Re: [PATCH v5 3/8] drm/xe/migrate: Add helper function to program identity map

[Matthew Brost <matthew.brost@intel.com>]

On Tue, Jul 16, 2024 at 10:54:04PM +0000, Akshata Jahagirdar wrote:
> Add an helper function to program identity map.
> 
> v2: Formatting nits
> 
> Signed-off-by: Akshata Jahagirdar <akshata.jahagirdar@intel.com>

One nit below, but can fixed at merge or in next rev.

With that:
Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> ---
>  drivers/gpu/drm/xe/xe_migrate.c | 88 ++++++++++++++++++---------------
>  1 file changed, 48 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index 85eec95c9bc2..6b952ed98a51 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/xe_migrate.c
> @@ -130,6 +130,51 @@ static u64 xe_migrate_vram_ofs(struct xe_device *xe, u64 addr)
>  	return addr + (256ULL << xe_pt_shift(2));
>  }
>  
> +static void xe_migrate_program_identity(struct xe_device *xe, struct xe_vm *vm, struct xe_bo *bo,
> +					u64 map_ofs, u64 vram_offset, u16 pat_index, u64 pt_ofs)

Maybe a better name for pt_ofs indicating it used to program the 2M PTEs? 

s/pt_ofs/pt_2m_ofs?

Matt

> +{
> +	u64 pos, ofs, flags;
> +	u64 entry;
> +	/* XXX: Unclear if this should be usable_size? */
> +	u64 vram_limit =  xe->mem.vram.actual_physical_size +
> +		xe->mem.vram.dpa_base;
> +	u32 level = 2;
> +
> +	ofs = map_ofs + XE_PAGE_SIZE * level + vram_offset * 8;
> +	flags = vm->pt_ops->pte_encode_addr(xe, 0, pat_index, level,
> +					    true, 0);
> +
> +	xe_assert(xe, IS_ALIGNED(xe->mem.vram.usable_size, SZ_2M));
> +
> +	/*
> +	 * Use 1GB pages when possible, last chunk always use 2M
> +	 * pages as mixing reserved memory (stolen, WOCPM) with a single
> +	 * mapping is not allowed on certain platforms.
> +	 */
> +	for (pos = xe->mem.vram.dpa_base; pos < vram_limit;
> +	     pos += SZ_1G, ofs += 8) {
> +		if (pos + SZ_1G >= vram_limit) {
> +			entry = vm->pt_ops->pde_encode_bo(bo, pt_ofs,
> +							  pat_index);
> +			xe_map_wr(xe, &bo->vmap, ofs, u64, entry);
> +
> +			flags = vm->pt_ops->pte_encode_addr(xe, 0,
> +							    pat_index,
> +							    level - 1,
> +							    true, 0);
> +
> +			for (ofs = pt_ofs; pos < vram_limit;
> +			     pos += SZ_2M, ofs += 8)
> +				xe_map_wr(xe, &bo->vmap, ofs, u64, pos | flags);
> +			break;	/* Ensure pos == vram_limit assert correct */
> +		}
> +
> +		xe_map_wr(xe, &bo->vmap, ofs, u64, pos | flags);
> +	}
> +
> +	xe_assert(xe, pos == vram_limit);
> +}
> +
>  static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
>  				 struct xe_vm *vm)
>  {
> @@ -253,47 +298,10 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
>  
>  	/* Identity map the entire vram at 256GiB offset */
>  	if (IS_DGFX(xe)) {
> -		u64 pos, ofs, flags;
> -		/* XXX: Unclear if this should be usable_size? */
> -		u64 vram_limit =  xe->mem.vram.actual_physical_size +
> -			xe->mem.vram.dpa_base;
> -
> -		level = 2;
> -		ofs = map_ofs + XE_PAGE_SIZE * level + 256 * 8;
> -		flags = vm->pt_ops->pte_encode_addr(xe, 0, pat_index, level,
> -						    true, 0);
> -
> -		xe_assert(xe, IS_ALIGNED(xe->mem.vram.usable_size, SZ_2M));
> -
> -		/*
> -		 * Use 1GB pages when possible, last chunk always use 2M
> -		 * pages as mixing reserved memory (stolen, WOCPM) with a single
> -		 * mapping is not allowed on certain platforms.
> -		 */
> -		for (pos = xe->mem.vram.dpa_base; pos < vram_limit;
> -		     pos += SZ_1G, ofs += 8) {
> -			if (pos + SZ_1G >= vram_limit) {
> -				u64 pt31_ofs = bo->size - XE_PAGE_SIZE;
> -
> -				entry = vm->pt_ops->pde_encode_bo(bo, pt31_ofs,
> -								  pat_index);
> -				xe_map_wr(xe, &bo->vmap, ofs, u64, entry);
> -
> -				flags = vm->pt_ops->pte_encode_addr(xe, 0,
> -								    pat_index,
> -								    level - 1,
> -								    true, 0);
> -
> -				for (ofs = pt31_ofs; pos < vram_limit;
> -				     pos += SZ_2M, ofs += 8)
> -					xe_map_wr(xe, &bo->vmap, ofs, u64, pos | flags);
> -				break;	/* Ensure pos == vram_limit assert correct */
> -			}
> -
> -			xe_map_wr(xe, &bo->vmap, ofs, u64, pos | flags);
> -		}
> +		u64 pt31_ofs = bo->size - XE_PAGE_SIZE;
>  
> -		xe_assert(xe, pos == vram_limit);
> +		xe_migrate_program_identity(xe, vm, bo, map_ofs, 256, pat_index, pt31_ofs);
> +		xe_assert(xe, (xe->mem.vram.actual_physical_size <= SZ_256G));
>  	}
>  
>  	/*
> -- 
> 2.34.1
>