[Qemu-devel] [PATCH v5 0/7] Deterministic replay extensions

[Pavel Dovgalyuk]

This set of patches is related to the reverse execution and deterministic 
replay of qemu execution. It includes recording and replaying of serial devices
and block devices operations.

With these patches one can record and deterministically replay behavior
of the system with connected disk drives and serial communication ports
(e.g., telnet terminal).

Patches for deterministic replay of the block devices intercept calls of
bdrv coroutine functions at the top of block drivers stack.
To record and replay block operations the drive must be configured
as following:
 -drive file=disk.qcow,if=none,id=img-direct
 -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay
 -device ide-hd,drive=img-blkreplay

blkreplay driver should be inserted between disk image and virtual driver
controller. Therefore all disk requests may be recorded and replayed.

v5 changes:
 - updated record/replay documentation (as suggested by Paolo Bonzini)
 - added record/replay support for qemu_chr_fe_write_all and 
qemu_chr_fe_read_all functions
 - added protection from chardevs unplugging in record/replay mode (as 
suggested by Paolo Bonzini)
 - minor chardevs record/replay changes (as suggested by Paolo Bonzini)
 - BH replay bugfix was moved to separate patch (as suggested by Stefan 
Hajnoczi)
 - fixed error message in replay events queue module

v4 changes:
 - minor fixes in blkreplay layer (as suggested by Kevin Wolf)
 - split qemu_clock_warp into two functions (as suggested by Paolo Bonzini)

v3 changes:
 - introduced bdrv_flush callback for block drivers
 - introduced block driver for recording block operations (as suggested by 
Kevin Wolf)
 - added documentation for block record/replay

v2 changes:
 - removed obsolete call of qemu_clock_warp
 - fixed record/replay of aio_cancel
 - simplified call sequence for blk_aio_ functions in non-replay mode (as 
suggested by Kevin Wolf)

---

Pavel Dovgalyuk (7):
      replay: character devices
      icount: remove obsolete warp call
      icount: decouple warp calls
      block: add flush callback
      replay: bh scheduling fix
      replay: fix error message
      replay: introduce block devices record/replay


 block/Makefile.objs       |    2 -
 block/blkreplay.c         |  159 +++++++++++++++++++++++++++++++++++++++++++
 block/io.c                |    7 ++
 cpus.c                    |   56 ++++++++-------
 docs/replay.txt           |   37 +++++++++-
 gdbstub.c                 |    2 -
 include/block/block_int.h |    7 ++
 include/qemu/timer.h      |   14 +++-
 include/sysemu/char.h     |   26 +++++++
 include/sysemu/replay.h   |   22 ++++++
 main-loop.c               |    2 -
 qemu-char.c               |  138 ++++++++++++++++++++++++++++++-------
 qemu-timer.c              |    4 +
 replay/Makefile.objs      |    1 
 replay/replay-char.c      |  167 +++++++++++++++++++++++++++++++++++++++++++++
 replay/replay-events.c    |   41 ++++++++++-
 replay/replay-internal.h  |   19 +++++
 replay/replay.c           |    2 -
 stubs/clock-warp.c        |    2 -
 stubs/replay.c            |    4 +
 20 files changed, 641 insertions(+), 71 deletions(-)
 create mode 100755 block/blkreplay.c
 create mode 100755 replay/replay-char.c

-- 
Pavel Dovgalyuk