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

[Oliver Upton]

On Fri, 9 Jun 2023 22:01:01 +0000, Oliver Upton wrote:
> 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.
> 
> [...]

Applied w/ an expanded description of what's wrong with the unadvertised
HAFDBS implementation, per Catalin's suggestion.

[1/3] arm64: errata: Mitigate Ampere1 erratum AC03_CPU_38 at stage-2
      https://git.kernel.org/kvmarm/kvmarm/c/6df696cd9bc1
[2/3] KVM: arm64: Refactor HFGxTR configuration into separate helpers
      https://git.kernel.org/kvmarm/kvmarm/c/ce4a36225753
[3/3] KVM: arm64: Prevent guests from enabling HA/HD on Ampere1
      https://git.kernel.org/kvmarm/kvmarm/c/082fdfd13841

--
Best,
Oliver