These drivers provide paravirtualised drivers for pre-PVops Linux
kernels which have the classic-Xen patches applied. They do not work
with kernels which are not patched with the classic-Xen patches. In
particular this includes all PVops kernels.

For 2.6.36 and newer you should use the "PVHVM" functionality which is
available in the mainline kernel.

To build do one of:

   ./mkbuildtree [<arch>]
   NB. You can override paths to Xen sources and a (stub) XenLinux
       build tree via the XEN and XL environment variable.

- or -
   make -C /path/to/kernel/build M=$PWD modules
   NB. This is your native kernel build tree (or a distro provided
       stub), not the XenLinux sources referred to in step 1.
   NB. If you are cross compiling, you need to set ARCH and
       CROSS_COMPILE too.

You get four modules, xen-platform-pci.ko, xen-vbd.ko, xen-vnif.ko and
xen-balloon.ko.  Load xen-platform-pci first, and then
whichever of xen-vbd, xen-vnif and xen-balloon.ko you happen to need.