From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH v1 1/2] arm: Add ability to relocate Xen in
 over 4GB space
Date: Fri, 8 May 2015 17:02:55 +0100
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To: Andrii Anisov <andrii.anisov@globallogic.com>
Cc: Iurii Konovalenko <iurii.konovalenko@globallogic.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Julien Grall <julien.grall@linaro.org>, Tim Deegan <tim@xen.org>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Julien Grall <julien.grall@citrix.com>
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On Wed, 2015-04-08 at 20:24 +0300, Andrii Anisov wrote:

I was thinking about this a little more...

> The context here is pretty simple: just a workaround of the real
> system limitations:
>      1. Renesas R-Car H2 evaluation board lager has 4GB of RAM, 2GB
>         mapped under 4GB boundary and 2GB over. 
>      2. The R-Car2 chip has IOMMU's for almost all active devices
>         except GPU. 
>      3. Within our system we need one user domain with 2GB of RAM and
>         dedicated GPU.
>      4. While doing PoC we have no access to the GPU driver(and
>         firmware) sources to introduce swiotlb here. 
> Having no option to handle GPU driver addressing with iommu (2) or
> swiotlb(4), it was decided to place the user domain described in 3
> within RAM below 4GB with 1:1 mapping. Therefore we needed to move all
> the rest (XEN, rest of domains) under 4GB.

Xen itself (i.e. .text and .data, no the heap etc) is at most 2MB. Are
your constraints such that at a 2GB-2MB (i.e. 2046M) domain would not be
acceptable?

Ian.