Module devices::virtio::wl

source ·
Expand description

This module implements the virtio wayland used by the guest to access the host’s wayland server.

The virtio wayland protocol is done over two queues: in and out. The in queue is used for sending commands to the guest that are generated by the host, usually messages from the wayland server. The out queue is for commands from the guest, usually requests to allocate shared memory, open a wayland server connection, or send data over an existing connection.

Each WlVfd represents one virtual file descriptor created by either the guest or the host. Virtual file descriptors contain actual file descriptors, either a shared memory file descriptor or a unix domain socket to the wayland server. In the shared memory case, there is also an associated slot that indicates which hypervisor memory slot the memory is installed into, as well as a page frame number that the guest can access the memory from.

The types starting with Ctrl are structures representing the virtio wayland protocol “on the wire.” They are decoded and executed in the execute function and encoded as some variant of WlResp for responses.

There is one WlState instance that contains every known vfd and the current state of in queue. The in queue requires extra state to buffer messages to the guest in case the in queue is already full. The WlState also has a control socket necessary to fulfill certain requests, such as those registering guest memory.

The Worker is responsible for the poll loop over all possible events, encoding/decoding from the virtio queue, and routing messages in and out of WlState. Possible events include the kill event, available descriptors on the in or out queue, and incoming data on any vfd’s socket.

Structs§

Enums§

Constants§

Functions§

Type Aliases§

Unions§