[libvirt-users] virtio_ioport_write: unexpected address

the guest is normally running, but the qemu log is printing the following message: what happen? thanks a lot. virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0 virtio_ioport_write: unexpected address 0x13 value 0x0