vsock — virtio-vsock

github.com/go-virtio/vsock is a pure-Go virtio-vsock (socket device) driver for the standard PCI-bound device (VID 0x1AF4, DID 0x1053). It implements the modern-transport (Virtio 1.0+) init sequence and the three-virtqueue packet path.

Scope

It owns device bring-up, the three virtqueues (rx / tx / event, Virtio 1.1 §5.10.2), and the on-the-wire struct virtio_vsock_hdr marshalling, exposing a packet-level SendPacket / ReceivePacket API.

It deliberately does not implement the connection state machine or the credit-based flow control (buf_alloc / fwd_cnt accounting) — those belong a layer up, exactly as net drives frames rather than TCP. The header's addressing and credit fields are surfaced on Packet so the upper layer can implement them.

Quick start

import virtiovsock "github.com/go-virtio/vsock"

vs, err := virtiovsock.OpenVirtioVsock(transport)
if err != nil {
    return err
}

// Connection-request packet to the host (CID 2), port 5000.
err = vs.SendPacket(virtiovsock.Packet{
    SrcCID:  vs.GuestCID,
    DstCID:  virtiovsock.CIDHost,
    SrcPort: 1024,
    DstPort: 5000,
    Type:    virtiovsock.TypeStream,
    Op:      virtiovsock.OpRequest,
})

pkt, err := vs.ReceivePacket(10000) // busy-poll budget

OpenVirtioVsock leaves the device in DRIVER_OK state with the rx and event queues pre-posted and GuestCID populated from device config.

License

BSD-3-Clause.