[Intel-gfx] [PATCH v3] drm/i915/ttm: fix sg_table construction
Das, Nirmoy
nirmoy.das at linux.intel.com
Mon Jul 11 09:53:53 UTC 2022
On 7/11/2022 10:58 AM, Matthew Auld wrote:
> If we encounter some monster sized local-memory page that exceeds the
> maximum sg length (UINT32_MAX), ensure that don't end up with some
> misaligned address in the entry that follows, leading to fireworks
> later. Also ensure we have some coverage of this in the selftests.
>
> v2(Chris):
> - Use round_down consistently to avoid udiv errors
> v3(Nirmoy):
> - Also update the max_segment in the selftest
>
> Fixes: f701b16d4cc5 ("drm/i915/ttm: add i915_sg_from_buddy_resource")
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6379
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das at intel.com>
> Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Cc: Nirmoy Das <nirmoy.das at linux.intel.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 11 ++++++++--
> drivers/gpu/drm/i915/i915_scatterlist.c | 19 +++++++++++++----
> drivers/gpu/drm/i915/i915_scatterlist.h | 6 ++++--
> drivers/gpu/drm/i915/intel_region_ttm.c | 10 ++++++---
> drivers/gpu/drm/i915/intel_region_ttm.h | 3 ++-
> .../drm/i915/selftests/intel_memory_region.c | 21 +++++++++++++++++--
> drivers/gpu/drm/i915/selftests/mock_region.c | 3 ++-
> 7 files changed, 58 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 7e1f8b83077f..c5c8aa1f8558 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -602,10 +602,15 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
> struct ttm_resource *res)
> {
> struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> + u64 page_alignment;
>
> if (!i915_ttm_gtt_binds_lmem(res))
> return i915_ttm_tt_get_st(bo->ttm);
>
> + page_alignment = bo->page_alignment << PAGE_SHIFT;
> + if (!page_alignment)
> + page_alignment = obj->mm.region->min_page_size;
> +
> /*
> * If CPU mapping differs, we need to add the ttm_tt pages to
> * the resulting st. Might make sense for GGTT.
> @@ -616,7 +621,8 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
> struct i915_refct_sgt *rsgt;
>
> rsgt = intel_region_ttm_resource_to_rsgt(obj->mm.region,
> - res);
> + res,
> + page_alignment);
> if (IS_ERR(rsgt))
> return rsgt;
>
> @@ -625,7 +631,8 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
> return i915_refct_sgt_get(obj->ttm.cached_io_rsgt);
> }
>
> - return intel_region_ttm_resource_to_rsgt(obj->mm.region, res);
> + return intel_region_ttm_resource_to_rsgt(obj->mm.region, res,
> + page_alignment);
> }
>
> static int i915_ttm_truncate(struct drm_i915_gem_object *obj)
> diff --git a/drivers/gpu/drm/i915/i915_scatterlist.c b/drivers/gpu/drm/i915/i915_scatterlist.c
> index 159571b9bd24..f63b50b71e10 100644
> --- a/drivers/gpu/drm/i915/i915_scatterlist.c
> +++ b/drivers/gpu/drm/i915/i915_scatterlist.c
> @@ -68,6 +68,7 @@ void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size)
> * drm_mm_node
> * @node: The drm_mm_node.
> * @region_start: An offset to add to the dma addresses of the sg list.
> + * @page_alignment: Required page alignment for each sg entry. Power of two.
> *
> * Create a struct sg_table, initializing it from a struct drm_mm_node,
> * taking a maximum segment length into account, splitting into segments
> @@ -77,15 +78,18 @@ void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size)
> * error code cast to an error pointer on failure.
