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Linux Lab

This project aims to create a Qemu-based Linux development Lab to easier the learning, development and testing of Linux Kernel.

For Linux 0.11, please try our Linux 0.11 Lab.

Docker Qemu Linux Lab



About 9 years ago, a tinylinux proposal: Work on Tiny Linux Kernel accepted by embedded linux foundation, therefore I have worked on this project for serveral months.

During the project cycle, several scripts written to verify if the adding tiny features (e.g. gc-sections) breaks the other kernel features on the main cpu architectures.

These scripts uses qemu-system-ARCH as the cpu/board simulator, basic boot+function tests have been done for ftrace+perf, accordingly, defconfigs, rootfs, test scripts have been prepared, at that time, all of them were simply put in a directory, without a design or holistic consideration.

They have slept in my harddisk for several years without any attention, untill one day, docker and novnc came to my world, at first, Linux 0.11 Lab was born, after that, Linux Lab was designed to unify all of the above scripts, defconfigs, rootfs and test scripts.

Now, Linux Lab becomes an intergrated Linux learning, development and testing environment, it supports:

Boards: Qemu based, 6+ main Architectures, 10+ popular boards, one make list command for all boards, qemu options are hidden. Components: Uboot, Linux / Modules, Buildroot, Qemu are configurable, patchable, compilable, buildable, Linux v5.1 supported. Prebuilt: all of above components have been prebuilt and put in board specific bsp submodule for instant using, qemu v2.12.0 prebuilt for arm/arm64. Rootfs: Builtin rootfs support include initrd, harddisk, mmc and nfs, configurable via ROOTDEV/ROOTFS, Ubuntu 18.04 for ARM available as docker image: tinylab/armv32-ubuntu. Docker: Environment (cross toolchains) available in one command in serveral minutes, 5 main architectures have builtin support, external ones configurable via make toolchain. Browser: usable via modern web browsers, once installed in a internet server, available everywhere via web vnc or web ssh. Network: Builtin bridge networking support, every board support network. Boot: Support serial port, curses (ssh friendly) and graphic booting. Testing: Support automatic testing via make test target. Debugging: debuggable via make debug target.

Continue reading for more features and usage.


See: http://tinylab.org/linux-lab/




Install docker

Docker is required by Linux Lab, please install it at first:


In order to run docker without password, please make sure your user is added in the docker group:

$ sudo usermod -aG docker $USER

In order to speedup docker images downloading, please configure a local docker mirror in /etc/default/docker, for example:

$ grep registry-mirror /etc/default/docker
DOCKER_OPTS="$DOCKER_OPTS --registry-mirror=https://docker.mirrors.ustc.edu.cn"
$ service docker restart

If still have errors like 'Client.Timeout exceeded while waiting headers', please try the other docker mirror sites:

In order to avoid network ip address conflict, please try following changes and restart docker:

$ grep bip /etc/default/docker
$ service docker restart

If the above changes not work, try something as following:

$ grep dockerd /lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd -H fd:// --bip= --registry-mirror=https://docker.mirrors.ustc.edu.cn
$ service docker restart

For Ubuntu 12.04, please install the new kernel at first, otherwise, docker will not work:

$ sudo apt-get install linux-generic-lts-trusty

Choose a working directory

If installed via Docker Toolbox, please enter into the /mnt/sda1 directory of the default system on Virtualbox, otherwise, after poweroff, the data will be lost for the default /root directory is only mounted in DRAM.

$ cd /mnt/sda1

For Linux, please simply choose one directory in ~/Downloads or ~/Documents.

$ cd ~/Documents

For Mac OSX, to compile Linux normally, please create a case sensitive filesystem as the working space at first:

$ hdiutil -type SPARSE create -size 60g -fs "Case-sensitive Journaled HFS+" -volname labspace labspace.dmg
$ hdiutil attach -mountpoint ~/Documents/labspace -no-browse labspace.dmg
$ cd ~/Documents/labspace

Download the lab

Use Ubuntu system as an example:

Download cloud lab framework, pull images and checkout linux-lab repository:

$ git clone https://gitee.com/tinylab/cloud-lab.git
$ cd cloud-lab/ && tools/docker/choose linux-lab

Run and login the lab

Launch the lab and login with the user and password printed in the console:

$ tools/docker/run linux-lab

Re-login the lab via web browser:

$ tools/docker/vnc linux-lab

The other login methods:

$ tools/docker/webvnc linux-lab   # The same as tools/docker/vnc
$ tools/docker/webssh linux-lab
$ tools/docker/ssh linux-lab
$ tools/docker/bash linux-lab

Summary of login methods:

Login Method Description Default User Where
webvnc/vnc web desktop ubuntu anywhere via internet
webssh web ssh ubuntu anywhere via internet
ssh normal ssh ubuntu localhost
bash docker bash root localhost

Update and rerun the lab

If want a newer version, we must back up any local changes at first, and then update everything:

$ tools/docker/update linux-lab

If fails, please try to clean up the containers:

$ tools/docker/rm-full

Or even clean up the whole environments:

