linux-kernel - Re: [PATCH 6.12 8/8] KVM: arm64: Eagerly switch ZCR

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Message-ID: <2025031946-myself-underling-0f4d@gregkh>
Date: Wed, 19 Mar 2025 06:55:54 -0700
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Mark Brown <broonie@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>, Marc Zyngier <maz@...nel.org>,
	Gavin Shan <gshan@...hat.com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Joey Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org, Fuad Tabba <tabba@...gle.com>
Subject: Re: [PATCH 6.12 8/8] KVM: arm64: Eagerly switch ZCR_EL{1,2}

On Wed, Mar 19, 2025 at 01:02:30PM +0000, Mark Brown wrote:
> On Wed, Mar 19, 2025 at 10:20:11AM +0000, Mark Rutland wrote:
> > On Wed, Mar 19, 2025 at 09:15:54AM +0000, Marc Zyngier wrote:
> 
> > > The result is that this change is turning a perfectly valid HYP VA
> > > into... something. Odds are that the masking/patching will not mess up
> > > the address, but this is completely buggy anyway. In general,
> > > kern_hyp_va() is not an idempotent operation.
> 
> > IIUC today it *happens* to be idempotent, but as you say that is not
> > guaranteed to remain the case, and this is definitely a logical bug.
> 
> I think so, yes.  I suspect the idempotency confused me.
> 
> > > Greg, it may be more prudent to unstage this series from 6.12-stable
> > > until we know for sure this is the only problem.
> 
> > As above, likewise with the v6.13 version.
> 
> Yes, please unstage these.  I'll send out new versions.

All now dropped from both queues, thanks.

greg k-h