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Re: [PATCH v5 4/7] ppc/pnv: Add a PnvChip pointer to PnvCore
From: |
David Gibson |
Subject: |
Re: [PATCH v5 4/7] ppc/pnv: Add a PnvChip pointer to PnvCore |
Date: |
Sun, 27 Oct 2019 17:54:36 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
On Thu, Oct 24, 2019 at 07:30:30PM +0200, Greg Kurz wrote:
> On Thu, 24 Oct 2019 13:38:12 +1100
> David Gibson <address@hidden> 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.
> >
>
> Ouch, we also have this pattern in xive_tctx_realize(). The XiveTCXT
> object has both a "cpu" property and a pointer to the vCPU.
>
> > 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) or b) customizing the property
> > definition so it's written directly into that field.
> >
>
> The pointer to the vCPU is used among other things to get the
> value of the PIR, which is needed by the presenting logic to
> match physical CAM lines. This is a _hot_ path so it's probably
> better to go for b).
Agreed.
--
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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- Re: [PATCH v5 3/7] ppc/pnv: Introduce a PnvCore reset handler, (continued)
[PATCH v5 5/7] ppc: Reset the interrupt presenter from the CPU reset handler, Cédric Le Goater, 2019/10/22
[PATCH v5 6/7] ppc/pnv: Fix naming of routines realizing the CPUs, Cédric Le Goater, 2019/10/22
[PATCH v5 7/7] spapr/xive: Set the OS CAM line at reset, Cédric Le Goater, 2019/10/22
Re: [PATCH v5 0/7] ppc: reset the interrupt presenter from the CPU reset handler, David Gibson, 2019/10/23