diff mbox series

[v3,5/5] vhost: message handling implemented as a callback array

Message ID 153698885466.23049.5627861471035122455.stgit@T460
State Superseded
Headers show
Series vhost: vhost_user.c code cleanup | expand

Commit Message

Nikolay Nikolaev Sept. 15, 2018, 5:20 a.m. UTC 
Introduce vhost_message_handlers, which maps the message request
type to the message handler. Then replace the switch construct
with a map and call.

Failing vhost_user_set_features is fatal and all processing should
stop immediately and propagate the error to the upper layers. Change
the code accordingly to reflect that.

Signed-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>

---
 lib/librte_vhost/vhost_user.c |  161 +++++++++++++++++------------------------
 1 file changed, 66 insertions(+), 95 deletions(-)

Comments

Maxime Coquelin Sept. 19, 2018, 7:37 a.m. UTC | #1 
On 09/15/2018 07:20 AM, Nikolay Nikolaev wrote:
> Introduce vhost_message_handlers, which maps the message request

> type to the message handler. Then replace the switch construct

> with a map and call.

> 

> Failing vhost_user_set_features is fatal and all processing should

> stop immediately and propagate the error to the upper layers. Change

> the code accordingly to reflect that.

> 

> Signed-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>

> ---

>   lib/librte_vhost/vhost_user.c |  161 +++++++++++++++++------------------------

>   1 file changed, 66 insertions(+), 95 deletions(-)

> 

> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c

> index 81c0396de..9004e1ac8 100644

> --- a/lib/librte_vhost/vhost_user.c

> +++ b/lib/librte_vhost/vhost_user.c

> @@ -73,6 +73,8 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {

>   

>   /* The possible results of a message handling function */

>   enum vh_result {

> +	/* Message handling failed with an unrecoverable error */

> +	VH_RESULT_FATAL = -2,

>   	/* Message handling failed */

>   	VH_RESULT_ERR   = -1,

>   	/* Message handling successful */

> @@ -206,7 +208,7 @@ vhost_user_set_features(struct virtio_net **pdev, VhostUserMsg *msg)

>   		RTE_LOG(ERR, VHOST_CONFIG,

>   			"(%d) received invalid negotiated features.\n",

>   			dev->vid);

> -		return VH_RESULT_ERR;

> +		return VH_RESULT_FATAL;

>   	}

>   

>   	if (dev->flags & VIRTIO_DEV_RUNNING) {

> @@ -222,7 +224,7 @@ vhost_user_set_features(struct virtio_net **pdev, VhostUserMsg *msg)

>   			RTE_LOG(ERR, VHOST_CONFIG,

>   				"(%d) features changed while device is running.\n",

>   				dev->vid);

> -			return VH_RESULT_ERR;

> +			return VH_RESULT_FATAL;

>   		}

>   

>   		if (dev->notify_ops->features_changed)

> @@ -1477,6 +1479,34 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, VhostUserMsg *msg)

>   	return VH_RESULT_OK;

>   }

>   

> +typedef int (*vhost_message_handler_t)(struct virtio_net **pdev, VhostUserMsg * msg);

