Re: [Qemu-ppc] [PATCH v5 04/36] ppc/xive: introduce the XiveRouter model

[David Gibson]

On Thu, Nov 22, 2018 at 05:50:07PM +1100, Benjamin Herrenschmidt wrote:
> On Thu, 2018-11-22 at 15:44 +1100, David Gibson wrote:
> > 
> > Sorry, didn't think of this in my first reply.
> > 
> > 1) Does the hardware ever actually write back to the EAS?  I know it
> > does for the END, but it's not clear why it would need to for the
> > EAS.  If not, we don't need the setter.
> 
> Nope, though the PAPR model will via hcalls

Right, bit AIUI the set_eas hook is about abstracting PAPR vs bare
metal details.  Since the hcall knows it's PAPR it can just update the
backing information for the EAS directly, and no need for an
abstracted hook.

> 
> > 
> > 2) The signatures are a bit odd here.  For the setter, a value would
> > make sense than a (XiveEAS *), since it's just a word.  For the getter
> > you could return the EAS value directly rather than using a pointer -
> > there's already a valid bit in the EAS so you can construct a value
> > with that cleared if the lisn is out of bounds.
> 

-- 
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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