Re: [Xen-devel] [PATCH 1/7] tools: ARM: vGICv3: avoid inserting optional DT properties

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Andre,

On 24/01/18 16:35, Andre Przywara wrote:
> On 24/01/18 16:08, Julien Grall wrote:
> > (+ Tools maintainers)
> >
> > Hi Andre,
> >
> > On 24/01/18 14:35, Andre Przywara wrote:
> > > When creating a GICv3 devicetree node, we currently insert the
> > > redistributor-stride and #redistributor-regions properties, with fixed
> > > values which are actually the architected ones. But those properties are
> > > optional and only needed to cover for broken platforms, where the values
> > > differ from the architected one. This will never be the case for the
> > I understand that the stride is defined by GICv3. But I don't think this
> > is true for the number of regions. Looking at the spec, multiple regions
> > seems to be allowed (see GICR_TYPER.Last). Did I miss anything?
> Well, the spec does indeed not say anything about it, but the DT binding
> description does:
> ==============
> Optional:
> ...
> - #redistributor-regions: The number of independent contiguous regions
>    occupied by the redistributors. Required if more than one such
>    region is present.
> ==============
>
> So we don't need it in our case, and in fact we don't implement
> *anything* to actually give the toolstack a choice. So we should
> consequently remove these lines, as they are pointless right now. Should
> we ever need to implement support for multiple regions, bringing this
> back is really our least concern.
I am not against this patch. However, the commit message should not 
induce that platform with more than 1 re-distributor regions are broken.
So I don't see anything which would prevent us to provide a guest memory 
map with multiple re-distributor regions.
Cheers,

--
Julien Grall

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