The
hv_storvsc
driver implements the virtual store device for
FreeBSD
guest
partitions running on Hyper-V.
FreeBSD
guest partitions running on Hyper-V do not have direct access to
storage devices attached to the Hyper-V server.
Although a
FreeBSD
guest can access storage devices using Hyper-V's
full emulation mode, the performance in this mode tends to be unsatisfactory.
To counter the above issues, the
hv_storvsc
driver implements a storage
Virtual
Service Consumer (VSC) that relays storage requests from the guest partition
to the storage Virtual Service Provider (VSP) hosted in the root partition
using the high performance data exchange infrastructure provided by
hv_vmbus(4)
driver.
The VSP in the root partition then forwards the storage related requests to
the physical storage device.
This driver functions by presenting a SCSI HBA interface to the Comman Access
Method (CAM) layer.
CAM control blocks (CCBs) are
converted into VSCSI protocol messages which are delivered to the root
partition VSP over the Hyper-V VMBus.
