drm/i915: Wa32bitGeneralStateOffset & Wa32bitInstructionBaseOffset

There are some allocations that must be only referenced by 32-bit
offsets. To limit the chances of having the first 4GB already full,
objects not requiring this workaround use DRM_MM_SEARCH_BELOW/
DRM_MM_CREATE_TOP flags

In specific, any resource used with flat/heapless (0x00000000-0xfffff000)
General State Heap (GSH) or Instruction State Heap (ISH) must be in a
32-bit range, because the General State Offset and Instruction State
Offset are limited to 32-bits.

Objects must have EXEC_OBJECT_SUPPORTS_48B_ADDRESS flag to indicate if
they can be allocated above the 32-bit address range. To limit the
chances of having the first 4GB already full, objects will use
DRM_MM_SEARCH_BELOW + DRM_MM_CREATE_TOP flags when possible.

The libdrm user of the EXEC_OBJECT_SUPPORTS_48B_ADDRESS flag is here:
http://lists.freedesktop.org/archives/intel-gfx/2015-September/075836.html

v2: Changed flag logic from neeeds_32b, to supports_48b.
v3: Moved 48-bit support flag back to exec_object. (Chris, Daniel)
v4: Split pin flags into PIN_ZONE_4G and PIN_HIGH; update PIN_OFFSET_MASK
to use last PIN_ defined instead of hard-coded value; use correct limit
check in eb_vma_misplaced. (Chris)
v5: Don't touch PIN_OFFSET_MASK and update workaround comment (Chris)
v6: Apply pin-high for ggtt too (Chris)
v7: Handle simultaneous pin-high and pin-mappable end correctly (Akash)
    Fix check for entries currently using +4GB addresses, use min_t and
    other polish in object_bind_to_vm (Chris)
v8: Commit message updated to point to libdrm patch.
v9: vmas are allocated in the correct ozone, so only check flag when the
    vma has not been allocated. (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v4)
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Michel Thierry
2015-10-01 13:33:57 +01:00
committed by Daniel Vetter
parent 9d91a1bfae
commit 101b506a7f
4 changed files with 34 additions and 7 deletions
@@ -590,10 +590,17 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
flags |= PIN_GLOBAL;
if (!drm_mm_node_allocated(&vma->node)) {
/* Wa32bitGeneralStateOffset & Wa32bitInstructionBaseOffset,
* limit address to the first 4GBs for unflagged objects.
*/
if ((entry->flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) == 0)
flags |= PIN_ZONE_4G;
if (entry->flags & __EXEC_OBJECT_NEEDS_MAP)
flags |= PIN_GLOBAL | PIN_MAPPABLE;
if (entry->flags & __EXEC_OBJECT_NEEDS_BIAS)
flags |= BATCH_OFFSET_BIAS | PIN_OFFSET_BIAS;
if ((flags & PIN_MAPPABLE) == 0)
flags |= PIN_HIGH;
}
ret = i915_gem_object_pin(obj, vma->vm, entry->alignment, flags);
@@ -671,6 +678,10 @@ eb_vma_misplaced(struct i915_vma *vma)
if (entry->flags & __EXEC_OBJECT_NEEDS_MAP && !obj->map_and_fenceable)
return !only_mappable_for_reloc(entry->flags);
if ((entry->flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) == 0 &&
(vma->node.start + vma->node.size - 1) >> 32)
return true;
return false;
}