Commit 8c949515 authored by Matthew Auld's avatar Matthew Auld
Browse files

drm/i915: use i915_sg_dma_sizes() for all backends 



We rely on page_sizes.sg in setup_scratch_page() reporting the correct
value if the underlying sgl is not contiguous, however in
get_pages_internal() we are only looking at the layout of the created
pages when calculating the sg_page_sizes, and not the final sgl, which
could in theory be completely different. In such a situation we might
incorrectly think we have a 64K scratch page, when it is actually only
4K or similar split over multiple non-contiguous entries, which could
lead to broken behaviour when touching the scratch space within the
padding of a 64K GTT page-table. For most of the other backends we
already just call i915_sg_dma_sizes() on the final mapping, so rather
just move that into __i915_gem_object_set_pages() to avoid such issues
coming back to bite us later.

v2: Update missing conversion in gvt

Suggested-by: default avatarTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221108103238.165447-1-matthew.auld@intel.com
parent ccb0e027

drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c

+1 −3
Original line number Diff line number Diff line
@@ -238,7 +238,6 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj) 
{

	struct drm_i915_private *i915 = to_i915(obj->base.dev);

	struct sg_table *sgt;

	unsigned int sg_page_sizes;



	assert_object_held(obj);
@@ -262,8 +261,7 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj) 
	    (!HAS_LLC(i915) && !IS_DG1(i915)))

		wbinvd_on_all_cpus();



	sg_page_sizes = i915_sg_dma_sizes(sgt->sgl);

	__i915_gem_object_set_pages(obj, sgt, sg_page_sizes);

	__i915_gem_object_set_pages(obj, sgt);



	return 0;

}

drivers/gpu/drm/i915/gem/i915_gem_internal.c

+1 −4
Original line number Diff line number Diff line
@@ -35,7 +35,6 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj) 
	struct drm_i915_private *i915 = to_i915(obj->base.dev);

	struct sg_table *st;

	struct scatterlist *sg;

	unsigned int sg_page_sizes;

	unsigned int npages;

	int max_order = MAX_ORDER;

	unsigned int max_segment;
@@ -64,7 +63,6 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj) 


	sg = st->sgl;

	st->nents = 0;

	sg_page_sizes = 0;



	do {

		int order = min(fls(npages) - 1, max_order);
@@ -83,7 +81,6 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj) 
		} while (1);



		sg_set_page(sg, page, PAGE_SIZE << order, 0);

		sg_page_sizes |= PAGE_SIZE << order;

		st->nents++;



		npages -= 1 << order;
@@ -105,7 +102,7 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj) 
		goto err;

	}



	__i915_gem_object_set_pages(obj, st, sg_page_sizes);

	__i915_gem_object_set_pages(obj, st);



	return 0;

drivers/gpu/drm/i915/gem/i915_gem_object.h

+1 −2
Original line number Diff line number Diff line
@@ -403,8 +403,7 @@ i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj, 
				unsigned long n);



void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,

				 struct sg_table *pages,

				 unsigned int sg_page_sizes);

				 struct sg_table *pages);



int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj);

int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj);

drivers/gpu/drm/i915/gem/i915_gem_pages.c

+3 −4
Original line number Diff line number Diff line
@@ -16,8 +16,7 @@ 
#include "i915_gem_mman.h"



void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,

				 struct sg_table *pages,

				 unsigned int sg_page_sizes)

				 struct sg_table *pages)

{

	struct drm_i915_private *i915 = to_i915(obj->base.dev);

	unsigned long supported = RUNTIME_INFO(i915)->page_sizes;
@@ -45,8 +44,8 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj, 


	obj->mm.pages = pages;



	GEM_BUG_ON(!sg_page_sizes);

	obj->mm.page_sizes.phys = sg_page_sizes;

	obj->mm.page_sizes.phys = i915_sg_dma_sizes(pages->sgl);

	GEM_BUG_ON(!obj->mm.page_sizes.phys);



	/*

	 * Calculate the supported page-sizes which fit into the given

drivers/gpu/drm/i915/gem/i915_gem_phys.c

+3 −6
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj) 


	/* We're no longer struct page backed */

	obj->mem_flags &= ~I915_BO_FLAG_STRUCT_PAGE;

	__i915_gem_object_set_pages(obj, st, sg->length);

	__i915_gem_object_set_pages(obj, st);



	return 0;
@@ -209,11 +209,8 @@ static int i915_gem_object_shmem_to_phys(struct drm_i915_gem_object *obj) 
	return 0;



err_xfer:

	if (!IS_ERR_OR_NULL(pages)) {

		unsigned int sg_page_sizes = i915_sg_dma_sizes(pages->sgl);



		__i915_gem_object_set_pages(obj, pages, sg_page_sizes);

	}

	if (!IS_ERR_OR_NULL(pages))

		__i915_gem_object_set_pages(obj, pages);

	return err;

}