Re: [PATCH v3] arm64: errata: Workaround NVIDIA Olympus device store/load ordering erratum

[Jason Gunthorpe]

On Thu, Jun 11, 2026 at 02:34:14PM +0100, Will Deacon wrote:
> I still reckon you should do something with the memcpy-to-io routines.
> A simple option could be to make dgh() a dmb on parts with the erratum?
> That at least moves the barrier out of the loop.

AFAIK only callers that know they are using WC memory should be
calling dgh() and in that case we know it is NORMAL-NC and we don't
need a different barrier

Other random users calling memcpy_to_io functions on real IO don't
have to do dgh(), and AFAIK it doesn't do anything on the Device
memory types?

Jason