Re: [Qemu-devel] [PATCH v18 00/21] Deterministic replay core

[Paolo Bonzini]

On 21/09/2015 09:12, Pavel Dovgaluk wrote:
> Hi!
> 
> Paolo, have you reviewed these patches?

Yes, I'll reply to a couple of them but there's no need to send v19.

Paolo

> Pavel Dovgalyuk
> 
>> -----Original Message-----
>> From: Pavel Dovgalyuk [mailto:address@hidden
>> Sent: Thursday, September 17, 2015 7:23 PM
>> To: address@hidden
>> Cc: address@hidden; address@hidden; address@hidden;
>> address@hidden; address@hidden; address@hidden; address@hidden;
>> address@hidden; address@hidden; address@hidden; address@hidden;
>> address@hidden; address@hidden
>> Subject: [PATCH v18 00/21] Deterministic replay core
>>
>> This set of patches is related to the reverse execution and deterministic
>> replay of qemu execution. This implementation of deterministic replay can
>> be used for deterministic debugging of guest code through gdb remote
>> interface.
>>
>> Core set of patches does not include support for reverse debugging commands
>> of gdb, block devices' operations, USB replay support.
>>
>> These patches include only core function of the replay,
>> excluding the support for replaying serial, audio, network, and USB devices'
>> operations. Reverse debugging and monitor commands were also excluded to
>> be submitted later as separate patches.
>>
>> Execution recording writes non-deterministic events log, which can be later
>> used for replaying the execution anywhere and for unlimited number of times.
>> It also supports checkpointing for faster rewinding during reverse debugging.
>> Execution replaying reads the log and replays all non-deterministic events
>> including external input, hardware clocks, and interrupts.
>>
>> Full version of deterministic replay has the following features:
>>  * Deterministically replays whole system execution and all contents of the 
>> memory,
>>    state of the hadrware devices, clocks, and screen of the VM.
>>  * Writes execution log into the file for latter replaying for multiple times
>>    on different machines.
>>  * Supports i386, x86_64, ARM, PowerPC, and MIPS hardware platforms.
>>  * Performs deterministic replay of all operations with keyboard and mouse
>>    input devices.
>>  * Supports auto-checkpointing for convenient reverse debugging.
>>
>> Usage of the record/replay core:
>>  * First, record the execution, by adding the following string to the 
>> command line:
>>    '-icount shift=7,rr=record,rrfile=replay.bin -net none'.
>>    Block devices' images are not actually changed in the recording mode,
>>    because all of the changes are written to the temporary overlay file.
>>  * Then you can replay it for the multiple times by using another command
>>    line option: '-icount shift=7,rr=replay,rrfile=replay.bin -net none'
>>  * '-net none' option should also be specified if network replay patches
>>    are not applied.
>>  * Do not add any disk images to VM, because they are not supported by
>>    the core patches.
>>
>> Papers with description of deterministic replay implementation:
>> http://www.computer.org/csdl/proceedings/csmr/2012/4666/00/4666a553-abs.html
>> http://dl.acm.org/citation.cfm?id=2786805.2803179
>>
>> Public repository with current version of the patches:
>> https://github.com/Dovgalyuk/qemu/tree/rr-17
>>
>> Modifications of qemu include:
>>  * wrappers for clock and time functions to save their return values in the 
>> log
>>  * saving different asynchronous events (e.g. system shutdown) into the log
>>  * synchronization of the threads from thread pool
>>  * recording/replaying user input (mouse and keyboard)
>>  * adding internal events for cpu and io synchronization
>>
>> v18 changes:
>>  * Patches were updated to match upstream version
>>  * Added missed replay-user.c file
>>
>> v17 changes:
>>  * Removed useless stub functions (as suggested by Paolo Bonzini)
>>  * Refined checkpoint-related code (as suggested by Paolo Bonzini)
>>  * Improved icount processing (as suggested by Paolo Bonzini)
>>  * Added checkpoint for suspend event (as suggested by Paolo Bonzini)
>>  * Fixed linux-user configurations build
>>  * Minor fixes
>>
>> v16 changes:
>>  * Several warnings were fixed
>>
>> v15 changes:
>>  * Tested record/replay with MIPS and PowerPC guests
>>  * Published the patches on github
