qga: add command guest-get-disks

Add API and stubs for new guest-get-disks command.

The command guest-get-fsinfo can be used to list information about disks
and partitions but it is limited only to mounted disks with filesystem.
This new command should allow listing information about disks of the VM
regardles whether they are mounted or not. This can be usefull for
management applications for mapping virtualized devices or pass-through
devices to device names in the guest OS.

Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>

qga/commands-posix.c

@@ -3051,3 +3051,9 @@ GuestDeviceInfoList *qmp_guest_get_devices(Error **errp)
 
     return NULL;
 }
+
+GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
+{
+    error_setg(errp, QERR_UNSUPPORTED);
+    return NULL;
+}

qga/commands-win32.c

@@ -2458,3 +2458,9 @@ GuestDeviceInfoList *qmp_guest_get_devices(Error **errp)
     }
     return head;
 }
+
+GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
+{
+    error_setg(errp, QERR_UNSUPPORTED);
+    return NULL;
+}

qga/qapi-schema.json

@@ -865,6 +865,37 @@
            'bus': 'int', 'target': 'int', 'unit': 'int',
            '*serial': 'str', '*dev': 'str'} }
 
+##
+# @GuestDiskInfo:
+#
+# @name: device node (Linux) or device UNC (Windows)
+# @partition: whether this is a partition or disk
+# @dependents: list of dependent devices; e.g. for LVs of the LVM this will
+#              hold the list of PVs, for LUKS encrypted volume this will
+#              contain the disk where the volume is placed.     (Linux)
+# @address: disk address information (only for non-virtual devices)
+# @alias: optional alias assigned to the disk, on Linux this is a name assigned
+#         by device mapper
+#
+# Since 5.2
+##
+{ 'struct': 'GuestDiskInfo',
+  'data': {'name': 'str', 'partition': 'bool', 'dependents': ['str'],
+           '*address': 'GuestDiskAddress', '*alias': 'str'} }
+
+##
+# @guest-get-disks:
+#
+# Returns: The list of disks in the guest. For Windows these are only the
+#          physical disks. On Linux these are all root block devices of
+#          non-zero size including e.g. removable devices, loop devices,
+#          NBD, etc.
+#
+# Since: 5.2
+##
+{ 'command': 'guest-get-disks',
+  'returns': ['GuestDiskInfo'] }
+
 ##
 # @GuestFilesystemInfo:
 #