If the configuration of an fibre channel VF is modified some time after it has been enabled and configured, the IOV framework will issue a callback to the PF driver. In this callback, the action parameter is set to DDI_CB_PCIV_CLASS_CONFIG, the cbarg parameter points to a fciov_conf_t structure containing information about the VF, and the fc_cmd field of the fciov_conf_t structure is set to FCIOV_VF_UPDCONFIG.
Upon receiving this callback, the PF driver must examine the fci_flags field to determine which of the VF attributes has changed. Based on the settings of this filed, the appropriate information must be retrieved from the data fields and used to update the VF configuration.