$ tools/docker/clean-all

Quickstart: Boot a board

Issue the following command to boot the prebuilt kernel and rootfs on the default vexpress-a9 board:

$ make boot

Login as 'root' user without password(password is empty), just input 'root' and press Enter:

Welcome to Linux Lab

linux-lab login: root

# uname -a
Linux linux-lab 5.1.0 #3 SMP Thu May 30 08:44:37 UTC 2019 armv7l GNU/Linux


Using boards

List available boards

List builtin boards:

$ make list
[ aarch64/raspi3 ]:
      ARCH     = arm64
      CPU     ?= cortex-a53
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/mmcblk0
[ aarch64/virt ]:
      ARCH     = arm64
      CPU     ?= cortex-a57
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/vda
[ arm/versatilepb ]:
      ARCH     = arm
      CPU     ?= arm926t
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/ram0
[ arm/vexpress-a9 ]:
      ARCH     = arm
      CPU     ?= cortex-a9
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/ram0
[ i386/pc ]:
      ARCH     = x86
      CPU     ?= i686
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/ram0
[ mipsel/malta ]:
      ARCH     = mips
      CPU     ?= mips32r2
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/ram0
[ ppc/g3beige ]:
      ARCH     = powerpc
      CPU     ?= generic
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/ram0
[ riscv32/virt ]:
      ARCH     = riscv
      CPU     ?= any
      LINUX   ?= v5.0.13
      ROOTDEV ?= /dev/vda
[ riscv64/virt ]:
      ARCH     = riscv
      CPU     ?= any
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/vda
[ x86_64/pc ]:
      ARCH     = x86
      CPU     ?= x86_64
      LINUX   ?= v5.1
      ROOTDEV ?= /dev/ram0

Choosing a board

By default, the default board: 'vexpress-a9' is used, we can configure, build and boot for a specific board with 'BOARD', for example:

$ make BOARD=malta
$ make boot

If using board, it only works on-the-fly, the setting will not be saved, this is helpful to run multiple boards at the same and not to disrupt each other:

$ make board=malta boot

This allows to run multi boards in different terminals or background at the same time.

Check the board specific configuration:

$ cat boards/arm/vexpress-a9/Makefile

Using as plugins

The 'Plugin' feature is supported by Linux Lab, to allow boards being added and maintained in standalone git repositories. Standalone repository is very important to ensure Linux Lab itself not grow up big and big while more and more boards being added in.

Book examples or the boards with a whole new cpu architecture benefit from such feature a lot, for book examples may use many boards and a new cpu architecture may need require lots of new packages (such as cross toolchains and the architecture specific qemu system tool).

Here maintains the available plugins:


Download board specific package and the kernel, buildroot source code:

$ make core-source -j3

Download one by one:

$ make bsp-source
$ make kernel-source
$ make root-source

Checking out

Checkout the target version of kernel and builroot:

$ make checkout

Checkout them one by one:

$ make kernel-checkout
$ make root-checkout

If checkout not work due to local changes, save changes and run to get a clean environment:

$ make kernel-cleanup
$ make root-cleanup

The same to qemu and uboot.


Apply available patches in boards/<BOARD>/bsp/patch/linux and patch/linux/:

$ make kernel-patch


Default Configuration

Configure kernel and buildroot with defconfig:

$ make config

Configure one by one, by default, use the defconfig in boards/<BOARD>/bsp/:

$ make kernel-defconfig
$ make root-defconfig

Configure with kernel patching:

$ make kernel-defconfig KP=1
$ make root-defconfig RP=1

Configure with specified defconfig:

$ make B=raspi3
$ make kernel-defconfig KCFG=bcmrpi3_defconfig
$ make root-defconfig KCFG=raspberrypi3_64_defconfig

If only defconfig name specified, search boards/ at first, and then the default configs path of buildroot, u-boot and linux-stable respectivly: buildroot/configs, u-boot/configs, linux-stable/arch//configs.

Manual Configuration

$ make kernel-menuconfig
$ make root-menuconfig

Old default configuration

$ make kernel-olddefconfig
$ make root-olddefconfig
$ make uboot-oldefconfig


Build kernel and buildroot together:

$ make build

Build them one by one:

$ make kernel
$ make root


Save all of the configs and rootfs/kernel/dtb images:

$ make save

Save configs and images to boards/<BOARD>/bsp/:

$ make kernel-saveconfig
$ make root-saveconfig

$ make root-save
$ make kernel-save


Boot with serial port (nographic) by default, exit with 'CTRL+a x', 'poweroff', 'reboot' or 'pkill qemu' (See poweroff hang):

$ make boot

Boot with graphic (Exit with 'CTRL+ALT+2 quit'):

$ make b=pc boot G=1 LINUX=v5.1
$ make b=versatilepb boot G=1 LINUX=v5.1
$ make b=g3beige boot G=1 LINUX=v5.1
$ make b=malta boot G=1 LINUX=v2.6.36
$ make b=vexpress-a9 boot G=1 LINUX=v4.6.7 // LINUX=v3.18.39 works too

Note: real graphic boot require LCD and keyboard drivers, the above boards work well, with linux v5.1, raspi3 and malta has tty0 console but without keyboard input.

vexpress-a9 and virt has no LCD support by default, but for the latest qemu, it is able to boot with G=1 and switch to serial console via the 'View' menu, this can not be used to test LCD and keyboard drivers. XOPTS specify the eXtra qemu options.

