[Intel-gfx] [PATCH v6 11/19] drm/i915/gen8: Initialize PDPs and PML4

[Goel, Akash]

Reviewed the patch & it looks fine.
Reviewed-by: "Akash Goel <akash.goel at intel.com>"

On 7/29/2015 9:53 PM, Michel Thierry wrote:
> Similar to PDs, while setting up a page directory pointer, make all entries
> of the pdp point to the scratch pd before mapping (and make all its entries
> point to the scratch page); this is to be safe in case of out of bound
> access or  proactive prefetch.
>
> Also add a scratch pdp, which the PML4 entries point to.
>
> v2: Handle scratch_pdp allocation failure correctly, and keep
> initialize_px functions together (Akash)
> v3: Rebase after Mika's ppgtt cleanup / scratch merge patch series. Rely on
> the added macros to initialize the pdps.
> v4: Rebase after final merged version of Mika's ppgtt/scratch patches
> (and removed commit message part related to v3).
> v5: Update commit message to also mention PML4 table initialization and
> the new scratch pdp (Akash).
>
> Suggested-by: Akash Goel <akash.goel at intel.com>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_gem_gtt.c | 38 +++++++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/i915/i915_gem_gtt.h |  1 +
>   2 files changed, 39 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 7070d42..73cfe56 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -602,6 +602,27 @@ static void free_pdp(struct drm_device *dev,
>   	}
>   }
>
> +static void gen8_initialize_pdp(struct i915_address_space *vm,
> +				struct i915_page_directory_pointer *pdp)
> +{
> +	gen8_ppgtt_pdpe_t scratch_pdpe;
> +
> +	scratch_pdpe = gen8_pdpe_encode(px_dma(vm->scratch_pd), I915_CACHE_LLC);
> +
> +	fill_px(vm->dev, pdp, scratch_pdpe);
> +}
> +
> +static void gen8_initialize_pml4(struct i915_address_space *vm,
> +				 struct i915_pml4 *pml4)
> +{
> +	gen8_ppgtt_pml4e_t scratch_pml4e;
> +
> +	scratch_pml4e = gen8_pml4e_encode(px_dma(vm->scratch_pdp),
> +					  I915_CACHE_LLC);
> +
> +	fill_px(vm->dev, pml4, scratch_pml4e);
> +}
> +
>   static void
>   gen8_setup_page_directory(struct i915_hw_ppgtt *ppgtt,
>   			  struct i915_page_directory_pointer *pdp,
> @@ -863,8 +884,20 @@ static int gen8_init_scratch(struct i915_address_space *vm)
>   		return PTR_ERR(vm->scratch_pd);
>   	}
>
> +	if (USES_FULL_48BIT_PPGTT(dev)) {
> +		vm->scratch_pdp = alloc_pdp(dev);
> +		if (IS_ERR(vm->scratch_pdp)) {
> +			free_pd(dev, vm->scratch_pd);
> +			free_pt(dev, vm->scratch_pt);
> +			free_scratch_page(dev, vm->scratch_page);
> +			return PTR_ERR(vm->scratch_pdp);
> +		}
> +	}
> +
>   	gen8_initialize_pt(vm, vm->scratch_pt);
>   	gen8_initialize_pd(vm, vm->scratch_pd);
> +	if (USES_FULL_48BIT_PPGTT(dev))
> +		gen8_initialize_pdp(vm, vm->scratch_pdp);
>
>   	return 0;
>   }
> @@ -873,6 +906,8 @@ static void gen8_free_scratch(struct i915_address_space *vm)
>   {
>   	struct drm_device *dev = vm->dev;
>
> +	if (USES_FULL_48BIT_PPGTT(dev))
> +		free_pdp(dev, vm->scratch_pdp);
>   	free_pd(dev, vm->scratch_pd);
>   	free_pt(dev, vm->scratch_pt);
>   	free_scratch_page(dev, vm->scratch_page);
> @@ -1074,6 +1109,7 @@ gen8_ppgtt_alloc_page_dirpointers(struct i915_address_space *vm,
>   			if (IS_ERR(pdp))
>   				goto unwind_out;
>
> +			gen8_initialize_pdp(vm, pdp);
>   			pml4->pdps[pml4e] = pdp;
>   			__set_bit(pml4e, new_pdps);
>   			trace_i915_page_directory_pointer_entry_alloc(vm,
> @@ -1353,6 +1389,8 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
>   		if (ret)
>   			goto free_scratch;
>
> +		gen8_initialize_pml4(&ppgtt->base, &ppgtt->pml4);
> +
>   		ppgtt->base.total = 1ULL << 48;
>   		ppgtt->switch_mm = gen8_48b_mm_switch;
>   	} else {
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 11d44b3..70c50e7 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -278,6 +278,7 @@ struct i915_address_space {
>   	struct i915_page_scratch *scratch_page;
>   	struct i915_page_table *scratch_pt;
>   	struct i915_page_directory *scratch_pd;
> +	struct i915_page_directory_pointer *scratch_pdp; /* GEN8+ & 48b PPGTT */
>
>   	/**
>   	 * List of objects currently involved in rendering.
>