[PATCH v4] arm64: errata: Work around AmpereOne's erratum AC04_CPU_23

[Will Deacon]

On Mon, May 19, 2025 at 11:56:51AM +0100, Catalin Marinas wrote:
> On Tue, May 13, 2025 at 11:45:14AM -0700, D Scott Phillips wrote:
> > On AmpereOne AC04, updates to HCR_EL2 can rarely corrupt simultaneous
> > translations for data addresses initiated by load/store instructions.
> > Only instruction initiated translations are vulnerable, not translations
> > from prefetches for example. A DSB before the store to HCR_EL2 is
> > sufficient to prevent older instructions from hitting the window for
> > corruption, and an ISB after is sufficient to prevent younger
> > instructions from hitting the window for corruption.
> > 
> > Signed-off-by: D Scott Phillips <scott at os.amperecomputing.com>
> > Reviewed-by: Oliver Upton <oliver.upton at linux.dev>
> 
> For the core arm64 bits:
> 
> Acked-by: Catalin Marinas <catalin.marinas at arm.com>
> 
> Marc, Will - any preference on how this should go in (kvm or arm64
> trees)?

I think it makes most sense to go via the kvm tree based on the diffstat.

Cheers,

Will