[Qemu-devel] [PATCH v2 0/2] Add machine type pc-1.0-qemu-kvm for live migrate compatibility with qemu-kvm

[Alex Bligh <alex@alex.org.uk>]

This patch series adds inbound migrate capability from qemu-kvm version
1.0. The main ideas are those set out in Cole Robinson's patch here:
http://pkgs.fedoraproject.org/cgit/qemu.git/tree/0001-Fix-migration-from-qemu-kvm.patch?h=f20
however, rather than patching statically (and breaking inbound
migration on existing machine types), I have added a new machine
type (pc-1.0-qemu-kvm) without affecting any other machine types.
The existing pc-1.0 machine type is renamed to pc-1.0-qemu-git,
with pc-1.0 becoming an alias for one or another, as selected
by a configure option (defaulting to pc-1.0-qemu-git, IE no
change).

This requires 'hot patching' the VMStateDescription in a couple of
places, which in turn is less than obvious as there may be (indeed
are for i8259) derived classes. Whilst pretty nausea-inducing, this
approach has the benefit of being entirely self-contained.

I developed this on qemu 2.0 but have forward ported it (trivially)
to master. My testing has been on a VM live-migrated-to-file from
Ubuntu Precise qemu-kvm 1.0.

I have given this a moderate degree of testing but it could do
with more.

Note that certain hardware devices (including QXL) will not
migrate properly due to a fundamental difference in their internal
state between versions.

Also note that (as expected) migratino from qemu-2.x to qemu-1.0
will not work, even if the machine types are the same.

Alex Bligh (2):
  Add machine type pc-1.0-qemu-kvm for live migrate compatibility with
    qemu-kvm
  Add configure option --enable-pc-1-0-qemu-kvm

 configure                |   12 ++++++++++++
 hw/acpi/piix4.c          |   49 ++++++++++++++++++++++++++++++++++++++++++++--
 hw/i386/pc_piix.c        |   39 +++++++++++++++++++++++++++++++++++-
 hw/timer/i8254_common.c  |   41 ++++++++++++++++++++++++++++++++++++++
 include/hw/acpi/piix4.h  |    1 +
 include/hw/timer/i8254.h |    2 ++
 6 files changed, 141 insertions(+), 3 deletions(-)

-- 
1.7.9.5