> */
> struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
> - u64 region_start)
> + u64 region_start,
> + u64 page_alignment)
> {
> - const u64 max_segment = SZ_1G; /* Do we have a limit on this? */
> + const u64 max_segment = round_down(UINT_MAX, page_alignment);
> u64 segment_pages = max_segment >> PAGE_SHIFT;
> u64 block_size, offset, prev_end;
> struct i915_refct_sgt *rsgt;
> struct sg_table *st;
> struct scatterlist *sg;
>
> + GEM_BUG_ON(!max_segment);
> +
> rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL);
> if (!rsgt)
> return ERR_PTR(-ENOMEM);
> @@ -112,6 +116,8 @@ struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
> sg = __sg_next(sg);
>
> sg_dma_address(sg) = region_start + offset;
> + GEM_BUG_ON(!IS_ALIGNED(sg_dma_address(sg),
> + page_alignment));
> sg_dma_len(sg) = 0;
> sg->length = 0;
> st->nents++;
> @@ -138,6 +144,7 @@ struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
> * i915_buddy_block list
> * @res: The struct i915_ttm_buddy_resource.
> * @region_start: An offset to add to the dma addresses of the sg list.
> + * @page_alignment: Required page alignment for each sg entry. Power of two.
> *
> * Create a struct sg_table, initializing it from struct i915_buddy_block list,
> * taking a maximum segment length into account, splitting into segments
> @@ -147,11 +154,12 @@ struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
> * error code cast to an error pointer on failure.
> */
> struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
> - u64 region_start)
> + u64 region_start,
> + u64 page_alignment)
> {
> struct i915_ttm_buddy_resource *bman_res = to_ttm_buddy_resource(res);
> const u64 size = res->num_pages << PAGE_SHIFT;
> - const u64 max_segment = rounddown(UINT_MAX, PAGE_SIZE);
> + const u64 max_segment = round_down(UINT_MAX, page_alignment);
> struct drm_buddy *mm = bman_res->mm;
> struct list_head *blocks = &bman_res->blocks;
> struct drm_buddy_block *block;
> @@ -161,6 +169,7 @@ struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
> resource_size_t prev_end;
>
> GEM_BUG_ON(list_empty(blocks));
> + GEM_BUG_ON(!max_segment);
>
> rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL);
> if (!rsgt)
> @@ -191,6 +200,8 @@ struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
> sg = __sg_next(sg);
>
> sg_dma_address(sg) = region_start + offset;
> + GEM_BUG_ON(!IS_ALIGNED(sg_dma_address(sg),
> + page_alignment));
> sg_dma_len(sg) = 0;
> sg->length = 0;
> st->nents++;
> diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915_scatterlist.h
> index 12c6a1684081..b13e4cdea923 100644
> --- a/drivers/gpu/drm/i915/i915_scatterlist.h
> +++ b/drivers/gpu/drm/i915/i915_scatterlist.h
> @@ -213,9 +213,11 @@ static inline void __i915_refct_sgt_init(struct i915_refct_sgt *rsgt,
> void i915_refct_sgt_init(struct i915_refct_sgt *rsgt, size_t size);
>
> struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node,
> - u64 region_start);
> + u64 region_start,
> + u64 page_alignment);
>
> struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res,
> - u64 region_start);
> + u64 region_start,
> + u64 page_alignment);
>
> #endif
> diff --git a/drivers/gpu/drm/i915/intel_region_ttm.c b/drivers/gpu/drm/i915/intel_region_ttm.c
> index 62ff77445b01..6873808a7015 100644
> --- a/drivers/gpu/drm/i915/intel_region_ttm.c
> +++ b/drivers/gpu/drm/i915/intel_region_ttm.c
> @@ -152,6 +152,7 @@ int intel_region_ttm_fini(struct intel_memory_region *mem)
> * Convert an opaque TTM resource manager resource to a refcounted sg_table.
> * @mem: The memory region.
> * @res: The resource manager resource obtained from the TTM resource manager.
> + * @page_alignment: Required page alignment for each sg entry. Power of two.
