docs/devel/reset.rst

9 This interface allows objects to be grouped (on a tree basis); so that the
14 The main object types which implement this interface are DeviceClass
20 This section documents the APIs which "users" of a resettable object should use
34   to the initial state corresponding to the start of QEMU; this might differ
39   This is called for a reset which is being done to put the system into a
40   clean state prior to loading a snapshot. (This corresponds to a reset
42   this the same as ``RESET_TYPE_COLD``. The main exception is devices which
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
54   such state during wake-ups, but might do so during cold resets. However, this
59   This is only used for S390 CPU objects; it clears interrupts, stops
63   This is only used for S390 CPU objects; it does everything
68 as equivalent to ``RESET_TYPE_COLD``; this will reduce the amount of
77 controllers end their reset operation. This point is handled internally by
112 This section documents the internals of the resettable interface.
115 machines from reset ordering problems. To address this, the reset operation
130    group which is being reset has had its *enter* phase executed. At this point
136 As said in previous section, the interface maintains a count of reset. This
148 the 'exit' phase and this sequencing makes sure no outstanding DMA request
155 This section documents the APIs that an implementation of a resettable object
238 This is equivalent to providing a trivial implementation of the hold and exit
246 This function returns true if the object parameter is currently under reset.
254 This function may be used if the object behavior has to be adapted
261 one of the reset phases, the only cases when this function will return
272 This section documents parts of the reset mechanism that you only need to know
285 need one. This method must return a pointer to ``ResettableState`` structure.
307 But there are actually some exceptions. To cope with this, the resettable API
308 provides ``resettable_change_parent()``. This function allows to set, update or
313 This function can be used at any time when not in a reset operation. During
320 There is currently 2 cases where this function is used:
335    ``qemu_system_reset_request()``. This schedules a reset, but the
337    That makes this safe to call from, for example, device models.
341    call this directly.
353    "hold" phase of this reset.
355 5. The most important object that this reset resets is the
356    'sysbus' bus. The sysbus bus is the root of the qbus tree. This
361    reset! (The most obvious example of this is CPU objects, but
364    type will be in this category.) You need to therefore arrange for these