Running OpenHCL
This chapter provides a high-level overview of different ways to launch and interact with OpenHCL.
High-level Overview
In order to run OpenHCL, an existing host VMM must first load the OpenHCL environment into a VM, much akin to existing virtual firmware layers, like UEFI, or BIOS1.
OpenHCL is distributed as an IGVM file (Independent Guest Virtual Machine), which encapsulates all the directives and data required to launch a particular virtual machine configuration on any given virtualization stack.
At this time, the only VMMs which are able to load and host OpenHCL IGVM files are Hyper-V, and OpenVMM.
Obtaining a copy of OpenHCL
To get started, ensure you have a copy of an OpenHCL IGVM firmware image, via one of the following options:
Building OpenHCL Locally
Follow the instructions on: Building OpenHCL.
Note: At this time, OpenHCL can only be built on Linux / WSL2.
Pre-Built Binaries
If you would prefer to try OpenHCL without building it from scratch, you can download pre-built copies of OpenHCL IGVM files from OpenVMM CI.
Simply select a successful pipeline run (should have a Green checkbox), and
scroll down to select an appropriate *-openhcl-igvm artifact for your
particular architecture and operating system.
Though, unlike UEFI / BIOS, OpenHCL is loaded into a distinct, higher privilege execution context within the VM, called VTL2.