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

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Aug 04, 2014 at 02:51:01PM +0100, Alex Bligh wrote:
> 
> On 4 Aug 2014, at 14:31, Michael S. Tsirkin <mst@redhat.com> wrote:
> 
> > On Fri, Aug 01, 2014 at 08:12:11PM +0100, Alex Bligh wrote:
> >> 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.
> > 
> > Ow come on.
> > Just add a flag and select the appropriate format based on it, using
> > field_exists.
> 
> I don't think it is that simple. All those things are initialised well
> before the command line is parsed.

You initialize both and select the correct one at migration time.

> Unless I'm missing what you are saying?

I think you are: check how vmstate_test_use_acpi_pci_hotplug
and vmstate_test_no_use_acpi_pci_hotplug are used
in vmstate_acpi.




> -- 
> Alex Bligh
> 
> 
>