VBox 6a: VBoxVMI: server skeleton and client connect #281

Parent

#269

What to build

A patched VirtualBox serves VBoxVMI on a per-VM Unix socket and libmicrovmi can connect to it with the VBoxVMI method. Server is a ring-3 module in the VMM behind VBOX_WITH_VMI, started at VM creation, enabled via VBoxInternal/VMI/... extradata. On branch vmi/vboxvmi based on VirtualBox main.

Acceptance criteria

• SOCK_SEQPACKET socket at a configurable path, default under the VirtualBox user home vmi/<vm-uuid>.sock, mode 0600, peer uid checked
• Message header with size, request id and command/event code; handshake carries magic and protocol version
• Off unless enabled per VM
• vboxvmi crate (pure Rust, unpublished, under ~/vmi) connects and handshakes
• VBoxInitParams gains a VBoxVMI variant (socket path); virtualbox-vmi feature; driver init succeeds
• First version of the protocol specification and design notes in the VirtualBox tree; user-manual section on enabling VBoxVMI
• ADR in libmicrovmi docs/adr/: VBoxVMI uses a Unix socket rather than shared memory

Blocked by

• VBox 1b: Run VirtualBox on the host with a test guest #271
• VBox 3b: MachineDebugger method: read path in libmicrovmi #275