From a36544d34c8b7e483386d29f9716ca9f4caad9fb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Tue, 27 Feb 2018 12:52:42 +0300 Subject: [PATCH] replay: make locking visible outside replay code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The replay_mutex_lock/unlock/locked functions are now going to be used for ensuring lock-step behaviour between the two threads. Make them public API functions and also provide stubs for non-QEMU builds on common paths. Signed-off-by: Alex Bennée Signed-off-by: Pavel Dovgalyuk Message-Id: <20180227095242.1060.16601.stgit@pasha-VirtualBox> Signed-off-by: Paolo Bonzini --- include/sysemu/replay.h | 13 +++++++++++++ replay/replay-internal.c | 2 +- replay/replay-internal.h | 6 +++--- stubs/replay.c | 8 ++++++++ 4 files changed, 25 insertions(+), 4 deletions(-) diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h index 401de12130..3ced6bc231 100644 --- a/include/sysemu/replay.h +++ b/include/sysemu/replay.h @@ -48,6 +48,19 @@ extern ReplayMode replay_mode; /* Name of the initial VM snapshot */ extern char *replay_snapshot; +/* Replay locking + * + * The locks are needed to protect the shared structures and log file + * when doing record/replay. They also are the main sync-point between + * the main-loop thread and the vCPU thread. This was a role + * previously filled by the BQL which has been busy trying to reduce + * its impact across the code. This ensures blocks of events stay + * sequential and reproducible. + */ + +void replay_mutex_lock(void); +void replay_mutex_unlock(void); + /* Replay process control functions */ /*! Enables recording or saving event log with specified parameters */ diff --git a/replay/replay-internal.c b/replay/replay-internal.c index 0d7e1d6bc4..7cdefeaa04 100644 --- a/replay/replay-internal.c +++ b/replay/replay-internal.c @@ -181,7 +181,7 @@ void replay_mutex_destroy(void) qemu_mutex_destroy(&lock); } -static bool replay_mutex_locked(void) +bool replay_mutex_locked(void) { return replay_locked; } diff --git a/replay/replay-internal.h b/replay/replay-internal.h index 8e4c701751..41eee66e9b 100644 --- a/replay/replay-internal.h +++ b/replay/replay-internal.h @@ -100,12 +100,12 @@ int64_t replay_get_qword(void); void replay_get_array(uint8_t *buf, size_t *size); void replay_get_array_alloc(uint8_t **buf, size_t *size); -/* Mutex functions for protecting replay log file */ +/* Mutex functions for protecting replay log file and ensuring + * synchronisation between vCPU and main-loop threads. */ void replay_mutex_init(void); void replay_mutex_destroy(void); -void replay_mutex_lock(void); -void replay_mutex_unlock(void); +bool replay_mutex_locked(void); /*! Checks error status of the file. */ void replay_check_error(void); diff --git a/stubs/replay.c b/stubs/replay.c index 9c8aa48c9c..04279abb2c 100644 --- a/stubs/replay.c +++ b/stubs/replay.c @@ -72,3 +72,11 @@ uint64_t blkreplay_next_id(void) { return 0; } + +void replay_mutex_lock(void) +{ +} + +void replay_mutex_unlock(void) +{ +}