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Deterministic Replay of QEMU Emulation
d/replay Record/replay functions are used for the deterministic replay of qemu execution. Execution recording writes a non-deterministic events log, which can be later used for replaying the execution anywhere and for unlimited number of times.
Deterministically replays whole system execution and all contents of the memory, state of the hardware devices, clocks, and screen of the VM. Record/replay system is based on saving and replaying non-deterministic events (e.g. keyboard input) and simulating deterministic ones (e.g. reading from HDD or memory of the VM). QEMU can’t execute the code in backwards direction, but can load a snapshot and replay forward to find the desired position or breakpoint.
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