>>  * Fixed replay mutex operation in icount mode
>>  * Fixed timers processing in record/replay mode
>>
>> v14 changes:
>>  * Minor fixes
>>
>> v13 changes:
>>  * Introduced "ptimer trigger" event (as suggested by Paolo Bonzini)
>>
>> v12 changes:
>>  * Removed block patches from the core patches set.
>>
>> v11 changes:
>>  * Fixed instructions event processing.
>>  * Added some mutex protection calls for replay.
>>  * Fixed replaying read operations for qcow2.
>>  * Fixed rtc reads on initializations stage.
>>  * Eliminated some warnings in replay module.
>>  * Fixed misprints in documentation for replay (as suggested by Eric Blake)
>>
>> v10 changes:
>>  * Fixed queue processing for bottom halves (as suggested by Paolo Bonzini)
>>  * Rewritten several replay functions (as suggested by Paolo Bonzini)
>>  * Some minor fixes.
>>
>> v9 changes:
>>  * Replaced fwrite/fread with putc/getc (as suggested by Paolo Bonzini)
>>  * Stopping virtual machine in case of replay file end (as suggested by 
>> Paolo Bonzini)
>>  * Removed one of the replay mutexes (as suggested by Paolo Bonzini)
>>  * Fixed RCU queue for bottom halves (as suggested by Paolo Bonzini)
>>  * Updated command line options' names (as suggested by Paolo Bonzini)
>>  * Added design document for record/replay (as suggested by Paolo Bonzini)
>>  * Simplified checkpoints for the timers
>>  * Added cloning InputEvent objects for replay (as suggested by Paolo 
>> Bonzini)
>>  * Added replay blockers instead of checking the command line (as suggested 
>> by Paolo Bonzini)
>>  * Some functions renaming and extracting.
>>
>> v8 changes:
>>  * Simplified processing of the shutdown event (as suggested by Paolo 
>> Bonzini)
>>  * Replaced stack of bottom halves in AIO context with QSIMPLEQ (as 
>> suggested by Paolo
>> Bonzini)
>>  * Moved replay_submode out of the series (as suggested by Paolo Bonzini)
>>  * Moved suffix option out of the series
>>  * Converted some of the defines into enums (as suggested by Paolo Bonzini)
>>  * Encapsulated save_tm/read_tm calls into the single function (as suggested 
>> by Paolo Bonzini)
>>  * Moved record/replay options to icount group (as suggested by Paolo 
>> Bonzini)
>>  * Updated mutex protection for the events queue (as suggested by Paolo 
>> Bonzini)
>>  * Added mutex to protect replay log file (as suggested by Paolo Bonzini)
>>  * Minor cleanups
>>
>> v7 changes:
>>  * Removed patches that were applied to upstream.
>>
>> v6 changes:
>>  * Fixed replay stub return value (as suggested by Eric Blake)
>>  * Fixed icount warping.
>>  * Virtual rt clock now uses cpu_get_clock() (as suggested by Paolo Bonzini)
>>  * Replated get_clock_realtime and get_clock calls with qemu clock requests 
>> (as suggested by
>> Paolo Bonzini)
>>  * Modified can_do_io logic to allow requesting icount from cpu_exec 
>> function (as suggested by
>> Paolo Bonzini)
>>  * Removed applied patches.
>>
>> v5 changes:
>>  * Minor changes.
>>  * Used fixed-width integer types for read/write functions (as suggested by 
>> Alex Bennee)
>>  * Moved savevm-related code out of the core.
>>  * Added new traced clock for deterministic virtual clock warping (as 
>> suggested by Paolo
>> Bonzini)
>>  * Fixed exception_index reset for user mode (as suggested by Paolo Bonzini)
>>  * Adopted Paolo's icount patches
>>  * Fixed hardware interrupts replaying
>>
>> v4 changes:
>>  * Updated block drivers to support new bdrv_open interface.
>>  * Moved migration patches into separate series (as suggested by Paolo 
>> Bonzini)
>>  * Fixed a bug in replay_break operation.
>>  * Fixed rtl8139 migration for replay.
>>  * Fixed 'period' parameter processing for record mode.
>>  * Fixed bug in 'reverse-stepi' implementation.
>>  * Fixed replay without making any snapshots (even the starting one).
>>  * Moved core replay patches into the separate series.
>>  * Fixed reverse step and reverse continue support.
>>  * Fixed several bugs in icount subsystem.
>>  * Reusing native qemu icount for replay instructions counting.
>>  * Separated core patches into their own series.
>>
>> v3 changes:
>>  * Fixed bug with replay of the aio write operations.
>>  * Added virtual clock based on replay icount.
>>  * Removed duplicated saving of interrupt_request CPU field.
>>  * Fixed some coding style issues.
