[dpdk-stable] [PATCH v2] net/virtio-user: fix advertising of protocol features

[Maxime Coquelin]

On 12/18/20 2:23 PM, Olivier Matz wrote:
> When connected to a vhost-user backend, the flag
> VHOST_USER_F_PROTOCOL_FEATURES is not advertised, preventing to do
> multiqueue (the VHOST_USER_PROTOCOL_F_MQ protocol feature is ignored by
> some backends if the VHOST_USER_F_PROTOCOL_FEATURES feature is not set).
> 
> When setting vhost-user features, advertise this flag if it was
> advertised by our peer.
> 
> Fixes: 8e7561054ac7 ("net/virtio: support vhost-user protocol features")
> Cc: stable at dpdk.org
> 
> Suggested-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
> ---
> 
> v2
> * fix obvious fallthrough case, sorry for the noise
> 
>  drivers/net/virtio/virtio_user/vhost_user.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
> index b93e65c60b..350eed4182 100644
> --- a/drivers/net/virtio/virtio_user/vhost_user.c
> +++ b/drivers/net/virtio/virtio_user/vhost_user.c
> @@ -297,13 +297,18 @@ vhost_user_sock(struct virtio_user_dev *dev,
>  		if (has_reply_ack)
>  			msg.flags |= VHOST_USER_NEED_REPLY_MASK;
>  		/* Fallthrough */
> -	case VHOST_USER_SET_FEATURES:
>  	case VHOST_USER_SET_PROTOCOL_FEATURES:
>  	case VHOST_USER_SET_LOG_BASE:
>  		msg.payload.u64 = *((__u64 *)arg);
>  		msg.size = sizeof(m.payload.u64);
>  		break;
>  
> +	case VHOST_USER_SET_FEATURES:
> +		msg.payload.u64 = *((__u64 *)arg) | (dev->device_features &
> +			(1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
> +		msg.size = sizeof(m.payload.u64);
> +		break;
> +
>  	case VHOST_USER_SET_OWNER:
>  	case VHOST_USER_RESET_OWNER:
>  		break;
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>

Thanks!
Maxime