When a fibre channel VF is to be unconfigured, 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_UNCONFIG.
Upon receiving this callback, the PF driver must unconfigure all the attributes of the VF and mark it as not usable. Under normal circumstances, this callback will be followed by additional callbacks with the DDI_CB_PCIV_VF_CONFIG action to disable the VF. See section Driver Callbacks for more information.