| ============= |
| 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 |