> +static vhost_message_handler_t vhost_message_handlers[VHOST_USER_MAX] = {

> +	[VHOST_USER_NONE] = NULL,

> +	[VHOST_USER_GET_FEATURES] = vhost_user_get_features,

> +	[VHOST_USER_SET_FEATURES] = vhost_user_set_features,

> +	[VHOST_USER_SET_OWNER] = vhost_user_set_owner,

> +	[VHOST_USER_RESET_OWNER] = vhost_user_reset_owner,

> +	[VHOST_USER_SET_MEM_TABLE] = vhost_user_set_mem_table,

> +	[VHOST_USER_SET_LOG_BASE] = vhost_user_set_log_base,

> +	[VHOST_USER_SET_LOG_FD] = vhost_user_set_log_fd,

> +	[VHOST_USER_SET_VRING_NUM] = vhost_user_set_vring_num,

> +	[VHOST_USER_SET_VRING_ADDR] = vhost_user_set_vring_addr,

> +	[VHOST_USER_SET_VRING_BASE] = vhost_user_set_vring_base,

> +	[VHOST_USER_GET_VRING_BASE] = vhost_user_get_vring_base,

> +	[VHOST_USER_SET_VRING_KICK] = vhost_user_set_vring_kick,

> +	[VHOST_USER_SET_VRING_CALL] = vhost_user_set_vring_call,

> +	[VHOST_USER_SET_VRING_ERR] = vhost_user_set_vring_err,

> +	[VHOST_USER_GET_PROTOCOL_FEATURES] = vhost_user_get_protocol_features,

> +	[VHOST_USER_SET_PROTOCOL_FEATURES] = vhost_user_set_protocol_features,

> +	[VHOST_USER_GET_QUEUE_NUM] = vhost_user_get_queue_num,

> +	[VHOST_USER_SET_VRING_ENABLE] = vhost_user_set_vring_enable,

> +	[VHOST_USER_SEND_RARP] = vhost_user_send_rarp,

> +	[VHOST_USER_NET_SET_MTU] = vhost_user_net_set_mtu,

> +	[VHOST_USER_SET_SLAVE_REQ_FD] = vhost_user_set_req_fd,

> +	[VHOST_USER_IOTLB_MSG] = vhost_user_iotlb_msg,

> +};

> +

> +

>   /* return bytes# of read on success or negative val on failure. */

>   static int

>   read_vhost_message(int sockfd, VhostUserMsg *msg)

> @@ -1629,6 +1659,7 @@ vhost_user_msg_handler(int vid, int fd)

>   	int ret;

>   	int unlock_required = 0;

>   	uint32_t skip_master = 0;

> +	int request;

>   

>   	dev = get_device(vid);

>   	if (dev == NULL)

> @@ -1721,100 +1752,40 @@ vhost_user_msg_handler(int vid, int fd)

>   			goto skip_to_post_handle;

>   	}

>   

> -	switch (msg.request.master) {

> -	case VHOST_USER_GET_FEATURES:

> -		ret = vhost_user_get_features(&dev, &msg);

> -		send_vhost_reply(fd, &msg);

> -		break;

> -	case VHOST_USER_SET_FEATURES:

> -		ret = vhost_user_set_features(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_GET_PROTOCOL_FEATURES:

> -		ret = vhost_user_get_protocol_features(&dev, &msg);

> -		send_vhost_reply(fd, &msg);

> -		break;

> -	case VHOST_USER_SET_PROTOCOL_FEATURES:

> -		ret = vhost_user_set_protocol_features(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_OWNER:

> -		ret = vhost_user_set_owner(&dev, &msg);

> -		break;

> -	case VHOST_USER_RESET_OWNER:

> -		ret = vhost_user_reset_owner(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_MEM_TABLE:

> -		ret = vhost_user_set_mem_table(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_LOG_BASE:

> -		ret = vhost_user_set_log_base(&dev, &msg);

> -		if (ret)

> -			goto skip_to_reply;

> -		/* it needs a reply */

> -		send_vhost_reply(fd, &msg);

> -		break;

> -	case VHOST_USER_SET_LOG_FD:

> -		ret = vhost_user_set_log_fd(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_VRING_NUM:

> -		ret = vhost_user_set_vring_num(&dev, &msg);

> -		break;

> -	case VHOST_USER_SET_VRING_ADDR:

> -		ret = vhost_user_set_vring_addr(&dev, &msg);

> -		break;

> -	case VHOST_USER_SET_VRING_BASE:

> -		ret = vhost_user_set_vring_base(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_GET_VRING_BASE:

> -		ret = vhost_user_get_vring_base(&dev, &msg);

> -		if (ret)

> -			goto skip_to_reply;

> -		send_vhost_reply(fd, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_VRING_KICK:

> -		ret = vhost_user_set_vring_kick(&dev, &msg);

