[Intel-gfx] [PATCH] drm/i915: use i915_sg_dma_sizes() for all backends

Matthew Auld
2022-11-07T17:46:04Z

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.

Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 4 +---
drivers/gpu/drm/i915/gem/i915_gem_internal.c | 5 +----
drivers/gpu/drm/i915/gem/i915_gem_object.h | 3 +--
drivers/gpu/drm/i915/gem/i915_gem_pages.c | 7 +++----
drivers/gpu/drm/i915/gem/i915_gem_phys.c | 9 +++------
drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 3 +--
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 4 +---
drivers/gpu/drm/i915/gem/selftests/huge_gem_object.c | 2 +-
drivers/gpu/drm/i915/gem/selftests/huge_pages.c | 10 +++-------
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 5 +----
drivers/gpu/drm/i915/selftests/mock_region.c | 2 +-
13 files changed, 19 insertions(+), 39 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index ec6f7ae47783..1df74f7aa3dc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -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;
}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
index 629acb403a2c..f66bcefc09ec 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
@@ -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;

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 6b9ecff42bb5..3db53769864c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -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);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 16f845663ff2..05a27723ebb8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -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
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
index 0d0e46dae559..68453572275b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
@@ -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;
}

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index 2f7804492cd5..9c759df700ca 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -247,7 +247,7 @@ static int shmem_get_pages(struct drm_i915_gem_object *obj)
if (i915_gem_object_can_bypass_llc(obj))
obj->cache_dirty = true;

- __i915_gem_object_set_pages(obj, st, i915_sg_dma_sizes(st->sgl));
+ __i915_gem_object_set_pages(obj, st);

return 0;

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index 0c70711818ed..bc9521078807 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -628,7 +628,7 @@ static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
sg_dma_len(pages->sgl),
POISON_INUSE);

- __i915_gem_object_set_pages(obj, pages, obj->stolen->size);
+ __i915_gem_object_set_pages(obj, pages);

return 0;
}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 25129af70f70..fb9ba712e63c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -815,8 +815,7 @@ static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,

GEM_BUG_ON(obj->mm.rsgt);
obj->mm.rsgt = rsgt;
- __i915_gem_object_set_pages(obj, &rsgt->table,
- i915_sg_dma_sizes(rsgt->table.sgl));
+ __i915_gem_object_set_pages(obj, &rsgt->table);
}

GEM_BUG_ON(bo->ttm && ((obj->base.size >> PAGE_SHIFT) < bo->ttm->num_pages));
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index ca7a388ba2bf..9348b1804d53 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -131,7 +131,6 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
const unsigned long num_pages = obj->base.size >> PAGE_SHIFT;
unsigned int max_segment = i915_sg_segment_size(obj->base.dev->dev);
struct sg_table *st;
- unsigned int sg_page_sizes;
struct page **pvec;
int ret;

@@ -170,8 +169,7 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
if (i915_gem_object_can_bypass_llc(obj))
obj->cache_dirty = true;

- sg_page_sizes = i915_sg_dma_sizes(st->sgl);
- __i915_gem_object_set_pages(obj, st, sg_page_sizes);
+ __i915_gem_object_set_pages(obj, st);

return 0;

diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_gem_object.c b/drivers/gpu/drm/i915/gem/selftests/huge_gem_object.c
index f963b8e1e37b..cbd9b624a788 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_gem_object.c
@@ -68,7 +68,7 @@ static int huge_get_pages(struct drm_i915_gem_object *obj)
if (i915_gem_gtt_prepare_pages(obj, pages))
goto err;

- __i915_gem_object_set_pages(obj, pages, PAGE_SIZE);
+ __i915_gem_object_set_pages(obj, pages);

return 0;

diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index 0cb99e75b0bc..beaf27e09e8a 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -136,7 +136,7 @@ static int get_huge_pages(struct drm_i915_gem_object *obj)
goto err;

GEM_BUG_ON(sg_page_sizes != obj->mm.page_mask);
- __i915_gem_object_set_pages(obj, st, sg_page_sizes);
+ __i915_gem_object_set_pages(obj, st);

return 0;

@@ -210,7 +210,6 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj)
const u64 max_len = rounddown_pow_of_two(UINT_MAX);
struct sg_table *st;
struct scatterlist *sg;
- unsigned int sg_page_sizes;
u64 rem;

st = kmalloc(sizeof(*st), GFP);
@@ -226,7 +225,6 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj)
rem = obj->base.size;
sg = st->sgl;
st->nents = 0;
- sg_page_sizes = 0;
do {
unsigned int page_size = get_largest_page_size(i915, rem);
unsigned int len = min(page_size * div_u64(rem, page_size),
@@ -239,8 +237,6 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj)
sg_dma_len(sg) = len;
sg_dma_address(sg) = page_size;

- sg_page_sizes |= len;
-
st->nents++;

rem -= len;
@@ -254,7 +250,7 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj)

i915_sg_trim(st);

- __i915_gem_object_set_pages(obj, st, sg_page_sizes);
+ __i915_gem_object_set_pages(obj, st);

return 0;
}
@@ -286,7 +282,7 @@ static int fake_get_huge_pages_single(struct drm_i915_gem_object *obj)
sg_dma_len(sg) = obj->base.size;
sg_dma_address(sg) = page_size;

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

return 0;
#undef GFP
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 27c733b00976..eae7d947d7de 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -61,7 +61,6 @@ static int fake_get_pages(struct drm_i915_gem_object *obj)
#define PFN_BIAS 0x1000
struct sg_table *pages;
struct scatterlist *sg;
- unsigned int sg_page_sizes;
typeof(obj->base.size) rem;

pages = kmalloc(sizeof(*pages), GFP);
@@ -74,7 +73,6 @@ static int fake_get_pages(struct drm_i915_gem_object *obj)
return -ENOMEM;
}

- sg_page_sizes = 0;
rem = obj->base.size;
for (sg = pages->sgl; sg; sg = sg_next(sg)) {
unsigned long len = min_t(typeof(rem), rem, BIT(31));
@@ -83,13 +81,12 @@ static int fake_get_pages(struct drm_i915_gem_object *obj)
sg_set_page(sg, pfn_to_page(PFN_BIAS), len, 0);
sg_dma_address(sg) = page_to_phys(sg_page(sg));
sg_dma_len(sg) = len;
- sg_page_sizes |= len;

rem -= len;
}
GEM_BUG_ON(rem);

- __i915_gem_object_set_pages(obj, pages, sg_page_sizes);
+ __i915_gem_object_set_pages(obj, pages);

return 0;
#undef GFP
diff --git a/drivers/gpu/drm/i915/selftests/mock_region.c b/drivers/gpu/drm/i915/selftests/mock_region.c
index bac21fe84ca5..6324eb32d4dd 100644
--- a/drivers/gpu/drm/i915/selftests/mock_region.c
+++ b/drivers/gpu/drm/i915/selftests/mock_region.c
@@ -41,7 +41,7 @@ static int mock_region_get_pages(struct drm_i915_gem_object *obj)
}

pages = &obj->mm.rsgt->table;
- __i915_gem_object_set_pages(obj, pages, i915_sg_dma_sizes(pages->sgl));
+ __i915_gem_object_set_pages(obj, pages);

return 0;

--
2.38.1