docs/system/replay.rst

4     Copyright (c) 2010-2022 Institute for System Programming
8     See the COPYING file in the top-level directory.
14 Execution recording writes a non-deterministic events log, which can be later
17 Execution replaying reads the log and replays all non-deterministic events
26  * Supports i386, x86_64, ARM, AArch64, Risc-V, MIPS, MIPS64, S390X, Alpha,
36     .. parsed-literal::
38         -icount shift=auto,rr=record,rrfile=replay.bin \\
39         -drive file=disk.qcow2,if=none,snapshot,id=img-direct \\
40         -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \\
41         -device ide-hd,drive=img-blkreplay \\
42         -netdev user,id=net1 -device rtl8139,netdev=net1 \\
43         -object filter-replay,id=replay,netdev=net1
47     .. parsed-literal::
49         -icount shift=auto,rr=replay,rrfile=replay.bin \\
50         -drive file=disk.qcow2,if=none,snapshot,id=img-direct \\
51         -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \\
52         -device ide-hd,drive=img-blkreplay \\
53         -netdev user,id=net1 -device rtl8139,netdev=net1 \\
54         -object filter-replay,id=replay,netdev=net1
61    for every enabled block device, as described in :ref:`block-label` section.
62  * ``-net none`` option should be specified when network is not used,
65    in :ref:`network-label` section.
70 ---------
72 Record/replay system is based on saving and replaying non-deterministic
74 from HDD or memory of the VM). Saving only non-deterministic events makes
77 The following non-deterministic data from peripheral devices is saved into
79 serial port input, and hardware clocks (they are non-deterministic
87 --------------------
91 of the virtual machine. Record/replay feature is enabled through ``-icount``
92 command-line option, making possible deterministic execution of the machine,
95 .. _block-label:
98 -------------
105 .. parsed-literal::
106     -drive file=disk.qcow2,if=none,snapshot,id=img-direct
107     -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay
108     -device ide-hd,drive=img-blkreplay
113 .. _snapshotting-label:
116 ------------
126 .. parsed-literal::
127     -icount shift=auto,rr=record,rrfile=replay.bin,rrsnapshot=snapshot_name
136 .. parsed-literal::
137     -drive file=disk.ovl,if=none,id=img-direct
138     -drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay
139     -device ide-hd,drive=img-blkreplay
151 .. parsed-literal::
153       -icount shift=auto,rr=replay,rrfile=record.bin,rrsnapshot=init \\
154       -net none -drive file=empty.qcow2,if=none,id=rr
159 .. _network-label:
162 ---------------
167 .. parsed-literal::
168     -netdev user,id=net1 -device rtl8139,netdev=net1
169     -object filter-replay,id=replay,netdev=net1
178 -------------
183 .. parsed-literal::
184     -audio pa,model=ac97
187 ------------
192 E.g., ``-serial stdio`` in record mode, and ``-serial null`` in replay mode.
195 -----------------
208  - ``reverse-stepi`` (or ``rsi``) - step one instruction backwards
209  - ``reverse-continue`` (or ``rc``) - find last breakpoint in the past
232 See the :ref:`snapshotting-label` section to learn more about running record/replay