drm/i915/gvt: use context lrc_reg_state for shadow ppgtt override

We can replace kmap by using context's lrc_reg_state directly
for shadow ppgtt table override.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200506095948.124979-1-zhenyuw@linux.intel.com

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -58,10 +58,8 @@ static void set_context_pdp_root_pointer(
 
 static void update_shadow_pdps(struct intel_vgpu_workload *workload)
 {
-	struct drm_i915_gem_object *ctx_obj =
-		workload->req->context->state->obj;
 	struct execlist_ring_context *shadow_ring_context;
-	struct page *page;
+	struct intel_context *ctx = workload->req->context;
 
 	if (WARN_ON(!workload->shadow_mm))
 		return;
@@ -69,11 +67,9 @@ static void update_shadow_pdps(struct intel_vgpu_workload *workload)
 	if (WARN_ON(!atomic_read(&workload->shadow_mm->pincount)))
 		return;
 
-	page = i915_gem_object_get_page(ctx_obj, LRC_STATE_PN);
-	shadow_ring_context = kmap(page);
+	shadow_ring_context = (struct execlist_ring_context *)ctx->lrc_reg_state;
 	set_context_pdp_root_pointer(shadow_ring_context,
 			(void *)workload->shadow_mm->ppgtt_mm.shadow_pdps);
-	kunmap(page);
 }
 
 /*