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[Qemu-devel] [RFC PATCH 00/17] reverse debugging
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [RFC PATCH 00/17] reverse debugging |
Date: |
Wed, 25 Apr 2018 15:45:34 +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-180207
---
Pavel Dovgalyuk (17):
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
migration: introduce icount field for snapshots
qcow2: introduce icount field for snapshots
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: flush events when exitting
timer: remove replay clock probe in deadline calculation
replay: refine replay-time module
translator: fix breakpoint processing
replay: flush rr queue before loading the vmstate
gdbstub: add reverse step support in replay mode
gdbstub: add reverse continue support in replay mode
accel/tcg/translator.c | 8 +
block/blkreplay.c | 8 +
block/io.c | 22 +++
block/qapi.c | 11 +-
block/qcow2-snapshot.c | 9 +
block/qcow2.h | 2
blockdev.c | 3
cpus.c | 19 ++-
docs/replay.txt | 12 +-
exec.c | 6 +
gdbstub.c | 50 +++++++-
hmp-commands-info.hx | 14 ++
hmp-commands.hx | 30 +++++
hmp.h | 3
include/block/snapshot.h | 1
include/sysemu/replay.h | 18 +++
migration/savevm.c | 11 +-
qapi/block-core.json | 5 +
qapi/block.json | 3
qapi/misc.json | 69 +++++++++++
replay/Makefile.objs | 3
replay/replay-debugging.c | 286 +++++++++++++++++++++++++++++++++++++++++++++
replay/replay-events.c | 14 --
replay/replay-internal.h | 10 +-
replay/replay-time.c | 27 ++--
replay/replay.c | 22 +++
stubs/replay.c | 10 ++
util/qemu-timer.c | 11 --
vl.c | 11 +-
29 files changed, 625 insertions(+), 73 deletions(-)
create mode 100644 replay/replay-debugging.c
--
Pavel Dovgalyuk
- [Qemu-devel] [RFC PATCH 00/17] reverse debugging,
Pavel Dovgalyuk <=
- [Qemu-devel] [RFC PATCH 01/17] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2018/04/25
- [Qemu-devel] [RFC PATCH 02/17] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2018/04/25
- [Qemu-devel] [RFC PATCH 03/17] replay: update docs for record/replay with block devices, Pavel Dovgalyuk, 2018/04/25
- [Qemu-devel] [RFC PATCH 04/17] replay: don't drain/flush bdrv queue while RR is working, Pavel Dovgalyuk, 2018/04/25
- [Qemu-devel] [RFC PATCH 06/17] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/04/25
- [Qemu-devel] [RFC PATCH 05/17] replay: finish record/replay before closing the disks, Pavel Dovgalyuk, 2018/04/25
- [Qemu-devel] [RFC PATCH 07/17] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/04/25