From nobody Fri Oct 24 21:59:48 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) 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=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1519725547652771.6514303133496; Tue, 27 Feb 2018 01:59:07 -0800 (PST) Received: from localhost ([::1]:35842 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqc2H-0006nb-0a for importer@patchew.org; Tue, 27 Feb 2018 04:59:01 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39602) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqbvs-0000yq-Ee for qemu-devel@nongnu.org; Tue, 27 Feb 2018 04:52:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eqbvo-0004jW-H1 for qemu-devel@nongnu.org; Tue, 27 Feb 2018 04:52:24 -0500 Received: from mail.ispras.ru ([83.149.199.45]:57366) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqbvo-0004jI-3y for qemu-devel@nongnu.org; Tue, 27 Feb 2018 04:52:20 -0500 Received: from [127.0.1.1] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id 2D2EB54006A; Tue, 27 Feb 2018 12:52:19 +0300 (MSK) From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Tue, 27 Feb 2018 12:52:20 +0300 Message-ID: <20180227095220.1060.58759.stgit@pasha-VirtualBox> In-Reply-To: <20180227095135.1060.36549.stgit@pasha-VirtualBox> References: <20180227095135.1060.36549.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] [PATCH v7 08/22] replay: added replay log format description 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: kwolf@redhat.com, peter.maydell@linaro.org, war2jordan@live.com, pavel.dovgaluk@ispras.ru, quintela@redhat.com, ciro.santilli@gmail.com, jasowang@redhat.com, mst@redhat.com, zuban32s@gmail.com, maria.klimushenkova@ispras.ru, dovgaluk@ispras.ru, kraxel@redhat.com, boost.lists@gmail.com, thomas.dullien@googlemail.com, pbonzini@redhat.com, alex.bennee@linaro.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 From: Pavel Dovgalyuk This patch adds description of the replay log file format into the docs/replay.txt. Signed-off-by: Pavel Dovgalyuk Acked-by: Paolo Bonzini --- docs/replay.txt | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 69 insertions(+) diff --git a/docs/replay.txt b/docs/replay.txt index 486c1e0..c52407f 100644 --- a/docs/replay.txt +++ b/docs/replay.txt @@ -232,3 +232,72 @@ Audio devices Audio data is recorded and replay automatically. The command line for reco= rding and replaying must contain identical specifications of audio hardware, e.g= .: -soundhw ac97 + +Replay log format +----------------- + +Record/replay log consits of the header and the sequence of execution +events. The header includes 4-byte replay version id and 8-byte reserved +field. Version is updated every time replay log format changes to prevent +using replay log created by another build of qemu. + +The sequence of the events describes virtual machine state changes. +It includes all non-deterministic inputs of VM, synchronization marks and +instruction counts used to correctly inject inputs at replay. + +Synchronization marks (checkpoints) are used for synchronizing qemu threads +that perform operations with virtual hardware. These operations may change +system's state (e.g., change some register or generate interrupt) and +therefore should execute synchronously with CPU thread. + +Every event in the log includes 1-byte event id and optional arguments. +When argument is an array, it is stored as 4-byte array length +and corresponding number of bytes with data. +Here is the list of events that are written into the log: + + - EVENT_INSTRUCTION. Instructions executed since last event. + Argument: 4-byte number of executed instructions. + - EVENT_INTERRUPT. Used to synchronize interrupt processing. + - EVENT_EXCEPTION. Used to synchronize exception handling. + - EVENT_ASYNC. This is a group of events. They are always processed + together with checkpoints. When such an event is generated, it is + stored in the queue and processed only when checkpoint occurs. + Every such event is followed by 1-byte checkpoint id and 1-byte + async event id from the following list: + - REPLAY_ASYNC_EVENT_BH. Bottom-half callback. This event synchronizes + callbacks that affect virtual machine state, but normally called + asyncronously. + Argument: 8-byte operation id. + - REPLAY_ASYNC_EVENT_INPUT. Input device event. Contains + parameters of keyboard and mouse input operations + (key press/release, mouse pointer movement). + Arguments: 9-16 bytes depending of input event. + - REPLAY_ASYNC_EVENT_INPUT_SYNC. Internal input synchronization event. + - REPLAY_ASYNC_EVENT_CHAR_READ. Character (e.g., serial port) device = input + initiated by the sender. + Arguments: 1-byte character device id. + Array with bytes were read. + - REPLAY_ASYNC_EVENT_BLOCK. Block device operation. Used to synchroni= ze + operations with disk and flash drives with CPU. + Argument: 8-byte operation id. + - REPLAY_ASYNC_EVENT_NET. Incoming network packet. + Arguments: 1-byte network adapter id. + 4-byte packet flags. + Array with packet bytes. + - EVENT_SHUTDOWN. Occurs when user sends shutdown event to qemu, + e.g., by closing the window. + - EVENT_CHAR_WRITE. Used to synchronize character output operations. + Arguments: 4-byte output function return value. + 4-byte offset in the output array. + - EVENT_CHAR_READ_ALL. Used to synchronize character input operations, + initiated by qemu. + Argument: Array with bytes that were read. + - EVENT_CHAR_READ_ALL_ERROR. Unsuccessful character input operation, + initiated by qemu. + Argument: 4-byte error code. + - EVENT_CLOCK + clock_id. Group of events for host clock read operations. + Argument: 8-byte clock value. + - EVENT_CHECKPOINT + checkpoint_id. Checkpoint for synchronization of + CPU, internal threads, and asynchronous input events. May be followed + by one or more EVENT_ASYNC events. + - EVENT_END. Last event in the log.