drm/xe/vm: move xe_svm_init() earlier

In xe_vm_close_and_put() we need to be able to call xe_svm_fini(),
however during vm creation we can call this on the error path, before
having actually initialised the svm state, leading to various splats
followed by a fatal NPD.

Fixes: 6fd979c ("drm/xe: Add SVM init / close / fini to faulting VMs")
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4967
Signed-off-by: Matthew Auld <[email protected]>
Cc: Matthew Brost <[email protected]>
Reviewed-by: Matthew Brost <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: matt-auld

drivers/gpu/drm/xe/xe_vm.c

@@ -1709,10 +1709,16 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
 		xe_pm_runtime_get_noresume(xe);
 	}
 
+	if (flags & XE_VM_FLAG_FAULT_MODE) {
+		err = xe_svm_init(vm);
+		if (err)
+			goto err_no_resv;
+	}
+
 	vm_resv_obj = drm_gpuvm_resv_object_alloc(&xe->drm);
 	if (!vm_resv_obj) {
 		err = -ENOMEM;
-		goto err_no_resv;
+		goto err_svm_fini;
 	}
 
 	drm_gpuvm_init(&vm->gpuvm, "Xe VM", DRM_GPUVM_RESV_PROTECTED, &xe->drm,
@@ -1783,12 +1789,6 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
 		}
 	}
 
-	if (flags & XE_VM_FLAG_FAULT_MODE) {
-		err = xe_svm_init(vm);
-		if (err)
-			goto err_close;
-	}
-
 	if (number_tiles > 1)
 		vm->composite_fence_ctx = dma_fence_context_alloc(1);
 
@@ -1802,6 +1802,11 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
 	xe_vm_close_and_put(vm);
 	return ERR_PTR(err);
 
+err_svm_fini:
+	if (flags & XE_VM_FLAG_FAULT_MODE) {
+		vm->size = 0; /* close the vm */
+		xe_svm_fini(vm);
+	}
 err_no_resv:
 	mutex_destroy(&vm->snap_mutex);
 	for_each_tile(tile, xe, id)