Message ID | 20171114081711.27640.38697.stgit@pasha-VirtualBox |
---|---|
State | New |
Headers | show |
Series | replay additions | expand |
On 14/11/2017 09:17, Pavel Dovgalyuk wrote: > From: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> > > This patch adds description of the replay log file format > into the docs/replay.txt. > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> > > --- > 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 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. > Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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 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.