1============= 2D-Bus VMState 3============= 4 5The QEMU dbus-vmstate object's aim is to migrate helpers' data running 6on a QEMU D-Bus bus. (refer to the :doc:`dbus` document for 7some recommendations on D-Bus usage) 8 9Upon migration, QEMU will go through the queue of 10``org.qemu.VMState1`` D-Bus name owners and query their ``Id``. It 11must be unique among the helpers. 12 13It will then save arbitrary data of each Id to be transferred in the 14migration stream and restored/loaded at the corresponding destination 15helper. 16 17For now, the data amount to be transferred is arbitrarily limited to 181Mb. The state must be saved quickly (a fraction of a second). (D-Bus 19imposes a time limit on reply anyway, and migration would fail if data 20isn't given quickly enough.) 21 22dbus-vmstate object can be configured with the expected list of 23helpers by setting its ``id-list`` property, with a comma-separated 24``Id`` list. 25 26.. only:: sphinx4 27 28 .. dbus-doc:: backends/dbus-vmstate1.xml 29 30.. only:: not sphinx4 31 32 .. warning:: 33 Sphinx 4 is required to build D-Bus documentation. 34 35 This is the content of ``backends/dbus-vmstate1.xml``: 36 37 .. literalinclude:: ../../backends/dbus-vmstate1.xml 38 :language: xml 39