> -		break;

> -	case VHOST_USER_SET_VRING_CALL:

> -		ret = vhost_user_set_vring_call(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_VRING_ERR:

> -		ret = vhost_user_set_vring_err(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_GET_QUEUE_NUM:

> -		ret = vhost_user_get_queue_num(&dev, &msg);

> -		send_vhost_reply(fd, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_VRING_ENABLE:

> -		ret = vhost_user_set_vring_enable(&dev, &msg);

> -		break;

> -	case VHOST_USER_SEND_RARP:

> -		ret = vhost_user_send_rarp(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_NET_SET_MTU:

> -		ret = vhost_user_net_set_mtu(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_SET_SLAVE_REQ_FD:

> -		ret = vhost_user_set_req_fd(&dev, &msg);

> -		break;

> -

> -	case VHOST_USER_IOTLB_MSG:

> -		ret = vhost_user_iotlb_msg(&dev, &msg);

> -		break;

> +	request = msg.request.master;

> +	if (request > VHOST_USER_NONE && request < VHOST_USER_MAX) {

> +		if (!vhost_message_handlers[request])

> +			goto skip_to_post_handle;

> +		ret = vhost_message_handlers[request](&dev, &msg);

>   

> -	default:

> -		ret = -1;

> -		break;

> +		switch (ret) {

> +		case VH_RESULT_FATAL:

> +			RTE_LOG(ERR, VHOST_CONFIG,

> +				"Processing %s failed with an unrecoverable error.\n",

> +				vhost_message_str[request]);

> +			/* Propagate the error to the upper layer */

> +			return -1;

If I'm not mistaken, you are missing to release the lock if it was
taken, which could stuck the PMD threads:

if (unlock_required)
	vhost_user_unlock_all_queue_pairs(dev);

Also the behavior is changed, as if the message for which handling 
failed has the VHOST_USER_NEED_REPLY flag set, error is reported to the
master, and function returns 0:

skip_to_reply:
	if (unlock_required)
		vhost_user_unlock_all_queue_pairs(dev);

	if (msg.flags & VHOST_USER_NEED_REPLY) {
		msg.payload.u64 = !!ret;
		msg.size = sizeof(msg.payload.u64);
		send_vhost_reply(fd, &msg);
	} else if (ret) {
		RTE_LOG(ERR, VHOST_CONFIG,
			"vhost message handling failed.\n");
		return -1;
	}


> +		case VH_RESULT_ERR:

> +			RTE_LOG(ERR, VHOST_CONFIG,

> +				"Processing %s failed.\n",

> +				vhost_message_str[request]);

> +			break;

> +		case VH_RESULT_OK:

> +			RTE_LOG(DEBUG, VHOST_CONFIG,

> +				"Processing %s succeeded.\n",

> +				vhost_message_str[request]);

> +			break;

> +		case VH_RESULT_REPLY:

> +			RTE_LOG(INFO, VHOST_CONFIG,

> +				"Processing %s succeeded and needs reply.\n",

> +				vhost_message_str[request]);

> +			send_vhost_reply(fd, &msg);

> +			break;

> +		}

> +	} else {

> +		RTE_LOG(ERR, VHOST_CONFIG,

> +			"Requested invalid message type %d.\n", request);

> +		ret = VH_RESULT_ERR;

>   	}

>   

>   skip_to_post_handle:

>
Nikolay Nikolaev Sept. 20, 2018, 6:34 a.m. UTC | #2 
On Wed, Sep 19, 2018 at 10:37 AM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>

>

>

> On 09/15/2018 07:20 AM, Nikolay Nikolaev wrote:

> > Introduce vhost_message_handlers, which maps the message request

> > type to the message handler. Then replace the switch construct

> > with a map and call.

> >

> > Failing vhost_user_set_features is fatal and all processing should

> > stop immediately and propagate the error to the upper layers. Change

> > the code accordingly to reflect that.

