Re: [RFC v2 4/9] vhost-vdpa: introduce vhost-vdpa net client

[Eric Blake <eblake@redhat.com>]

On 5/8/20 11:32 AM, Cindy Lu wrote:
> From: Tiwei Bie <tiwei.bie@intel.com>
> 
> This patch set introduces a new net client type: vhost-vdpa.
> vhost-vdpa net client will set up a vDPA device which is specified
> by a "vhostdev" parameter.
> 
> Co-authored-by: Lingshan Zhu <lingshan.zhu@intel.com>
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---

Just looking at UI:


> +++ b/qapi/net.json
> @@ -441,6 +441,23 @@
>       '*queues':        'int' } }
>   
>   ##
> +# @NetdevVhostVDPAOptions:
> +#
> +# Vhost-vdpa network backend
> +#
> +# @vhostdev: name of a vdpa dev path in sysfs
> +#
> +# @queues: number of queues to be created for multiqueue vhost-vdpa
> +#          (default: 1) (Since 5.1)

No need to mark a 'since' tag on a member introduced at the same time as 
the overall struct itself.

> +#
> +# Since: 5.1
> +##
> +{ 'struct': 'NetdevVhostVDPAOptions',
> +  'data': {
> +    '*vhostdev':     'str',

What does this default to if omitted?

> +    '*fd':           'str',

Not documented above.

> +    '*queues':       'int' } }
> +##

Missing blank line separator.

>   # @NetClientDriver:
>   #
>   # Available netdev drivers.
> @@ -451,7 +468,7 @@
>   ##
>   { 'enum': 'NetClientDriver',
>     'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
> -            'bridge', 'hubport', 'netmap', 'vhost-user' ] }
> +            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }

Missing a line above that 'vhost-vdpa' is new to 5.1.


> @@ -2749,6 +2756,18 @@ qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,sha
>        -device virtio-net-pci,netdev=net0
>   @end example
>   
> +@item -netdev vhost-vdpa,vhostdev=/path/to/dev
> +Establish a vhost-vdpa netdev, backed by a vhostdev. The chardev should
> +be a unix domain socket backed one. The vhost-vdpa uses a specifically defined
> +protocol to pass vhost ioctl replacement messages to an application on the other
> +end of the socket.
> +Example:
> +@example
> +qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \
> +     -numa node,memdev=mem \
> +     -netdev type=vhost-vdpa,id=net0,vhostdev=/path/to/dev \
> +     -device virtio-net-pci,netdev=net0
> +@end example
>   @item -netdev hubport,id=@var{id},hubid=@var{hubid}[,netdev=@var{nd}]
>   
>   Create a hub port on the emulated hub with ID @var{hubid}.
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org