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

Resolvers for storvsp SCSI and IDE accelerator devices.

test_helpers

StorVSP test helpers.

Structs

RangeError

ScsiController

ScsiControllerDisk

A disk that can be added to a SCSI controller.

ScsiPathInUse

ScsiPathNotInUse

StorageDevice