* Shrikanth Hegde <[email protected]> [2026-09-04 15:34:50]:
Thanks Shrikanth for taking a look.
>
>
> On 9/2/26 6:05 PM, Srikar Dronamraju wrote:
> > Coregroup support on powerpc has so far been limited to PowerVM LPARs.
> > However, PowerNV can also support coregroups when firmware exposes the
> > required coregroup information through the associativity hierarchy.
> >
>
> Existing firmware does expose this info already?
The corresponding skiboot changes were sent to the skiboot mailing list.
>
> > Detect coregroup support by checking whether primary_domain_index is the
> > penultimate domain in the CPU node's ibm,associativity property. On
> > PowerNV, a non-penultimate primary_domain_index indicates that firmware
> > provides an additional level for coregroup information.
> >
> > This keeps the logic compatible with PowerVM systems, where
> > primary_domain_index is likewise not the penultimate associativity
> > domain.
> >
>
> Could you please put the ibm,associativity on this powernv? as well
> PowerVM's so that one understands it better?
With this patch and the skiboot change, the ibm,associativity will look
similar.
For example on a Power10 Baremetal box with skiboot changes.
$ lsprop /proc/device-tree/cpus/PowerPC,POWER10@*/ibm,associativity |& head -n
20
PowerPC,POWER10@0/ibm,associativity
00000005 00000000 00000000 00000000 00000000 00000000
PowerPC,POWER10@100/ibm,associativity
00000005 00000000 00000001 00000001 00000002 00000000
PowerPC,POWER10@108/ibm,associativity
00000005 00000000 00000001 00000001 00000002 00000002
PowerPC,POWER10@10/ibm,associativity
00000005 00000000 00000000 00000000 00000001 00000004
PowerPC,POWER10@110/ibm,associativity
00000005 00000000 00000001 00000001 00000003 00000004
PowerPC,POWER10@118/ibm,associativity
00000005 00000000 00000001 00000001 00000003 00000006
PowerPC,POWER10@120/ibm,associativity
00000005 00000000 00000001 00000001 00000002 00000008
PowerPC,POWER10@128/ibm,associativity
00000005 00000000 00000001 00000001 00000002 0000000a
PowerPC,POWER10@130/ibm,associativity
00000005 00000000 00000001 00000001 00000003 0000000c
PowerPC,POWER10@138/ibm,associativity
00000005 00000000 00000001 00000001 00000003 0000000e
>
> > Signed-off-by: Srikar Dronamraju <[email protected]>
> > ---
> > Changelog from v2:
> > - Handle comments from Ritesh (one hunk needed to be moved from patch 2 to
> > patch 3 to build correctly)
> >
> > Changelog from v1:
> > https://lkml.kernel.org/r/[email protected]
> > - Handle comments from Christophe Leroy; make code more flat
> >
> > arch/powerpc/mm/numa.c | 58 ++++++++++++++++++++++++++++++++++--------
> > 1 file changed, 48 insertions(+), 10 deletions(-)
--
Thanks and Regards
Srikar Dronamraju
