Build ACRN from Source¶

Introduction¶

Following a general embedded system programming model, the ACRN hypervisor is designed to be customized at build-time per hardware platform and per usage scenario, rather than one binary for all scenarios.

The hypervisor binary is generated based on Kconfig configuration settings. Instruction about these settings can be found in Configuring the hypervisor.

Note

A generic configuration named hypervisor/arch/x86/configs/generic.config is provided to help developers try out ACRN more easily. This configuration will likely work for most x86-based platforms, supported with limited features. This configuration can be enabled by specifying BOARD=generic in the make command line.

A primary reason one binary for all platforms and all usage scenarios is not supported is because dynamic configuration parsing is restricted in ACRN hypervisor, for the following considerations:

Meeting functional safety requirements Absence of dynamic objects is required in functional safety standards. Implementation of dynamic parsing would introduce dynamic objects. Avoiding use of dynamic parsing would help the ACRN hypervisor meet functional safety requirements.
Reduce complexity ACRN is a lightweight reference hypervisor, built for embedded IoT. As new platforms for embedded systems are rapidly introduced, support for one binary would require more and more complexity in the hypervisor, something we need to avoid.
Keep small footprint Implementation of dynamic parsing would introduce hundreds or thousands of code. Avoiding dynamic parsing would help keep Lines of Code (LOC) of the hypervisor in a desirable range (around 30K).
Improve boot up time Dynamic parsing at runtime would increase the boot up time. Using build-time configuration and not dynamic parsing would help improve boot up time of the hypervisor.

You can build the ACRN hypervisor, device model, and tools from source, by following these steps.

Install build tools and dependencies¶

ACRN development is supported on popular Linux distributions, each with their own way to install development tools:

Note

ACRN uses menuconfig, a python3 text-based user interface (TUI) for configuring hypervisor options and using python’s kconfiglib library.

On a Clear Linux OS development system, install the necessary tools:

$ sudo swupd bundle-add os-clr-on-clr os-core-dev python3-basic
$ pip3 install --user kconfiglib

On a Ubuntu/Debian development system:

$ sudo apt install gcc \
     git \
     make \
     gnu-efi \
     libssl-dev \
     libpciaccess-dev \
     uuid-dev \
     libsystemd-dev \
     libevent-dev \
     libxml2-dev \
     libusb-1.0-0-dev \
     python3 \
     python3-pip \
     libblkid-dev \
     e2fslibs-dev \
     pkg-config
$ sudo pip3 install kconfiglib

Note

You need to use gcc version 7.3.* or higher else you will run into issue #1396. Follow these instructions to install the gcc-7 package on Ubuntu 16.04:

$ sudo add-apt-repository ppa:ubuntu-toolchain-r/test
$ sudo apt update
$ sudo apt install g++-7 -y
$ sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 60 \
                     --slave /usr/bin/g++ g++ /usr/bin/g++-7

Note

ACRN development requires binutils version 2.27 (or higher). You can verify your version of binutils with the command apt show binutils. While Ubuntu 18.04 has a new version of binutils the default version on Ubuntu 16.04 needs updating (see issue #1133).

$ wget https://mirrors.ocf.berkeley.edu/gnu/binutils/binutils-2.27.tar.gz
$ tar xzvf binutils-2.27.tar.gz && cd binutils-2.27
$ ./configure
$ make
$ sudo make install

Note

Ubuntu 14.04 requires libsystemd-journal-dev instead of libsystemd-dev as indicated above.

On a Fedora/Redhat development system:

$ sudo dnf install gcc \
     git \
     make \
     findutils \
     gnu-efi-devel \
     libuuid-devel \
     openssl-devel \
     libpciaccess-devel \
     systemd-devel \
     libxml2-devel \
     libevent-devel \
     libusbx-devel \
     python3 \
     python3-pip \
     libblkid-devel \
     e2fsprogs-devel
$ sudo pip3 install kconfiglib

On a CentOS development system:

$ sudo yum install gcc \
        git \
        make \
        gnu-efi-devel \
        libuuid-devel \
        openssl-devel \
        libpciaccess-devel \
        systemd-devel \
        libxml2-devel \
        libevent-devel \
        libusbx-devel \
        python34 \
        python34-pip \
        libblkid-devel \
        e2fsprogs-devel
$ sudo pip3 install kconfiglib

Note

You may need to install EPEL for installing python3 via yum for CentOS 7. For CentOS 6 you need to install pip manually. Please refer to https://pip.pypa.io/en/stable/installing for details.

Build the hypervisor, device model and tools¶

The acrn-hypervisor repository has four main components in it:

The ACRN hypervisor code located in the hypervisor directory
The EFI stub code located in the efi-stub directory
The ACRN devicemodel code located in the devicemodel directory
The ACRN tools source code located in the tools directory

You can build all these components in one go as follows:

$ git clone https://github.com/projectacrn/acrn-hypervisor
$ cd acrn-hypervisor
$ make

The build results are found in the build directory.

Note

if you wish to use a different target folder for the build artifacts, set the O (that is capital letter ‘O’) to the desired value. Example: make O=build-nuc BOARD=nuc6cayh.

Generating the documentation is described in details in the ACRN documentation generation tutorial.

Follow the same instructions to boot and test the images you created from your build.

Configuring the hypervisor¶

The ACRN hypervisor leverages Kconfig to manage configurations, powered by Kconfiglib. A default configuration is generated based on the board you have selected via the BOARD= command line parameter. You can make further changes to that default configuration to adjust to your specific requirements.

To generate hypervisor configurations, you need to build the hypervisor individually. The following steps generate a default but complete configuration, based on the platform selected, assuming that you are under the top-level directory of acrn-hypervisor. The configuration file, named .config, can be found under the target folder of your build.

$ cd hypervisor
$ make defconfig BOARD=nuc6cayh

The BOARD specified is used to select a defconfig under arch/x86/configs/. The other command-line based options (e.g. RELEASE) take no effects when generating a defconfig.

Modify the hypervisor configurations¶

To modify the hypervisor configurations, you can either edit .config manually, or invoke a TUI-based menuconfig, powered by kconfiglib, by executing make menuconfig. As an example, the following commands, assuming that you are under the top-level directory of acrn-hypervisor, generate a default configuration file for UEFI, allow you to modify some configurations and build the hypervisor using the updated .config.

$ cd hypervisor
$ make defconfig BOARD=nuc6cayh
$ make menuconfig              # Modify the configurations per your needs
$ make                         # Build the hypervisor with the new .config

Note

Menuconfig is python3 only.

Refer to the help on menuconfig for a detailed guide on the interface.

$ pydoc3 menuconfig

Create a new default configuration¶

Currently the ACRN hypervisor looks for default configurations under hypervisor/arch/x86/configs/<BOARD>.config, where <BOARD> is the specified platform. The following steps allow you to create a defconfig for another platform based on a current one.

$ cd hypervisor
$ make defconfig BOARD=nuc6cayh
$ make menuconfig         # Modify the configurations
$ make savedefconfig      # The minimized config reside at build/defconfig
$ cp build/defconfig arch/x86/configs/xxx.config

Then you can re-use that configuration by passing the name (xxx in the example above) to ‘BOARD=’:

$ make defconfig BOARD=xxx