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Re: [Qemu-devel] [PATCH v6 00/25] Fixing record/replay and adding revers
From: |
Pavel Dovgalyuk |
Subject: |
Re: [Qemu-devel] [PATCH v6 00/25] Fixing record/replay and adding reverse debugging |
Date: |
Thu, 13 Sep 2018 16:40:03 +0300 |
> From: Paolo Bonzini [mailto:address@hidden
> On 12/09/2018 10:17, Pavel Dovgalyuk wrote:
> > 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:
> > - fixes of record/replay caused by the QEMU core changes
> > - 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
> > - adding new clock for correct timer events from vnc and slirp
> > - other record/replay fixes
> >
> > The patches are available in the repository:
> > https://github.com/ispras/qemu/tree/rr-180911
> >
> > 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 (25):
> > 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: flush events when exiting
> > 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
> > replay: describe reverse debugging in docs/replay.txt
> > replay: allow loading any snapshots before recording
> > replay: wake up vCPU when replaying
> > replay: replay BH for IDE trim operation
> > replay: add BH oneshot event for block layer
> > timer: introduce new virtual clock
> > slirp: fix ipv6 timers
> > ui: fix virtual timers
> >
> >
> > accel/tcg/translator.c | 9 +
> > 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 | 50 +++++---
> > docs/interop/qcow2.txt | 4 +
> > docs/replay.txt | 45 +++++++
> > exec.c | 6 +
> > gdbstub.c | 50 +++++++-
> > hmp-commands-info.hx | 14 ++
> > hmp-commands.hx | 30 +++++
> > hmp.h | 3
> > hw/ide/core.c | 3
> > include/block/snapshot.h | 1
> > include/qemu/timer.h | 9 +
> > include/sysemu/replay.h | 26 ++++
> > migration/savevm.c | 15 +-
> > qapi/block-core.json | 5 +
> > qapi/block.json | 3
> > qapi/misc.json | 68 +++++++++++
> > replay/Makefile.objs | 3
> > replay/replay-debugging.c | 287
> > +++++++++++++++++++++++++++++++++++++++++++++
> > replay/replay-events.c | 30 +++--
> > replay/replay-internal.h | 9 +
> > replay/replay-snapshot.c | 17 ++-
> > replay/replay-time.c | 32 ++---
> > replay/replay.c | 38 ++++++
> > slirp/ip6_icmp.c | 7 +
> > stubs/Makefile.objs | 1
> > stubs/replay-user.c | 9 +
> > stubs/replay.c | 10 ++
> > ui/input.c | 8 +
> > util/qemu-timer.c | 2
> > vl.c | 18 ++-
> > 38 files changed, 791 insertions(+), 92 deletions(-)
> > create mode 100644 replay/replay-debugging.c
> > create mode 100644 stubs/replay-user.c
> >
>
> For now I'm queuing 12, 14, 19, 20 (pending question to you) and 23-25.
What about patch 21?
Pavel Dovgalyuk
- [Qemu-devel] [PATCH v6 22/25] replay: add BH oneshot event for block layer, (continued)
[Qemu-devel] [PATCH v6 23/25] timer: introduce new virtual clock, Pavel Dovgalyuk, 2018/09/12
[Qemu-devel] [PATCH v6 24/25] slirp: fix ipv6 timers, Pavel Dovgalyuk, 2018/09/12
[Qemu-devel] [PATCH v6 25/25] ui: fix virtual timers, Pavel Dovgalyuk, 2018/09/12
Re: [Qemu-devel] [PATCH v6 00/25] Fixing record/replay and adding reverse debugging, Paolo Bonzini, 2018/09/13
- Re: [Qemu-devel] [PATCH v6 00/25] Fixing record/replay and adding reverse debugging,
Pavel Dovgalyuk <=
[Qemu-devel] [PATCH v6 00/25] Fixing record/replay and adding reverse debugging, Artem Pisarenko, 2018/09/30