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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Thu, 18 Jan 2018 08:27:52 +1100
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Subject: Re: [Qemu-devel] [PATCH v2 02/19] spapr: introduce a skeleton for
 the XIVE interrupt controller
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To: =?ISO-8859-1?Q?C=E9dric?= Le Goater <clg@kaod.org>, David Gibson <david@gibson.dropbear.id.au>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Greg Kurz <groug@kaod.org>

On Wed, 2018-01-17 at 15:39 +0100, C=C3=A9dric Le Goater wrote:
> Migration is a problem. We will need both backend QEMU objects to be=20
> available anyhow if we want to migrate. So we are back to the current=20
> solution creating both QEMU objects but we can try to defer some of the=
=20
> KVM inits and create the KVM device on demand at CAS time.

Do we have a way to migrate a piece of info from the machine *first*
that indicate what type of XICS/XIVE to instanciate ?

> The next problem is the ICP object that currently needs the KVM device=20
> fd to connect the vcpus ... So, we will need to change that also.=20
> That is probably the biggest problem today. We need a way to disconnect=
=20
> the vpcu from the KVM device and see how we can defer the connection.
> I need to make sure this is possible, I can check that without XIVE

Ben.