Booting Xen

Booting Xen
===========

 Xen follows the zImage protocol defined for 32-bit ARM Linux[1] and the
 Image protocol defined for ARM64 Linux[2].

 In both cases the recommendation to boot in HYP/EL2 mode is a strict
 requirement for Xen.

 The exceptions to this on 32-bit ARM are as follows:

  Xen does not require the machine type to be passed in r1. This
  register is ignored (so may be invalid or the actual machine type).

  Xen does not support the ATAG list and requires Device
  Tree. Therefore r2 must point to the physical address of device tree
  block (dtb) in system RAM.

  NOTE: although Xen uses the zImage protocol there is no compression

  actually used. This should be transparent to the bootloader. The
  zImage protocol should still be used and not the stricter "raw
  (non-zImage)" protocol described in arm/Booting.

 There are no exception on 64-bit ARM.

 [1] linux/Documentation/arm/Booting
 Latest version: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/arm/Booting

 [2] linux/Documentation/arm64/booting.txt
 Latest version: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/arm64/booting.txt