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[for-5.0 PATCH 00/11] Support for reverse debugging with GDB
From: |
Pavel Dovgalyuk |
Subject: |
[for-5.0 PATCH 00/11] Support for reverse debugging with GDB |
Date: |
Mon, 23 Dec 2019 12:45:49 +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
The patches are available in the repository:
https://github.com/ispras/qemu/tree/rr-191223
---
Pavel Dovgaluk (11):
replay: provide an accessor for rr filename
qcow2: introduce icount field for snapshots
migration: introduce icount field for snapshots
qapi: introduce replay.json for record/replay-related stuff
replay: introduce info hmp/qmp command
replay: introduce breakpoint at the specified step
replay: implement replay-seek command
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
MAINTAINERS | 1
accel/tcg/translator.c | 1
block/qapi.c | 18 ++
block/qcow2-snapshot.c | 9 +
block/qcow2.h | 3
blockdev.c | 10 +
cpus.c | 19 ++-
docs/interop/qcow2.txt | 4 +
docs/replay.txt | 33 +++++
exec.c | 8 +
gdbstub.c | 64 ++++++++-
hmp-commands-info.hx | 14 ++
hmp-commands.hx | 53 +++++++
include/block/snapshot.h | 1
include/monitor/hmp.h | 4 +
include/sysemu/replay.h | 24 +++
migration/savevm.c | 17 ++
qapi/Makefile.objs | 2
qapi/block-core.json | 8 +
qapi/block.json | 3
qapi/misc.json | 18 --
qapi/qapi-schema.json | 1
qapi/replay.json | 121 +++++++++++++++++
replay/Makefile.objs | 1
replay/replay-debugging.c | 325 +++++++++++++++++++++++++++++++++++++++++++++
replay/replay-internal.h | 6 +
replay/replay.c | 22 +++
stubs/replay.c | 10 +
28 files changed, 761 insertions(+), 39 deletions(-)
create mode 100644 qapi/replay.json
create mode 100644 replay/replay-debugging.c
--
Pavel Dovgalyuk
- [for-5.0 PATCH 00/11] Support for reverse debugging with GDB,
Pavel Dovgalyuk <=
- [for-5.0 PATCH 01/11] replay: provide an accessor for rr filename, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 02/11] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 03/11] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 04/11] qapi: introduce replay.json for record/replay-related stuff, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 05/11] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 06/11] replay: introduce breakpoint at the specified step, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 07/11] replay: implement replay-seek command, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 08/11] replay: flush rr queue before loading the vmstate, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 09/11] gdbstub: add reverse step support in replay mode, Pavel Dovgalyuk, 2019/12/23
- [for-5.0 PATCH 10/11] gdbstub: add reverse continue support in replay mode, Pavel Dovgalyuk, 2019/12/23