> >

> > Signed-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>

> > ---

> >   lib/librte_vhost/vhost_user.c |  161 +++++++++++++++++------------------------

> >   1 file changed, 66 insertions(+), 95 deletions(-)

> >

> > diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c

> > index 81c0396de..9004e1ac8 100644

> > --- a/lib/librte_vhost/vhost_user.c

> > +++ b/lib/librte_vhost/vhost_user.c

> > @@ -73,6 +73,8 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {

> >

> >   /* The possible results of a message handling function */

> >   enum vh_result {

> > +     /* Message handling failed with an unrecoverable error */

> > +     VH_RESULT_FATAL = -2,

> >       /* Message handling failed */

> >       VH_RESULT_ERR   = -1,

> >       /* Message handling successful */

> > @@ -206,7 +208,7 @@ vhost_user_set_features(struct virtio_net **pdev, VhostUserMsg *msg)

> >               RTE_LOG(ERR, VHOST_CONFIG,

> >                       "(%d) received invalid negotiated features.\n",

> >                       dev->vid);

> > -             return VH_RESULT_ERR;

> > +             return VH_RESULT_FATAL;

> >       }

> >

> >       if (dev->flags & VIRTIO_DEV_RUNNING) {

> > @@ -222,7 +224,7 @@ vhost_user_set_features(struct virtio_net **pdev, VhostUserMsg *msg)

> >                       RTE_LOG(ERR, VHOST_CONFIG,

> >                               "(%d) features changed while device is running.\n",

> >                               dev->vid);

> > -                     return VH_RESULT_ERR;

> > +                     return VH_RESULT_FATAL;

> >               }

> >

> >               if (dev->notify_ops->features_changed)

> > @@ -1477,6 +1479,34 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, VhostUserMsg *msg)

> >       return VH_RESULT_OK;

> >   }

> >

> > +typedef int (*vhost_message_handler_t)(struct virtio_net **pdev, VhostUserMsg * msg);

> > +static vhost_message_handler_t vhost_message_handlers[VHOST_USER_MAX] = {

> > +     [VHOST_USER_NONE] = NULL,

> > +     [VHOST_USER_GET_FEATURES] = vhost_user_get_features,

> > +     [VHOST_USER_SET_FEATURES] = vhost_user_set_features,

> > +     [VHOST_USER_SET_OWNER] = vhost_user_set_owner,

> > +     [VHOST_USER_RESET_OWNER] = vhost_user_reset_owner,

> > +     [VHOST_USER_SET_MEM_TABLE] = vhost_user_set_mem_table,

> > +     [VHOST_USER_SET_LOG_BASE] = vhost_user_set_log_base,

> > +     [VHOST_USER_SET_LOG_FD] = vhost_user_set_log_fd,

> > +     [VHOST_USER_SET_VRING_NUM] = vhost_user_set_vring_num,

> > +     [VHOST_USER_SET_VRING_ADDR] = vhost_user_set_vring_addr,

> > +     [VHOST_USER_SET_VRING_BASE] = vhost_user_set_vring_base,

> > +     [VHOST_USER_GET_VRING_BASE] = vhost_user_get_vring_base,

> > +     [VHOST_USER_SET_VRING_KICK] = vhost_user_set_vring_kick,

> > +     [VHOST_USER_SET_VRING_CALL] = vhost_user_set_vring_call,

> > +     [VHOST_USER_SET_VRING_ERR] = vhost_user_set_vring_err,

> > +     [VHOST_USER_GET_PROTOCOL_FEATURES] = vhost_user_get_protocol_features,

> > +     [VHOST_USER_SET_PROTOCOL_FEATURES] = vhost_user_set_protocol_features,

> > +     [VHOST_USER_GET_QUEUE_NUM] = vhost_user_get_queue_num,

> > +     [VHOST_USER_SET_VRING_ENABLE] = vhost_user_set_vring_enable,

> > +     [VHOST_USER_SEND_RARP] = vhost_user_send_rarp,

> > +     [VHOST_USER_NET_SET_MTU] = vhost_user_net_set_mtu,

> > +     [VHOST_USER_SET_SLAVE_REQ_FD] = vhost_user_set_req_fd,

> > +     [VHOST_USER_IOTLB_MSG] = vhost_user_iotlb_msg,

> > +};

