[Intel-gfx] [PATCH v5] drm/i915: Wa32bitGeneralStateOffset & Wa32bitInstructionBaseOffset

[Michel Thierry]

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 Intructions 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.

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)

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> (v4)
Signed-off-by: Michel Thierry <michel.thierry at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h            |  2 ++
 drivers/gpu/drm/i915/i915_gem.c            | 14 ++++++++++++--
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 13 +++++++++++++
 include/uapi/drm/i915_drm.h                |  3 ++-
 4 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3fbfce5..cda6366 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2768,6 +2768,8 @@ void i915_gem_vma_destroy(struct i915_vma *vma);
 #define PIN_OFFSET_BIAS	(1<<3)
 #define PIN_USER	(1<<4)
 #define PIN_UPDATE	(1<<5)
+#define PIN_ZONE_4G	(1<<6)
+#define PIN_HIGH	(1<<7)
 #define PIN_OFFSET_MASK (~4095)
 int __must_check
 i915_gem_object_pin(struct drm_i915_gem_object *obj,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 43719b8..1372259 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3722,6 +3722,8 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 fence_alignment, unfenced_alignment;
 	u64 size, fence_size;
+	u32 search_flag = DRM_MM_SEARCH_DEFAULT;
+	u32 alloc_flag = DRM_MM_CREATE_DEFAULT;
 	u64 start =
 		flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0;
 	u64 end =
@@ -3763,6 +3765,14 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
 						   obj->tiling_mode,
 						   false);
 		size = flags & PIN_MAPPABLE ? fence_size : obj->base.size;
+
+		if (flags & PIN_HIGH) {
+			search_flag = DRM_MM_SEARCH_BELOW;
+			alloc_flag = DRM_MM_CREATE_TOP;
+		}
+
+		if (flags & PIN_ZONE_4G)
+			end = (1ULL << 32);
 	}
 
 	if (alignment == 0)
@@ -3805,8 +3815,8 @@ search_free:
 						  size, alignment,
 						  obj->cache_level,
 						  start, end,
-						  DRM_MM_SEARCH_DEFAULT,
-						  DRM_MM_CREATE_DEFAULT);
+						  search_flag,
+						  alloc_flag);
 	if (ret) {
 		ret = i915_gem_evict_something(dev, vm, size, alignment,
 					       obj->cache_level,
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 600db74..ff50619 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -588,11 +588,20 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
 	if (entry->flags & EXEC_OBJECT_NEEDS_GTT)
 		flags |= PIN_GLOBAL;
 
+	/* Wa32bitGeneralStateOffset & Wa32bitInstructionBaseOffset,
+	 * limit address to the first 4GBs for unflagged objects.
+	 */
+	flags |= PIN_ZONE_4G;
+	if (entry->flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS)
+		flags &= ~PIN_ZONE_4G;
+
 	if (!drm_mm_node_allocated(&vma->node)) {
 		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);
@@ -670,6 +679,10 @@ 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) &&
+	    (vma->node.start + vma->node.size) >= (1ULL << 32))
+		return true;
+
 	return false;
 }
 
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index f88cc1c..b91cf45 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -685,7 +685,8 @@ struct drm_i915_gem_exec_object2 {
 #define EXEC_OBJECT_NEEDS_FENCE (1<<0)
 #define EXEC_OBJECT_NEEDS_GTT	(1<<1)
 #define EXEC_OBJECT_WRITE	(1<<2)
-#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_WRITE<<1)
+#define EXEC_OBJECT_SUPPORTS_48B_ADDRESS (1<<3)
+#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_SUPPORTS_48B_ADDRESS<<1)
 	__u64 flags;
 
 	__u64 rsvd1;
-- 
2.4.5