drm/amd/amdgpu: add check that shadow page tables are GPU-accessible

Skip amdgpu_gem_va_update_vm otherwise. Also clean up the check for the
non-shadow page tables using the new helper function.

This fixes a crash with the stack trace:

amdgpu_gem_va_update_vm
-> amdgpu_vm_update_page_directory
 -> amdgpu_ttm_bind
  -> amdgpu_gtt_mgr_alloc

v2: actually check bo->shadow instead of just checking bo twice
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

@@ -471,12 +471,15 @@ int amdgpu_gem_metadata_ioctl(struct drm_device *dev, void *data,
 
 static int amdgpu_gem_va_check(void *param, struct amdgpu_bo *bo)
 {
-	unsigned domain = amdgpu_mem_type_to_domain(bo->tbo.mem.mem_type);
-
 	/* if anything is swapped out don't swap it in here,
 	   just abort and wait for the next CS */
+	if (!amdgpu_bo_gpu_accessible(bo))
+		return -ERESTARTSYS;
+
+	if (bo->shadow && !amdgpu_bo_gpu_accessible(bo->shadow))
+		return -ERESTARTSYS;
 
-	return domain == AMDGPU_GEM_DOMAIN_CPU ? -ERESTARTSYS : 0;
+	return 0;
 }
 
 /**