blockdev: Add blockdev-insert-medium

And a helper function for that, which directly takes a pointer to the
BDS to be inserted instead of its node-name (which will be used for
implementing 'change' using blockdev-insert-medium).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qapi/block-core.json

@@ -1940,6 +1940,23 @@
 { 'command': 'blockdev-remove-medium',
   'data': { 'device': 'str' } }
 
+##
+# @blockdev-insert-medium:
+#
+# Inserts a medium (a block driver state tree) into a block device. That block
+# device's tray must currently be open (unless there is no attached guest
+# device) and there must be no medium inserted already.
+#
+# @device:    block device name
+#
+# @node-name: name of a node in the block driver state graph
+#
+# Since: 2.5
+##
+{ 'command': 'blockdev-insert-medium',
+  'data': { 'device': 'str',
+            'node-name': 'str'} }
+
 
 ##
 # @BlockErrorAction