mirror of https://github.com/rust-vmm/vhost-device.git synced 2025-12-26 14:41:23 +00:00

Manos Pitsidianakis a1e013286f Move all crates to workspace root

Having all the workspace crates under the crates/ directory is
unnecessary. Rust documentation itself recommends all crates to be in
the root directory:

https://doc.rust-lang.org/book/ch14-03-cargo-workspaces.html#creating-the-second-package-in-the-workspace

I paste the text content here, in case the online page ever changes or
becomes unavailable:

    ## Creating the Second Package in the Workspace

    Next, let’s create another member package in the workspace and call it add_one. Change the top-level Cargo.toml to specify the add_one path in the members list:

    Filename: Cargo.toml

    [workspace]

    members = [
        "adder",
        "add_one",
    ]

    Then generate a new library crate named add_one:

    $ cargo new add_one --lib
         Created library `add_one` package

    Your add directory should now have these directories and files:

    ├── Cargo.lock
    ├── Cargo.toml
    ├── add_one
    │   ├── Cargo.toml
    │   └── src
    │       └── lib.rs
    ├── adder
    │   ├── Cargo.toml
    │   └── src
    │       └── main.rs
    └── target

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>

2023-10-16 12:03:57 +05:30

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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.

MockGpioDevice support

As connecting VM guests to random GPIO pins on your host is generally asking for trouble you can enable the "mock_gpio" feature in your build:

cargo build --features "mock_gpio"

You can then enable simulated GPIOs using the 's' prefix:

--device-list s4,s8

Which will create two gpio devices, the first with 4 pins and the second with 8. By default updates are display via env logger:

vhost-device-gpio -s /tmp/vus.sock -c 1 -l s4
[2023-09-14T14:15:14Z INFO  vhost_device_gpio::mock_gpio] gpio dummy0 set value to 1
[2023-09-14T14:15:14Z INFO  vhost_device_gpio::mock_gpio] gpio dummy0 set direction to 1
[2023-09-14T14:15:14Z INFO  vhost_device_gpio::mock_gpio] gpio dummy0 set direction to 0
[2023-09-14T14:15:19Z INFO  vhost_device_gpio::mock_gpio] gpio dummy1 set value to 1
[2023-09-14T14:15:19Z INFO  vhost_device_gpio::mock_gpio] gpio dummy1 set direction to 1
[2023-09-14T14:15:19Z INFO  vhost_device_gpio::mock_gpio] gpio dummy1 set direction to 0

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

Apache License, Version 2.0
BSD-3-Clause License

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