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From: Arnd Bergmann <arnd@arndb.de>
Date: Thu, 06 Nov 2014 14:33:16 +0100
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Subject: Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic
	ACPI v5.1 table generation
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To: linaro-acpi@lists.linaro.org
Cc: Mark Rutland <mark.rutland@arm.com>, Peter Maydell <peter.maydell@linaro.org>, "tech@virtualopensystems.com" <tech@virtualopensystems.com>, Hanjun Guo <hanjun.guo@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>

On Thursday 06 November 2014 13:30:01 Mark Rutland wrote:
> 
> There is no way of doing this with DT. There has been work into DT
> fragments/overlays where portions can be added to the tree dynamically,
> but that's controlled by the OS rather than the hypervisor, and there's
> no standard for communicating what has been hotplugged to trigger
> changes to the tree, so it's not quite the same. It really only works
> for tightly coupled hw/kernel/userspace combinations (i.e. embedded).
> 
> Depending on how you implement the hot-add/remove you might be able to
> get away with an initial static configuration translated from DT. If you
> need to describe what might be hotplugged from the start, then I suspect
> you cannot get away with translating a DT in general.

I believe IBM POWER 5/6/7 servers have an interface to update the DT
from the hypervisor, but it's not a nice interface, so we may want to
avoid duplicating that.

	Arnd