[Crash-utility] kdump format may be updated

[Dave Anderson]

Kazuo Moriwaka wrote:

> Hello,
>
> From: Dave Anderson <anderson at redhat.com>
> Subject: Re: [Crash-utility] kdump format may be updated
> Date: Tue, 17 Oct 2006 09:01:32 -0400
>
> > As we discussed before, it would have been preferable in my
> > opinion to have the starting-point mfn value for all the domains,
> > thereby making the dumpfile usable for all domains instead of
> > just dom0.  But I will be happy with at least getting this change
> > in place so that crash can be used directly on the xen dumpfile
> > for dom0 analysis without having to run it through some other
> > utility.
>
> Yes, I remember the discussion and I think it is possible to make headers.
> Now, Magnus is cleaning the patch.  He and I discussed, but I'm not
> enough to convince him that dom0 information is need for crash.

Just to clarify this discussion.  Magnus's patch *does* include the
dom0 cr3 information for x86, and I am quite happy with that.  With that
single, simple, dom0 cr3 value, the crash utility can use the common
xen/dom0 vmcore file unmodified.

What I don't understand is whether the same thing is going to be done
for x86_64?

NT_XEN_DOM0_CR3 is #define'd in xen/include/xen/elfcore.h in
this patch:

  [Xen-devel] [PATCH 02/04] Kexec / Kdump: Code shared between x86_32 and x86_64

NT_XEN_DOM0_CR3 is used by the find_dom0_cr3() function in
xen/arch/x86/crash.c, in this patch:

  [Xen-devel] [PATCH 03/04] Kexec / Kdump: x86_32 specific code

But there is no analogous x86_64 usage in this patch:

  [Xen-devel] [PATCH 04/04] Kexec / Kdump: x86_64 specific code

Is NT_XEN_DOM0_CR3 not being used by x86_64 by mistake,
or on purpose?  Or perhaps you're saying that it's going to be
pulled out completely?


>
> I know you don't want to treat xen binary file with crash, but I'm
> not clear why.  Please discuss with him directly to make up xen kdump
> file formats.  The patch will be merged into xen-3.0.4.
> I hope we can find solution before merge.
>

The crash utility is wholly based upon the internal structure
of the Linux kernel.

Dave