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[Qemu-devel] [PATCH v7 00/19] Fixing record/replay and adding reverse de
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v7 00/19] Fixing record/replay and adding reverse debugging |
Date: |
Wed, 10 Oct 2018 16:33:34 +0300 |
User-agent: |
StGit/0.17.1-dirty |
GDB remote protocol supports reverse debugging of the targets.
It includes 'reverse step' and 'reverse continue' operations.
The first one finds the previous step of the execution,
and the second one is intended to stop at the last breakpoint that
would happen when the program is executed normally.
Reverse debugging is possible in the replay mode, when at least
one snapshot was created at the record or replay phase.
QEMU can use these snapshots for travelling back in time with GDB.
Running the execution in replay mode allows using GDB reverse debugging
commands:
- reverse-stepi (or rsi): Steps one instruction to the past.
QEMU loads on of the prior snapshots and proceeds to the desired
instruction forward. When that step is reaches, execution stops.
- reverse-continue (or rc): Runs execution "backwards".
QEMU tries to find breakpoint or watchpoint by loaded prior snapshot
and replaying the execution. Then QEMU loads snapshots again and
replays to the latest breakpoint. When there are no breakpoints in
the examined section of the execution, QEMU finds one more snapshot
and tries again. After the first snapshot is processed, execution
stops at this snapshot.
The set of patches include the following modifications:
- gdbstub update for reverse debugging support
- functions that automatically perform reverse step and reverse
continue operations
- hmp/qmp commands for manipulating the replay process
- improvement of the snapshotting for saving the execution step
in the snapshot parameters
- other record/replay fixes
The patches are available in the repository:
https://github.com/ispras/qemu/tree/rr-181010
v7 changes:
- rebased to the new master with upstreamed patches from the series
- several improvements in hmp/qmp commands handling (suggested by Markus
Armbruster)
- fixed record/replay with '-rtc base' option enabled
- added document with virtual hardware requirements
v6 changes:
- rebased to the new version of master
- fixed build of linux-user configurations
- added new clock for slirp and vnc timers
v5 changes:
- multiple fixes of record/replay bugs appeared after QEMU core update
- changed reverse debugging to 'since 3.1'
v4 changes:
- changed 'since 2.13' to 'since 3.0' in json (as suggested by Eric Blake)
v3 changes:
- Fixed PS/2 bug with save/load vm, which caused failures of the replay.
- Rebased to the new code base.
- Minor fixes.
v2 changes:
- documented reverse debugging
- fixed start vmstate loading in record mode
- documented qcow2 changes (as suggested by Eric Blake)
- made icount SnapshotInfo field optional (as suggested by Eric Blake)
- renamed qmp commands (as suggested by Eric Blake)
- minor changes
---
Pavel Dovgalyuk (19):
block: implement bdrv_snapshot_goto for blkreplay
replay: disable default snapshot for record/replay
replay: update docs for record/replay with block devices
replay: don't drain/flush bdrv queue while RR is working
replay: finish record/replay before closing the disks
qcow2: introduce icount field for snapshots
migration: introduce icount field for snapshots
replay: provide and accessor for rr filename
replay: introduce info hmp/qmp command
replay: introduce breakpoint at the specified step
replay: implement replay-seek command to proceed to the desired step
replay: refine replay-time module
replay: flush rr queue before loading the vmstate
gdbstub: add reverse step support in replay mode
gdbstub: add reverse continue support in replay mode
replay: describe reverse debugging in docs/replay.txt
replay: add BH oneshot event for block layer
replay: init rtc after enabling the replay
replay: document development rules
accel/tcg/translator.c | 1
block/blkreplay.c | 8 +
block/block-backend.c | 3
block/io.c | 22 +++
block/qapi.c | 17 ++
block/qcow2-snapshot.c | 9 +
block/qcow2.h | 2
blockdev.c | 10 +
cpus.c | 19 ++-
docs/devel/replay.txt | 45 ++++++
docs/interop/qcow2.txt | 4 +
docs/replay.txt | 45 ++++++
exec.c | 6 +
gdbstub.c | 50 +++++++
hmp-commands-info.hx | 14 ++
hmp-commands.hx | 44 ++++++
hmp.h | 4 +
include/block/snapshot.h | 1
include/sysemu/replay.h | 20 +++
migration/savevm.c | 15 +-
qapi/block-core.json | 7 +
qapi/block.json | 3
qapi/misc.json | 77 +++++++++++
replay/Makefile.objs | 3
replay/replay-debugging.c | 319 +++++++++++++++++++++++++++++++++++++++++++++
replay/replay-events.c | 16 ++
replay/replay-internal.h | 7 +
replay/replay-time.c | 32 ++---
replay/replay.c | 26 ++++
stubs/Makefile.objs | 1
stubs/replay-user.c | 9 +
stubs/replay.c | 10 +
vl.c | 22 ++-
33 files changed, 818 insertions(+), 53 deletions(-)
create mode 100644 docs/devel/replay.txt
create mode 100644 replay/replay-debugging.c
create mode 100644 stubs/replay-user.c
--
Pavel Dovgalyuk
- [Qemu-devel] [PATCH v7 00/19] Fixing record/replay and adding reverse debugging,
Pavel Dovgalyuk <=
- [Qemu-devel] [PATCH v7 01/19] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 02/19] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 03/19] replay: update docs for record/replay with block devices, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 04/19] replay: don't drain/flush bdrv queue while RR is working, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 05/19] replay: finish record/replay before closing the disks, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 06/19] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 07/19] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 08/19] replay: provide and accessor for rr filename, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 09/19] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 11/19] replay: implement replay-seek command to proceed to the desired step, Pavel Dovgalyuk, 2018/10/10