Re: [PATCH v5 4/7] ppc/pnv: Add a PnvChip pointer to PnvCore

[David Gibson]

On Thu, Oct 24, 2019 at 11:57:05AM +0200, Cédric Le Goater wrote:
> On 24/10/2019 04:38, David Gibson wrote:
> > On Tue, Oct 22, 2019 at 06:38:09PM +0200, Cédric Le Goater wrote:
> >> We will use it to reset the interrupt presenter from the CPU reset
> >> handler.
> >>
> >> Signed-off-by: Cédric Le Goater <address@hidden>
> >> Reviewed-by: Greg Kurz <address@hidden>
> >> ---
> >>  include/hw/ppc/pnv_core.h | 3 +++
> >>  hw/ppc/pnv_core.c         | 3 ++-
> >>  2 files changed, 5 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/include/hw/ppc/pnv_core.h b/include/hw/ppc/pnv_core.h
> >> index bfbd2ec42aa6..55eee95104da 100644
> >> --- a/include/hw/ppc/pnv_core.h
> >> +++ b/include/hw/ppc/pnv_core.h
> >> @@ -31,6 +31,8 @@
> >>  #define PNV_CORE_GET_CLASS(obj) \
> >>       OBJECT_GET_CLASS(PnvCoreClass, (obj), TYPE_PNV_CORE)
> >>  
> >> +typedef struct PnvChip PnvChip;
> >> +
> >>  typedef struct PnvCore {
> >>      /*< private >*/
> >>      CPUCore parent_obj;
> >> @@ -38,6 +40,7 @@ typedef struct PnvCore {
> >>      /*< public >*/
> >>      PowerPCCPU **threads;
> >>      uint32_t pir;
> >> +    PnvChip *chip;
> > 
> > I don't love having this as a redundant encoding of the information
> > already in the property, since it raises the possibility of confusing
> > bugs if they ever got out of sync.
> 
> Indeed.
> 
> > It's not a huge deal, but it would be nice to at least to at least
> > consider either a) grabbing the property everywhere you need it (if
> > there aren't too many places) 
> 
> We need the chip at core creation and core reset to call the 
> interrupt chip handlers. These are not hot path but the pointer
> seemed practical.
> 
> > or b) customizing the property
> > definition so it's written directly into that field.
> 
> OK. That is better than just a link.

I guess.  If there are only two non hot path callers, it seems like it
might be simpler to just pull it out of the property at those places.

-- 
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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