In the VDUSE Kernel driver, when the device is attached to Vhost-vDPA, it happens that the queues ready state is changed after DRIVER_OK Virtio status bit has been set.

The problem is that the .set_vq_ready() vDPA callback of the VDUSE Kernel driver only saves the state but does not notify the VDUSE userspace application. It results in some queues to never be enabled.

Other vDPA physical devices drivers, such as mlx5, configures the hardware in the callback.

A similar approach could be implemented in the VDUSE Kernel driver, by introducing a new message.