Re: [Qemu-devel] Kernel core dumps from qemu

[Chris Smith]

* Paul Brook:

> What you actually want to do is use the the existing snapshot/savevm  
> mechanism, and postprocess that into whatever format you want.

No argument.  It's not so hot having two places doing the same thing.  

But it's slow to write and slow to read, and changes in the layout
would be bad, and automatic tools would have a harder time finding 
a particular dump.

* Avi Kivity:

> I suggest 'dump -filter ... blah'. I guess for larger cores this is 
> better than postprocessing, if it can be done without buffering all of RAM.

Standard vmcore only alters the header.  crash doesn't even need that.
Others can use a temp disk file if necessary, essentially the same
as haveing the dump command do it.

* me:

> Maybe it should use XML.

XML, not.  But I think an ASCII representation of CPUState makes sense.

  regs[0]=0xffffffffffffffff
  regs[1]=0xffffffffffffffff
    ...
  eip=0xffffffffffffffff
  eflags=0xffffffffffffffff
    ...

Parseable with scanf, no endian issues, robust against additions
and deletions and permutations.  strings(1) prints it out.