Comment 18 for bug 886521

So, in summary, for all pre-3.2 kernels in all flavours that have CONFIG_XEN_PVHVM=y (i.e. the appropriate flavours in Lucid, Maverick, Natty, Oneiric) we need to modify/add:
   CONFIG_XEN_BLKDEV_FRONTEND=y
   CONFIG_XEN_NETDEV_FRONTEND=y
   CONFIG_XEN_PLATFORM_PCI=y

For kernels without CONFIG_XEN_PVHVM=y, we need do nothing, as they don't have PV driver support anyway.

For Precise, we don't need to do anything, as CONFIG_XEN_PLATFORM_PCI has been deprecated, and per comment #13, CONFIG_XEN_BLKDEV_FRONTEND and CONFIG_XEN_BLKDEV_FRONTEND have already moved from 'm' to 'y'.

Assuming that's correct, I might try knocking up some patches tomorrow.