aboutsummaryrefslogtreecommitdiff
path: root/replay/replay-debugging.c
AgeCommit message (Collapse)Author
2022-12-14qapi replay: Elide redundant has_FOO in generated CMarkus Armbruster
The has_FOO for pointer-valued FOO are redundant, except for arrays. They are also a nuisance to work with. Recent commit "qapi: Start to elide redundant has_FOO in generated C" provided the means to elide them step by step. This is the step for qapi/replay.json. Said commit explains the transformation in more detail. The invariant violations mentioned there do not occur here. Cc: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20221104160712.3005652-22-armbru@redhat.com>
2021-02-08migration: wire up support for snapshot device selectionDaniel P. Berrangé
Modify load_snapshot/save_snapshot to accept the device list and vmstate node name parameters previously added to the block layer. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210204124834.774401-9-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08migration: control whether snapshots are ovewrittenDaniel P. Berrangé
The traditional HMP "savevm" command will overwrite an existing snapshot if it already exists with the requested name. This new flag allows this to be controlled allowing for safer behaviour with a future QMP command. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210204124834.774401-8-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08block: rename and alter bdrv_all_find_snapshot semanticsDaniel P. Berrangé
Currently bdrv_all_find_snapshot() will return 0 if it finds a snapshot, -1 if an error occurs, or if it fails to find a snapshot. New callers to be added want to distinguish between the error scenario and failing to find a snapshot. Rename it to bdrv_all_has_snapshot and make it return -1 on error, 0 if no snapshot is found and 1 if snapshot is found. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210204124834.774401-7-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08block: allow specifying name of block device for vmstate storageDaniel P. Berrangé
Currently the vmstate will be stored in the first block device that supports snapshots. Historically this would have usually been the root device, but with UEFI it might be the variable store. There needs to be a way to override the choice of block device to store the state in. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210204124834.774401-6-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08block: add ability to specify list of blockdevs during snapshotDaniel P. Berrangé
When running snapshot operations, there are various rules for which blockdevs are included/excluded. While this provides reasonable default behaviour, there are scenarios that are not well handled by the default logic. Some of the conditions do not have a single correct answer. Thus there needs to be a way for the mgmt app to provide an explicit list of blockdevs to perform snapshots across. This can be achieved by passing a list of node names that should be used. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210204124834.774401-5-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08migration: Make save_snapshot() return bool, not 0/-1Philippe Mathieu-Daudé
Just for consistency, following the example documented since commit e3fe3988d7 ("error: Document Error API usage rules"), return a boolean value indicating an error is set or not. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210204124834.774401-3-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-08block: push error reporting into bdrv_all_*_snapshot functionsDaniel P. Berrangé
The bdrv_all_*_snapshot functions return a BlockDriverState pointer for the invalid backend, which the callers then use to report an error message. In some cases multiple callers are reporting the same error message, but with slightly different text. In the future there will be more error scenarios for some of these methods, which will benefit from fine grained error message reporting. So it is helpful to push error reporting down a level. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> [PMD: Initialize variables] Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210204124834.774401-2-berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-01-08Remove superfluous timer_del() callsPeter Maydell
This commit is the result of running the timer-del-timer-free.cocci script on the whole source tree. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20201215154107.3255-4-peter.maydell@linaro.org
2020-11-09replay: remove some dead codePavel Dovgalyuk
This patch removes dead code in replay_continue_stop() function. Signed-off-by: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru> Reported-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <160455661411.3455.4177953912304752892.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-06replay: create temporary snapshot at debugger connectionPavel Dovgalyuk
When record/replay does not uses overlays for storing the snapshots, user is not capable of issuing reverse debugging commands. This patch adds creation of the VM snapshot on the temporary overlay image, when the debugger connects to QEMU. Therefore the execution can be rewind to the moment of the debugger connection while debugging the virtual machine. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> -- v6: - dropped unused error processing (suggested by Philippe Mathieu-Daudé) Message-Id: <160174524096.12451.11651270339216758643.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-06gdbstub: add reverse continue support in replay modePavel Dovgalyuk
This patch adds support of the reverse continue operation for gdbstub. Reverse continue finds the last breakpoint that would happen in normal execution from the beginning to the current moment. Implementation of the reverse continue replays the execution twice: to find the breakpoints that were hit and to seek to the last breakpoint. Reverse continue loads the previous snapshot and tries to find the breakpoint since that moment. If there are no such breakpoints, it proceeds to the earlier snapshot, and so on. When no breakpoints or watchpoints were hit at all, execution stops at the beginning of the replay log. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Message-Id: <160174522930.12451.6994758004725016836.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-06gdbstub: add reverse step support in replay modePavel Dovgalyuk
GDB remote protocol supports two reverse debugging commands: reverse step and reverse continue. This patch adds support of the first one to the gdbstub. Reverse step is intended to step one instruction in the backwards direction. This is not possible in regular execution. But replayed execution is deterministic, therefore we can load one of the prior snapshots and proceed to the desired step. It is equivalent to stepping one instruction back. There should be at least one snapshot preceding the debugged part of the replay log. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> -- v4 changes: - inverted condition in cpu_handle_guest_debug (suggested by Alex Bennée) Message-Id: <160174522341.12451.1498758422543765253.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-06replay: implement replay-seek commandPavel Dovgalyuk
This patch adds hmp/qmp commands replay_seek/replay-seek that proceed the execution to the specified instruction count. The command automatically loads nearest snapshot and replays the execution to find the desired instruction count. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Acked-by: Markus Armbruster <armbru@redhat.com> -- v4 changes: - fixed HMP command description indent - removed useless error_free call Message-Id: <160174521180.12451.14033112911009278753.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-06replay: introduce breakpoint at the specified stepPavel Dovgalyuk
This patch introduces replay_break, replay_delete_break qmp and hmp commands. These commands allow stopping at the specified instruction. It may be useful for debugging when there are some known events that should be investigated. replay_break command has one argument - number of instructions executed since the start of the replay. replay_delete_break removes previously set breakpoint. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Acked-by: Markus Armbruster <armbru@redhat.com> -- v4 changes: - removed useless error_free call Message-Id: <160174520606.12451.7056879546045599378.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-06replay: introduce info hmp/qmp commandPavel Dovgalyuk
This patch introduces 'info replay' monitor command and corresponding qmp request. These commands request the current record/replay mode, replay log file name, and the instruction count (number of recorded/replayed instructions). The instruction count can be used with the replay_seek/replay_break commands added in the next two patches. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-Id: <160174520026.12451.13112161947433306561.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>