static int vfio_pci_set_intx_unmask(struct vfio_pci_device *vdev,
				    unsigned index, unsigned start,
				    unsigned count, uint32_t flags, void *data)
{
	if (!is_intx(vdev) || start != 0 || count != 1)
		return -EINVAL;

	if (flags & VFIO_IRQ_SET_DATA_NONE) {
		vfio_pci_intx_unmask(vdev);
	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
		uint8_t unmask = *(uint8_t *)data;
		if (unmask)
			vfio_pci_intx_unmask(vdev);
	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
		int32_t fd = *(int32_t *)data;
		if (fd >= 0)
			return vfio_virqfd_enable((void *) vdev,
						  vfio_pci_intx_unmask_handler,
						  vfio_send_intx_eventfd, NULL,
						  &vdev->ctx[0].unmask, fd);

		vfio_virqfd_disable(&vdev->ctx[0].unmask);
	}

	return 0;
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.