arm-autonomy: Create arm-autonomy-host image

Create minimal image suitable for an arm-autonomy-host containing:
- the boot packagegroup
- the ssh server packagegroup
- xen base tools
- qemu (required to start xen guests)

Change-Id: If864fc6b768cbe4ca19bfe24753c008146b7550c
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/README.md

@@ -40,6 +40,11 @@ Images
 ------
 This layer is adding the following images:
 
+* arm-autonomy-host-image-minimal: this image includes all elements required
+  to create a minimal arm-autonomy-host system. This includes xen and tools to
+  manage xen guests. This image depends on 'arm-autonomy-host' distribution
+  feature.
+
 Recipes and classes
 -------------------
 This layer is adding the following recipes and classes:

meta-arm-autonomy/recipes-core/images/arm-autonomy-host-image-minimal.bb

@@ -0,0 +1,27 @@
+# Recipe to create a minimal Arm Autonomy stack host image
+
+DESCRIPTION = "Arm Autonomy stack host minimal image"
+
+inherit core-image
+
+LICENSE = "MIT"
+
+# Includes minimal set required to start and manage guest. The xen specific
+# modules are not explicitly included as they are built as part of the kernel
+# image for performance reasons. Includes all kernel modules anyway as it makes
+# life easier and does not cost that much in size.
+IMAGE_INSTALL += " \
+    packagegroup-core-boot \
+    packagegroup-core-ssh-openssh \
+    kernel-modules \
+    xen-base \
+    qemu \
+    "
+
+python __anonymous() {
+    if bb.utils.contains('DISTRO_FEATURES', 'arm-autonomy-host', False, True, d):
+        raise bb.parse.SkipRecipe("DISTRO_FEATURES does not contain 'arm-autonomy-host'")
+
+    if bb.utils.contains('DISTRO_FEATURES', 'xen', False, True, d):
+        raise bb.parse.SkipRecipe("DISTRO_FEATURES does not contain 'xen'")
+}