[Qemu-devel] [PATCH 0/3] Migration Debugging Helper Device

[Alexander Graf]

This patch set adds support for a simple migration debugging method.

It adds a device that exports all metadata required to read a migration
stream from an external program as part of the migration stream. The
external program then does not need to have any knowledge of device internals
of the target virtual machine.

The patch set also adds a python script that serves as such an external program,
allowing users to easily introspect the contents of a live migrated stream.

This approach consciously does not modify any way QEMU operates. To QEMU, it is
completely transparent. QEMU does not read that stream either, so you can not
use it to recover from migration breakage within the code. For that, we should
simply improve the migration protocol to be more future proof.

This approach is about enabling offline introspection of migration stream data
and structure, so that we have one more tool in our hands to see what goes wrong
inside a virtual machine.

  Example decoded migration: http://csgraf.de/mig/mig.txt
  Presentation: https://www.youtube.com/watch?v=iq1x40Qsrew
  Slides: https://www.dropbox.com/s/otp2pk2n3g087zp/Live%20Migration.pdf

Alexander Graf (3):
  Export savevm handlers outside of savevm.c
  Add migration debug device
  Add migration stream analyzation script

 hw/misc/Makefile.objs        |   1 +
 hw/misc/debug_migration.c    | 498 +++++++++++++++++++++++++++++++++++++++++++
 include/qemu/savevm.h        |  28 +++
 savevm.c                     |  24 +--
 scripts/analyze-migration.py | 483 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 1012 insertions(+), 22 deletions(-)
 create mode 100644 hw/misc/debug_migration.c
 create mode 100644 include/qemu/savevm.h
 create mode 100755 scripts/analyze-migration.py

-- 
1.7.12.4