Re: [PATCH v3 0/5] Add a vhost RPMsg API

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, May 27, 2020 at 08:05:36PM +0200, Guennadi Liakhovetski wrote:
> v3:
> - address several checkpatch warnings
> - address comments from Mathieu Poirier
> 
> v2:
> - update patch #5 with a correct vhost_dev_init() prototype
> - drop patch #6 - it depends on a different patch, that is currently
>   an RFC
> - address comments from Pierre-Louis Bossart:
>   * remove "default n" from Kconfig
> 
> Linux supports RPMsg over VirtIO for "remote processor" /AMP use
> cases. It can however also be used for virtualisation scenarios,
> e.g. when using KVM to run Linux on both the host and the guests.
> This patch set adds a wrapper API to facilitate writing vhost
> drivers for such RPMsg-based solutions. The first use case is an
> audio DSP virtualisation project, currently under development, ready
> for review and submission, available at
> https://github.com/thesofproject/linux/pull/1501/commits
> A further patch for the ADSP vhost RPMsg driver will be sent
> separately for review only since it cannot be merged without audio
> patches being upstreamed first.


RPMsg over virtio has several problems. One is that it's
not specced at all. Before we add more stuff, I'd like so
see at least an attempt at describing what it's supposed to do.

Another it's out of line with 1.0 spec passing guest
endian data around. Won't work if host and guest
endian-ness do not match. Should pass eveything in LE and
convert.

It's great to see it's seeing active development finally.
Do you think you will have time to address these?



> Thanks
> Guennadi
> 
> Guennadi Liakhovetski (5):
>   vhost: convert VHOST_VSOCK_SET_RUNNING to a generic ioctl
>   vhost: (cosmetic) remove a superfluous variable initialisation
>   rpmsg: move common structures and defines to headers
>   rpmsg: update documentation
>   vhost: add an RPMsg API
> 
>  Documentation/rpmsg.txt          |   6 +-
>  drivers/rpmsg/virtio_rpmsg_bus.c |  78 +-------
>  drivers/vhost/Kconfig            |   7 +
>  drivers/vhost/Makefile           |   3 +
>  drivers/vhost/rpmsg.c            | 382 +++++++++++++++++++++++++++++++++++++++
>  drivers/vhost/vhost.c            |   2 +-
>  drivers/vhost/vhost_rpmsg.h      |  74 ++++++++
>  include/linux/virtio_rpmsg.h     |  81 +++++++++
>  include/uapi/linux/rpmsg.h       |   3 +
>  include/uapi/linux/vhost.h       |   4 +-
>  10 files changed, 559 insertions(+), 81 deletions(-)
>  create mode 100644 drivers/vhost/rpmsg.c
>  create mode 100644 drivers/vhost/vhost_rpmsg.h
>  create mode 100644 include/linux/virtio_rpmsg.h
> 
> -- 
> 1.9.3