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

[Pavel Dovgaluk]

> -----Original Message-----
> From: address@hidden [mailto:address@hidden On Behalf Of
> Peter Crosthwaite
> Sent: Friday, June 27, 2014 10:11 AM
> To: Pavel Dovgaluk; Fréderic Konrad
> Cc: address@hidden Developers; Paolo Bonzini
> Subject: Re: [Qemu-devel] Reverse execution and deterministic replay
> 
> 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.

Do you mean describing the details in patches that I should submit?

> > 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?

Our implementation is not related to Fred Konrad.

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

Of course I will post a full RFC with details of implementation.

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

Pavel Dovgaluk