$ make b=vexpress-a9 CONSOLE=ttyAMA0 boot G=1 LINUX=v5.1
$ make b=raspi3 CONSOLE=ttyAMA0 XOPTS="-serial vc -serial vc" boot G=1 LINUX=v5.1

Boot with curses graphic (friendly to ssh login, not work for all boards, exit with 'ESC+2 quit' or 'ALT+2 quit'):

$ make b=pc boot G=2

Boot with prebuilt kernel and rootfs (if no new available, simple use make boot):

$ make boot PBK=1 PBD=1 PBR=1

Boot with new kernel, dtb and rootfs if exists (if new available, simple use make boot):

$ make boot PBK=0 PBD=0 PBR=0

Boot without Uboot (only versatilepb and vexpress-a9 boards tested):

$ make boot U=0

Boot with different rootfs (depends on board, check /dev/ after boot):

$ make boot ROOTDEV=/dev/ram      // support by all boards, basic boot method
$ make boot ROOTDEV=/dev/nfs      // depends on network driver, only raspi3 not work
$ make boot ROOTDEV=/dev/sda
$ make boot ROOTDEV=/dev/mmcblk0
$ make boot ROOTDEV=/dev/vda      // virtio based block device

Boot with extra kernel command line (XKCLI = eXtra Kernel Command LIne):

$ make boot ROOTDEV=/dev/nfs XKCLI="init=/bin/bash"

List supported options:

$ make list-ROOTDEV
$ make list-BOOTDEV
$ make list-CCORI
$ make list-NETDEV
$ make list-LINUX
$ make list-UBOOT
$ make list-QEMU

And more 'xxx-list' are also supported with 'list-xxx', for example:

$ make list-features
$ make list-modules
$ make list-gcc



non-interactive configuration

A tool named scripts/config in linux kernel is helpful to get/set the kernel config options non-interactively, based on it, both of kernel-getconfig/k-gc and kernel-setconfig/k-sc are added to tune the kernel options, with them, we can simply "enable/disable/setstr/setval/getstate" of a kernel option or many at the same time:

Get state of a kernel module:

$ make kernel-getconfig m=minix_fs
Getting kernel config: MINIX_FS ...


Enable a kernel module:

$ make kernel-setconfig m=minix_fs
Setting kernel config: m=minix_fs ...


Enable new kernel config: minix_fs ...

More control commands of kernel-setconfig including y, n, c, o, s, v:

`y`, build the modules in kernel or enable anther kernel options.
`c`, build the modules as pluginable modules, just like `m`.
`o`, build the modules as pluginable modules, just like `m`.
`n`, disable a kernel option.
`s`, `RTC_SYSTOHC_DEVICE="rtc0"`, set the rtc device to rtc0
`v`, `v=PANIC_TIMEOUT=5`, set the kernel panic timeout to 5 secs.

Operates many options in one command line:

$ make k-sc m=tun,minix_fs y=ikconfig v=panic_timeout=5 s=DEFAULT_HOSTNAME=linux-lab n=debug_info
$ make k-gc o=tun,minix,ikconfig,panic_timeout,hostname
using kernel modules

Build all internel kernel modules:

$ make modules
$ make modules-install
$ make root-rebuild     // not need for nfs boot
$ make boot

List available modules in modules/, boards/<BOARD>/bsp/modules/:

$ make m-l

If m argument specified, list available modules in modules/, boards/<BOARD>/bsp/modules/ and linux-stable/:

$ make m-l m=hello
     1	m=hello ; M=$PWD/modules/hello
$ make m-l m=tun,minix
     1	c=TUN ; m=tun ; M=drivers/net
     2	c=MINIX_FS ; m=minix ; M=fs/minix

Enable one kernel module:

$ make kernel-getconfig m=minix_fs
Getting kernel config: MINIX_FS ...


$ make kernel-setconfig m=minix_fs
Setting kernel config: m=minix_fs ...


Enable new kernel config: minix_fs ...

Build one kernel module (e.g. minix.ko):

$ make m M=fs/minix/
$ make m m=minix

Install and clean the module:

$ make m-i M=fs/minix/
$ make m-c M=fs/minix/

More flexible usage:

$ make kernel-setconfig m=tun
$ make kernel x=tun.ko M=drivers/net
$ make kernel x=drivers/net/tun.ko
$ make kernel-run drivers/net/tun.ko

Build external kernel modules (the same as internel modules):

$ make m m=hello
$ make k x=$PWD/modules/hello/hello.ko
using kernel features

Kernel features are abstracted in `feature/linux/, including their configurations patchset, it can be used to manage both of the out-of-mainline and in-mainline features.

