[PATCH v3 25/30] drm/xe: Add BO flags required for SVM

[Matthew Brost <matthew.brost@intel.com>]

Add XE_BO_FLAG_CPU_ADDR_MIRROR to indicate BO is tied to SVM range.
While these BO's are kernel allocations, we need a VM reference in this
case which this flag indicates. In addition, we do not support CCS on
these BO's either. The later can be revisited later.

v2:
 - Take VM ref for system allocator BOs
v3:
 - s/XE_BO_FLAG_SYSTEM_ALLOC/XE_BO_FLAG_CPU_ADDR_MIRROR (Thomas)
 - Better commit message (Thomas)
 - Drop XE_BO_FLAG_SKIP_CLEAR for now
 - Add comment about possibly supporting CCS (Thomas)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_bo.c | 12 ++++++++----
 drivers/gpu/drm/xe/xe_bo.h |  1 +
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index a670a0444e03..0c1134d6209c 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -1222,7 +1222,7 @@ static void xe_ttm_bo_destroy(struct ttm_buffer_object *ttm_bo)
 		xe_drm_client_remove_bo(bo);
 #endif
 
-	if (bo->vm && xe_bo_is_user(bo))
+	if (bo->vm && (xe_bo_is_user(bo) || bo->flags & XE_BO_FLAG_CPU_ADDR_MIRROR))
 		xe_vm_put(bo->vm);
 
 	mutex_lock(&xe->mem_access.vram_userfault.lock);
@@ -1418,7 +1418,8 @@ struct xe_bo *___xe_bo_create_locked(struct xe_device *xe, struct xe_bo *bo,
 	int err;
 
 	/* Only kernel objects should set GT */
-	xe_assert(xe, !tile || type == ttm_bo_type_kernel);
+	xe_assert(xe, !tile || type == ttm_bo_type_kernel ||
+		  flags & XE_BO_FLAG_CPU_ADDR_MIRROR);
 
 	if (XE_WARN_ON(!size)) {
 		xe_bo_free(bo);
@@ -1614,7 +1615,7 @@ __xe_bo_create_locked(struct xe_device *xe,
 	 * by having all the vm's bo refereferences released at vm close
 	 * time.
 	 */
-	if (vm && xe_bo_is_user(bo))
+	if (vm && (xe_bo_is_user(bo) || bo->flags & XE_BO_FLAG_CPU_ADDR_MIRROR))
 		xe_vm_get(vm);
 	bo->vm = vm;
 
@@ -2465,8 +2466,11 @@ bool xe_bo_needs_ccs_pages(struct xe_bo *bo)
 	 * system memory (i.e., it allows XE_PL_TT placement), FlatCCS
 	 * can't be used since there's no CCS storage associated with
 	 * non-VRAM addresses.
+	 *
+	 * XXX: Can we support CCS with CPU address mirroring?
 	 */
-	if (IS_DGFX(xe) && (bo->flags & XE_BO_FLAG_SYSTEM))
+	if (IS_DGFX(xe) && ((bo->flags & XE_BO_FLAG_SYSTEM) ||
+	    (bo->flags & XE_BO_FLAG_CPU_ADDR_MIRROR)))
 		return false;
 
 	return true;
diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
index d9386ab03140..a281e0187ebe 100644
--- a/drivers/gpu/drm/xe/xe_bo.h
+++ b/drivers/gpu/drm/xe/xe_bo.h
@@ -47,6 +47,7 @@
 					 XE_BO_FLAG_GGTT1 | \
 					 XE_BO_FLAG_GGTT2 | \
 					 XE_BO_FLAG_GGTT3)
+#define XE_BO_FLAG_CPU_ADDR_MIRROR	BIT(22)
 
 /* this one is trigger internally only */
 #define XE_BO_FLAG_INTERNAL_TEST	BIT(30)
-- 
2.34.1