From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: Design doc of adding ACPI support for arm64 on Xen
 - version 5
Date: Wed, 2 Sep 2015 13:58:38 +0100
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To: Julien Grall <julien.grall@citrix.com>, Shannon Zhao <zhaoshenglong@huawei.com>, Shannon Zhao <shannon.zhao@linaro.org>, xen-devel <xen-devel@lists.xen.org>, Christoffer Dall <christoffer.dall@linaro.org>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Stefano Stabellini <stefano.stabellini@citrix.com>, Jan Beulich <jbeulich@suse.com>, Parth
	Dixit <parth.dixit@linaro.org>, andrew@fubar.geek.nz, Boris Ostrovsky <boris.ostrovsky@oracle.com>, David Vrabel <david.vrabel@citrix.com>, Roger Pau Monne <roger.pau@citrix.com>
Cc: Hangaohuai <hangaohuai@huawei.com>, "Huangpeng (Peter)" <peter.huangpeng@huawei.com>
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On Mon, 2015-08-31 at 13:34 +0100, Julien Grall wrote:
> 
> No, see my answer above. I'm suggesting to re-use the same trick as we 
> do for the grant table region. We know that this region will never be 
> allocated in the DOM0 address space either because of the direct mapping 
> or because it's very unlikely in the case of the non-direct mapping (Xen 
> RAM region is very high).

Slight aside: If/when we ever manage to find a system which doesn't need
1:1 for dom0 RAM and therefore can support this latter case we will
probably need to revisit the selection of the memory region for both the
gnttab and these tables rather than hope it is unlikely they will clash.

But for now using the same mechanism for these tables as we do for the
gnttab region makes sense, and if/when things change the answer will likely
be the same.