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[Qemu-devel] [PULL 56/69] replay: added replay log format description
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 56/69] replay: added replay log format description |
Date: |
Tue, 13 Mar 2018 23:47:06 +0100 |
From: Pavel Dovgalyuk <address@hidden>
This patch adds description of the replay log file format
into the docs/replay.txt.
Signed-off-by: Pavel Dovgalyuk <address@hidden>
Acked-by: Paolo Bonzini <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
docs/replay.txt | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)
diff --git a/docs/replay.txt b/docs/replay.txt
index 486c1e0e9d..c52407fe23 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 recording
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 synchronize
+ 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.
--
2.14.3
- [Qemu-devel] [PULL 49/69] hw/alpha/dp264: Add the ISA DMA controller, (continued)
- [Qemu-devel] [PULL 49/69] hw/alpha/dp264: Add the ISA DMA controller, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 48/69] hw/isa/superio: Add the SMC FDC37C669 Super I/O, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 45/69] hw/isa/vt82c686: Add the TYPE_VT82C686B_SUPERIO, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 44/69] hw/isa/vt82c686: Rename vt82c686b_init() -> vt82c686b_isa_init(), Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 43/69] hw/mips/mips_fulong2e: Factor out vt82c686b_southbridge_init(), Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 51/69] hw/i386/pc: Factor out the superio code, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 50/69] hw/alpha/dp264: Use the TYPE_SMC37C669_SUPERIO, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 52/69] cpu-exec: fix exception_index handling, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 53/69] replay: fix processing async events, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 54/69] replay: fixed replay_enable_events, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 56/69] replay: added replay log format description,
Paolo Bonzini <=
- [Qemu-devel] [PULL 55/69] replay: fix save/load vm for non-empty queue, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 57/69] replay: save prior value of the host clock, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 60/69] replay: make locking visible outside replay code, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 59/69] replay/replay-internal.c: track holding of replay_lock, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 58/69] replay/replay.c: bump REPLAY_VERSION again, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 61/69] replay: don't destroy mutex at exit, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 62/69] replay: push replay_mutex_lock up the call tree, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 64/69] replay: avoid recursive call of checkpoints, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 63/69] replay: check return values of fwrite, Paolo Bonzini, 2018/03/13
- [Qemu-devel] [PULL 65/69] scripts/replay-dump.py: replay log dumper, Paolo Bonzini, 2018/03/13