Re: [Qemu-ppc] [Qemu-devel] [PATCH 2/5] target-ppc: Register and handle HCALL to receive updated RTAS region

[David Gibson]

On Tue, Aug 26, 2014 at 04:15:40PM +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2014-08-26 at 15:39 +1000, David Gibson wrote:
> > On Mon, Aug 25, 2014 at 07:15:26PM +0530, Aravinda Prasad wrote:
> > > Receive updates from SLOF about the updated rtas-base.
> > > A separate patch for SLOF [1] adds functionality to invoke a
> > > a private HCALL whenever OS issues instantiate-rtas with
> > > a new rtas-base.
> > > 
> > > This is required as qemu needs to know the updated rtas-base
> > > as it allocates error reporting structure in RTAS space upon
> > > a machine check exception.
> > 
> > This also seems really awkward.  Specifically it seems like a rather
> > arbitrary and complex division of what qemu's responsible for and what
> > SLOF is responsible for.
> > 
> > Instead I'd suggest that we add an H_INSTANTIATE_RTAS hcall, and we
> > move the loading of the spapr-rtas blob from normal reset to when that
> > hcall is invoked.
> 
> Beware that SLOF needs to call RTAS for its own reasons...
> 
> So it would be instanciated twice.

I don't see that that would cause a big problem, or am I missing
something?

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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