Get the current version from the download section. Extract it into some directory.

In order to compile MiXen, you need a somewhat current source tree of Xen or at least the public header files from it.

The downloaded configuration expects the xen source in the directory /src/xen. If you have it somewhere else, you need to adapt the name in the file config/std accordingly. Edit it and change the definition of XENROOT.

The build process for MiXen allows for the source tree to be left unmodified. In order to make use of this feature, just change to some directory, where you want the build to take place, like e.g. /tmp/MiXen. Then invoke the utility config/config from the MiXen source tree, providing the name of the file where the configuration is defined, like e.g. arch/amd64/config/ramdisk. By default, config creates a Makefile for BSD make. If you want or need to use GNU make instead, invoke config/config with the option -g.

Now simply invoke make. The result is the MiXen ramdisk kernel built in your current directory. Move it somewhere the Xen client boot process can find it.