$ make f-l
[ feature/linux ]:
  + 9pnet
  + core
    - debug
    - module
  + ftrace
    - v2.6.36
      * env.g3beige
      * env.malta
      * env.pc
      * env.versatilepb
    - v2.6.37
      * env.g3beige
  + gcs
    - v2.6.36
      * env.g3beige
      * env.malta
      * env.pc
      * env.versatilepb
  + kft
    - v2.6.36
      * env.malta
      * env.pc
  + uksm
    - v2.6.38

Verified boards and linux versions are recorded there, so, it should work without any issue if the environment not changed.

For example, to enable kernel modules support, simply do:

$ make f f=module
$ make kernel-olddefconfig
$ make kernel

For kft feature in v2.6.36 for malta board:

$ make BOARD=malta
$ export LINUX=v2.6.36
$ make kernel-checkout
$ make kernel-patch
$ make kernel-defconfig
$ make f f=kft
$ make kernel-olddefconfig
$ make kernel
$ make boot


Choose one of the tested boards: versatilepb and vexpress-a9.

$ make BOARD=vexpress-a9

Download Uboot:

$ make uboot-source

Checkout the specified version:

$ make uboot-checkout

Patching with necessary changes, BOOTDEV and ROOTDEV available, use tftp by default.

$ make uboot-patch

Use tftp, sdcard or flash explicitly, should run make uboot-checkout before a new uboot-patch:

$ make uboot-patch BOOTDEV=tftp
$ make uboot-patch BOOTDEV=sdcard
$ make uboot-patch BOOTDEV=flash

BOOTDEV is used to specify where to store and load the images for uboot, ROOTDEV is used to tell kernel where to load the rootfs.


$ make uboot-defconfig
$ make uboot-menuconfig


$ make uboot

Boot with BOOTDEV and ROOTDEV, use tftp by default:

$ make boot U=1

Use tftp, sdcard or flash explicitly:

$ make boot U=1 BOOTDEV=tftp
$ make boot U=1 BOOTDEV=sdcard
$ make boot U=1 BOOTDEV=flash

We can also change ROOTDEV during boot, for example:

$ make boot U=1 BOOTDEV=flash ROOTDEV=/dev/nfs

Clean images if want to update ramdisk, dtb and uImage:

$ make uboot-images-clean
$ make uboot-clean

Save uboot images and configs:

$ make uboot-save
$ make uboot-saveconfig


Builtin qemu may not work with the newest linux kernel, so, we need compile and add external prebuilt qemu, this has been tested on vexpress-a9 and virt board.

At first, build qemu-system-ARCH:

$ make B=vexpress-a9

$ make qemu-download
$ make qemu-checkout
$ make qemu-patch
$ make qemu-defconfig
$ make qemu
$ make qemu-save

qemu-ARCH-static and qemu-system-ARCH can not be compiled together. to build qemu-ARCH-static, please enable QEMU_US=1 in board specific Makefile and rebuild it.

If QEMU and QTOOL specified, the one in bsp submodule will be used in advance of one installed in system, but the first used is the one just compiled if exists.

While porting to newer kernel, Linux 5.0 hangs during boot on qemu 2.5, after compiling a newer qemu 2.12.0, no hang exists. please take notice of such issue in the future kernel upgrade.


The pace of Linux mainline is very fast, builtin toolchains can not keep up, to reduce the maintaining pressure, external toolchain feature is added. for example, ARM64/virt, CCVER and CCPATH has been added for it.

List available prebuilt toolchains:

$ make gcc-list

Download, decompress and enable the external toolchain:

$ make gcc

Switch compiler version if exists, for example:

$ make gcc-switch CCORI=internal GCC=4.7

$ make gcc-switch CCORI=linaro

If not external toolchain there, the builtin will be used back.

If no builtin toolchain exists, please must use this external toolchain feature, currently, aarch64, arm, riscv, mipsel, ppc, i386, x86_64 support such feature.

GCC version can be configured in board specific Makefile for Linux, Uboot, Qemu and Root, for example:

GCC[LINUX_v2.6.11.12] = 4.4

With this configuration, GCC will be switched automatically during defconfig and compiling of the specified Linux v2.6.11.12.

To build host tools, host gcc should be configured too(please specify b=i386/pc explicitly):

$ make gcc-list b=i386/pc
$ make gcc-switch CCORI=internal GCC=4.8 b=i386/pc


Builtin rootfs is minimal, is not enough for complex application development, which requires modern Linux distributions.

Such a type of rootfs has been introduced and has been released as docker image, ubuntu 18.04 is added for arm32v7 at first, more later.

Run it via docker directly:

$ docker run -it tinylab/arm32v7-ubuntu

Extract it out and run in Linux Lab:


$ tools/rootfs/docker/extract.sh tinylab/arm32v7-ubuntu arm
$ make boot B=vexpress-a9 U=0 V=1 MEM=1024M ROOTDEV=/dev/nfs ROOTFS=$PWD/prebuilt/fullroot/tmp/tinylab-arm32v7-ubuntu


$ tools/rootfs/docker/extract.sh tinylab/arm64v8-ubuntu arm
$ make boot B=raspi3 V=1 ROOTDEV=/dev/mmcblk0 ROOTFS=$PWD/prebuilt/fullroot/tmp/tinylab-arm64v8-ubuntu

More rootfs from docker can be found:

$ docker search arm64 | egrep "ubuntu|debian"
arm64v8/ubuntu   Ubuntu is a Debian-based Linux operating system  25
arm64v8/debian   Debian is a Linux distribution that's composed  20


Compile the kernel with debugging options:

$ make feature feature=debug
$ make kernel-olddefconfig
$ make kernel

Compile with one thread:

$ make kernel JOBS=1

And then debug it directly:

$ make debug

It will open a new terminal, load the scripts from .gdbinit, run gdb automatically.

