arm-autonomy: Create xenguest-mkimage

Create a xenguest-mkimage tool to create Xen guest images.
Add documentation to explain what is a xenguest-image and how to use
xenguest-mkimage.

Change-Id: Id87240a4dfac2723f1dcceb8bfe969a7633ef261
Issue-Id: SCM-767
Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Diego Sueiro <diego.sueiro@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-autonomy/documentation/xenguest-mkimage.md

@@ -0,0 +1,119 @@
+Xenguest mkimage
+================
+
+Introduction
+------------
+
+xenguest-mkimage is a tool to create and modify images to be used as Guest with
+Xen. It defines a format to store completely defined guests as a file or as
+a directory and provides options to create and modify those images.
+
+A xenguest image contains all elements required to create a xen guest.
+This is the base elements like a Xen configuration and a Linux kernel binary
+but also some more advanced elements like init scripts or a disk definition.
+
+The format is made to be deployable easily by storing everything in a single
+file and provide tools to easily manipulate the images. It can also easily be
+extended to have features like encryption or signature of images, updates or
+complex configurations by providing features to have init script that will be
+executed on the host embedded inside the image.
+
+Xenguest images content
+-----------------------
+
+### params.cfg
+
+This file contains parameters that can be used by tools to configure some
+functionalities on the host. This can be used by init scripts to have
+configurable parameters as it is sourced before calling init scripts.
+
+### guest.cfg and guest.d
+
+guest.cfg is the main xen configuration and guest.d contains optional
+configuration parts. All those will be merged into one final xen configuration
+before starting the guest.
+
+### files
+This directory contains files that can be used by the xen configuration, for
+example the binary of the kernel referenced in xen configuration).
+This is where the kernel binary, the dtb or a ramdisk will be stored.
+
+### init.pre, init.d and init.post
+These directories contain init scripts that will be executed on the host
+during the guest startup. Those must be shell scripts and each directory
+contains scripts called at a different time:
+ - init.pre: scripts executed before the guest is created. This can be used
+     to prepare some features required to create the guest in xen or to
+     generate part of the xen configuration dynamically.
+ - init.d: scripts executed when the guest has been created but before it is
+     started. This can be used to do some xenstore operations or configure the
+     guest behaviour using xl, for example.
+ - init.post: scripts executed just after starting the guest. This can be
+     used to configure things created by xen for the guest like network
+     network interfaces.
+
+When a directory contains several scripts, those will be called in alphabetical
+order.
+
+### disk.cfg and disk-files
+disk.cfg contains the guest disk description (disk size and disk partitions).
+The file contains the following entries:
+- `DISK_SIZE=X`: size of the disk to create in GB
+- `DISK_PARTX=SIZE:FS:CONTENT`: create a partition number X (1 to 4) with a
+  size of SIZE GB, format it with filesystem FS (can be ext2, ext3, ext4, vfat
+  or swap) and extract CONTENT as initial partition content
+  (.tar[.gz|.xz|.bz2] file or img file to be dumped in the partition). FS and
+  CONTENT can be empty.
+
+The disk-files contain files to be used for initializing the disk partitions
+content. Those should be used to create a LVM or a physical disk and initialize
+it (create partitions, format them and put the initial content).
+
+Usage
+-----
+
+xenguest-mkimage is a shell script which must be called like this:
+`xenguest-mkimage OPERATION XENGUEST [OPTIONS]`
+
+### Operations
+- create: create a xenguest image. If XENGUEST is an existing empty directory,
+  the image is created as a directory otherwise it will be created as a file.
+- check: verify that XENGUEST is a valid xenguest image.
+- update: modify a xenguest image (see --help for a list of operations).
+- pack: pack a xenguest image directory into a xenguest image file. The file to
+  be created must be given as 3rd argument.
+- extract: extract a xenguest image file into a directory. The destination
+  directory must be given as 3rd argument.
+- dump-xenconfig: dump xenguest image xen configuration.
+- dump-diskconfig: dump xenguest image disk configuration.
+- dump-paramsconfig: dump xenguest image parameters configuration.
+
+For a detailed help on available operations, please use:
+`xenguest-mkimage --help`
+
+### Options
+- --kernel=FILE: add kernel FILE as guest kernel. This is both adding the file
+  to the image and modifying the xen configuration to use it.
+- --xen-memory=SIZE: set the guest memory size in MB.
+- --xen-extra: add a kernel command line argument. This can be called several
+  times to add several command line options.
+- --xen-device-tree=FILE: add dtb FILE as device tree. This both adding the
+  file to the image and modifying the xen configuration to use it.
+- --init-script=FILE: add guest init script. The script is embedded inside the
+  image file. Several script can be added and the basename of FILE is used to
+  distinguish them (calling the option twice with the same file will update the
+  script in the image with the second one).
+ --disk-size=SIZE: set the guest disk size to SIZE in GB. Calling this with 0
+  disable the guest disk.
+- --disk-add-part=NUM:SIZE:FS:CONTENT: This is adding a partition to the
+  xenguest image disk. The partition is described with the arguments:
+  - NUM: partition number.
+  - SIZE: partition size in GB.
+  - FS: filesystem to format the partition with. This can be ext2, ext3, ext4,
+    vfat of swap. If empty the partition is not formated.
+  - CONTENT: tar of img file to use to initialize the partition. The file must
+    be added to the image using --disk-add-file=FILE:CONTENT.
+
+For a detailed help on available options, please use:
+`xenguest-mkimage OPERATION --help`
+