> > +

> > +

> >   /* return bytes# of read on success or negative val on failure. */

> >   static int

> >   read_vhost_message(int sockfd, VhostUserMsg *msg)

> > @@ -1629,6 +1659,7 @@ vhost_user_msg_handler(int vid, int fd)

> >       int ret;

> >       int unlock_required = 0;

> >       uint32_t skip_master = 0;

> > +     int request;

> >

> >       dev = get_device(vid);

> >       if (dev == NULL)

> > @@ -1721,100 +1752,40 @@ vhost_user_msg_handler(int vid, int fd)

> >                       goto skip_to_post_handle;

> >       }

> >

> > -     switch (msg.request.master) {

> > -     case VHOST_USER_GET_FEATURES:

> > -             ret = vhost_user_get_features(&dev, &msg);

> > -             send_vhost_reply(fd, &msg);

> > -             break;

> > -     case VHOST_USER_SET_FEATURES:

> > -             ret = vhost_user_set_features(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_GET_PROTOCOL_FEATURES:

> > -             ret = vhost_user_get_protocol_features(&dev, &msg);

> > -             send_vhost_reply(fd, &msg);

> > -             break;

> > -     case VHOST_USER_SET_PROTOCOL_FEATURES:

> > -             ret = vhost_user_set_protocol_features(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_OWNER:

> > -             ret = vhost_user_set_owner(&dev, &msg);

> > -             break;

> > -     case VHOST_USER_RESET_OWNER:

> > -             ret = vhost_user_reset_owner(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_MEM_TABLE:

> > -             ret = vhost_user_set_mem_table(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_LOG_BASE:

> > -             ret = vhost_user_set_log_base(&dev, &msg);

> > -             if (ret)

> > -                     goto skip_to_reply;

> > -             /* it needs a reply */

> > -             send_vhost_reply(fd, &msg);

> > -             break;

> > -     case VHOST_USER_SET_LOG_FD:

> > -             ret = vhost_user_set_log_fd(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_VRING_NUM:

> > -             ret = vhost_user_set_vring_num(&dev, &msg);

> > -             break;

> > -     case VHOST_USER_SET_VRING_ADDR:

> > -             ret = vhost_user_set_vring_addr(&dev, &msg);

> > -             break;

> > -     case VHOST_USER_SET_VRING_BASE:

> > -             ret = vhost_user_set_vring_base(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_GET_VRING_BASE:

> > -             ret = vhost_user_get_vring_base(&dev, &msg);

> > -             if (ret)

> > -                     goto skip_to_reply;

> > -             send_vhost_reply(fd, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_VRING_KICK:

> > -             ret = vhost_user_set_vring_kick(&dev, &msg);

> > -             break;

> > -     case VHOST_USER_SET_VRING_CALL:

> > -             ret = vhost_user_set_vring_call(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_VRING_ERR:

> > -             ret = vhost_user_set_vring_err(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_GET_QUEUE_NUM:

> > -             ret = vhost_user_get_queue_num(&dev, &msg);

> > -             send_vhost_reply(fd, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_VRING_ENABLE:

> > -             ret = vhost_user_set_vring_enable(&dev, &msg);

> > -             break;

> > -     case VHOST_USER_SEND_RARP:

> > -             ret = vhost_user_send_rarp(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_NET_SET_MTU:

> > -             ret = vhost_user_net_set_mtu(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_SET_SLAVE_REQ_FD:

> > -             ret = vhost_user_set_req_fd(&dev, &msg);

> > -             break;

> > -

> > -     case VHOST_USER_IOTLB_MSG:

> > -             ret = vhost_user_iotlb_msg(&dev, &msg);

> > -             break;

> > +     request = msg.request.master;

