Add vhost-device I2C support

.gitignore

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+kcov_output/
+target/
+.vscode/
+*.swp

CODEOWNERS

@@ -1,2 +1,2 @@
 # Add the list of code owners here (using their GitHub username)
-* gatekeeper-PullAssigner
+* gatekeeper-PullAssigner @vireshk

Cargo.toml

@@ -1,12 +1,5 @@
-[package]
-name = "crate-template"
-version = "0.1.0"
-authors = ["TODO"]
-description = "This is a template for creating rust-vmm repositories."
-repository = "https://github.com/rust-vmm/crate-template"
-readme = "README.md"
-keywords = ["virt"]
-license = "Apache-2.0 OR BSD-3-Clause"
-edition = "2018"
+[workspace]
 
-[dependencies]
+members = [
+    "src/i2c",
+]

README.md

@@ -1,41 +1,11 @@
-# Crate Name
+# vhost-device
 
 ## Design
 
-TODO: This section should have a high-level design of the crate.
+This repository hosts various 'vhost-user' device backends in their own crates.
+See their individual README.md files for specific information about those
+crates.
 
-Some questions that might help in writing this section:
-- What is the purpose of this crate?
-- What are the main components of the crate? How do they interact which each
-  other?
+Here is the list of device backends that we support:
 
-## Usage
-
-TODO: This section describes how the crate is used.
-
-Some questions that might help in writing this section:
-- What traits do users need to implement?
-- Does the crate have any default/optional features? What is each feature
-  doing?
-- Is this crate used by other rust-vmm components? If yes, how?
-
-## Examples
-
-TODO: Usage examples.
-
-```rust
-use my_crate;
-
-...
-```
-
-## License
-
-**!!!NOTICE**: The BSD-3-Clause license is not included in this template.
-The license needs to be manually added because the text of the license file
-also includes the copyright. The copyright can be different for different
-crates. If the crate contains code from CrosVM, the crate must add the
-CrosVM copyright which can be found
-[here](https://chromium.googlesource.com/chromiumos/platform/crosvm/+/master/LICENSE).
-For crates developed from scratch, the copyright is different and depends on
-the contributors.
+- [I2C](https://github.com/rust-vmm/vhost-device/blob/master/src/i2c/README.md)

coverage_config_x86_64.json

@@ -1,5 +1,5 @@
 {
-  "coverage_score": 90,
+  "coverage_score": 36.7,
   "exclude_path": "",
   "crate_features": ""
 }

src/i2c/Cargo.toml

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+[package]
+name = "vhost-device-i2c"
+version = "0.1.0"
+authors = ["Viresh Kumar <[email protected]>"]
+description = "vhost i2c backend device"
+repository = "https://github.com/rust-vmm/vhost-device"
+readme = "README.md"
+keywords = ["i2c", "vhost", "virt", "backend"]
+license = "Apache-2.0 OR BSD-3-Clause"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+clap = { version = "=3.0.0-beta.2",  features = ["yaml"] }
+epoll = "4.3"
+libc = ">=0.2.95"
+log = ">=0.4.6"
+vhost = { git = "https://github.com/rust-vmm/vhost", features = ["vhost-user-slave"] }
+vhost-user-backend = { git = "https://github.com/rust-vmm/vhost-user-backend" }
+virtio-bindings = ">=0.1"
+vm-memory = ">=0.3.0"
+vmm-sys-util = ">=0.8.0"

src/i2c/README.md

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+# 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:
+      <bus>:<client_addr>[:<client_addr>],[<bus>:<client_addr>[:<client_addr>]]
+
+      Example: --device-list "2:32:21,3:10:23"
+
+  Here,
+      bus (decimal): adatper bus number. e.g. 2 for /dev/i2c-2, 3 for /dev/i2c-3.
+      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 0:32
+
+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 \
+      ...

src/i2c/src/cli.yaml

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+name: vhost-device-i2c
+version: "0.1.0"
+author: "Viresh Kumar <[email protected]>"
+about: Virtio I2C backend daemon.
+
+settings:
+    - ArgRequiredElseHelp
+
+args:
+  # Connection to sockets
+  - socket_path:
+      short: s
+      long: socket-path
+      value_name: FILE
+      takes_value: true
+      about: Location of vhost-user Unix domain socket. This is suffixed by 0,1,2..socket_count-1.
+  - socket_count:
+      short: c
+      long: socket-count
+      value_name: INT
+      takes_value: true
+      about: Number of guests (sockets) to connect to. Default = 1.
+  # I2C device list on host
+  - devices:
+      short: l
+      long: device-list
+      value_name: PATH
+      takes_value: true
+      about: List of I2C bus and clients in format <bus>:<client_addr>[:<client_addr>][,<bus>:<client_addr>[:<client_addr>]]
+
+groups:
+  - required_args:
+      args:
+        - socket_path
+      args:
+        - devices
+      required: true