Re: [Qemu-devel] Reverse execution and deterministic replay

[Peter Crosthwaite]

Hi Pavel,

On Fri, Jun 27, 2014 at 3:18 PM, Pavel Dovgaluk
<address@hidden> wrote:
> Hello!
>
> We want to publish set of patches related to the reverse execution and 
> deterministic replay of qemu.
> Our implementation of deterministic replay can be used for deterministic and 
> reverse debugging of
> guest code through gdb remote interface.
>
> Execution recording writes non-deterministic events log, which can be later 
> used for replaying the
> execution anywhere and for unlimited number of times. It also supports 
> checkpointing for faster
> rewinding during reverse debugging. Execution replaying reads the log and 
> replays all
> non-deterministic events including external input, hardware clocks, and 
> interrupts.
>
> Reverse execution has the following features:
>  * Deterministically replays whole system execution and all contents of the 
> memory,
>    state of the hadrware devices, clocks, and screen of the VM.
>  * Writes execution log into the file for latter replaying for multiple times
>    on different machines.
>  * Supports i386, x86_64, and ARM hardware platforms.
>  * Performs deterministic replay of all operations with keyboard, mouse, 
> network adapters,
>    audio devices, serial interfaces, and physical USB devices connected to 
> the emulator.
>  * Provides support for gdb reverse debugging commands like reverse-step and 
> reverse-continue.
>  * Supports auto-checkpointing for convenient reverse debugging.
>  * Allows "going to the live execution" from the replay mode.
>
> Our implementation is completely tested for qemu 1.5 and is in beta state for 
> 2.0.50.
>
> Some details about our implementation of reverse execution can be found in 
> paper:
> http://www.computer.org/csdl/proceedings/csmr/2012/4666/00/4666a553-abs.html
>

Add relevant implementation details to the git commit messages.

> Can anyone review our patches?
>

Fred Konrad is doing a series on reverse exe at the moment. CC. Is the
an independent implementation of the same thing or are you building on
it?

I suggest posting a full RFC, this looks to me just like a cover
letter but without a series.

Note that we are going into hard freeze imminently so there will be
some delay for merge.

Regards,
Peter

> Pavel Dovgaluk
>
>
>