drm/i915/mtl: Update cache coherency setting for context structure

As context structure is shared memory for CPU/GPU, Wa_22016122933 is
needed for this memory block as well.

Signed-off-by: Zhanjun Dong <zhanjun.dong@intel.com>
CC: Fei Yang <fei.yang@intel.com>
Reviewed-by: Fei Yang <fei.yang@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230706174704.177929-1-zhanjun.dong@intel.com

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

@@ -1092,8 +1092,15 @@ __lrc_alloc_state(struct intel_context *ce, struct intel_engine_cs *engine)
 
 	obj = i915_gem_object_create_lmem(engine->i915, context_size,
 					  I915_BO_ALLOC_PM_VOLATILE);
-	if (IS_ERR(obj))
+	if (IS_ERR(obj)) {
 		obj = i915_gem_object_create_shmem(engine->i915, context_size);
+		/*
+		 * Wa_22016122933: For MTL the shared memory needs to be mapped
+		 * as WC on CPU side and UC (PAT index 2) on GPU side
+		 */
+		if (IS_METEORLAKE(engine->i915))
+			i915_gem_object_set_cache_coherency(obj, I915_CACHE_NONE);
+	}
 	if (IS_ERR(obj))
 		return ERR_CAST(obj);