Re: [PATCH v2 0/4] RISC-V: ACPI: Add PPTT support

[Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>]

Hi Drew!

On 10/20/2026 7:29 PM, Drew Fustini wrote:
> On Thu, Oct 15, 2026 at 12:19:53PM +0530, Sunil V L wrote:
>> Hi all,
>>
>> This series adds ACPI Processor Properties Topology Table (PPTT) support to
>> the RISC-V virt machine. PPTT allows the guest to discover the processor and
>> cache topology exposed by the machine, which is useful for making better
>> scheduling and cache-management decisions.
> 
> Thanks for picking up PPTT support. I can now rebase the RQSC support
> [1] on this series.
> 
> However, RQSC actually needs PPTT revision 3, because it adds cache IDs
> to the PPTT. The RQSC table references a capacity controller's cache by
> the PPTT cache ID. In Linux, find_acpi_cache_level_from_id() and
> acpi_pptt_get_cpumask_from_cache_id() return -ENOENT if PPTT rev < 3.
> 
> There is a new MPAM series by Jinjie Ruan which contains the patch
> "[PATCH 04/37] hw/acpi: Build PPTT rev 3 with cache IDs for MPAM
> cross-references" [2]. It bumps build_pptt() to revision 3 and gives
> every cache node an ID.
> 
> I could just base the RQSC series on this PPTT series and that patch
> 03/37. But maybe there is a better way to coordinate adding PPTT v3?

This PPTT support is acked and I believe we'll queue it in riscv-to-apply.next
shortly.

As for the PPTT rev3 patch in the "Add Arm MPAM emulation", my suggestion is
to put that on top of your series (i.e. your series will contain that patch).
That ARM series has 37 patches and might take awhile to go through, and your
work relies only on patch 04 ...  which happens to be an arch agnostic patch.
I believe it's fine for us to push it via the riscv queue.

I see that the author from the ARM series is CCed here.  Jinjie Ruan, are you
okay with us pushing your patch via the RISC-V tree?  It'll unblock Drew's work
and you'll have one less patch to worry about in your ARM MPAM work.


Thanks,
Daniel





> 
> Thanks,
> Drew
> 
> [1] https://lore.kernel.org/all/20260202-riscv-rqsc-v1-0-dcf448a3ed73@kernel.org/
> [2] https://lore.kernel.org/all/tencent_F9C68A515AC6C40BE2C32DB314E14CCB7106@qq.com/