[PATCH v3 0/4] Add virtio transport for AF_VSOCK

Michael S. Tsirkin
Wed, 09 Dec 2015 20:12:50 -0000

On Wed, Dec 09, 2015 at 08:03:49PM +0800, Stefan Hajnoczi
wrote:
> Note: the virtio-vsock device specification is currently under review but
not
> yet finalized.  Please review this code but don't merge until I send an
update
> when the spec is finalized.  Thanks!

Yes, this should have RFC in the subject.

> v3:
>  * Remove unnecessary 3-way handshake, just do REQUEST/RESPONSE instead
>    of REQUEST/RESPONSE/ACK
>  * Remove SOCK_DGRAM support and focus on SOCK_STREAM first
>    (also drop v2 Patch 1, it's only needed for SOCK_DGRAM)
>  * Only allow host->guest connections (same security model as latest
>    VMware)
>  * Don't put vhost vsock driver into staging
>  * Add missing Kconfig dependencies (Arnd Bergmann <arnd at
arndb.de>)
>  * Remove unneeded variable used to store return value
>    (Fengguang Wu <fengguang.wu at intel.com> and Julia Lawall
>    <julia.lawall at lip6.fr>)
>
> v2:
>  * Rebased onto Linux v4.4-rc2
>  * vhost: Refuse to assign reserved CIDs
>  * vhost: Refuse guest CID if already in use
>  * vhost: Only accept correctly addressed packets (no spoofing!)
>  * vhost: Support flexible rx/tx descriptor layout
>  * vhost: Add missing total_tx_buf decrement
>  * virtio_transport: Fix total_tx_buf accounting
>  * virtio_transport: Add virtio_transport global mutex to prevent races
>  * common: Notify other side of SOCK_STREAM disconnect (fixes shutdown
>    semantics)
>  * common: Avoid recursive mutex_lock(tx_lock) for write_space (fixes
deadlock)
>  * common: Define VIRTIO_VSOCK_TYPE_STREAM/DGRAM hardware interface
constants
>  * common: Define VIRTIO_VSOCK_SHUTDOWN_RCV/SEND hardware interface
constants
>  * common: Fix peer_buf_alloc inheritance on child socket
>
> This patch series adds a virtio transport for AF_VSOCK (net/vmw_vsock/).
> AF_VSOCK is designed for communication between virtual machines and
> hypervisors.  It is currently only implemented for VMware's VMCI
transport.
>
> This series implements the proposed virtio-vsock device specification from
> here:
> http://permalink.gmane.org/gmane.comp.emulators.virtio.devel/980
>
> Most of the work was done by Asias He and Gerd Hoffmann a while back.  I
have
> picked up the series again.
>
> The QEMU userspace changes are here:
> https://github.com/stefanha/qemu/commits/vsock
>
> Why virtio-vsock?
> -----------------
> Guest<->host communication is currently done over the virtio-serial
device.
> This makes it hard to port sockets API-based applications and is limited to
> static ports.
>
> virtio-vsock uses the sockets API so that applications can rely on familiar
> SOCK_STREAM semantics.  Applications on the host can easily connect to
guest
> agents because the sockets API allows multiple connections to a listen
socket
> (unlike virtio-serial).  This simplifies the guest<->host
communication and
> eliminates the need for extra processes on the host to arbitrate
virtio-serial
> ports.
>
> Overview
> --------
> This series adds 3 pieces:
>
> 1. virtio_transport_common.ko - core virtio vsock code that uses vsock.ko
>
> 2. virtio_transport.ko - guest driver
>
> 3. drivers/vhost/vsock.ko - host driver
>
> Howto
> -----
> The following kernel options are needed:
>   CONFIG_VSOCKETS=y
>   CONFIG_VIRTIO_VSOCKETS=y
>   CONFIG_VIRTIO_VSOCKETS_COMMON=y
>   CONFIG_VHOST_VSOCK=m
>
> Launch QEMU as follows:
>   # qemu ... -device vhost-vsock-pci,id=vhost-vsock-pci0,guest-cid=3
>
> Guest and host can communicate via AF_VSOCK sockets.  The host's CID
(address)
> is 2 and the guest must be assigned a CID (3 in the example above).
>
> Status
> ------
> This patch series implements the latest draft specification.  Please
review.
>
> Asias He (4):
>   VSOCK: Introduce virtio-vsock-common.ko
>   VSOCK: Introduce virtio-vsock.ko
>   VSOCK: Introduce vhost-vsock.ko
>   VSOCK: Add Makefile and Kconfig
>
>  drivers/vhost/Kconfig                   |  10 +
>  drivers/vhost/Makefile                  |   4 +
>  drivers/vhost/vsock.c                   | 628 +++++++++++++++++++++++
>  drivers/vhost/vsock.h                   |   4 +
>  include/linux/virtio_vsock.h            | 203 ++++++++
>  include/uapi/linux/virtio_ids.h         |   1 +
>  include/uapi/linux/virtio_vsock.h       |  87 ++++
>  net/vmw_vsock/Kconfig                   |  18 +
>  net/vmw_vsock/Makefile                  |   2 +
>  net/vmw_vsock/virtio_transport.c        | 466 +++++++++++++++++
>  net/vmw_vsock/virtio_transport_common.c | 854
++++++++++++++++++++++++++++++++
>  11 files changed, 2277 insertions(+)
>  create mode 100644 drivers/vhost/vsock.c
>  create mode 100644 drivers/vhost/vsock.h
>  create mode 100644 include/linux/virtio_vsock.h
>  create mode 100644 include/uapi/linux/virtio_vsock.h
>  create mode 100644 net/vmw_vsock/virtio_transport.c
>  create mode 100644 net/vmw_vsock/virtio_transport_common.c
>
> --
> 2.5.0