drm/i915/gt: Export the pinned context constructor and destructor

Allow internal clients to create and destroy a pinned context.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210617063018.92802-7-thomas.hellstrom@linux.intel.com

drivers/gpu/drm/i915/gt/intel_engine.h

@@ -19,7 +19,9 @@
 #include "intel_workarounds.h"
 
 struct drm_printer;
+struct intel_context;
 struct intel_gt;
+struct lock_class_key;
 
 /* Early gen2 devices have a cacheline of just 32 bytes, using 64 is overkill,
  * but keeps the logic simple. Indeed, the whole purpose of this macro is just
@@ -256,6 +258,15 @@ struct i915_request *
 intel_engine_find_active_request(struct intel_engine_cs *engine);
 
 u32 intel_engine_context_size(struct intel_gt *gt, u8 class);
+struct intel_context *
+intel_engine_create_pinned_context(struct intel_engine_cs *engine,
+				   struct i915_address_space *vm,
+				   unsigned int ring_size,
+				   unsigned int hwsp,
+				   struct lock_class_key *key,
+				   const char *name);
+
+void intel_engine_destroy_pinned_context(struct intel_context *ce);
 
 void intel_engine_init_active(struct intel_engine_cs *engine,
 			      unsigned int subclass);

drivers/gpu/drm/i915/gt/intel_engine_cs.c

@@ -810,11 +810,13 @@ intel_engine_init_active(struct intel_engine_cs *engine, unsigned int subclass)
 #endif
 }
 
-static struct intel_context *
-create_pinned_context(struct intel_engine_cs *engine,
-		      unsigned int hwsp,
-		      struct lock_class_key *key,
-		      const char *name)
+struct intel_context *
+intel_engine_create_pinned_context(struct intel_engine_cs *engine,
+				   struct i915_address_space *vm,
+				   unsigned int ring_size,
+				   unsigned int hwsp,
+				   struct lock_class_key *key,
+				   const char *name)
 {
 	struct intel_context *ce;
 	int err;
@@ -825,6 +827,10 @@ create_pinned_context(struct intel_engine_cs *engine,
 
 	__set_bit(CONTEXT_BARRIER_BIT, &ce->flags);
 	ce->timeline = page_pack_bits(NULL, hwsp);
+	ce->ring = __intel_context_ring_size(ring_size);
+
+	i915_vm_put(ce->vm);
+	ce->vm = i915_vm_get(vm);
 
 	err = intel_context_pin(ce); /* perma-pin so it is always available */
 	if (err) {
@@ -843,7 +849,7 @@ create_pinned_context(struct intel_engine_cs *engine,
 	return ce;
 }
 
-static void destroy_pinned_context(struct intel_context *ce)
+void intel_engine_destroy_pinned_context(struct intel_context *ce)
 {
 	struct intel_engine_cs *engine = ce->engine;
 	struct i915_vma *hwsp = engine->status_page.vma;
@@ -863,8 +869,9 @@ create_kernel_context(struct intel_engine_cs *engine)
 {
 	static struct lock_class_key kernel;
 
-	return create_pinned_context(engine, I915_GEM_HWS_SEQNO_ADDR,
-				     &kernel, "kernel_context");
+	return intel_engine_create_pinned_context(engine, engine->gt->vm, SZ_4K,
+						  I915_GEM_HWS_SEQNO_ADDR,
+						  &kernel, "kernel_context");
 }
 
 /**
@@ -907,7 +914,7 @@ static int engine_init_common(struct intel_engine_cs *engine)
 	return 0;
 
 err_context:
-	destroy_pinned_context(ce);
+	intel_engine_destroy_pinned_context(ce);
 	return ret;
 }
 
@@ -969,7 +976,7 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine)
 		fput(engine->default_state);
 
 	if (engine->kernel_context)
-		destroy_pinned_context(engine->kernel_context);
+		intel_engine_destroy_pinned_context(engine->kernel_context);
 
 	GEM_BUG_ON(!llist_empty(&engine->barrier_tasks));
 	cleanup_status_page(engine);