It equals to:

$ make boot DEBUG=1

to automate debug testing:

$ make test DEBUG=1


Use 'aarch64/virt' as the demo board here.

$ make BOARD=virt

Prepare for testing, install necessary files/scripts in system/:

$ make rootdir
$ make root-install
$ make root-rebuild

Simply boot and poweroff (See poweroff hang):

$ make test

Don't poweroff after testing:

$ make test TEST_FINISH=echo

Run guest test case:

$ make test TEST_CASE=/tools/ftrace/trace.sh

Run guest test cases (COMMAND_LINE_SIZE must be big enough, e.g. 4096, see cmdline_size feature below):

$ make test TEST_BEGIN=date TEST_END=date TEST_CASE='ls /root,echo hello world'

Reboot the guest system for several times:

$ make test TEST_REBOOT=2

NOTE: reboot may 1) hang, 2) continue; 3) timeout killed, TEST_TIMEOUT=30; 4) timeout continue, TIMEOUT_CONTINUE=1

Test a feature of a specified linux version on a specified board(cmdline_size feature is for increase COMMAND_LINE_SIZE to 4096):

$ make test f=kft LINUX=v2.6.36 b=malta TEST_PREPARE=board-init,kernel-cleanup

NOTE: board-init and kernel-cleanup make sure test run automatically, but kernel-cleanup is not safe, please save your code before use it!! To cleanup all of root,uboot,qemu and kernel, please use cleanup instead.

Test a kernel module:

$ make test m=hello

Test multiple kernel modules:

$ make test m=exception,hello

Test modules with specified ROOTDEV, nfs boot is used by default, but some boards may not support network:

$ make test m=hello,exception TEST_RD=/dev/ram0

Run test cases while testing kernel modules (test cases run between insmod and rmmod):

$ make test m=exception TEST_BEGIN=date TEST_END=date TEST_CASE='ls /root,echo hello world' TEST_PREPARE=board-init,kernel-cleanup f=cmdline_size

Run test cases while testing internal kernel modules:

$ make test m=lkdtm TEST_BEGIN='mount -t debugfs debugfs /mnt' TEST_CASE='echo EXCEPTION ">" /mnt/provoke-crash/DIRECT'

Run test cases while testing internal kernel modules, pass kernel arguments:

$ make test m=lkdtm lkdtm_args='cpoint_name=DIRECT cpoint_type=EXCEPTION'

Run test without feature-init (save time if not necessary, FI=FEATURE_INIT):

$ make test m=lkdtm lkdtm_args='cpoint_name=DIRECT cpoint_type=EXCEPTION' FI=0
$ make raw-test m=lkdtm lkdtm_args='cpoint_name=DIRECT cpoint_type=EXCEPTION'

Run test with module and the module's necessary dependencies (check with make kernel-menuconfig):

$ make test m=lkdtm y=runtime_testing_menu,debug_fs lkdtm_args='cpoint_name=DIRECT cpoint_type=EXCEPTION'

Run test without feature-init, boot-init, boot-finish and no TEST_PREPARE:

$ make boot-test m=lkdtm lkdtm_args='cpoint_name=DIRECT cpoint_type=EXCEPTION'

Test a kernel module and make some targets before testing:

$ make test m=exception TEST=kernel-checkout,kernel-patch,kernel-defconfig

Test everything in one command (from download to poweroff, see poweroff hang):

$ make test TEST=kernel-full,root-full TEST_PREPARE=board-init,cleanup

Test everything in one command (with uboot while support, e.g. vexpress-a9):

$ make test TEST=kernel-full,root-full,uboot-full TEST_PREPARE=board-init,cleanup

Test kernel hang during boot, allow to specify a timeout, timeout must happen while system hang:

$ make test TEST_TIMEOUT=30s

Test kernel debug:

$ make test DEBUG=1


To transfer files between Qemu Board and Host, three methods are supported by default:

Install files to rootfs

Simply put the files with a relative path in system/, install and rebuild the rootfs:

$ cd system/
$ mkdir system/root/
$ touch system/root/new_file
$ make root-install
$ make root-rebuild
$ make boot G=1

Share with NFS

Boot the board with ROOTDEV=/dev/nfs,

Boot/Qemu Board:

$ make boot ROOTDEV=/dev/nfs


$ make env-dump | grep ROOTDIR
ROOTDIR = /linux-lab/<BOARD>/bsp/root/<BUILDROOT_VERSION>/rootfs

Transfer via tftp

Using tftp server of host from the Qemu board with the tftp command.