> > +     if (request > VHOST_USER_NONE && request < VHOST_USER_MAX) {

> > +             if (!vhost_message_handlers[request])

> > +                     goto skip_to_post_handle;

> > +             ret = vhost_message_handlers[request](&dev, &msg);

> >

> > -     default:

> > -             ret = -1;

> > -             break;

> > +             switch (ret) {

> > +             case VH_RESULT_FATAL:

> > +                     RTE_LOG(ERR, VHOST_CONFIG,

> > +                             "Processing %s failed with an unrecoverable error.\n",

> > +                             vhost_message_str[request]);

> > +                     /* Propagate the error to the upper layer */

> > +                     return -1;

> If I'm not mistaken, you are missing to release the lock if it was

> taken, which could stuck the PMD threads:

>

> if (unlock_required)

>         vhost_user_unlock_all_queue_pairs(dev);

>

> Also the behavior is changed, as if the message for which handling

> failed has the VHOST_USER_NEED_REPLY flag set, error is reported to the

> master, and function returns 0:

>

> skip_to_reply:

>         if (unlock_required)

>                 vhost_user_unlock_all_queue_pairs(dev);

>

>         if (msg.flags & VHOST_USER_NEED_REPLY) {

>                 msg.payload.u64 = !!ret;

>                 msg.size = sizeof(msg.payload.u64);

>                 send_vhost_reply(fd, &msg);

>         } else if (ret) {

>                 RTE_LOG(ERR, VHOST_CONFIG,

>                         "vhost message handling failed.\n");

>                 return -1;

>         }

>


Thanks Maxime. I'll revisit this patch and post new version in the
next couple of day.

Nikolay NIkolaev
>

> > +             case VH_RESULT_ERR:

> > +                     RTE_LOG(ERR, VHOST_CONFIG,

> > +                             "Processing %s failed.\n",

> > +                             vhost_message_str[request]);

> > +                     break;

> > +             case VH_RESULT_OK:

> > +                     RTE_LOG(DEBUG, VHOST_CONFIG,

> > +                             "Processing %s succeeded.\n",

> > +                             vhost_message_str[request]);

> > +                     break;

> > +             case VH_RESULT_REPLY:

> > +                     RTE_LOG(INFO, VHOST_CONFIG,

> > +                             "Processing %s succeeded and needs reply.\n",

> > +                             vhost_message_str[request]);

> > +                     send_vhost_reply(fd, &msg);

> > +                     break;

> > +             }

> > +     } else {

> > +             RTE_LOG(ERR, VHOST_CONFIG,

> > +                     "Requested invalid message type %d.\n", request);

> > +             ret = VH_RESULT_ERR;

> >       }

> >

> >   skip_to_post_handle:

> >
diff mbox series

Patch

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 81c0396de..9004e1ac8 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -73,6 +73,8 @@  static const char *vhost_message_str[VHOST_USER_MAX] = {
 
 /* The possible results of a message handling function */
 enum vh_result {
+	/* Message handling failed with an unrecoverable error */
+	VH_RESULT_FATAL = -2,
 	/* Message handling failed */
 	VH_RESULT_ERR   = -1,
 	/* Message handling successful */
@@ -206,7 +208,7 @@  vhost_user_set_features(struct virtio_net **pdev, VhostUserMsg *msg)
 		RTE_LOG(ERR, VHOST_CONFIG,
 			"(%d) received invalid negotiated features.\n",
 			dev->vid);
-		return VH_RESULT_ERR;
+		return VH_RESULT_FATAL;
 	}
 
 	if (dev->flags & VIRTIO_DEV_RUNNING) {
@@ -222,7 +224,7 @@  vhost_user_set_features(struct virtio_net **pdev, VhostUserMsg *msg)
 			RTE_LOG(ERR, VHOST_CONFIG,
 				"(%d) features changed while device is running.\n",
 				dev->vid);
-			return VH_RESULT_ERR;
+			return VH_RESULT_FATAL;
 		}
 
 		if (dev->notify_ops->features_changed)
@@ -1477,6 +1479,34 @@  vhost_user_iotlb_msg(struct virtio_net **pdev, VhostUserMsg *msg)
 	return VH_RESULT_OK;
 }
 
