1 unstable release
0.1.0 | Jul 24, 2023 |
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#1288 in Hardware support
66 downloads per month
80KB
2K
SLoC
vhost-device-i2c - I2C emulation backend daemon
Description
This program is a vhost-user backend that emulates a VirtIO I2C bus. This program takes the layout of the i2c bus and its devices on the host OS and then talks to them via the /dev/i2c-X interface when a request comes from the guest OS for an I2C or SMBUS device.
This program is tested with QEMU's -device vhost-user-i2c-pci
but should
work with any virtual machine monitor (VMM) that supports vhost-user. See the
Examples section below.
Synopsis
vhost-device-i2c [OPTIONS]
Options
.. program:: vhost-device-i2c
.. option:: -h, --help
Print help.
.. option:: -s, --socket-path=PATH
Location of vhost-user Unix domain sockets, this path will be suffixed with 0,1,2..socket_count-1.
.. option:: -c, --socket-count=INT
Number of guests (sockets) to attach to, default set to 1.
.. option:: -l, --device-list=I2C-DEVICES
I2c device list at the host OS in the format: :<client_addr>[:<client_addr>],[:<client_addr>[:<client_addr>]]
Example: --device-list "i915 gmbus dpd:32:21,DPDDC-D:10:23"
Here, bus-name: is adatper's name. e.g. value of /sys/bus/i2c/devices/i2c-0/name. client_addr (decimal): address for client device, 32 == 0x20.
Examples
The daemon should be started first:
::
host# vhost-device-i2c --socket-path=vi2c.sock --socket-count=1 --device-list "i915 gmbus dpd:32"
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=vi2c.sock,id=vi2c
-device vhost-user-i2c-pci,chardev=vi2c,id=i2c
-m 4096
-object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on
-numa node,memdev=mem
...
License
This project is licensed under either of
- Apache License, Version 2.0
- BSD-3-Clause License
Dependencies
~6–8MB
~139K SLoC