blk — virtio-blk

github.com/go-virtio/blk is a pure-Go virtio-blk (block device) driver for the standard PCI-bound device (VID 0x1AF4, DID 0x1042). It implements the modern-transport (Virtio 1.0+) init sequence and the request-queue I/O path.

Scope

Like net this package owns device bring-up, the single request virtqueue, and the on-the-wire request format — the header + data + status descriptor chain (Virtio 1.1 §5.2.6, built with common.AddChain) — exposing a block-level ReadBlocks / WriteBlocks / Flush API. The protocol sector size is always 512 bytes (BlockSize).

VIRTIO_BLK_F_RO is honoured (read-only devices reject writes); no other feature bit is negotiated.

The device backing the driver is the host's concern and is transparent to the guest — it can be a local disk image or a network volume served over NBD (with NBD itself tunnelled through WireGuard or TLS). The driver just sees a block device.

Quick start

import virtioblk "github.com/go-virtio/blk"

vb, err := virtioblk.OpenVirtioBlk(transport)
if err != nil {
    return err
}
// capacity in sectors and bytes
_ = vb.Capacity * virtioblk.BlockSize

// Read sectors 0..3 (4 × 512 B).
data, err := vb.ReadBlocks(0, 4)

// Write two sectors at LBA 100, then flush.
err = vb.WriteBlocks(100, make([]byte, 2*virtioblk.BlockSize))
err = vb.Flush()

License

BSD-3-Clause.