vhost-device/crates/gpio
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 gpio: update License in source files and readme 2022-10-27 11:19:40 -06:00

vhost-device-gpio - GPIO emulation backend daemon

Description

This program is a vhost-user backend that emulates a VirtIO GPIO device. This program takes a list of gpio devices on the host OS and then talks to them via the /dev/gpiochip{X} interface when a request comes from the guest OS for an GPIO device.

This program is tested with QEMU's -device vhost-user-gpio-pci but should work with any virtual machine monitor (VMM) that supports vhost-user. See the Examples section below.

Synopsis

vhost-device-gpio [OPTIONS]

Options

.. program:: vhost-device-gpio

.. 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=GPIO-DEVICES

GPIO device list at the host OS in the format: [:]

  Example: --device-list "2:4:7"

Here, each GPIO devices correspond to a separate guest instance, i.e. the number of devices in the device-list must match the number of sockets in the --socket-count. For example, the GPIO device 0 will be allocated to the guest with "0" path.

Examples

The daemon should be started first:

::

host# vhost-device-gpio --socket-path=gpio.sock --socket-count=1 --device-list 0:3

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=vgpio.sock,id=vgpio
-device vhost-user-gpio-pci,chardev=vgpio,id=gpio
-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