| commit | 1f328f69d0740ca7c61e65262a21f1b9827a32ba | [log] [tgz] |
|---|---|---|
| author | Android Build Coastguard Worker <[email protected]> | Wed Nov 15 00:14:43 2023 +0000 |
| committer | Android Build Coastguard Worker <[email protected]> | Wed Nov 15 00:14:43 2023 +0000 |
| tree | 3315405c216c4173af9f5e918430b4da07bbeb0f | |
| parent | 1a7b93335ab39852e1ae2fd0561544d1ead22fc7 [diff] | |
| parent | 2cbb10c1a177e5723db74a163dcab1b2a24cbf42 [diff] |
Snap for 11097608 from 2cbb10c1a177e5723db74a163dcab1b2a24cbf42 to 24Q1-release Change-Id: I819cc43fd307c5e90eea5a433b9477bc6da7aacc
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.
Supporting Xen requires special handling while mapping the guest memory. The vm-memory crate implements xen memory mapping support via a separate feature xen, and this crate uses the same feature name to enable Xen support.
Also, for xen mappings, the memory regions passed by the frontend contains few extra fields as described in the vhost-user protocol documentation.
It was decided by the rust-vmm maintainers to keep the interface simple and build the crate for either standard Unix memory mapping or Xen, and not both.