$ ifconfig br0
inet addr:  Bcast:  Mask:
$ cd tftpboot/
$ ls tftpboot
kft.patch kft.log

Qemu Board:

$ ls
$ tftp -g -r kft.patch
$ tftp -p -r kft.log -l kft_data.log

Note: while put file from Qemu board to host, must create an empty file in host firstly. Buggy?

Share with 9p virtio

To enable 9p virtio for a new board, please refer to qemu 9p setup. qemu must be compiled with --enable-virtfs, and kernel must enable the necessary options.

Reconfigure the kernel with:

CONFIG_NET_9P_DEBUG=y (Optional)
CONFIG_PCI_HOST_GENERIC=y (only needed for the QEMU Arm 'virt' board)

If using -virtfs or -device virtio-9p-pci option for qemu, must enable the above PCI related options, otherwise will not work:

9pnet_virtio: no channels available for device hostshare
mount: mounting hostshare on /hostshare failed: No such file or directory'

-device virtio-9p-device requires less kernel options.

To enable the above options, please simply type:

$ make feature f=9pnet $ make kernel-olddefconfig

Docker host:

$ modprobe 9pnet_virtio
$ lsmod | grep 9p
9pnet_virtio           17519  0
9pnet                  72068  1 9pnet_virtio


$ make BOARD=virt

$ make root-install	       # Install mount/umount scripts, ref: system/etc/init.d/S50sharing
$ make root-rebuild

$ touch hostshare/test     # Create a file in host

$ make boot U=0 ROOTDEV=/dev/ram0 PBR=1 SHARE=1

$ make boot SHARE=1 SHARE_DIR=modules   # for external modules development

$ make boot SHARE=1 SHARE_DIR=output/aarch64/linux-v5.1-virt/   # for internal modules learning

$ make boot SHARE=1 SHARE_DIR=examples   # for c/assembly learning

Qemu Board:

$ ls /hostshare/       # Access the file in guest
$ touch /hostshare/guest-test   # Create a file in guest

Verified boards with Linux v5.1:

aarch64/virt: virtio-9p-device (virtio-9p-pci breaks nfsroot)
arm/vexpress-a9: only work with virtio-9p-device and without uboot booting
arm/versatilepb: only work with virtio-9p-pci
x86_64/pc, only work with virtio-9p-pci
i386/pc, only work with virtio-9p-pci
riscv64/virt, work with virtio-9p-pci and virtio-9p-dev
riscv32/virt, work with virtio-9p-pci and virtio-9p-dev


Add a new board

Choose a board supported by qemu

list the boards, use arm as an example:

$ qemu-system-arm -M ?

Create the board directory

Use vexpress-a9 as an example:

$ mkdir boards/arm/vexpress-a9/

Clone a Makefile from an existing board

Use versatilepb as an example:

$ cp boards/arm/versatilebp/Makefile boards/arm/vexpress-a9/Makefile

Configure the variables from scratch

Comment everything, add minimal ones and then others.

Please refer to doc/qemu/qemu-doc.html or the online one http://qemu.weilnetz.de/qemu-doc.html.

At the same time, prepare the configs

We need to prepare the configs for linux, buildroot and even uboot.

Buildroot has provided many examples about buildroot and kernel configuration:

  • buildroot: buildroot/configs/qemu_ARCH_BOARD_defconfig
  • kernel: buildroot/board/qemu/ARCH-BOARD/linux-VERSION.config

Uboot has also provided many default configs:

  • uboot: u-boot/configs/vexpress_ca9x4_defconfig

Kernel itself also:

  • kernel: linux-stable/arch/arm/configs/vexpress_defconfig

Linux Lab itself also provide many working configs too, the -clone target is a good helper to utilize existing configs:

$ make list-kernel
v4.12 v5.0.10 v5.1
$ make kernel-clone LINUX=v5.1 LINUX_NEW=v5.4
$ make kernel-menuconfig
$ make kernel-saveconfig

$ make list-root
2016.05 2019.02.2
$ make root-clone BUILDROOT=2019.02.2 BUILDROOT_NEW=2019.11
$ make root-menuconfig
$ make root-saveconfig

Edit the configs and Makefile untill they match our requirements.

$ make kernel-menuconfig
$ make root-menuconfig
$ make board-edit

The configuration must be put in boards/<BOARD>/ and named with necessary version and arch info, use raspi3 as an example:

$ make kernel-saveconfig
$ make root-saveconfig
$ ls boards/aarch64/raspi3/bsp/configs/
buildroot_2019.02.2_defconfig  linux_v5.1_defconfig

2019.02.2 is the buildroot version, v5.1 is the kernel version, both of these variables should be configured in boards/<BOARD>/Makefile.

Choose the versions of kernel, rootfs and uboot

Please use 'tag' instead of 'branch', use kernel as an example:

$ cd linux-stable
$ git tag

If want v5.1 kernel, just put a line "LINUX = v5.1" in boards/<BOARD>/Makefile.

