drm/i915: align the vma start to the largest gtt page size
For the 48b PPGTT try to align the vma start address to the required
page size boundary to guarantee we use said page size in the gtt. If we
are dealing with multiple page sizes, we can't guarantee anything and
just align to the largest. For soft pinning and objects which need to be
tightly packed into the lower 32bits we don't force any alignment.
v2: various improvements suggested by Chris
v3: use set_pages and better placement of page_sizes
v4: prefer upper_32_bits()
v5: assign vma->page_sizes = vma->obj->page_sizes directly
prefer sizeof(vma->page_sizes)
v6: fixup checking of end to exclude GGTT (which are assumed to be
limited to 4G).
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006145041.21673-9-matthew.auld@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006221833.32439-8-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 49bf495..5d41644 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -493,6 +493,22 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
if (ret)
goto err_clear;
} else {
+ /*
+ * We only support huge gtt pages through the 48b PPGTT,
+ * however we also don't want to force any alignment for
+ * objects which need to be tightly packed into the low 32bits.
+ *
+ * Note that we assume that GGTT are limited to 4GiB for the
+ * forseeable future. See also i915_ggtt_offset().
+ */
+ if (upper_32_bits(end - 1) &&
+ vma->page_sizes.sg > I915_GTT_PAGE_SIZE) {
+ u64 page_alignment =
+ rounddown_pow_of_two(vma->page_sizes.sg);
+
+ alignment = max(alignment, page_alignment);
+ }
+
ret = i915_gem_gtt_insert(vma->vm, &vma->node,
size, alignment, obj->cache_level,
start, end, flags);