diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c index 0bf93947d89d9..aacf4856ccb4c 100644 --- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c +++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c @@ -368,6 +368,27 @@ static int igt_check_page_sizes(struct i915_vma *vma) err = -EINVAL; } + /* + * The dma-api is like a box of chocolates when it comes to the + * alignment of dma addresses, however for LMEM we have total control + * and so can guarantee alignment, likewise when we allocate our blocks + * they should appear in descending order, and if we know that we align + * to the largest page size for the GTT address, we should be able to + * assert that if we see 2M physical pages then we should also get 2M + * GTT pages. If we don't then something might be wrong in our + * construction of the backing pages. + * + * Maintaining alignment is required to utilise huge pages in the ppGGT. + */ + if (i915_gem_object_is_lmem(obj) && + IS_ALIGNED(vma->node.start, SZ_2M) && + vma->page_sizes.sg & SZ_2M && + vma->page_sizes.gtt < SZ_2M) { + pr_err("gtt pages mismatch for LMEM, expected 2M GTT pages, sg(%u), gtt(%u)\n", + vma->page_sizes.sg, vma->page_sizes.gtt); + err = -EINVAL; + } + if (obj->mm.page_sizes.gtt) { pr_err("obj->page_sizes.gtt(%u) should never be set\n", obj->mm.page_sizes.gtt);