| commit | d65bd280d9f4e192a884f1761e4b097c11aae6de | [log] [tgz] |
|---|---|---|
| author | Chirantan Ekbote <chirantan@chromium.org> | Tue Jun 22 10:31:54 2021 |
| committer | Commit Bot <commit-bot@chromium.org> | Thu Sep 09 08:26:50 2021 |
| tree | a16f56700fe99dcf66356f31b28198e3d3e45e69 | |
| parent | 02f8b005f568d7d959e1d977c36cbcf635f97043 [diff] |
CHROMIUM: Use File for device request fd There is nothing in the vhost-user documentation or spec that says this must be a socket for fs device requests. It's not even guaranteed that it is an fd for a UnixStream. Change the type to a File and leave it up to the backend to convert it into a more specialized type if necessary. Upstream PR: https://github.com/rust-vmm/vhost/pull/49 BUG=b:179755651 TEST=cargo test Cq-Depend: chromium:2987594 Change-Id: I52ce0c62e0627a87462be8e0a44fa534763f10ed Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/rust-vmm/vhost/+/2988140 Tested-by: Chirantan Ekbote <chirantan@chromium.org> Commit-Queue: Chirantan Ekbote <chirantan@chromium.org> Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>
A pure rust library for vDPA, vhost and vhost-user.
The vhost crate aims to help implementing dataplane for virtio backend drivers. It supports three different types of dataplane drivers:
The main relationship among Traits and Structs exported by the vhost crate is as below:
The vhost drivers in Linux provide in-kernel virtio device emulation. Normally the hypervisor userspace process emulates I/O accesses from the guest. Vhost puts virtio emulation code into the kernel, taking hypervisor userspace out of the picture. This allows device emulation code to directly call into kernel subsystems instead of performing system calls from userspace. The hypervisor relies on ioctl based interfaces to control those in-kernel vhost drivers, such as vhost-net, vhost-scsi and vhost-vsock etc.
The vhost-user protocol aims to implement vhost backend drivers in userspace, which complements the ioctl interface used to control the vhost implementation in the Linux kernel. It implements the control plane needed to establish virtqueue sharing with a user space process on the same host. It uses communication over a Unix domain socket to share file descriptors in the ancillary data of the message.
The protocol defines two sides of the communication, master and slave. Master is the application that shares its virtqueues, slave is the consumer of the virtqueues. Master and slave can be either a client (i.e. connecting) or server (listening) in the socket communication.