>>  * Renamed QMP commands for controlling reverse execution (as suggested by 
>> Eric Blake)
>>  * Replay mode and submode implemented as QAPI enumerations (as suggested by 
>> Eric Blake)
>>  * Added description and example for replay-info command (as suggested by 
>> Eric Blake)
>>  * Added information about the current breakpoint to the output of 
>> replay-info (as suggested
>> by Eric Blake)
>>  * Updated version id for HPET vmstate (as suggested by Paolo Bonzini)
>>  * Removed static fields from parallel vmstate (as suggested by Paolo 
>> Bonzini)
>>  * New vmstate fields for mc146818rtc, pckbd, kvmapic, serial, fdc, rtl8139 
>> moved to
>> subsection (as suggested by Paolo Bonzini)
>>  * Disabled textmode cursor blinking, when virtual machine is stopped (as 
>> suggested by Paolo
>> Bonzini)
>>  * Extracted saving of exception_index to separate patch (as suggested by 
>> Paolo Bonzini)
>>
>> v2 changes:
>>  * Patches are split to be reviewable and bisectable (as suggested by Kirill 
>> Batuzov)
>>  * Added QMP versions of replay commands (as suggested by Eric Blake)
>>  * Removed some optional features of replay to make patches cleaner
>>  * Minor changes and code cleanup were made
>>
>> ---
>>
>> Pavel Dovgalyuk (21):
>>       i386: partial revert of interrupt poll fix
>>       replay: global variables and function stubs
>>       replay: internal functions for replay log
>>       replay: introduce mutex to protect the replay log
>>       replay: introduce icount event
>>       cpu-exec: allow temporary disabling icount
>>       cpu: replay instructions sequence
>>       i386: interrupt poll processing
>>       replay: interrupts and exceptions
>>       replay: asynchronous events infrastructure
>>       replay: recording and replaying clock ticks
>>       replay: shutdown event
>>       icount: improve counting for record/replay
>>       replay: checkpoints
>>       bottom halves: introduce bh call function
>>       replay: ptimer
>>       typedef: add typedef for QemuOpts
>>       replay: initialization and deinitialization
>>       replay: replay blockers for devices
>>       replay: command line options
>>       replay: recording of the user input
>>
>>
>>  Makefile.target           |    1
>>  async.c                   |    7 +
>>  cpu-exec.c                |   62 +++++++-
>>  cpus.c                    |   57 +++++---
>>  docs/replay.txt           |  168 ++++++++++++++++++++++
>>  exec.c                    |    2
>>  hw/bt/hci.c               |    7 +
>>  hw/core/ptimer.c          |    7 +
>>  include/block/aio.h       |    5 +
>>  include/exec/exec-all.h   |    1
>>  include/qapi/qmp/qerror.h |    3
>>  include/qemu/option.h     |    5 -
>>  include/qemu/typedefs.h   |    3
>>  include/ui/input.h        |    2
>>  main-loop.c               |    3
>>  qapi-schema.json          |   18 ++
>>  qapi/common.json          |    6 +
>>  qemu-options.hx           |    8 +
>>  qemu-timer.c              |   48 +++++-
>>  replay/Makefile.objs      |    6 +
>>  replay/replay-events.c    |  274 ++++++++++++++++++++++++++++++++++++
>>  replay/replay-input.c     |  160 +++++++++++++++++++++
>>  replay/replay-internal.c  |  206 +++++++++++++++++++++++++++
>>  replay/replay-internal.h  |  140 ++++++++++++++++++
>>  replay/replay-time.c      |   64 ++++++++
>>  replay/replay-user.c      |   36 +++++
>>  replay/replay.c           |  342 
>> +++++++++++++++++++++++++++++++++++++++++++++
>>  replay/replay.h           |  120 ++++++++++++++++
>>  stubs/Makefile.objs       |    1
>>  stubs/replay.c            |   32 ++++
>>  target-i386/cpu.c         |   10 -
>>  target-i386/seg_helper.c  |    3
>>  translate-all.c           |    2
>>  ui/input.c                |   27 +++-
>>  vl.c                      |   53 ++++++-
>>  35 files changed, 1820 insertions(+), 69 deletions(-)
>>  create mode 100755 docs/replay.txt
>>  create mode 100755 replay/Makefile.objs
>>  create mode 100755 replay/replay-events.c
>>  create mode 100755 replay/replay-input.c
>>  create mode 100755 replay/replay-internal.c
>>  create mode 100755 replay/replay-internal.h
>>  create mode 100755 replay/replay-time.c
>>  create mode 100755 replay/replay-user.c
>>  create mode 100755 replay/replay.c
>>  create mode 100755 replay/replay.h
>>  create mode 100755 stubs/replay.c
>>
>> --
>> Pavel Dovgalyuk
>