Re: [Qemu-devel] [PATCH v4 2/8] replay: save/load initial state

["Pavel Dovgalyuk" <dovgaluk@ispras.ru>]

> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> On 21/09/2016 17:49, Pavel Dovgalyuk wrote:
> >> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> >> On 21/09/2016 13:33, Pavel Dovgalyuk wrote:
> >>> +New VM snapshots may be created in replay mode. They can be used later
> >>> +to recover the desired VM state. All VM states created in replay mode
> >>> +are associated with the moment of time in the replay scenario.
> >>> +After recovering the VM state replay will start from that position.
> >>> +
> >>> +Default starting snapshot name may be specified with icount field
> >>> +rrsnapshot as follows:
> >>> + -icount shift=7,rr=record,rrfile=replay.bin,rrsnapshot=snapshot_name
> >>> +
> >>> +This snapshot is created at start of recording and restored at start
> >>> +of replaying. It also can be loaded while replaying to roll back
> >>> +the execution.
> >>
> >> Should you mention somewhere that you need -snapshot for raw images?
> >
> > Do you mean when rrsnapshot is used with raw images?
> 
> I mean that (if I understand correctly) raw images are corrupted if you
> don't use -snapshot (the record overwrites them, and the replay reads
> overwritten data).

I tried running record/replay with raw image. Record finished without an error,
but replay couldn't start, because there was no snapshot to load.
I think the solution is checking savevm return code and exiting if snapshot cannot be created.

Pavel Dovgalyuk