Re: [Qemu-devel] [PATCH 1/4] vhost-user: fix multiple queue specification

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

On Fri, Jan 12, 2018 at 03:56:55PM +0100, Maxime Coquelin wrote:
> The number of queues supported by the slave is queried with
> message VHOST_USER_GET_QUEUE_NUM, not with message
> VHOST_USER_GET_PROTOCOL_FEATURES.
> 
> Also, looking at master and slave implemntations, the payload
> returned by the slave is the number of queue pairs supported
> by the slave, not the number of queues.

virtio doesn't have a concept of queue pairs. virtio net does
have a concept of a tx/rx pair for purposes of steering.

Would this be a slave bug then?

I've applied the 1st chunk for now.

> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  docs/interop/vhost-user.txt | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
> index d49444e037..8a14191a1e 100644
> --- a/docs/interop/vhost-user.txt
> +++ b/docs/interop/vhost-user.txt
> @@ -214,8 +214,8 @@ Multiple queue is treated as a protocol extension, hence the slave has to
>  implement protocol features first. The multiple queues feature is supported
>  only when the protocol feature VHOST_USER_PROTOCOL_F_MQ (bit 0) is set.
>  
> -The max number of queues the slave supports can be queried with message
> -VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the number of
> +The max number of queue pairs the slave supports can be queried with message
> +VHOST_USER_GET_QUEUE_NUM. Master should stop when the number of
>  requested queues is bigger than that.
>  
>  As all queues share one connection, the master uses a unique index for each
> @@ -537,7 +537,7 @@ Master message types
>        Master payload: N/A
>        Slave payload: u64
>  
> -      Query how many queues the backend supports. This request should be
> +      Query how many queue pairs the backend supports. This request should be
>        sent only when VHOST_USER_PROTOCOL_F_MQ is set in queried protocol
>        features by VHOST_USER_GET_PROTOCOL_FEATURES.
>  
> -- 
> 2.14.3