We are incorrectly limiting the max allocation size as per the mm
max_order, which is effectively the largest power-of-two that we can fit
in the region size. However, it's normal to setup the region or
allocator with a non-power-of-two size(for example 3G), which we should
already handle correctly, except it seems for the early too-big-check.
v2: make sure we also exercise the I915_BO_ALLOC_CONTIGUOUS path, which
is quite different, since for that we are actually limited by the
largest power-of-two that we can fit within the region size. (Chris)
Fixes: b908be543e44 ("drm/i915: support creating LMEM objects")
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: CQ Tang <cq.tang@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_memory_region.c | 2 +-
.../drm/i915/selftests/intel_memory_region.c | 77 +++++++++++++++++++
drivers/gpu/drm/i915/selftests/mock_region.c | 2 +-
3 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
index 6b5e9d88646d..180e1078ef7c 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -87,7 +87,7 @@ __intel_memory_region_get_pages_buddy(struct intel_memory_region *mem,
min_order = ilog2(size) - ilog2(mem->mm.chunk_size);
}
- if (size > BIT(mem->mm.max_order) * mem->mm.chunk_size)
+ if (size > mem->mm.size)
return -E2BIG;
n_pages = size >> ilog2(mem->mm.chunk_size);
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 334b0648e253..0aeba8e3af28 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -261,6 +261,82 @@ static int igt_mock_contiguous(void *arg)
return err;
}
+static int igt_mock_splintered_region(void *arg)
+{
+ struct intel_memory_region *mem = arg;
+ struct drm_i915_private *i915 = mem->i915;
+ struct drm_i915_gem_object *obj;
+ unsigned int expected_order;
+ LIST_HEAD(objects);
+ u64 size;
+ int err = 0;
+
+ /*
+ * Sanity check we can still allocate everything even if the
+ * mm.max_order != mm.size. i.e our starting address space size is not a
+ * power-of-two.
+ */
+
+ size = (SZ_4G - 1) & PAGE_MASK;
+ mem = mock_region_create(i915, 0, size, PAGE_SIZE, 0);
+ if (IS_ERR(mem))
+ return PTR_ERR(mem);
+
+ if (mem->mm.size != size) {
+ pr_err("%s size mismatch(%llu != %llu)\n",
+ __func__, mem->mm.size, size);
+ err = -EINVAL;
+ goto out_put;
+ }
+
+ expected_order = get_order(rounddown_pow_of_two(size));
+ if (mem->mm.max_order != expected_order) {
+ pr_err("%s order mismatch(%u != %u)\n",
+ __func__, mem->mm.max_order, expected_order);
+ err = -EINVAL;
+ goto out_put;
+ }
+
+ obj = igt_object_create(mem, &objects, size, 0);
+ if (IS_ERR(obj)) {
+ err = PTR_ERR(obj);
+ goto out_close;
+ }
+
+ close_objects(mem, &objects);
+
+ /*
+ * While we should be able allocate everything without any flag
+ * restrictions, if we consider I915_BO_ALLOC_CONTIGUOUS then we are
+ * actually limited to the largest power-of-two for the region size i.e
+ * max_order, due to the inner workings of the buddy allocator. So make
+ * sure that does indeed hold true.
+ */
+
+ obj = igt_object_create(mem, &objects, size, I915_BO_ALLOC_CONTIGUOUS);
+ if (!IS_ERR(obj)) {
+ pr_err("%s too large contiguous allocation was not rejected\n",
+ __func__);
+ err = -EINVAL;
+ goto out_close;
+ }
+
+ obj = igt_object_create(mem, &objects, rounddown_pow_of_two(size),
+ I915_BO_ALLOC_CONTIGUOUS);
+ if (IS_ERR(obj)) {
+ pr_err("%s largest possible contiguous allocation failed\n",
+ __func__);
+ err = PTR_ERR(obj);
+ goto out_close;
+ }
+
+out_close:
+ close_objects(mem, &objects);
+out_put:
+ intel_memory_region_put(mem);
+ return err;
+}
+
static int igt_gpu_write_dw(struct intel_context *ce,
struct i915_vma *vma,
u32 dword,
@@ -771,6 +847,7 @@ int intel_memory_region_mock_selftests(void)
static const struct i915_subtest tests[] = {
SUBTEST(igt_mock_fill),
SUBTEST(igt_mock_contiguous),
+ SUBTEST(igt_mock_splintered_region),
};
struct intel_memory_region *mem;
struct drm_i915_private *i915;
diff --git a/drivers/gpu/drm/i915/selftests/mock_region.c b/drivers/gpu/drm/i915/selftests/mock_region.c
index 09660f5a0a4c..979d96f27c43 100644
--- a/drivers/gpu/drm/i915/selftests/mock_region.c
+++ b/drivers/gpu/drm/i915/selftests/mock_region.c
@@ -24,7 +24,7 @@ mock_object_create(struct intel_memory_region *mem,
struct drm_i915_private *i915 = mem->i915;
struct drm_i915_gem_object *obj;
- if (size > BIT(mem->mm.max_order) * mem->mm.chunk_size)
+ if (size > mem->mm.size)
return ERR_PTR(-E2BIG);
obj = i915_gem_object_alloc();
--
2.26.2
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