[PATCH v3] powerpc/mm: Remove kvm radix prefetch workaround for Power9 DD2.2

[Paul Mackerras]

On Fri, Dec 06, 2019 at 02:17:22PM +1100, Jordan Niethe wrote:
> Commit a25bd72badfa ("powerpc/mm/radix: Workaround prefetch issue with
> KVM") introduced a number of workarounds as coming out of a guest with
> the mmu enabled would make the cpu would start running in hypervisor
> state with the PID value from the guest. The cpu will then start
> prefetching for the hypervisor with that PID value.
> 
> In Power9 DD2.2 the cpu behaviour was modified to fix this. When
> accessing Quadrant 0 in hypervisor mode with LPID != 0 prefetching will
> not be performed. This means that we can get rid of the workarounds for
> Power9 DD2.2 and later revisions. Add a new cpu feature
> CPU_FTR_P9_RADIX_PREFETCH_BUG to indicate if the workarounds are needed.
> 
> Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>

Acked-by: Paul Mackerras <paulus at ozlabs.org>