They provide prebuilt packages for a number of distros. See: https://github.com/facebook/hhvm/wiki/Prebuilt%20Packages%20for%20HHVM On Ubuntu 14.04, you first need to enable the package repository:

wget -O - http://dl.hhvm.com/conf/hhvm.gpg.key | sudo apt-key add -
echo deb http://dl.hhvm.com/ubuntu trusty main | sudo tee /etc/apt/sources.list.d/hhvm.list
sudo apt-get update

You can then install the package with:

sudo apt-get install hhvm

Then enable HHVM as FastCGI:

/usr/share/hhvm/install_fastcgi.sh

To make sure that HHVM automatically restarts at boot, run:

sudo update-rc.d hhvm defaults

Though for some reason, you need the full file paths in the url. hhvm.server.default_document doesn't seem to work. So you need to do things like: http://your.ip.address/index.html Presumably you could use rewrite directives in Apache to work around this.