vhost-device-scmi - Man Page

vhost-user backend for a VirtIO SCMI device

Synopsis

vhost-device-scmi -s|--socket-path path [-d|--device spec]

vhost-device-scmi [-h|--help]

Description

This program is a vhost-user backend for a VirtIO SCMI device. It provides SCMI access to various entities on the host; not necessarily only those providing an SCMI interface themselves.

It is tested with QEMU’s -device vhost-user-scmi-pci but should work with any virtual machine monitor (VMM) that supports vhost-user. See Examples section below.

Options

-h, --help: Print help.
-s, --socket-path=PATH: Location of the vhost-user Unix domain sockets.
-d, --device=SPEC: SCMI device specification in the format ID,PROPERTY=VALUE,.... For example: -d iio,path=/sys/bus/iio/devices/iio:device0,channel=in_accel. Can be used multiple times for multiple exposed devices. If no device is specified then no device will be provided to the guest OS but VirtIO SCMI will be still available there.
--help-devices: List help on all the available devices.

Examples

The daemon should be started first:

host# vhost-device-scmi --socket-path=scmi.sock --device fake,name=foo

The QEMU invocation needs to create a chardev socket the device can use to communicate as well as share the guests memory over a memfd:

host# qemu-system \
   -chardev socket,path=scmi.sock,id=scmi \
   -device vhost-user-scmi-pci,chardev=vscmi,id=scmi \
   -machine YOUR-MACHINE-OPTIONS,memory-backend=mem \
   -m 4096 \
   -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \
   ...