Crate storvsp 

VMBus SCSI controller emulator (StorVSP).

StorVSP implements the Hyper-V synthetic SCSI protocol — a VMBus-based transport that carries SCSI CDBs between the guest’s storvsc driver and the VMM. This is not a standard SCSI transport (like iSCSI or SAS); it’s a Hyper-V-specific wire format defined in [storvsp_protocol].

Architecture

The crate uses a multi-worker model. The primary VMBus channel handles protocol version negotiation (Win6 through Blue); sub-channels process I/O in parallel. Each worker owns a VMBus ring and processes packets concurrently via FuturesUnordered.

StorVSP handles the transport (ring buffer management, GPADL setup, packet framing, sub-channel lifecycle) and a few SCSI control commands directly (REPORT_LUNS, INQUIRY for absent targets). All actual I/O is delegated to [AsyncScsiDisk] implementations — StorVSP never interprets SCSI data CDBs itself.

For the channel/sub-channel model, CPU affinity, and performance characteristics, see the StorVSP Channels & Subchannels page in the OpenVMM Guide.

Key types

• StorageDevice — the VMBus device. Implements VmbusDevice and SaveRestoreVmbusDevice.
• ScsiController — manages attached disks by [ScsiPath]. Supports runtime attach/remove.
• ScsiControllerDisk — wraps Arc<dyn AsyncScsiDisk>.

Performance

Poll-mode optimization: when pending I/O count exceeds poll_mode_queue_depth, the worker switches from interrupt-driven to busy-poll for new requests, reducing guest exit frequency. Future storage for SCSI request processing is pooled to avoid allocation on the hot path.

Modules

resolver

Resolver for a SCSI controller.

test_helpers

StorVSP test helpers.

Structs

RangeError

ScsiController

ScsiControllerDisk

A disk that can be added to a SCSI controller.

ScsiPathInUse

ScsiPathNotInUse

StorageDevice