On Fri, 31 Jan 2014 13:17:53 -0200 Eduardo Habkost <ehabkost@redhat.com> wrote:
On Fri, Jan 31, 2014 at 03:50:23PM +0100, Paolo Bonzini wrote:
Il 31/01/2014 15:48, Igor Mammedov ha scritto:
that's abusing of object-add interface and due to recent changes, object-add won't accept arbitrary objects.
I hope that sooner or later device hotplug will be doable with object-add too. But yes, in the meanwhile device_add could work, and this patch series is in the right direction anyway.
In that case, what is holding us from setting cannot_instantiate_with_device_add_yet on TYPE_X86_CPU? I don't think we can recommend using "-device" for CPUs just yet, but we would need to allow it in case object-add doesn't work.
(But I liked the fact that object-add worked and (it looks like) it didn't run realize(). All libvirt needs is to be able to create the object and get instance_init() run, no need for realize() to run.)
I still need to read the reasoning behind the object-add changes. But is there some chance we could allow object-add to work for TYPE_X86_CPU subclasses, to avoid the device_add/cannot_instantiate_with_device_add_yet issues?
you can hack around by inheriting from UserCreatable interface, but question is what kind of information libvirt would expect from -object xxx-cpu if it's going to read/interpret feature words then CPU.instance_init() is not sufficient, since properties (read as compat props) and realize() itself are changing feature words and CPU model guest is going to see is very different from what -object would create. It looks like only -device would be able to create actual CPU models, but for -device to work we need as minimum this series and conversion of CPU features to properties in tree. Then I guess we can override cannot_instantiate_with_device_add_yet for x86 CPUs.
-- Eduardo
-- Regards, Igor