Or clone a kernel config from the old one or the official defconfig:

$ make kernel-clone LINUX_NEW=v5.3 LINUX=v5.1


$ make B=i386/pc
$ pushd linux-stable && git checkout v5.4 && popd
$ make kernel-clone LINUX_NEW=v5.4 KCFG=i386_defconfig

If no tag existed, a virtual tag name with the real commmit number can be configured as following:

LINUX = v2.6.11.12
LINUX[LINUX_v2.6.11.12] = 8e63197f

# The real commit number

Linux version specific ROOTFS are also supported:

ROOTFS[LINUX_v2.6.12.6]  ?= $(BSP_ROOT)/$(BUILDROOT)/rootfs32.cpio.gz

Configure, build and boot them

Use kernel as an example:

$ make kernel-defconfig
$ make kernel-menuconfig
$ make kernel
$ make boot

The same to rootfs, uboot and even qemu.

Save the images and configs

$ make root-save
$ make kernel-save
$ make uboot-save

$ make root-saveconfig
$ make kernel-saveconfig
$ make uboot-saveconfig

Upload everything

At last, upload the images, defconfigs, patchset to board specific bsp submodule repository.

Firstly, get the remote bsp repository address as following:

$ git remote show origin
* remote origin
  Fetch URL: https://gitee.com/tinylab/qemu-aarch64-raspi3/
  Push  URL: https://gitee.com/tinylab/qemu-aarch64-raspi3/
  HEAD branch: master
  Remote branch:
    master tracked
  Local branch configured for 'git pull':
    master merges with remote master
  Local ref configured for 'git push':
    master pushes to master (local out of date)

Then, fork this repository from gitee.com, upload your changes, and send your pull request.

Learning Assembly

Linux Lab has added many assembly examples in examples/assembly:

$ cd examples/assembly
$ ls
aarch64  arm  mips64el	mipsel	powerpc  powerpc64  README.md  x86  x86_64
$ make -s -C aarch64/
Hello, ARM64!

Running any make goals

Linux Lab allows to access Makefile goals easily via xxx-run, for example:

$ make kernel-run help
$ make kernel-run menuconfig

$ make root-run help
$ make root-run busybox-menuconfig

$ make uboot-run help
$ make uboot-run menuconfig

-run goals allows to run sub-make goals of kernel, root and uboot directly without entering into their own building directory.


Poweroff hang

Both of the 'poweroff' and 'reboot' commands not work on these boards currently (LINUX=v5.1):

  • mipsel/malta (exclude LINUX=v2.6.36)
  • aarch64/raspi3
  • arm/versatilepb

System will directly hang there while running 'poweroff' or 'reboot', to exit qemu, please pressing 'CTRL+a x' or using 'pkill qemu'.

To test such boards automatically, please make sure setting 'TEST_TIMEOUT', e.g. make test TEST_TIMEOUT=50.

Welcome to fix up them.

Boot with missing sdl2 libraries failure

That's because the docker image is not updated, just rerun the lab (please must not use 'tools/docker/restart' here for it not using the new docker image):

$ tools/docker/pull linux-lab
$ tools/docker/rerun linux-lab


$ tools/docker/update linux-lab

With 'tools/docker/update', every docker images and source code will be updated, it is preferred.

NFS/tftpboot not work

If nfs or tftpboot not work, please run modprobe nfsd in host side and restart the net services via /configs/tools/restart-net-servers.sh and please make sure not use tools/docker/trun.

Run tools without sudo

To use the tools under tools without sudo, please make sure add your account to the docker group and reboot your system to take effect:

$ sudo usermod -aG docker $USER

Speed up docker images downloading

To optimize docker images download speed, please edit DOCKER_OPTS in /etc/default/docker via referring to tools/docker/install.

Docker network conflicts with LAN

We assume the docker network is, if not, we'd better change it as following:

$ sudo vim /etc/default/docker

$ sudo vim /lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd -H fd:// --bip=

Please restart docker service and lab container to make this change works:

$ sudo service docker restart
$ tools/docker/rerun linux-lab

If lab network still not work, please try another private network address and eventually to avoid conflicts with LAN address.

Why not allow running Linux Lab in local host

The full function of Linux Lab depends on the full docker environment managed by Cloud Lab, so, please really never try and therefore please don't complain about why there are lots of packages missing failures and even the other weird issues.

Linux Lab is designed to use pre-installed environment with the docker technology and save our life by avoiding the packages installation issues in different systems, so, Linux Lab would never support local host using even in the future.

Why kvm speedding up is disabled

kvm only supports both of qemu-system-i386 and qemu-system-x86_64 currently, and it also requires the cpu and bios support, otherwise, you may get this error log:

modprobe: ERROR: could not insert 'kvm_intel': Operation not supported

Check cpu virtualization support, if nothing output, then, cpu not support virtualization:

$ cat /proc/cpuinfo | egrep --color=always "vmx|svm"

If cpu supports, we also need to make sure it is enabled in bios features, simply reboot your computer, press 'Delete' to enter bios, please make sure the 'Intel virtualization technology' feature is 'enabled'.

How to switch windows in vim

CTRL+w is used in both of browser and vim, to switch from one window to another, please use 'CTRL+Left' or 'CTRL+Right' key instead, Linux Lab has remapped 'CTRL+Right' to CTRL+w and 'CTRL+Left' to CTRL+p.

