From nobody Thu Oct 30 04:03:16 2025 Delivered-To: importer@patchew.org Received-SPF: temperror (zoho.com: Error in retrieving data from DNS) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=temperror (zoho.com: Error in retrieving data from DNS) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1509448942933523.9151620532889; Tue, 31 Oct 2017 04:22:22 -0700 (PDT) Received: from localhost ([::1]:44851 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e9UcS-0000H7-0e for importer@patchew.org; Tue, 31 Oct 2017 07:22:08 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39991) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e9UP3-00053d-Qr for qemu-devel@nongnu.org; Tue, 31 Oct 2017 07:08:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e9UOu-0007AC-05 for qemu-devel@nongnu.org; Tue, 31 Oct 2017 07:08:17 -0400 Received: from mail.ispras.ru ([83.149.199.45]:42342) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e9UOt-00079L-IP for qemu-devel@nongnu.org; Tue, 31 Oct 2017 07:08:07 -0400 Received: from [127.0.1.1] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id DC6EE54006A; Tue, 31 Oct 2017 14:08:06 +0300 (MSK) From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Tue, 31 Oct 2017 14:08:07 +0300 Message-ID: <20171031110807.5836.50809.stgit@pasha-VirtualBox> In-Reply-To: <20171031110641.5836.43266.stgit@pasha-VirtualBox> References: <20171031110641.5836.43266.stgit@pasha-VirtualBox> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 83.149.199.45 Subject: [Qemu-devel] [RFC PATCH 16/26] replay: make locking visible outside replay code X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dovgaluk@ispras.ru Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_6 Z_629925259 SPT_0 From: Alex Benn=C3=A9e 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 Benn=C3=A9e --- include/sysemu/replay.h | 14 ++++++++++++++ replay/replay-internal.c | 5 ++--- replay/replay-internal.h | 5 ++--- stubs/replay.c | 15 +++++++++++++++ 4 files changed, 33 insertions(+), 6 deletions(-) diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h index b86d6bb..9973849 100644 --- a/include/sysemu/replay.h +++ b/include/sysemu/replay.h @@ -47,6 +47,20 @@ extern ReplayMode replay_mode; /* Name of the initial VM snapshot */ extern char *replay_snapshot; =20 +/* 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); +bool replay_mutex_locked(void); + /* Replay process control functions */ =20 /*! Enables recording or saving event log with specified parameters */ diff --git a/replay/replay-internal.c b/replay/replay-internal.c index 157c863..e6b2fdb 100644 --- a/replay/replay-internal.c +++ b/replay/replay-internal.c @@ -181,7 +181,7 @@ void replay_mutex_destroy(void) =20 static __thread bool replay_locked; =20 -static bool replay_mutex_locked(void) +bool replay_mutex_locked(void) { return replay_locked; } @@ -204,7 +204,7 @@ void replay_mutex_unlock(void) void replay_save_instructions(void) { if (replay_file && replay_mode =3D=3D REPLAY_MODE_RECORD) { - replay_mutex_lock(); + g_assert(replay_mutex_locked()); int diff =3D (int)(replay_get_current_step() - replay_state.curren= t_step); =20 /* Time can only go forward */ @@ -215,6 +215,5 @@ void replay_save_instructions(void) replay_put_dword(diff); replay_state.current_step +=3D diff; } - replay_mutex_unlock(); } } diff --git a/replay/replay-internal.h b/replay/replay-internal.h index 8e4c701..f5f8e96 100644 --- a/replay/replay-internal.h +++ b/replay/replay-internal.h @@ -100,12 +100,11 @@ 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); =20 -/* Mutex functions for protecting replay log file */ +/* Mutex functions for protecting replay log file and ensuring + * synchronisation between vCPU and main-loop threads. */ =20 void replay_mutex_init(void); void replay_mutex_destroy(void); -void replay_mutex_lock(void); -void replay_mutex_unlock(void); =20 /*! Checks error status of the file. */ void replay_check_error(void); diff --git a/stubs/replay.c b/stubs/replay.c index 9991ee5..cb050ef 100644 --- a/stubs/replay.c +++ b/stubs/replay.c @@ -73,3 +73,18 @@ uint64_t blkreplay_next_id(void) { return 0; } + +void replay_mutex_lock(void) +{ + abort(); +} + +void replay_mutex_unlock(void) +{ + abort(); +} + +bool replay_mutex_locked(void) +{ + return false; +}