Re: [Qemu-devel] [RFC PATCH 08/26] ppc/xive: add flags to the XIVE interrupt source

[David Gibson]

On Mon, Jul 24, 2017 at 05:00:57PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2017-07-24 at 14:36 +1000, David Gibson wrote:
> > On Wed, Jul 05, 2017 at 07:13:21PM +0200, Cédric Le Goater wrote:
> > > These flags define some characteristics of the source :
> > > 
> > >  - XIVE_SRC_H_INT_ESB  the Event State Buffer are controlled with a
> > >                        specific hcall H_INT_ESB
> > 
> > What's the other option?
> 
> Direct MMIO access. Normally all interrupts use normal MMIOs,
> each interrupts has an associated MMIO page with special MMIOs
> to control the source state (PQ bits). This is something I added
> to the PAPR spec (and the OPAL <-> Linux interface) to allow firmware
> to work around broken HW (which happens on some P9 versions).

Ok.. and that's something that can be decided at runtime?

-- 
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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