vhost-user: fix shared object return values

VHOST_USER_BACKEND_SHARED_OBJECT_ADD and
VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE state
in the spec that they return 0 for successful
operations, non-zero otherwise. However,
implementation relies on the return types
of the virtio-dmabuf library, with opposite
semantics (true if everything is correct,
false otherwise). Therefore, current
implementation violates the specification.

Revert the logic so that the implementation
of the vhost-user handling methods matches
the specification.

Fixes: 043e127a126bb3ceb5fc753deee27d261fd0c5ce
Fixes: 160947666276c5b7f6bca4d746bcac2966635d79
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Albert Esteve <aesteve@redhat.com>
Message-Id: <20241022124615.585596-1-aesteve@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index d1b0893b4d..f170f0b25b 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1623,9 +1623,14 @@ vhost_user_backend_handle_shared_object_add(struct vhost_dev *dev,
     QemuUUID uuid;
 
     memcpy(uuid.data, object->uuid, sizeof(object->uuid));
-    return virtio_add_vhost_device(&uuid, dev);
+    return !virtio_add_vhost_device(&uuid, dev);
 }
 
+/*
+ * Handle VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE backend requests.
+ *
+ * Return: 0 on success, 1 on error.
+ */
 static int
 vhost_user_backend_handle_shared_object_remove(struct vhost_dev *dev,
                                                VhostUserShared *object)
@@ -1639,16 +1644,16 @@ vhost_user_backend_handle_shared_object_remove(struct vhost_dev *dev,
         struct vhost_dev *owner = virtio_lookup_vhost_device(&uuid);
         if (dev != owner) {
             /* Not allowed to remove non-owned entries */
-            return 0;
+            return 1;
         }
         break;
     }
     default:
         /* Not allowed to remove non-owned entries */
-        return 0;
+        return 1;
     }
 
-    return virtio_remove_resource(&uuid);
+    return !virtio_remove_resource(&uuid);
 }
 
 static bool vhost_user_send_resp(QIOChannel *ioc, VhostUserHeader *hdr,