vhost-device/crates/i2c
Erik Schilling a9de87a1ce tree-wide: bubble up errors from daemon threads
There was a mix of just unwrapping (panicking) and catching and logging
errors. The unwrapping is not allowing for particulary pretty error
handling, so let's bubble the errors up by not crashing the thread,
but by just returning a Result<()> than is received when joining the
threads.

Not all .unwrap() uses were translated since a followup PR (#389) will
rework that code anyway (and get rid of the .unwrap() in the process).

Signed-off-by: Erik Schilling <erik.schilling@linaro.org>
2023-07-11 13:30:01 +05:30
..
src tree-wide: bubble up errors from daemon threads 2023-07-11 13:30:01 +05:30
Cargo.toml tree-wide: drop the Eq trait from Error 2023-07-11 13:30:01 +05:30
CHANGELOG.md Add CHANGELOG.md to all crates 2023-07-07 22:06:45 +05:30
LICENSE-APACHE Symlink license files into crate folders 2023-07-04 14:56:52 +05:30
LICENSE-BSD-3-Clause Symlink license files into crate folders 2023-07-04 14:56:52 +05:30
README.md i2c: Accept bus names instead of numbers 2022-12-05 17:15:38 +05:30

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