+typedef int (*vhost_message_handler_t)(struct virtio_net **pdev, VhostUserMsg * msg);
+static vhost_message_handler_t vhost_message_handlers[VHOST_USER_MAX] = {
+	[VHOST_USER_NONE] = NULL,
+	[VHOST_USER_GET_FEATURES] = vhost_user_get_features,
+	[VHOST_USER_SET_FEATURES] = vhost_user_set_features,
+	[VHOST_USER_SET_OWNER] = vhost_user_set_owner,
+	[VHOST_USER_RESET_OWNER] = vhost_user_reset_owner,
+	[VHOST_USER_SET_MEM_TABLE] = vhost_user_set_mem_table,
+	[VHOST_USER_SET_LOG_BASE] = vhost_user_set_log_base,
+	[VHOST_USER_SET_LOG_FD] = vhost_user_set_log_fd,
+	[VHOST_USER_SET_VRING_NUM] = vhost_user_set_vring_num,
+	[VHOST_USER_SET_VRING_ADDR] = vhost_user_set_vring_addr,
+	[VHOST_USER_SET_VRING_BASE] = vhost_user_set_vring_base,
+	[VHOST_USER_GET_VRING_BASE] = vhost_user_get_vring_base,
+	[VHOST_USER_SET_VRING_KICK] = vhost_user_set_vring_kick,
+	[VHOST_USER_SET_VRING_CALL] = vhost_user_set_vring_call,
+	[VHOST_USER_SET_VRING_ERR] = vhost_user_set_vring_err,
+	[VHOST_USER_GET_PROTOCOL_FEATURES] = vhost_user_get_protocol_features,
+	[VHOST_USER_SET_PROTOCOL_FEATURES] = vhost_user_set_protocol_features,
+	[VHOST_USER_GET_QUEUE_NUM] = vhost_user_get_queue_num,
+	[VHOST_USER_SET_VRING_ENABLE] = vhost_user_set_vring_enable,
+	[VHOST_USER_SEND_RARP] = vhost_user_send_rarp,
+	[VHOST_USER_NET_SET_MTU] = vhost_user_net_set_mtu,
+	[VHOST_USER_SET_SLAVE_REQ_FD] = vhost_user_set_req_fd,
+	[VHOST_USER_IOTLB_MSG] = vhost_user_iotlb_msg,
+};
+
+
 /* return bytes# of read on success or negative val on failure. */
 static int
 read_vhost_message(int sockfd, VhostUserMsg *msg)
@@ -1629,6 +1659,7 @@  vhost_user_msg_handler(int vid, int fd)
 	int ret;
 	int unlock_required = 0;
 	uint32_t skip_master = 0;
+	int request;
 
 	dev = get_device(vid);
 	if (dev == NULL)
@@ -1721,100 +1752,40 @@  vhost_user_msg_handler(int vid, int fd)
 			goto skip_to_post_handle;
 	}
 
