There was a large refactoring done in CTL to allow multiple ioctl frontend ports (and respective devices) to be created, particularly for bhyve. Unfortunately, respective part of bhyve functionality got lost somehow from the original virtio-scsi commit. This change allows wanted device path to be specified in either of two ways:
-s 6,virtio-scsi,/dev/cam/ctl1.1
-s 6,virtio-scsi,dev=/dev/cam/ctl2.3
If neither is specified, the default /dev/cam/ctl device is used.

While there, remove per-queue CTL device opening, which IMO makes no sense at this point.