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authorPavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>2022-05-27 13:46:18 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2022-06-06 09:26:53 +0200
commit60618e2d77691e44bb78e23b2b0cf07b5c405e56 (patch)
tree992cfb9f63c5a9d8962cffcf678e8c6445993556 /replay
parent75bbe5e5ec2867f098a31bfd553a1fb084289cc2 (diff)
replay: rewrite async event handling
This patch decouples checkpoints and async events. It was a tricky part of replay implementation. Now it becomes much simpler and easier to maintain. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Acked-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <165364837856.688121.8785039478408995979.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'replay')
-rw-r--r--replay/replay-events.c20
-rw-r--r--replay/replay-internal.h6
-rw-r--r--replay/replay-snapshot.c1
-rw-r--r--replay/replay.c74
4 files changed, 38 insertions, 63 deletions
diff --git a/replay/replay-events.c b/replay/replay-events.c
index ac47c89834..db1decf9dd 100644
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -170,12 +170,11 @@ void replay_block_event(QEMUBH *bh, uint64_t id)
}
}
-static void replay_save_event(Event *event, int checkpoint)
+static void replay_save_event(Event *event)
{
if (replay_mode != REPLAY_MODE_PLAY) {
/* put the event into the file */
replay_put_event(EVENT_ASYNC);
- replay_put_byte(checkpoint);
replay_put_byte(event->event_kind);
/* save event-specific data */
@@ -206,34 +205,27 @@ static void replay_save_event(Event *event, int checkpoint)
}
/* Called with replay mutex locked */
-void replay_save_events(int checkpoint)
+void replay_save_events(void)
{
g_assert(replay_mutex_locked());
- g_assert(checkpoint != CHECKPOINT_CLOCK_WARP_START);
- g_assert(checkpoint != CHECKPOINT_CLOCK_VIRTUAL);
while (!QTAILQ_EMPTY(&events_list)) {
Event *event = QTAILQ_FIRST(&events_list);
- replay_save_event(event, checkpoint);
+ replay_save_event(event);
replay_run_event(event);
QTAILQ_REMOVE(&events_list, event, events);
g_free(event);
}
}
-static Event *replay_read_event(int checkpoint)
+static Event *replay_read_event(void)
{
Event *event;
if (replay_state.read_event_kind == -1) {
- replay_state.read_event_checkpoint = replay_get_byte();
replay_state.read_event_kind = replay_get_byte();
replay_state.read_event_id = -1;
replay_check_error();
}
- if (checkpoint != replay_state.read_event_checkpoint) {
- return NULL;
- }
-
/* Events that has not to be in the queue */
switch (replay_state.read_event_kind) {
case REPLAY_ASYNC_EVENT_BH:
@@ -294,11 +286,11 @@ static Event *replay_read_event(int checkpoint)
}
/* Called with replay mutex locked */
-void replay_read_events(int checkpoint)
+void replay_read_events(void)
{
g_assert(replay_mutex_locked());
while (replay_state.data_kind == EVENT_ASYNC) {
- Event *event = replay_read_event(checkpoint);
+ Event *event = replay_read_event();
if (!event) {
break;
}
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 97649ed8d7..d6e631a394 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -87,8 +87,6 @@ typedef struct ReplayState {
int32_t read_event_kind;
/*! Asynchronous event id read from the log */
uint64_t read_event_id;
- /*! Asynchronous event checkpoint id read from the log */
- int32_t read_event_checkpoint;
} ReplayState;
extern ReplayState replay_state;
@@ -152,9 +150,9 @@ void replay_finish_events(void);
/*! Returns true if there are any unsaved events in the queue */
bool replay_has_events(void);
/*! Saves events from queue into the file */
-void replay_save_events(int checkpoint);
+void replay_save_events(void);
/*! Read events from the file into the input queue */
-void replay_read_events(int checkpoint);
+void replay_read_events(void);
/*! Adds specified async event to the queue */
void replay_add_event(ReplayAsyncEventKind event_kind, void *opaque,
void *opaque2, uint64_t id);
diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
index e8767a1937..7e935deb15 100644
--- a/replay/replay-snapshot.c
+++ b/replay/replay-snapshot.c
@@ -61,7 +61,6 @@ static const VMStateDescription vmstate_replay = {
VMSTATE_UINT64(block_request_id, ReplayState),
VMSTATE_INT32(read_event_kind, ReplayState),
VMSTATE_UINT64(read_event_id, ReplayState),
- VMSTATE_INT32(read_event_checkpoint, ReplayState),
VMSTATE_END_OF_LIST()
},
};
diff --git a/replay/replay.c b/replay/replay.c
index 2d3607998a..ccd7edec76 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -22,7 +22,7 @@
/* Current version of the replay mechanism.
Increase it when file format changes. */
-#define REPLAY_VERSION 0xe0200a
+#define REPLAY_VERSION 0xe0200b
/* Size of replay log header */
#define HEADER_SIZE (sizeof(uint32_t) + sizeof(uint64_t))
@@ -171,64 +171,49 @@ void replay_shutdown_request(ShutdownCause cause)
bool replay_checkpoint(ReplayCheckpoint checkpoint)
{
- bool res = false;
- static bool in_checkpoint;
assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
- if (!replay_file) {
- return true;
- }
-
- if (in_checkpoint) {
- /*
- Recursion occurs when HW event modifies timers.
- Prevent performing icount warp in this case and
- wait for another invocation of the checkpoint.
- */
- g_assert(replay_mode == REPLAY_MODE_PLAY);
- return false;
- }
- in_checkpoint = true;
-
replay_save_instructions();
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
if (replay_next_event_is(EVENT_CHECKPOINT + checkpoint)) {
replay_finish_event();
- } else if (replay_state.data_kind != EVENT_ASYNC) {
- res = false;
- goto out;
+ } else {
+ return false;
}
- replay_read_events(checkpoint);
- /* replay_read_events may leave some unread events.
- Return false if not all of the events associated with
- checkpoint were processed */
- res = replay_state.data_kind != EVENT_ASYNC;
} else if (replay_mode == REPLAY_MODE_RECORD) {
g_assert(replay_mutex_locked());
replay_put_event(EVENT_CHECKPOINT + checkpoint);
- /* This checkpoint belongs to several threads.
- Processing events from different threads is
- non-deterministic */
- if (checkpoint != CHECKPOINT_CLOCK_WARP_START
- /* FIXME: this is temporary fix, other checkpoints
- may also be invoked from the different threads someday.
- Asynchronous event processing should be refactored
- to create additional replay event kind which is
- nailed to the one of the threads and which processes
- the event queue. */
- && checkpoint != CHECKPOINT_CLOCK_VIRTUAL) {
- replay_save_events(checkpoint);
- }
- res = true;
}
-out:
- in_checkpoint = false;
- return res;
+ return true;
+}
+
+void replay_async_events(void)
+{
+ static bool processing = false;
+ /*
+ * If we are already processing the events, recursion may occur
+ * in case of incorrect implementation when HW event modifies timers.
+ * Timer modification may invoke the icount warp, event processing,
+ * and cause the recursion.
+ */
+ g_assert(!processing);
+ processing = true;
+
+ replay_save_instructions();
+
+ if (replay_mode == REPLAY_MODE_PLAY) {
+ g_assert(replay_mutex_locked());
+ replay_read_events();
+ } else if (replay_mode == REPLAY_MODE_RECORD) {
+ g_assert(replay_mutex_locked());
+ replay_save_events();
+ }
+ processing = false;
}
-bool replay_has_checkpoint(void)
+bool replay_has_event(void)
{
bool res = false;
if (replay_mode == REPLAY_MODE_PLAY) {
@@ -236,6 +221,7 @@ bool replay_has_checkpoint(void)
replay_account_executed_instructions();
res = EVENT_CHECKPOINT <= replay_state.data_kind
&& replay_state.data_kind <= EVENT_CHECKPOINT_LAST;
+ res = res || replay_state.data_kind == EVENT_ASYNC;
}
return res;
}