-	switch (msg.request.master) {
-	case VHOST_USER_GET_FEATURES:
-		ret = vhost_user_get_features(&dev, &msg);
-		send_vhost_reply(fd, &msg);
-		break;
-	case VHOST_USER_SET_FEATURES:
-		ret = vhost_user_set_features(&dev, &msg);
-		break;
-
-	case VHOST_USER_GET_PROTOCOL_FEATURES:
-		ret = vhost_user_get_protocol_features(&dev, &msg);
-		send_vhost_reply(fd, &msg);
-		break;
-	case VHOST_USER_SET_PROTOCOL_FEATURES:
-		ret = vhost_user_set_protocol_features(&dev, &msg);
-		break;
-
-	case VHOST_USER_SET_OWNER:
-		ret = vhost_user_set_owner(&dev, &msg);
-		break;
-	case VHOST_USER_RESET_OWNER:
-		ret = vhost_user_reset_owner(&dev, &msg);
-		break;
-
-	case VHOST_USER_SET_MEM_TABLE:
-		ret = vhost_user_set_mem_table(&dev, &msg);
-		break;
-
-	case VHOST_USER_SET_LOG_BASE:
-		ret = vhost_user_set_log_base(&dev, &msg);
-		if (ret)
-			goto skip_to_reply;
-		/* it needs a reply */
-		send_vhost_reply(fd, &msg);
-		break;
-	case VHOST_USER_SET_LOG_FD:
-		ret = vhost_user_set_log_fd(&dev, &msg);
-		break;
-
-	case VHOST_USER_SET_VRING_NUM:
-		ret = vhost_user_set_vring_num(&dev, &msg);
-		break;
-	case VHOST_USER_SET_VRING_ADDR:
-		ret = vhost_user_set_vring_addr(&dev, &msg);
-		break;
-	case VHOST_USER_SET_VRING_BASE:
-		ret = vhost_user_set_vring_base(&dev, &msg);
-		break;
-
-	case VHOST_USER_GET_VRING_BASE:
-		ret = vhost_user_get_vring_base(&dev, &msg);
-		if (ret)
-			goto skip_to_reply;
-		send_vhost_reply(fd, &msg);
-		break;
-
-	case VHOST_USER_SET_VRING_KICK:
-		ret = vhost_user_set_vring_kick(&dev, &msg);
-		break;
-	case VHOST_USER_SET_VRING_CALL:
-		ret = vhost_user_set_vring_call(&dev, &msg);
-		break;
-
-	case VHOST_USER_SET_VRING_ERR:
-		ret = vhost_user_set_vring_err(&dev, &msg);
-		break;
-
-	case VHOST_USER_GET_QUEUE_NUM:
-		ret = vhost_user_get_queue_num(&dev, &msg);
-		send_vhost_reply(fd, &msg);
-		break;
-
-	case VHOST_USER_SET_VRING_ENABLE:
-		ret = vhost_user_set_vring_enable(&dev, &msg);
-		break;
-	case VHOST_USER_SEND_RARP:
-		ret = vhost_user_send_rarp(&dev, &msg);
-		break;
-
-	case VHOST_USER_NET_SET_MTU:
-		ret = vhost_user_net_set_mtu(&dev, &msg);
-		break;
-
-	case VHOST_USER_SET_SLAVE_REQ_FD:
-		ret = vhost_user_set_req_fd(&dev, &msg);
-		break;
-
-	case VHOST_USER_IOTLB_MSG:
-		ret = vhost_user_iotlb_msg(&dev, &msg);
-		break;
+	request = msg.request.master;
+	if (request > VHOST_USER_NONE && request < VHOST_USER_MAX) {
+		if (!vhost_message_handlers[request])
+			goto skip_to_post_handle;
+		ret = vhost_message_handlers[request](&dev, &msg);
 
-	default:
-		ret = -1;
-		break;
+		switch (ret) {
+		case VH_RESULT_FATAL:
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"Processing %s failed with an unrecoverable error.\n",
+				vhost_message_str[request]);
+			/* Propagate the error to the upper layer */
+			return -1;
+		case VH_RESULT_ERR:
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"Processing %s failed.\n",
+				vhost_message_str[request]);
+			break;
+		case VH_RESULT_OK:
+			RTE_LOG(DEBUG, VHOST_CONFIG,
+				"Processing %s succeeded.\n",
+				vhost_message_str[request]);
+			break;
+		case VH_RESULT_REPLY:
+			RTE_LOG(INFO, VHOST_CONFIG,
+				"Processing %s succeeded and needs reply.\n",
+				vhost_message_str[request]);
+			send_vhost_reply(fd, &msg);
+			break;
+		}
+	} else {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"Requested invalid message type %d.\n", request);
+		ret = VH_RESULT_ERR;
 	}
 
 skip_to_post_handle: