Subject: Re: [PATCH 0/3] KVM: arm64: Work around Ampere1 erratum AC03_CPU_38

From: Marc Zyngier <[email-masked]>
Date: Thu, 15 Jun 2023 10:51:42 +0100

On Fri, 09 Jun 2023 23:01:01 +0100,
Oliver Upton <[email-masked]> wrote:
> 
> Hi folks,
> 
> Small series to work around a CPU erratum on AmpereOne. While the
> implementation does not advertise support for FEAT_HAFDBS (due to
> another erratum), the associated control bits do not have RES0 behavior
> as required by the architecture.
> 
> Usage of HAFDBS at stage-1 is unaffected, since HA and HD are only
> enabled on implementations that advertise the feature. However, KVM
> relies on HA having RES0 semantics if the feature isn't implemented. The
> end result is that KVM enables a broken hardware access flag
> implementation that could lead to correctness issues.
> 
> Applies to 6.4-rc1. Tested with access_tracking_perf_test, verifying
> that KVM is indeed taking Access Flag faults.

For the series:

Reviewed-by: Marc Zyngier <[email-masked]>

	M.

-- 
Without deviation from the norm, progress is not possible.

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