Re: [Intel-gfx] [PATCH v3 0/2] Don't use stolen memory or BAR mappings for ring buffers

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 16/02/2023 01:10, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
> 
> Instruction from hardware arch is that stolen memory and BAR mappings
> are unsafe for use as ring buffers. There can be issues with cache
> aliasing due to the CPU access going to memory via the BAR. So, don't
> do it.
> 
> v2: Dont use BAR mappings either.
> Make conditional on LLC so as not to change platforms that don't need
> to change (Daniele).
> Add 'Fixes' tags (Tvrtko).
> v3: Fix dumb typo.
> 
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> 
> 
> John Harrison (2):
>    drm/i915: Don't use stolen memory for ring buffers with LLC
>    drm/i915: Don't use BAR mappings for ring buffers with LLC
> 
>   drivers/gpu/drm/i915/gt/intel_ring.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)

It is doing what it laid out as the problem statement so series looks 
good to me.

Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko