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Pavel Dovgalyuk > -----Original Message----- > From: Pavel Dovgalyuk [mailto:pavel.dovga...@gmail.com] > Sent: Monday, December 23, 2019 12:46 PM > To: qemu-devel@nongnu.org > Cc: kw...@redhat.com; peter.mayd...@linaro.org; crosthwaite.pe...@gmail.com; > boost.li...@gmail.com; artem.k.pisare...@gmail.com; quint...@redhat.com; > ciro.santi...@gmail.com; jasow...@redhat.com; m...@redhat.com; > arm...@redhat.com; > mre...@redhat.com; maria.klimushenk...@ispras.ru; dovga...@ispras.ru; > kra...@redhat.com; > pavel.dovga...@ispras.ru; thomas.dull...@googlemail.com; pbonz...@redhat.com; > alex.ben...@linaro.org; dgilb...@redhat.com; r...@twiddle.net > Subject: [for-5.0 PATCH 00/11] Support for reverse debugging with GDB > > 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
