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

Message ID 153698885466.23049.5627861471035122455.stgit@T460
State Superseded, archived
Delegated to: Maxime Coquelin
Headers show
Series
  • vhost: vhost_user.c code cleanup
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Checks

Context Check Description
ci/Intel-compilation success Compilation OK

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:
> >

Patch
diff mbox series

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: