docs/devel/reset.rst

10 whole group can be reset consistently. Each individual member object does not
18 ----------------
24 You can apply a reset to an object using ``resettable_assert_reset()``. You need
43   have some non-deterministic state they want to reinitialize to a different
45   must not reinitialize on a snapshot-load reset.
49   its devices during wake-up (from the ``MachineClass::wakeup()`` method), this
50   reset type should be used for such a request. Devices can utilize this reset
51   type to differentiate the reset requested during machine wake-up from other
52   reset requests. For example, RAM content must not be lost during wake-up, and
53   memory devices like virtio-mem that provide additional RAM must not reset
54   such state during wake-ups, but might do so during cold resets. However, this
55   reset type should not be used for wake-up detection, as not every machine
56   type issues a device reset request during wake-up.
78 maintaining a count of in-progress resets; it is crucial to call
88 non-resettable object and it will trigger a run time assert error. Since most
94 - ``device_cold_reset()``
95 - ``bus_cold_reset()``
101 Device and bus functions co-exist because there can be semantic differences
109 Multi-phase mechanism
110 ---------------------
114 The resettable interface uses a multi-phase system to relieve objects and
125    local state of the object; it must not do anything that has a side-effect
131    devices can do actions that affect other objects.
148 -------------------------------------
177         if (myclass->parent_phases.enter) {
178             myclass->parent_phases.enter(obj, type);
181         mydev->var = 0;
189         if (myclass->parent_phases.hold) {
190             myclass->parent_phases.hold(obj, type);
193         qemu_set_irq(mydev->irq, 1);
201         if (myclass->parent_phases.exit) {
202             myclass->parent_phases.exit(obj, type);
205         qemu_set_irq(mydev->irq, 0);
222                                            &myclass->parent_phases);
231                                        &myclass->parent_phases);
250 while in reset state. For example if a device has an irq input,
251 it will probably need to ignore it while in reset; then it can for
252 example check the reset state at the beginning of the irq callback.
265 ----------------------------
270 people can ignore it.
308 This function can be used at any time when not in a reset operation. During
312 do so: the function is a no-op as long as old and new parent are NULL or not
324 ----------------------------
344    the three-phase mechanism listed above. It resets all objects
358    rather than from ``TYPE_SYS_BUS_DEVICE`` or some other plugs-into-a-bus