[External] [PATCH v4 0/3] RISC-V: Detect Ssqosid extension and handle srmcfg CSR

[Drew Fustini]

On Fri, Oct 10, 2025 at 08:23:50PM +0800, yunhui cui wrote:
> Hi Drew,
[snip]
> > I think it makes sense to first focus on the detection of Ssqosid and
> > handling of srmcfg when switching tasks. It has been tested against a
> > QEMU branch that implements Ssqosid and CBQRI [6]. A test driver [7]
> > was used to set srmcfg for the current process. This allows switch_to
> > to be tested without resctrl.
> 
> Could we consider submitting the entire QoS functionality as a single
> integrated patchset (indicating the upstream branch that the patchset
> is based on)? This should include the content from
> https://lore.kernel.org/linux-riscv/20230419111111.477118-1-dfustini@baylibre.com/

Thanks for the feedback. I had thought that submitting Ssqosid
separately would streamline the review of the parts that most affects
existing arch/riscv code (like switch_to.h) before adding code for CBQRI
and resctrl integration.

But I have gotten similar feedback from another person too. I can post a
complete series that adds Ssqosid and CBQRI support including the
resctrl interface. I have a cbqri branch [1] on top of riscv/for-next.
I need to clean up some of the code, and then I can send a series with
ssqosid+cbqri.

That cbqri branch just has device tree support in order to demonstrate
the resctrl functionality. However, I did also work on support for the
ACPI RQSC table earlier this year for a proof of concept [2]. I have
been thinking that I will hold back the ACPI support until after Ssqosid
and CBQRI support is reviewed. It also depends on some improvements
regarding the ACPI PPTT table that James Morse is currently working on for
ARM MPAM support [3].

Thanks,
Drew

[1] https://git.kernel.org/pub/scm/linux/kernel/git/fustini/linux.git/log/?h=b4/cbqri
[2] https://lf-rise.atlassian.net/wiki/spaces/HOME/pages/433291272/ACPI+RQSC+Proof+of+Concept
[3] https://lore.kernel.org/all/20250910204309.20751-1-james.morse@arm.com/