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Re: [Qemu-devel] [RFC PATCH v2 00/49] Series short description


From: Frederic Konrad
Subject: Re: [Qemu-devel] [RFC PATCH v2 00/49] Series short description
Date: Fri, 18 Jul 2014 10:10:20 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0

On 17/07/2014 13:01, Pavel Dovgalyuk wrote:
This set of patches is related to the reverse execution and deterministic
replay of qemu execution  Our implementation of deterministic replay can
be used for deterministic and reverse debugging of guest code through gdb
remote interface.

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.

Reverse execution 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, and ARM hardware platforms.
  * Performs deterministic replay of all operations with keyboard, mouse, 
network adapters,
    audio devices, serial interfaces, and physical USB devices connected to the 
emulator.
  * Provides support for gdb reverse debugging commands like reverse-step and 
reverse-continue.
  * Supports auto-checkpointing for convenient reverse debugging.

Usage of the record/replay:
  * First, record the execution, by adding '-record fname=replay.bin' to the
    command line.
  * Then you can replay it for the multiple times by using another command
    line option: '-replay fname=replay.bin'
  * Virtual machine should have at least one virtual disk, which is used to
    store checkpoints. If you want to enable automatic checkpointing, simply
    add ',period=XX' to record options, where XX is the checkpointing period
    in seconds.
  * Using of the network adapters in record/replay mode is possible with
    the following command-line options:
    - '-net user' (or another host adapter) in record mode
    - '-net replay' in replay mode. Every host network adapter should be
      replaced by 'replay' when replaying the execution.
  * Reverse debugging can be used through gdb remote interface.
    reverse-stepi and reverse-continue commands are supported. Other reverse
    commands should also work, because they reuse these ones.
  * Monitor is extended by the following commands:
    - replay_info - prints information about replay mode and current step
      (number of instructions executed)
    - replay_break - sets "breakpoint" at the specified instructions count.
    - replay_seek - rewinds (using the checkpoints, if possible) to the
      specified step of replay log.

Paper with short description of deterministic replay implementation:
http://www.computer.org/csdl/proceedings/csmr/2012/4666/00/4666a553-abs.html

Modifications of qemu include:
  * adding missed fields of the virtual devices' states to the vmstate
    structures to allow deterministic saving and restoring the VM state
  * adding virtual clock-based timers to vmstate structures, because virtual
    clock is the part of the virtual machine state
  * modification of block layer to support automatic creation of the overlay
    files to store the changes and snapshots while recording
  * disabling of system reset while loading VM state to avoid generating of
    interrupts by reset handlers
  * adding warpers 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 bottom halves execution
  * synchronization of the threads from thread pool
  * recording/replaying user input (mouse and keyboard), input from virtual
    serial ports, incoming network packets, input from connected USB devices
  * adding HMP/QMP commands to monitor for controlling replay execution

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

Thanks for reshaping the patches.
We are a little busy just now, but I will review that as soon as possible.

Thanks,
Fred


---

Pavel Dovgalyuk (49):
       acpi: accurate overflow check
       integratorcp: adding vmstate for save/restore
       pcspk: adding vmstate for save/restore
       fdc: adding vmstate for save/restore
       parallel: adding vmstate for save/restore
       serial: fixing vmstate for save/restore
       kvmapic: fixing loading vmstate
       hpet: fixing saving and loading process
       pckbd: adding new fields to vmstate
       rtl8139: adding new fields to vmstate
       piix: do not raise irq while loading vmstate
       mc146818rtc: add missed field to vmstate
       pl031: add missed field to vmstate
       ide pci: reset status field before loading the vmstate
       softmmu: fixing usage of cpu_st/ld* from helpers
       target: save cpu state fields
       target-i386: update fp status fix
       migration: add vmstate for int8 and char arrays
       replay: global variables and function stubs
       block: add suffix parameter to bdrv_open functions
       sysemu: system functions for replay
       replay: internal functions for replay log
       cpu: invent instruction count for accurate replay
       target-arm: instructions counting code for replay
       target-i386: instructions counting code for replay
       replay: interrupts and exceptions
       vga: do not use virtual clock for blinking cursor
       replay: asynchronous events infrastructure
       replay: recording and replaying clock ticks
       replay: recording and replaying different timers
       replay: shutdown event
       replay: checkpoints
       replay: bottom halves
       replay: replay aio requests
       replay: thread pool
       pl031: vmstate in replay mode
       replay: initialization and deinitialization
       replay: command line options
       replay: snapshotting the virtual machine
       replay: recording of the user input
       tap-win32: destroy the thread at exit
       replay: network packets record/replay
       replay: audio data record/replay
       replay: serial port
       replay: USB passthrough
       replay: replay_info command
       replay: replay_break command
       replay: replay_seek_step command
       gdbstub: reverse debugging


