Building OpenHCL
Prerequisites:
Reminder: OpenHCL cannot currently be built on Windows hosts!
An OpenHCL IGVM firmware image is composed of several distinct binaries and
artifacts. For example: the openvmm_hcl
usermode binary, the OpenHCL boot
shim, the OpenHCL Linux kernel and initrd, etc....
Some of these components are built directly out of the OpenVMM repo, whereas others must be downloaded as pre-built artifacts from other associated repos. Various tools and scripts will then transform, package, and re-package these artifacts into a final OpenHCL IGVM firmware binary.
Fortunately, we don't expect you do to all those steps manually!
All the complexity of installing the correct system dependencies, building the
right binaries, downloading the right artifacts, etc... is neatly encapsulated
behind a single cargo xflowey build-igvm
command, which orchestrates the
entire end-to-end OpenHCL build process.
Using the build-igvm
flow is as simple as running:
cargo xflowey build-igvm [RECIPE]
The first build will take some time as all the dependencies are installed/downloaded/built.
Note: At this time, OpenHCL can only be built on Linux (or WSL2)!
A "recipe" corresponds to one of the pre-defined IGVM SKUs that are actively supported and tested in OpenVMM's build infrastructure.
A single recipe encodes all the details of what goes into an individual IGVM
file, such as what build flags openvmm_hcl
should be built with, what goes
into a VTL2 initrd, what igvmfilegen
manifest is being used, etc...
- e.g:
x64
, for a "standard" x64 IGVM - e.g:
aarch64
, for a "standard" aarch64 IGVM - e.g:
x64-cvm
, for a x64 CVM IGVM - e.g:
x64-test-linux-direct
, for x64 IGVM booting a test linux direct image - for a full list of available recipes, please run
cargo xflowey build-igvm --help
New recipes can be added by modifying the build-igvm
source code.
Build output is then binplaced to: flowey-out/artifacts/build-igvm/{release-mode}/{recipe}/openhcl-{recipe}.bin
So, for example:
cargo xflowey build-igvm x64-cvm
# output: flowey-out/artifacts/build-igvm/debug/x64-cvm/openhcl-x64-cvm.bin
cargo xflowey build-igvm x64 --release
# output: flowey-out/artifacts/build-igvm/release/x64/openhcl-x64.bin
cargo xflowey build-igvm
is designed to be used as part of the
developer inner-loop, and does NOT have a stable CLI suitable for CI or any
other form of production automation!
In-tree pipelines and automation should interface with the underlying flowey
infrastructure that powers cargo xflowey build-igvm
, without relying on
the details of its CLI.
Building ohcldiag-dev
ohcldiag-dev
is typically built as a Windows binary.
This can be done directly from Windows, or using cross-compilation from WSL2, as described in the Suggested Dev Environment section of the Guide.
The command to build ohcldiag-dev
is simply:
# you may need to run `rustup target add x86_64-pc-windows-msvc` first
cargo build -p ohcldiag-dev --target x86_64-pc-windows-msvc
Note: Thanks to x86 emulation built into Windows, ohcldiag-dev.exe
that is
built for x64 Windows will work on Aarch64 Windows as well.
Troubleshooting
This section documents some common errors you may encounter while building OpenHCL.
If you are still running into issues, consider filing an issue on the OpenVMM GitHub Issue tracker.
Help! The build failed due to a missing dependency!
If you don't mind having xflowey
install some dependencies globally on your
machine (i.e: via apt install
, or rustup toolchain add
), you can pass
--auto-install-deps
to your invocation of build-igvm
.
Alternatively - build-igvm
should emit useful human-readable error messages
when it encounters a dependency that isn't installed, with a suggestion on how
to install it.
If it doesn't - please file an Issue!
Help! Everything is rebuilding even though I only made a small change!
Cargo's target triple handling can be a bit buggy. Try running with:
CARGO_BUILD_TARGET=x86_64-unknown-linux-gnu cargo build-igvm [RECIPE]
or adding the below to your .bashrc:
export CARGO_BUILD_TARGET=x86_64-unknown-linux-gnu
Build Customization
Aside from building IGVM files corresponding the the built-in IGVM recipes,
build-igvm
also offers a plethora of customization options for developers who
wish to build specialized custom IGVM files for local testing.
Some examples of potentially useful customization include:
-
--override-manifest
: Override the recipe'sigvmfilegen
manifest file via, in order to tweak different kernel command line options, different VTL0 boot configuration, or different VTL2 memory sizes. -
--custom-openvmm-hcl
: Specify a pre-builtopenvmm_hcl
binary. This is useful in case you have already built it with some custom settings, e.g.:cargo build --target x86_64-unknown-linux-musl -p openvmm_hcl --features myfeature cargo xflowey build-igvm x64 --custom-openvmm-hcl target/x86_64-unknown-linux-musl/debug/openvmm_hcl
-
Specify a custom VTL2 kernel
vmlinux
/Image
, instead of using a pre-packed stable/dev kernel.cargo xflowey build-igvm x64 --custom-kernel path/to/my/prebuilt/vmlinux
For a full list of available customizations, refer to build-igvm --help
.
Advanced
Depending on what you're doing, you may need to build the individual components that go into an OpenHCL IGVM build.
Our flowey
-based pipelines handle the complexities of properly invoking and
orchestrating the various individual build tools / scripts used to construct
IGVM files, but a sufficiently motivated user can go through these steps
manually.
Please consult the source code for cargo xflowey build-igvm
for a breakdown of
all build steps and available customization options.
Note that the canonical "source of truth" for how to build end-to-end OpenHCL IGVM files are these build scripts themselves, and the specific flow is subject to change over time!