[Crash-utility] dom0 analysis for IA64

[Itsuro ODA]

Hi Dave,

The attached patch enables to analyze dom0 linux from
whole memory dump on IA64. (for crash-4.0-4.1)
It is just quick hack.
(I was asked from IA64 Xen developers and made it.)

Each domain manages own machine memory by domain.arch.mm.pgd
in IA64. It is 3-level page table.
I thougnt the mfn of domain.arch.mm.pgd can be regarded as
p2m_mfn.

I intended to modify as less existent code as possible.
But this patch is a bit tricky. And the memory usage is
large if the machine memory layout is sparse.
(maybe xen_kdump_p2m should be prepare for each arch ?)

Would you consider to support dom0 analysis for IA64 ?

I prepared two sample dumps. Please find from the following
URLs.

1) http://people.valinux.co.jp/~oda/20070510-sample-dump-1.tar
  contents:
  - vmcore.gz
    This is taken by a hard assist dump. netdump style ELF vmcore.
    So XEN_ELFNOTE_CRASH_INFO does not exist.
  - vmcore.ka.gz
    It is coverted to kdump style and added XEN_ELFNOTE_CRASH_INFO
    manually.
  - vmlinux.debug.gz
    for dom0 analysis
  - xen-syms-2.6.18-8.el5.gz
    for xencrash

  To get p2m_mfn, xencrash's doms command is usefull.
--------------------------------------------------------------------------
# crash xen-syms-2.6.18-8.el5 vmcore
...
crash> doms
   DID       DOMAIN      ST T  MAXPAGE  TOTPAGE VCPU     SHARED_I          P2M_MFN    
  32753 f000000007ac8080 RU O     0        0      0          0              ----      
  32754 f000000007acc080 RU X     0        0      0          0              ----      
> 32767 f000000007ff8080 RU I     0        0      4          0              ----      
      0 f000000007aa4080 RU 0   10000    fc28     1  f000000007a88000       1abb7     
>*    1 f000000007a78080 RU U   10603    10603    3  f000000007a5c000       1a909     
crash> 
----------------------------------------------------------------------------

  Then normal crash session with --p2m_mfn option.
----------------------------------------------------------------------------
# crash --p2m_mfn=1abb7 vmlinux.debug vmcore 
...
----------------------------------------------------------------------------

  vmcore.ka has XEN_ELFNOTE_CRASH_INFO. so --p2m_mfn option not need.
----------------------------------------------------------------------------
# crash vmlinux.debug vmcore.ka
...
----------------------------------------------------------------------------

  --p2m_mfn option is effective only if a vmcore has XEN_ELFNOTE_CRASH_INFO
  now.
  I think specifying --p2m_mfn option is regarded as the vmcore is
  XEN_CORE_DUMPFILE(). The patch supports this.
  I think it is necessary for dumps which does not have
  XEN_ELFNOTE_CRASH_INFO such as above sample.

2) http://people.valinux.co.jp/~oda/20070510-sample-dump-2.tar
  contents:
  - vmcore.tiger.iomem_machine.gz
    taken by Xen kdump
  - vmlinux-xen-ia64.bz2
  - xen-syms-ia64.bz2

  I asked Xen kdump developper (simon at valinux) to add "p2m_mfn" to
  XEN_ELFNOTE_CRASH_INFO. 
  So this change of Xen kdump is not open yet.
  If this is OK for crash, it will be commited.

Thanks.  
-- 
Itsuro ODA <oda at valinux.co.jp>
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