From: Juraj Marcin <jmarcin@redhat.com>
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>
---
docs/devel/reset.rst | 12 +++++++++++-
hw/i386/pc.c | 2 +-
include/hw/resettable.h | 2 ++
3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/docs/devel/reset.rst b/docs/devel/reset.rst
index ed41e09f16..74c7c0171a 100644
--- a/docs/devel/reset.rst
+++ b/docs/devel/reset.rst
@@ -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.
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 79a626a3eb..80a65d965f 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -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();
}
diff --git a/include/hw/resettable.h b/include/hw/resettable.h
index 94f6f22e3c..fd862f1e9f 100644
--- a/include/hw/resettable.h
+++ b/include/hw/resettable.h
@@ -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;
--
2.46.1