============= D-Bus VMState

The QEMU dbus-vmstate object's aim is to migrate helpers' data running on a QEMU D-Bus bus. (refer to the :doc:dbus document for some recommendations on D-Bus usage)

Upon migration, QEMU will go through the queue of org.qemu.VMState1 D-Bus name owners and query their Id. It must be unique among the helpers.

It will then save arbitrary data of each Id to be transferred in the migration stream and restored/loaded at the corresponding destination helper.

For now, the data amount to be transferred is arbitrarily limited to 1Mb. The state must be saved quickly (a fraction of a second). (D-Bus imposes a time limit on reply anyway, and migration would fail if data isn't given quickly enough.)

dbus-vmstate object can be configured with the expected list of helpers by setting its id-list property, with a comma-separated Id list.

.. only:: sphinx4

.. dbus-doc:: backends/dbus-vmstate1.xml

.. only:: not sphinx4

.. warning:: Sphinx 4 is required to build D-Bus documentation.

  This is the content of ``backends/dbus-vmstate1.xml``:

.. literalinclude:: ../../backends/dbus-vmstate1.xml :language: xml