Re: [Intel-gfx] [PATCH 19/19] drm/i915/gtt/dgfx: place the PD in LMEM

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

On 12/04/2021 10:05, Matthew Auld wrote:
> It's a requirement that for dgfx we place all the paging structures in
> device local-memory.
> 
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/gen8_ppgtt.c |  5 ++++-
>   drivers/gpu/drm/i915/gt/intel_gtt.c  | 27 +++++++++++++++++++++++++--
>   drivers/gpu/drm/i915/gt/intel_gtt.h  |  1 +
>   3 files changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> index f83496836f0f..11fb5df45a0f 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> @@ -712,7 +712,10 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt)
>   	 */
>   	ppgtt->vm.has_read_only = !IS_GEN_RANGE(gt->i915, 11, 12);
>   
> -	ppgtt->vm.alloc_pt_dma = alloc_pt_dma;
> +	if (HAS_LMEM(gt->i915))
> +		ppgtt->vm.alloc_pt_dma = alloc_pt_lmem;
> +	else
> +		ppgtt->vm.alloc_pt_dma = alloc_pt_dma;
>   
>   	err = gen8_init_scratch(&ppgtt->vm);
>   	if (err)
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
> index d386b89e2758..1eeeab45445c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
> @@ -7,10 +7,23 @@
>   
>   #include <linux/fault-inject.h>
>   
> +#include "gem/i915_gem_lmem.h"
>   #include "i915_trace.h"
>   #include "intel_gt.h"
>   #include "intel_gtt.h"
>   
> +struct drm_i915_gem_object *alloc_pt_lmem(struct i915_address_space *vm, int sz)
> +{
> +	struct drm_i915_gem_object *obj;
> +
> +	obj = i915_gem_object_create_lmem(vm->i915, sz, 0);
> +
> +	/* ensure all dma objects have the same reservation class */
> +	if (!IS_ERR(obj))
> +		obj->base.resv = &vm->resv;
> +	return obj;
> +}
> +
>   struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm, int sz)
>   {
>   	struct drm_i915_gem_object *obj;
> @@ -27,9 +40,14 @@ struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm, int sz)
>   
>   int map_pt_dma(struct i915_address_space *vm, struct drm_i915_gem_object *obj)
>   {
> +	enum i915_map_type type;
>   	void *vaddr;
>   
> -	vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
> +	type = I915_MAP_WB;
> +	if (i915_gem_object_is_lmem(obj))
> +		type = I915_MAP_WC;

Not trusting the "always coherent" helper from earlier in the series?

Regards,

Tvrtko

> +
> +	vaddr = i915_gem_object_pin_map_unlocked(obj, type);
>   	if (IS_ERR(vaddr))
>   		return PTR_ERR(vaddr);
>   
> @@ -39,9 +57,14 @@ int map_pt_dma(struct i915_address_space *vm, struct drm_i915_gem_object *obj)
>   
>   int map_pt_dma_locked(struct i915_address_space *vm, struct drm_i915_gem_object *obj)
>   {
> +	enum i915_map_type type;
>   	void *vaddr;
>   
> -	vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
> +	type = I915_MAP_WB;
> +	if (i915_gem_object_is_lmem(obj))
> +		type = I915_MAP_WC;
> +
> +	vaddr = i915_gem_object_pin_map(obj, type);
>   	if (IS_ERR(vaddr))
>   		return PTR_ERR(vaddr);
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
> index 40e486704558..44ce27c51631 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> @@ -527,6 +527,7 @@ int setup_scratch_page(struct i915_address_space *vm);
>   void free_scratch(struct i915_address_space *vm);
>   
>   struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm, int sz);
> +struct drm_i915_gem_object *alloc_pt_lmem(struct i915_address_space *vm, int sz);
>   struct i915_page_table *alloc_pt(struct i915_address_space *vm);
>   struct i915_page_directory *alloc_pd(struct i915_address_space *vm);
>   struct i915_page_directory *__alloc_pd(int npde);
> 
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