bsp/xen: Add information on Xen/ARM BSP

Add a README for the new xen bsp.

user/bsps/arm/xen.rst

@@ -0,0 +1,79 @@
+.. SPDX-License-Identifier: CC-BY-SA-4.0
+
+.. Copyright (C) 2019 DornerWorks
+.. Copyright (C) 2019 Jeff Kubascik <jeff.kubascik@dornerworks.com>
+
+xen (Xen on ARM)
+================
+
+This BSP enables RTEMS to run as a guest virtual machine in AArch32 mode on the
+Xen hypervisor for ARMv8 platforms.
+
+Drivers:
+
+* Clock: ARMv7-AR Generic Timer
+
+* Console: Virtual PL011 device
+
+* Interrupt: GICv2
+
+BSP variants:
+
+* xen_virtual: completely virtualized guest with no dependence on underlying
+  hardware
+
+The xen_virtual BSP variant relies on standard Xen features, so it should be
+able to run on any ARMv8 platform.
+
+Xen allows for the passthrough of hardware peripherals to guest virtual
+machines. BSPs could be added in the future targeting specific hardware
+platforms and include the appropriate drivers.
+
+This BSP was tested with Xen running on the Xilinx Zynq UltraScale+ MPSoC using
+the Virtuosity distribution maintained by DornerWorks.
+
+Execution
+---------
+
+This procedure describes how to run the ticker sample application that should
+already be built with the BSP.
+
+The ``ticker.exe`` file can be found in the BSP build tree at:
+
+.. code-block:: none
+
+    arm-rtems5/c/xen_virtual/testsuites/samples/ticker.exe
+
+The ``ticker.exe`` elf file must be translated to a binary format.
+
+.. code-block:: none
+
+    arm-rtems5-objcopy -O binary ticker.exe ticker.bin
+
+Then place the ``ticker.bin`` file on the dom0 filesystem.
+
+From the dom0 console, create a configuration file ``ticker.cfg`` with the
+following contents.
+
+.. code-block:: none
+
+    name = "ticker"1G
+    kernel = "ticker.bin"
+    memory = 8
+    vcpus = 1
+    gic_version = "v2"
+    vuart = "sbsa_uart"
+
+Create the virtual machine and attach to the virtual vpl011 console.
+
+.. code-block:: none
+
+    xl create ticker.cfg && xl console -t vuart ticker
+
+To return back to the dom0 console, press both ``Ctrl`` and ``]`` on your
+keyboard.
+
+Additional Information
+----------------------
+
+* `Virtuosity distribution <https://dornerworks.com/xen/virtuosity>`_

user/bsps/bsps-arm.rst

@@ -25,5 +25,6 @@ arm (ARM)
 .. include:: arm/smdk2410.rst
 .. include:: arm/stm32f4.rst
 .. include:: arm/tms570.rst
+.. include:: arm/xen.rst
 .. include:: arm/xilinx-zynq.rst
 .. include:: arm/xilinx-zynqmp.rst