How to delete typo in shell command line

Long keypress not work in novnc client currently, so, long 'Delete' not work, please use 'alt+delete' or 'alt+backspace' instead, more tips:

  • Bash

    • ctrl+a/e (begin/end)
    • ctrl+home/end (forward/backward)
    • alt+delete/backspace (delete one word backward)
    • alt+d (delete one word forward)
    • ctrl+u/k (delete all to begin, delete all to end)
  • Vim

    • ^/$ (begin/end)
    • w/b; ctrl+home/end (forward/backward)
    • db (delete one word backward)
    • dw (delete one word forward)
    • d^/d$ (delete all to begin, delete all to end)

How to tune the screen size

The screen size of lab is captured by xrandr, if not work, please check and set your own, for example:

Get available screen size values:

$ xrandr --current
Screen 0: minimum 1 x 1, current 1916 x 891, maximum 16384 x 16384
Virtual1 connected primary 1916x891+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1916x891      60.00*+
   2560x1600     59.99
   1920x1440     60.00
   1856x1392     60.00
   1792x1344     60.00
   1920x1200     59.88
   1600x1200     60.00
   1680x1050     59.95
   1400x1050     59.98
   1280x1024     60.02
   1440x900      59.89
   1280x960      60.00
   1360x768      60.02
   1280x800      59.81
   1152x864      75.00
   1280x768      59.87
   1024x768      60.00
   800x600       60.32
   640x480       59.94

Choose one and configure it:

$ cd /path/to/cloud-lab
$ tools/docker/rm-all
$ SCREEN_SIZE=800x600 tools/docker/run linux-lab

If want the default one, please remove the manual setting at first:

$ cd /path/to/cloud-lab
$ rm configs/linux-lab/docker/.screen_size
$ tools/docker/rm-all
$ tools/docker/run linux-lab

How to exit qemu

  1. Serial Port Console: Exit with 'CTRL+A X'
  2. Curses based Graphic: Exit with 'ESC+2 quit' Or 'ALT+2 quit'
  3. X based Graphic: Exit with 'CTRL+ALT+2 quit'

How to work in fullscreen mode

Open the left sidebar, press the 'Fullscreen' button.

How to record video

  • Enable recording

    Open the left sidebar, press the 'Settings' button, config 'File/Title/Author/Category/Tags/Description' and enable the 'Record Screen' option.

  • Start recording

    Press the 'Connect' button.

  • Stop recording

    Press the 'Disconnect' button.

  • Replay recorded video

    Press the 'Play' button.

  • Share it

    Videos are stored in 'cloud-lab/recordings', share it with help from showdesk.io.

Linux Lab not response

The VNC connection may hang for some unknown reasons and therefore Linux Lab may not response sometimes, to restore it, please press the flush button of web browser or re-connect after explicitly disconnect.

Language input switch shortcuts

In order to switch English/Chinese input method, please use 'CTRL+s' shortcuts, it is used instead of 'CTRL+space' to avoid conflicts with local system.

No working init found

This means the rootfs.ext2 image may be broken, please remove it and try make boot again, for example:

$ rm boards/aarch64/raspi3/bsp/root/2019.02.2/rootfs.ext2
$ make boot

make boot command can create this image automatically.

linux/compiler-gcc7.h: No such file or directory

This means using a newer gcc than the one linux kernel version supported, there are two solutions, one is switching to an older gcc version with 'make gcc-switch', use i386/pc board as an example:

$ make gcc-list
$ make gcc-switch CCORI=internal GCC=4.4

Network not work

If ping not work, please check one by one:

DNS issue: if ping work, please check /etc/resolv.conf and make sure it is the same as your host configuration.

IP issue: if ping not work, please refer to network conflict issue and change the ip range of docker containers.

linux-lab/configs: Permission denied

This may happen at make boot while the repository is cloned with root user, please simply update the owner of cloud-lab/ directory:

$ cd /path/to/cloud-lab
$ sudo chown $USER:$USER -R ./
$ tools/docker/rerun linux-lab

Or directly use sudo make boot.

Client.Timeout exceeded while waiting headers

This means must configure one of the following docker images mirror sites:

Configuration in Ubuntu:

$ echo "DOCKER_OPTS=\"\$DOCKER_OPTS --registry-mirror=<your accelerate address>\"" | sudo tee -a /etc/default/docker
$ sudo service docker restart

VNC login fails with wrong password

VNC login fails while using mismatched password, to fix up such issue, please clean up all and rerun it:

$ tools/docker/clean linux-lab
$ tools/docker/rerun linux-lab

scripts/Makefile.headersinst: Missing UAPI file: ./include/uapi/linux/netfilter/xt_CONNMARK.h

This means MAC OSX not use Case sensitive filesystem, create one using hdiutil or Disk Utility yourself:

$ hdiutil create -type SPARSE -size 60g -fs "Case-sensitive Journaled HFS+" -volname labspace labspace.dmg
$ hdiutil attach -mountpoint ~/Documents/labspace -no-browse labspace.dmg
$ cd ~/Documents/labspace

Contact and Sponsor

Our contact wechat is tinylab, welcome to join our user & developer discussion group.

Contact us and Sponsor via wechat


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