[Intel-xe] [PATCH] drm/xe: Use fast virtual copy engine for migrate engine on PVC

[Matthew Brost]

Some copy hardware engine instances are faster than others on PVC, use a
virtual engine of these plus the reserved instance for the migrate
engine on PVC. The idea being if a fast instance is available it will be
used and the throughput of kernel copies, clears, and pagefault
servicing will be higher.

Cc: Bruce Chang <yu.bruce.chang at intel.com>
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_engine.h    |  2 ++
 drivers/gpu/drm/xe/xe_hw_engine.c | 20 ++++++++++++++++++++
 drivers/gpu/drm/xe/xe_migrate.c   |  7 ++++---
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_engine.h b/drivers/gpu/drm/xe/xe_engine.h
index 1cf7f23c4afd..0a9c35ea3d34 100644
--- a/drivers/gpu/drm/xe/xe_engine.h
+++ b/drivers/gpu/drm/xe/xe_engine.h
@@ -26,6 +26,8 @@ void xe_engine_destroy(struct kref *ref);
 
 struct xe_engine *xe_engine_lookup(struct xe_file *xef, u32 id);
 
+u32 xe_hw_engine_fast_copy_logical_mask(struct xe_gt *gt);
+
 static inline struct xe_engine *xe_engine_get(struct xe_engine *engine)
 {
 	kref_get(&engine->refcount);
diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
index 63a4efd5edcc..b5335f8f7dd3 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine.c
+++ b/drivers/gpu/drm/xe/xe_hw_engine.c
@@ -600,3 +600,23 @@ bool xe_hw_engine_is_reserved(struct xe_hw_engine *hwe)
 	return xe->info.supports_usm && hwe->class == XE_ENGINE_CLASS_COPY &&
 		hwe->instance == gt->usm.reserved_bcs_instance;
 }
+
+u32 xe_hw_engine_fast_copy_logical_mask(struct xe_gt *gt)
+{
+	struct xe_device *xe = gt_to_xe(gt);
+	struct xe_hw_engine *hwe;
+	const u32 fast_physical_mask = 0x5b;	/* 0, 1, 3, 5, 7 */
+	u32 fast_logical_mask = 0;
+	enum xe_hw_engine_id id;
+
+	/* XXX: We only support this function on PVC for now */
+	XE_BUG_ON(!(xe->info.platform == XE_PVC));
+
+	for_each_hw_engine(hwe, gt, id) {
+		if ((fast_physical_mask | gt->usm.reserved_bcs_instance) &
+		    BIT(hwe->instance))
+			fast_logical_mask |= hwe->logical_instance;
+	}
+
+	return fast_logical_mask;
+}
diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index 11c8af9c6c92..4a7fec5d619d 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -345,11 +345,12 @@ struct xe_migrate *xe_migrate_init(struct xe_gt *gt)
 							   XE_ENGINE_CLASS_COPY,
 							   gt->usm.reserved_bcs_instance,
 							   false);
-		if (!hwe)
+		u32 logical_mask = xe_hw_engine_fast_copy_logical_mask(gt);
+
+		if (!hwe || !logical_mask)
 			return ERR_PTR(-EINVAL);
 
-		m->eng = xe_engine_create(xe, vm,
-					  BIT(hwe->logical_instance), 1,
+		m->eng = xe_engine_create(xe, vm, logical_mask, 1,
 					  hwe, ENGINE_FLAG_KERNEL);
 	} else {
 		m->eng = xe_engine_create_class(xe, gt, vm,
-- 
2.34.1