linux-kernel - Re: [PATCH v4 0/5] initialize SCTRL2

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Message-ID: <aLXjVNCbT6YeWlSS@e129823.arm.com>
Date: Mon, 1 Sep 2025 19:17:56 +0100
From: Yeoreum Yun <yeoreum.yun@....com>
To: Dave Martin <Dave.Martin@....com>
Cc: catalin.marinas@....com, will@...nel.org, broonie@...nel.org,
	oliver.upton@...ux.dev, anshuman.khandual@....com, robh@...nel.org,
	james.morse@....com, mark.rutland@....com, joey.gouly@....com,
	ahmed.genidi@....com, kevin.brodsky@....com,
	scott@...amperecomputing.com, mbenes@...e.cz,
	james.clark@...aro.org, frederic@...nel.org, rafael@...nel.org,
	pavel@...nel.org, ryan.roberts@....com, suzuki.poulose@....com,
	maz@...nel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	kvmarm@...ts.linux.dev
Subject: Re: [PATCH v4 0/5] initialize SCTRL2_ELx

Hi Dave,

> On Thu, Aug 21, 2025 at 06:24:03PM +0100, Yeoreum Yun wrote:
> > This series introduces initial support for the SCTLR2_ELx registers in Linux.
> > The feature is optional starting from ARMv8.8/ARMv9.3,
> > and becomes mandatory from ARMv8.9/ARMv9.4.
> >
> > Currently, Linux has no strict need to modify SCTLR2_ELx--
> > at least assuming that firmware initializes
> > these registers to reasonable defaults.
> >
> > However, several upcoming architectural features will require configuring
> > control bits in these registers.
> > Notable examples include FEAT_PAuth_LR and FEAT_CPA2.
>
> This looks OK to me now, except for one or two minor issues (see
> replies to the patches).
>
> I think we will need a way of testing all the code paths before this
> should be merged, though.
>
> Have you tested all the code paths, or are there some things that have
> not been tested?

I've tested for pKVM, nested and nhve and crash path
(I do my best what can I do for modified path).

>
>
> Since this code is not useful by itself, it may make sense to delay
> merging it until we have patches for a feature that depends on SCTLR2.

Whatever I pass this detiermination for maintainer.

>
> Cheers
> ---Dave

--
Sincerely,
Yeoreum Yun