crosvm/third_party/vmm_vhost
Keiichi Watanabe a6da8a5406 vmm_vhost: vhost_user: Use IoSliceMut in recv_into_bufs()
Replace `&mut [u8]` in recv_into_bufs() with IoSliceMut.
Note that recv_into_bufs_all()'s interface is unchanged as it changes
internal cursor with advance().

BUG=none
TEST=cargo test --features=vhost-user-master,vhost-user-slave

Change-Id: I74666cd2472f879a473c07dbe617add79d0ca903
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3302693
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Commit-Queue: Keiichi Watanabe <keiichiw@chromium.org>
2021-12-01 09:45:38 +00:00
..
.buildkite third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
.cargo third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
.github third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
docs third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
src vmm_vhost: vhost_user: Use IoSliceMut in recv_into_bufs() 2021-12-01 09:45:38 +00:00
.gitignore third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
.gitmodules third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
Cargo.toml third_party/vmm_vhost: switch to our vm_memory crate 2021-11-17 23:01:34 +00:00
CODEOWNERS third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
coverage_config_aarch64.json third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
coverage_config_x86_64.json third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
LICENSE third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
LICENSE-BSD-3-Clause third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
LICENSE-BSD-Chromium third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
PRESUBMIT.cfg third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00
README.md third_party/vmm_vhost: Add vmm_vhost code into /third_party/ 2021-11-10 08:42:11 +00:00

vHost

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:

  • vhost: the dataplane is implemented by linux kernel
  • vhost-user: the dataplane is implemented by dedicated vhost-user servers
  • vDPA(vhost DataPath Accelerator): the dataplane is implemented by hardwares

The main relationship among Traits and Structs exported by the vhost crate is as below:

vhost Architecture

Kernel-based vHost Backend Drivers

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.

vHost-user Backend Drivers

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.