Re: [PATCH V9 5/6] virtio: introduce a mdev based transport

Cornelia Huck
2019-11-06T11:01:21Z

On Wed, 6 Nov 2019 15:05:47 +0800
Jason Wang <jasowang@redhat.com> wrote:

> This patch introduces a new mdev transport for virtio. This is used to
> use kernel virtio driver to drive the mediated device that is capable
> of populating virtqueue directly.
>
> A new virtio-mdev driver will be registered to the mdev bus, when a
> new virtio-mdev device is probed, it will register the device with
> mdev based config ops. This means it is a software transport between
> mdev driver and mdev device. The transport was implemented through
> device specific ops which is a part of mdev_parent_ops now.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> drivers/virtio/Kconfig | 13 ++
> drivers/virtio/Makefile | 1 +
> drivers/virtio/virtio_mdev.c | 406 +++++++++++++++++++++++++++++++++++
> 3 files changed, 420 insertions(+)
> create mode 100644 drivers/virtio/virtio_mdev.c
>
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index 078615cf2afc..558ac607d107 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -43,6 +43,19 @@ config VIRTIO_PCI_LEGACY
>
> If unsure, say Y.
>
> +config VIRTIO_MDEV
> + tristate "MDEV driver for virtio devices"
> + depends on VFIO_MDEV && VIRTIO
> + default n
> + help
> + This driver provides support for virtio based paravirtual
> + device driver over MDEV bus. This requires your environemnt
> + has appropriate virtio mdev device implementation which may
> + operate on the physical device that the datapath of virtio
> + could be offloaded to hardware.

That sentence is a bit confusing to me... what about

"For this to be useful, you need an appropriate virtio mdev device
implementation that operates on a physical device to allow the datapath
of virtio to be offloaded to hardware."

?

> +
> + If unsure, say M

Building this as a module should not hurt (but please add a trailing
'.' here :)

> +
> config VIRTIO_PMEM
> tristate "Support for virtio pmem driver"
> depends on VIRTIO

With the changes above,

Reviewed-by: Cornelia Huck <cohuck@redhat.com>