> From: Ciro Santilli [mailto:ciro.santi...@gmail.com] > Did you manage to reproduce and solve the savevm and loadvm problems I > mentioned at: > http://lists.nongnu.org/archive/html/qemu-devel/2018-04/msg05219.html > ?
I've tried to debug your scenario and found a bug in saving/loading PS/2 keyboard state. Here is the patch for fixing it: https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg02518.html Maybe it will help for your debugging scenario. Pavel Dovgalyuk > > I still observe them on the current patch. > > On Sat, Apr 28, 2018 at 1:36 PM, Pavel Dovgalyuk > <pavel.dovga...@ispras.ru> 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: > > - 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-180428 > > > > 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: 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 > > replay: describe reverse debugging in docs/replay.txt > > replay: allow loading any snapshots before recording > > > > > > accel/tcg/translator.c | 8 + > > block/blkreplay.c | 8 + > > block/io.c | 22 +++ > > block/qapi.c | 17 ++- > > block/qcow2-snapshot.c | 9 + > > block/qcow2.h | 2 > > blockdev.c | 10 ++ > > cpus.c | 19 ++- > > 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 > > include/block/snapshot.h | 1 > > include/sysemu/replay.h | 18 +++ > > 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 | 14 -- > > replay/replay-internal.h | 10 +- > > replay/replay-snapshot.c | 17 ++- > > replay/replay-time.c | 27 ++-- > > replay/replay.c | 22 +++ > > stubs/replay.c | 10 ++ > > util/qemu-timer.c | 11 -- > > vl.c | 18 ++- > > 31 files changed, 695 insertions(+), 81 deletions(-) > > create mode 100644 replay/replay-debugging.c > > > > -- > > Pavel Dovgalyuk
