvm -c 2 -m 84M -i boot.img -n elinux -t linux -b 64 -v -d -C "console=hvc0 loglevel=8 consolelog=9 loglevel=8 consolelog=9" -D virtio_console,@pty:

If the creation is successful, the following log output will be generated.

    [INFO ] no rootfs is point using ramdisk if exist
    root@genericarmv8:~# [INFO ] boot image infomation :
    [INFO ] magic        - ANDROID!
    [INFO ] kernel_size  - 0x877800
    [INFO ] kernel_addr  - 0x80080000
    [INFO ] ramdisk_size - 0x104e21
    [INFO ] ramdisk_addr - 0x83000000
    [INFO ] dtb_size     - 0xcc4
    [INFO ] dtb_addr     - 0x83e00000
    [INFO ] tags_addr    - 0x0
    [INFO ] page_size    - 0x800
    [INFO ] name         -
    [INFO ] cmdline      - console=hvc0 loglevel=8 consolelog=9
    [INFO ] create new vm *
    [INFO ]         -name       : elinux
    [INFO ]         -os_type    : linux
    [INFO ]         -nr_vcpus   : 2
    [INFO ]         -bit64      : 1
    [INFO ]         -mem_size   : 0x5400000
    [INFO ]         -mem_start  : 0x80000000
    [INFO ]         -entry      : 0x80080000
    [INFO ]         -setup_data : 0x83e00000
    [DEBUG] load kernel image: 0x80000 0x800 0x877800
    [DEBUG] load ramdisk image:0x3000000 0x878000 0x104e21
    [DEBUG] vdev : irq-32 gpa-0x7fad895000 gva-0x40000000
    [INFO ] ***********************************************
    [INFO ] virt-console backend redirected to /dev/pts/1
    [INFO ] ***********************************************
    [INFO ] add cmdline - console=hvc0 loglevel=8 consolelog=9 loglevel=8 consolelog=9
    [INFO ]         - delete cpu@2
    [INFO ]         - delete cpu@3
    [INFO ]         - delete cpu@4
    [INFO ]         - delete cpu@5
    [INFO ]         - delete cpu@6
    [INFO ]         - delete cpu@7
    [DEBUG] found 1 rsv memory region
    [DEBUG] add rsv memory region : 0x80000000 0x10000
    [INFO ] setup memory 0x0 0x80 0x0 0x4005
    [INFO ] set ramdisk : 0x83000000 0x104e21
    [INFO ] add vdev success addr-0x40000000 virq-32

Minos currently supports the virtio-console backend driver. After creating the VM, you can log in to the VM with terminal tools such as minicom. (In FVP, you need to wait for a while. The VM startup speed depends on the performance of the host. You can turn off the FVP’s cache to speed up the startup.)

    # minicom /dev/pts/1

Make a custom bootimage

The default ramdisk.img in the boot.img provided by Minos is based on the default rootfs configuration of the busybox. If you need to customize your own ramdisk, it is also very simple. You only need to repackage the ramdisk.img, Image and dtb file.

    # dtc -I dts -O dtb -o guest-vm.dtb guest-vm.dts
    # abootimg --create boot.img -c kerneladdr=0x80080000 -c ramdiskaddr=0x83000000 -c secondaddr=0x83e00000 -c cmdline="console=hvc0 loglevel=8 consolelog=9" -k Image -s guest-vm.dtb -r ramdisk.img

Is there an architectural decision that makes GICv2 support impossible? Very few of the current family of 96Boards have both GICv3 and virtualization support.

GICV2 support virtualization, but there is no plan to support GICv2 recently. may add GICv2 support after all the virtio device is enabled.