[PATCH v5 04/34] ACPI / PPTT: Find cache level by cache-id

[Jonathan Cameron]

On Mon, 17 Nov 2025 16:59:43 +0000
Ben Horgan <ben.horgan at arm.com> wrote:

> From: James Morse <james.morse at arm.com>
> 
> The MPAM table identifies caches by id. The MPAM driver also wants to know
> the cache level to determine if the platform is of the shape that can be
> managed via resctrl. Cacheinfo has this information, but only for CPUs that
> are online.
> 
> Waiting for all CPUs to come online is a problem for platforms where
> CPUs are brought online late by user-space.
> 
> Add a helper that walks every possible cache, until it finds the one
> identified by cache-id, then return the level.
> 
> Signed-off-by: James Morse <james.morse at arm.com>
> Signed-off-by: Ben Horgan <ben.horgan at arm.com>
> Reviewed-by: Gavin Shan <gshan at redhat.com>
> Reviewed-by: Fenghua Yu <fenghuay at nvidia.com>
> Tested-by: Fenghua Yu <fenghuay at nvidia.com>
> Tested-by: Shaopeng Tan <tan.shaopeng at jp.fujitsu.com>
> Tested-by: Carl Worth <carl at os.amperecomputing.com>
> Tested-by: Gavin Shan <gshan at redhat.com>
> Tested-by: Zeng Heng <zengheng4 at huawei.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron at huawei.com>