Re: [Qemu-devel] [PATCH v2 4/4] spec/vhost-user: add VHOST_USER_PROTOCOL_F_VERSATILE_SLAVE

[Marc-André Lureau]

Hi

On Thu, Nov 24, 2016 at 7:20 AM Wei Wang <address@hidden> wrote:

> The VHOST_USER_PROTOCOL_F_VERSATILE_SLAVE protocol feature indicates
> that the slave side implementation supports different types of devices.
> The master tells the slave what type of device to create by sending
> the VHOST_USER_SET_DEV_INFO message.
>
> Signed-off-by: Wei Wang <address@hidden>
> ---
>  docs/specs/vhost-user.txt | 21 ++++++++++++++++-----
>  1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index fdc99ea..da1314d 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -264,11 +264,12 @@ restarted.
>  Protocol features
>  -----------------
>
> -#define VHOST_USER_PROTOCOL_F_MQ             0
> -#define VHOST_USER_PROTOCOL_F_LOG_SHMFD      1
> -#define VHOST_USER_PROTOCOL_F_RARP           2
> -#define VHOST_USER_PROTOCOL_F_REPLY_ACK      3
> -#define VHOST_USER_PROTOCOL_F_VHOST_PCI      4
> +#define VHOST_USER_PROTOCOL_F_MQ               0
> +#define VHOST_USER_PROTOCOL_F_LOG_SHMFD        1
> +#define VHOST_USER_PROTOCOL_F_RARP             2
> +#define VHOST_USER_PROTOCOL_F_REPLY_ACK        3
> +#define VHOST_USER_PROTOCOL_F_VHOST_PCI        4
> +#define VHOST_USER_PROTOCOL_F_VERSATILE_SLAVE  5
>

 I would rather name it after the message,
VHOST_USER_PROTOCOL_F_SET_DEV_INFO

>
>  Message types
>  -------------
> @@ -514,6 +515,16 @@ Message types
>        #define VHOST_USER_SET_PEER_CONNECTION_F_CREATE    2
>        #define VHOST_USER_SET_PEER_CONNECTION_F_DESTROY   3
>
> + * VHOST_USER_SET_DEV_INFO
> +
> +      Id: 21
> +      Equivalent ioctl: N/A
> +      Master payload: u64
>
+
> +      The master sends the device type info to the slave.
>

What is the meaning of this payload? Is it the virtio device id? better be
explicit about it.

If it is the case, I would name the message "VHOST_USER_SET_DEVICE_ID".



> +      This request should be sent only when
> VHOST_USER_PROTOCOL_F_VERSATILE_SLAVE
> +      has been negotiated.
> +
>  VHOST_USER_PROTOCOL_F_REPLY_ACK:
>  -------------------------------
>  The original vhost-user specification only demands replies for certain
> --
> 2.7.4
>
> --
Marc-André Lureau