HHVM is officially supported on most major linux platforms, with limited support for MacOS.
The easiest way to get going with HHVM is to use one of our supported prebuilt packages. Currently prebuilt packages are available for:
In addition to the normal stable packages, there are supported LTS releases for the above distributions; see the release schedule for details.
For normal usage, using a prebuilt package is the best course of action for ease of installation and stability. However, if you want to live on the bleeding edge and get the latest and greatest code as it is checked into GitHub, you can compile HHVM straight from source. Check the compilation instructions for both the supported Linux and Mac OS X distros.
If we support a prebuilt package for a distribution, we support compiling it from source as well.
Whether you are using a prebuilt package or compiling from source, the Hack Typechecker is also part of the installation of HHVM.
There are wikis of unsupported HHVM platforms for packages and compilation as well.