Deterministic Replay of QEMU Emulation

QEMU version 9.0.94 includes a record/replay feature that allows for deterministic replay of virtual machine execution. This functionality records non-deterministic events, such as keyboard input and network packets, while simulating deterministic events like memory reads. The recorded execution log can be replayed multiple times on different machines, supporting various hardware platforms including x86, ARM, and PowerPC. To utilize this feature, users must run QEMU in icount mode, which enables deterministic execution. The command lines for recording and replaying differ only in the option for the rr parameter. The record/replay system also supports snapshotting, allowing users to create VM snapshots during replay for state recovery. Network interactions are managed through a replay filter, and audio and serial port data are recorded automatically. Additionally, reverse debugging capabilities are available, enabling users to step back through execution using GDB commands. This feature requires at least one snapshot to be created during the recording process. Overall, the record/replay functionality enhances debugging and testing capabilities within QEMU.

- QEMU's record/replay feature allows deterministic replay of VM execution.

- It supports various hardware platforms and requires icount mode for operation.

- Users can create snapshots during replay for state recovery.

- Network interactions and audio/serial data are automatically recorded.

- Reverse debugging is enabled through GDB commands, requiring snapshots.