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reset: Add RESET_TYPE_WAKEUP

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Some devices need to distinguish cold start reset from waking up from a
suspended state. This patch adds new value to the enum, and updates the
i386 wakeup method to use this new reset type.

Message-ID: <20240904103722.946194-3-jmarcin@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
Juraj Marcin 2024-09-04 12:37:13 +02:00 committed by David Hildenbrand
parent 1b063fe2df
commit 759cbb4ee9
3 changed files with 14 additions and 2 deletions
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12
docs/devel/reset.rst
View File

@ -44,6 +44,17 @@ The Resettable interface handles reset types with an enum ``ResetType``:
value on each cold reset, such as RNG seed information, and which they
must not reinitialize on a snapshot-load reset.
``RESET_TYPE_WAKEUP``
If the machine supports waking up from a suspended state and needs to reset
its devices during wake-up (from the ``MachineClass::wakeup()`` method), this
reset type should be used for such a request. Devices can utilize this reset
type to differentiate the reset requested during machine wake-up from other
reset requests. For example, RAM content must not be lost during wake-up, and
memory devices like virtio-mem that provide additional RAM must not reset
such state during wake-ups, but might do so during cold resets. However, this
reset type should not be used for wake-up detection, as not every machine
type issues a device reset request during wake-up.
``RESET_TYPE_S390_CPU_NORMAL``
This is only used for S390 CPU objects; it clears interrupts, stops
processing, and clears the TLB, but does not touch register contents.
@ -53,7 +64,6 @@ The Resettable interface handles reset types with an enum ``ResetType``:
``RESET_TYPE_S390_CPU_NORMAL`` does and also clears the PSW, prefix,
FPC, timer and control registers. It does not touch gprs, fprs or acrs.
Devices which implement reset methods must treat any unknown ``ResetType``
as equivalent to ``RESET_TYPE_COLD``; this will reduce the amount of
existing code we need to change if we add more types in future.

2
hw/i386/pc.c
View File

@ -1732,7 +1732,7 @@ static void pc_machine_reset(MachineState *machine, ResetType type)
static void pc_machine_wakeup(MachineState *machine)
{
cpu_synchronize_all_states();
pc_machine_reset(machine, RESET_TYPE_COLD);
pc_machine_reset(machine, RESET_TYPE_WAKEUP);
cpu_synchronize_all_post_reset();
}

2
include/hw/resettable.h
View File

@ -29,6 +29,7 @@ typedef struct ResettableState ResettableState;
* Types of reset.
*
* + Cold: reset resulting from a power cycle of the object.
* + Wakeup: reset resulting from a wake-up from a suspended state.
*
* TODO: Support has to be added to handle more types. In particular,
* ResettableState structure needs to be expanded.
@ -36,6 +37,7 @@ typedef struct ResettableState ResettableState;
typedef enum ResetType {
RESET_TYPE_COLD,
RESET_TYPE_SNAPSHOT_LOAD,
RESET_TYPE_WAKEUP,
RESET_TYPE_S390_CPU_INITIAL,
RESET_TYPE_S390_CPU_NORMAL,
} ResetType;