[Intel-gfx] [PATCH] gen8_ppgtt: Use correct huge page manager for MTL

[Matthew Auld]

On 17/02/2023 19:18, Jonathan Cavitt wrote:
> MTL currently uses gen8_ppgtt_insert_huge when managing huge pages.  This is because
> MTL reports as not supporting 64K pages, or more accurately, the system that reports
> whether a platform has 64K pages reports false for MTL.  This is only half correct,
> as the 64K page support reporting system only cares about 64K page support for LMEM,
> which MTL doesn't have.
> 
> MTL should be using xehpsdv_ppgtt_insert_huge.  However, simply changing over to
> using that manager doesn't resolve the issue because MTL is expecting the virtual
> address space for the page table to be flushed after initialization, so we must also
> add a flush statement there.
> 
> Signed-off-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>

Although it looks like the hugepage mock tests are failing with this. I 
assume the mock device just uses some "max" gen version or so, which now 
triggers this path. Any ideas for that?

> ---
>   drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> index 4daaa6f55668..9c571185395f 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> @@ -570,6 +570,7 @@ xehpsdv_ppgtt_insert_huge(struct i915_address_space *vm,
>   			}
>   		} while (rem >= page_size && index < max);
>   
> +		drm_clflush_virt_range(vaddr, PAGE_SIZE);
>   		vma_res->page_sizes_gtt |= page_size;
>   	} while (iter->sg && sg_dma_len(iter->sg));
>   }
> @@ -707,7 +708,7 @@ static void gen8_ppgtt_insert(struct i915_address_space *vm,
>   	struct sgt_dma iter = sgt_dma(vma_res);
>   
>   	if (vma_res->bi.page_sizes.sg > I915_GTT_PAGE_SIZE) {
> -		if (HAS_64K_PAGES(vm->i915))
> +		if (GRAPHICS_VER_FULL(vm->i915) >= IP_VER(12, 50))
>   			xehpsdv_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);
>   		else
>   			gen8_ppgtt_insert_huge(vm, vma_res, &iter, cache_level, flags);