Re: [External] [PATCH v2 3/8] riscv: Add support for srmcfg CSR from Ssqosid extension

From: Drew Fustini <fustini@kernel.org>
To: yunhui cui <cuiyunhui@bytedance.com>
Cc: "Adrien Ricciardi" <aricciardi@baylibre.com>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Atish Kumar Patra" <atishp@rivosinc.com>,
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	"Borislav Petkov" <bp@alien8.de>,
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Subject: Re: [External] [PATCH v2 3/8] riscv: Add support for srmcfg CSR from Ssqosid extension
Date: Sat, 27 Jun 2026 14:58:18 -0700	[thread overview]
Message-ID: <akBHesvINKE+nCXF@x1> (raw)
In-Reply-To: <CAEEQ3wkhiE=TdFTzEn39GVWSgGnaN0raBpmd=6sYaoh304LNBg@mail.gmail.com>

On Sat, Jun 27, 2026 at 05:38:28PM +0800, yunhui cui wrote:
> Hi Drew,
> 
> On Thu, Jun 25, 2026 at 9:40 AM Drew Fustini <fustini@kernel.org> wrote:
[..]
> > +config RISCV_ISA_SSQOSID
> > +       bool "Ssqosid extension support for supervisor mode Quality of Service ID"
> > +       depends on 64BIT
> 
> Why is 64BIT required here?

Sashiko raised many potential issues related to RV32 in reviews of my
RFC series: 

v3: https://sashiko.dev/#/patchset/20260414-ssqosid-cbqri-rqsc-v7-0-v3-0-b3b2e7e9847a%40kernel.org
v4: https://sashiko.dev/#/patchset/20260510-ssqosid-cbqri-rqsc-v7-0-v4-0-eb53831ef683%40kernel.org
v5: https://sashiko.dev/#/patchset/20260524-ssqosid-cbqri-rqsc-v7-0-v5-0-78d3a7ba9dbe%40kernel.org
v6: https://sashiko.dev/#/patchset/20260601-ssqosid-cbqri-rqsc-v7-0-v6-0-baf00f50028a%40kernel.org

RV32 systems with CBQRI didn't seem likely to me so I decided requiring
64BIT would eliminate the potential issues that Sashiko raised. If there
is actually a 32-bit implementation that someone knows of, then I would
be happy to re-evaluate RV32 support.

Thanks,
Drew