> *
> * The gem backends typically use sg-tables for operations on the underlying
> * io_memory. So provide a way for the backends to translate the
> @@ -161,16 +162,19 @@ int intel_region_ttm_fini(struct intel_memory_region *mem)
> */
> struct i915_refct_sgt *
> intel_region_ttm_resource_to_rsgt(struct intel_memory_region *mem,
> - struct ttm_resource *res)
> + struct ttm_resource *res,
> + u64 page_alignment)
> {
> if (mem->is_range_manager) {
> struct ttm_range_mgr_node *range_node =
> to_ttm_range_mgr_node(res);
>
> return i915_rsgt_from_mm_node(&range_node->mm_nodes[0],
> - mem->region.start);
> + mem->region.start,
> + page_alignment);
> } else {
> - return i915_rsgt_from_buddy_resource(res, mem->region.start);
> + return i915_rsgt_from_buddy_resource(res, mem->region.start,
> + page_alignment);
> }
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_region_ttm.h b/drivers/gpu/drm/i915/intel_region_ttm.h
> index cf9d86dcf409..98fba5155619 100644
> --- a/drivers/gpu/drm/i915/intel_region_ttm.h
> +++ b/drivers/gpu/drm/i915/intel_region_ttm.h
> @@ -24,7 +24,8 @@ int intel_region_ttm_fini(struct intel_memory_region *mem);
>
> struct i915_refct_sgt *
> intel_region_ttm_resource_to_rsgt(struct intel_memory_region *mem,
> - struct ttm_resource *res);
> + struct ttm_resource *res,
> + u64 page_alignment);
>
> void intel_region_ttm_resource_free(struct intel_memory_region *mem,
> struct ttm_resource *res);
> diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> index 73eb53edb8de..3b18e5905c86 100644
> --- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> @@ -451,7 +451,6 @@ static int igt_mock_splintered_region(void *arg)
>
> static int igt_mock_max_segment(void *arg)
> {
> - const unsigned int max_segment = rounddown(UINT_MAX, PAGE_SIZE);
> struct intel_memory_region *mem = arg;
> struct drm_i915_private *i915 = mem->i915;
> struct i915_ttm_buddy_resource *res;
> @@ -460,7 +459,10 @@ static int igt_mock_max_segment(void *arg)
> struct drm_buddy *mm;
> struct list_head *blocks;
> struct scatterlist *sg;
> + I915_RND_STATE(prng);
> LIST_HEAD(objects);
> + unsigned int max_segment;
> + unsigned int ps;
> u64 size;
> int err = 0;
>
> @@ -472,7 +474,13 @@ static int igt_mock_max_segment(void *arg)
> */
>
> size = SZ_8G;
> - mem = mock_region_create(i915, 0, size, PAGE_SIZE, 0, 0);
> + ps = PAGE_SIZE;
> + if (i915_prandom_u64_state(&prng) & 1)
> + ps = SZ_64K; /* For something like DG2 */
> +
> + max_segment = round_down(UINT_MAX, ps);
> +
> + mem = mock_region_create(i915, 0, size, ps, 0, 0);
> if (IS_ERR(mem))
> return PTR_ERR(mem);
>
> @@ -498,12 +506,21 @@ static int igt_mock_max_segment(void *arg)
> }
>
> for (sg = obj->mm.pages->sgl; sg; sg = sg_next(sg)) {
> + dma_addr_t daddr = sg_dma_address(sg);
> +
> if (sg->length > max_segment) {
> pr_err("%s: Created an oversized scatterlist entry, %u > %u\n",
> __func__, sg->length, max_segment);
> err = -EINVAL;
> goto out_close;
> }
> +
> + if (!IS_ALIGNED(daddr, ps)) {
> + pr_err("%s: Created an unaligned scatterlist entry, addr=%pa, ps=%u\n",
> + __func__, &daddr, ps);
> + err = -EINVAL;
> + goto out_close;
> + }
> }
>
> out_close:
> diff --git a/drivers/gpu/drm/i915/selftests/mock_region.c b/drivers/gpu/drm/i915/selftests/mock_region.c
> index 670557ce1024..bac21fe84ca5 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_region.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_region.c
> @@ -33,7 +33,8 @@ static int mock_region_get_pages(struct drm_i915_gem_object *obj)
> return PTR_ERR(obj->mm.res);
>
> obj->mm.rsgt = intel_region_ttm_resource_to_rsgt(obj->mm.region,
> - obj->mm.res);
> + obj->mm.res,
> + obj->mm.region->min_page_size);
> if (IS_ERR(obj->mm.rsgt)) {
> err = PTR_ERR(obj->mm.rsgt);
> goto err_free_resource;
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