  Makefile.target                  |    1
  arch_init.c                      |    8
  async.c                          |   45 ++
  audio/audio.c                    |   14 +
  audio/audio_win_int.h            |    3
  audio/winwaveaudio.c             |  167 +++++++--
  block.c                          |  134 ++++++-
  block/blkdebug.c                 |    2
  block/blkverify.c                |    4
  block/cow.c                      |    2
  block/qcow.c                     |    2
  block/qcow2.c                    |   10 -
  block/qed.c                      |    2
  block/raw-posix.c                |    6
  block/raw-win32.c                |    4
  block/sheepdog.c                 |    4
  block/vmdk.c                     |    8
  block/vvfat.c                    |    2
  blockdev.c                       |   11 -
  cpu-exec.c                       |   34 +-
  cpus.c                           |   81 ++++
  dma-helpers.c                    |   10 -
  exec.c                           |   12 +
  gdbstub.c                        |   79 +++-
  hmp-commands.hx                  |   41 ++
  hw/acpi/core.c                   |    7
  hw/arm/integratorcp.c            |   38 ++
  hw/audio/pcspk.c                 |   19 +
  hw/block/fdc.c                   |   11 -
  hw/block/virtio-blk.c            |   10 -
  hw/char/parallel.c               |   22 +
  hw/char/serial.c                 |  115 ++++--
  hw/display/vga.c                 |    4
  hw/i386/kvmvapic.c               |   22 +
  hw/ide/ahci.c                    |    4
  hw/ide/atapi.c                   |    9
  hw/ide/core.c                    |   18 +
  hw/ide/pci.c                     |   10 +
  hw/input/pckbd.c                 |    3
  hw/intc/apic_common.c            |    5
  hw/net/rtl8139.c                 |    5
  hw/pci-host/piix.c               |   22 +
  hw/timer/arm_timer.c             |    2
  hw/timer/hpet.c                  |   13 -
  hw/timer/mc146818rtc.c           |    5
  hw/timer/pl031.c                 |   35 +-
  hw/usb/hcd-uhci.c                |    2
  hw/usb/host-libusb.c             |  525 ++++++++++++++++++---------
  include/block/aio.h              |   17 +
  include/block/block.h            |   21 +
  include/block/thread-pool.h      |    4
  include/exec/cpu-defs.h          |    1
  include/exec/cpu_ldst_template.h |   28 +
  include/exec/exec-all.h          |   31 ++
  include/hw/host-libusb.h         |  105 +++++
  include/migration/vmstate.h      |   13 +
  include/qemu-common.h            |    3
  include/qemu/main-loop.h         |    1
  include/qemu/timer.h             |   48 ++
  include/qom/cpu.h                |    4
  include/sysemu/char.h            |   25 +
  include/sysemu/cpus.h            |    1
  include/sysemu/sysemu.h          |    2
  include/ui/input.h               |    2
  main-loop.c                      |    5
  monitor.c                        |   49 +++
  net/Makefile.objs                |    1
  net/clients.h                    |    3
  net/dump.c                       |    6
  net/hub.c                        |    1
  net/net-replay.c                 |   66 +++
  net/net.c                        |    7
  net/slirp.c                      |   14 +
  net/socket.c                     |   35 ++
  net/tap-win32.c                  |   25 +
  net/tap.c                        |   23 +
  net/vde.c                        |   14 +
  qapi-schema.json                 |   62 +++
  qemu-char.c                      |   55 +++
  qemu-img.c                       |    6
  qemu-io-cmds.c                   |    2
  qemu-io.c                        |    4
  qemu-nbd.c                       |    2
  qemu-options.hx                  |   28 +
  qemu-timer.c                     |   45 ++
  qmp-commands.hx                  |   60 +++
  replay/Makefile.objs             |   11 +
  replay/replay-audio.c            |  228 ++++++++++++
  replay/replay-char.c             |   99 +++++
  replay/replay-debug.c            |  148 ++++++++
  replay/replay-events.c           |  381 ++++++++++++++++++++
  replay/replay-input.c            |  107 ++++++
  replay/replay-internal.c         |  159 ++++++++
  replay/replay-internal.h         |  224 ++++++++++++
  replay/replay-net.c              |  190 ++++++++++
  replay/replay-qmp.c              |   57 +++
  replay/replay-time.c             |  181 +++++++++
  replay/replay-usb.c              |  188 ++++++++++
  replay/replay.c                  |  735 ++++++++++++++++++++++++++++++++++++++
  replay/replay.h                  |  218 +++++++++++
  savevm.c                         |   32 +-
  slirp/slirp.c                    |    9
  softmmu_template.h               |   18 +
  stubs/Makefile.objs              |    1
  stubs/replay.c                   |   42 ++
  target-arm/Makefile.objs         |    1
  target-arm/helper.h              |    3
  target-arm/machine.c             |    5
  target-arm/replay_helper.c       |   38 ++
  target-arm/translate.c           |   62 +++
  target-i386/Makefile.objs        |    1
  target-i386/cpu.c                |    1
  target-i386/cpu.h                |    8
  target-i386/fpu_helper.c         |    5
  target-i386/helper.h             |    3
  target-i386/machine.c            |    7
  target-i386/replay_helper.c      |   38 ++
  target-i386/translate.c          |   91 ++++-
  tests/test-thread-pool.c         |    7
  thread-pool.c                    |   53 ++-
  trace-events                     |    2
  translate-all.c                  |   15 +
  ui/input.c                       |   79 +++-
  util/iov.c                       |    4
  vl.c                             |  108 +++++-
  vmstate.c                        |    6
  126 files changed, 5433 insertions(+), 543 deletions(-)
  create mode 100755 include/hw/host-libusb.h
  create mode 100755 net/net-replay.c
  create mode 100755 replay/Makefile.objs
  create mode 100755 replay/replay-audio.c
  create mode 100755 replay/replay-char.c
  create mode 100755 replay/replay-debug.c
  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-net.c
  create mode 100755 replay/replay-qmp.c
  create mode 100755 replay/replay-time.c
  create mode 100755 replay/replay-usb.c
  create mode 100755 replay/replay.c
  create mode 100755 replay/replay.h
  create mode 100755 stubs/replay.c
  create mode 100755 target-arm/replay_helper.c
  create mode 100755 target-i386/replay_helper.c





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