Re: [PATCH] powerpc/numa: Fix topology_physical_package_id() on pSeries

[Daniel Henrique Barboza <danielhb413@gmail.com>]

On 3/12/21 11:31 AM, Cédric Le Goater wrote:
> Initial commit 15863ff3b8da ("powerpc: Make chip-id information
> available to userspace") introduce a cpu_to_chip_id() routine for the
> PowerNV platform using the "ibm,chip-id" property to query the chip id
> of a CPU. But PAPR does not specify such a property and the node id
> query is broken.
> 
> Use cpu_to_node() instead which guarantees to have a correct value on
> all platforms, PowerNV an pSeries.

It is worth mentioning that that this patch will change how
topology_physical_package_id() represents in a QEMU guest. Right now, ibm,chip-id
in QEMU is matching the socket-id. After this patch, topology_physical_package_id()
will now match the NUMA id of the CPU.



Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>

> 
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Cc: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>   arch/powerpc/include/asm/topology.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index 3beeb030cd78..887c42a4e43d 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -123,7 +123,7 @@ static inline int cpu_to_coregroup_id(int cpu)
>   #ifdef CONFIG_PPC64
>   #include <asm/smp.h>
>   
> -#define topology_physical_package_id(cpu)	(cpu_to_chip_id(cpu))
> +#define topology_physical_package_id(cpu)	(cpu_to_node(cpu))
>   
>   #define topology_sibling_cpumask(cpu)	(per_cpu(cpu_sibling_map, cpu))
>   #define topology_core_cpumask(cpu)	(cpu_cpu_mask(cpu))
>