[v5,02/15] ethdev: add support for hairpin queue

Message ID 1571837852-45975-3-git-send-email-orika@mellanox.com (mailing list archive)
State Superseded, archived
Delegated to: Ferruh Yigit
Headers
Series add hairpin feature |

Checks

Context Check Description
ci/checkpatch warning coding style issues
ci/Intel-compilation fail Compilation issues

Commit Message

Ori Kam Oct. 23, 2019, 1:37 p.m. UTC
This commit introduce hairpin queue type.

The hairpin queue in build from Rx queue binded to Tx queue.
It is used to offload traffic coming from the wire and redirect it back
to the wire.

There are 3 new functions:
- rte_eth_dev_hairpin_capability_get
- rte_eth_rx_hairpin_queue_setup
- rte_eth_tx_hairpin_queue_setup

In order to use the queue, there is a need to create rte_flow
with queue / RSS action that targets one or more of the Rx queues.

Signed-off-by: Ori Kam <orika@mellanox.com>
---
V5:
 - add function to check if queue is hairpin queue.
 - modify log messages to be more distinct.
 - update log messages to be only on one line.
 - change peer_n to peer_count.

V4:
 - update according to ML comments.

V3:
 - update according to ML comments.

V2:
 - update according to ML comments.

---
 lib/librte_ethdev/rte_ethdev.c           | 217 +++++++++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev.h           | 141 +++++++++++++++++++-
 lib/librte_ethdev/rte_ethdev_core.h      |  91 ++++++++++++-
 lib/librte_ethdev/rte_ethdev_driver.h    |  44 +++++++
 lib/librte_ethdev/rte_ethdev_version.map |   3 +
 5 files changed, 488 insertions(+), 8 deletions(-)
  

Comments

Andrew Rybchenko Oct. 24, 2019, 7:54 a.m. UTC | #1
Hi Ori,

thanks for review notes applied. Please, see below.

On 10/23/19 4:37 PM, Ori Kam wrote:
> This commit introduce hairpin queue type.
>
> The hairpin queue in build from Rx queue binded to Tx queue.
> It is used to offload traffic coming from the wire and redirect it back
> to the wire.
>
> There are 3 new functions:
> - rte_eth_dev_hairpin_capability_get
> - rte_eth_rx_hairpin_queue_setup
> - rte_eth_tx_hairpin_queue_setup
>
> In order to use the queue, there is a need to create rte_flow
> with queue / RSS action that targets one or more of the Rx queues.
>
> Signed-off-by: Ori Kam <orika@mellanox.com>

Just a bit below
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>

[snip]

> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 78da293..199e96e 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -923,6 +923,13 @@ struct rte_eth_dev *
>   
>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_start, -ENOTSUP);
>   
> +	if (rte_eth_dev_is_rx_hairpin_queue(dev, rx_queue_id) == 1) {

I think the function should return bool and it results should be
used as is without == 1 or something like this.
Everyrwhere in the patch.

[snip]

> diff --git a/lib/librte_ethdev/rte_ethdev_driver.h b/lib/librte_ethdev/rte_ethdev_driver.h
> index c404f17..98023d7 100644
> --- a/lib/librte_ethdev/rte_ethdev_driver.h
> +++ b/lib/librte_ethdev/rte_ethdev_driver.h
> @@ -26,6 +26,50 @@
>    */
>   #define RTE_ETH_QUEUE_STATE_STOPPED 0
>   #define RTE_ETH_QUEUE_STATE_STARTED 1
> +#define RTE_ETH_QUEUE_STATE_HAIRPIN 2
> +
> +/**
> + * @internal
> + * Check if the selected Rx queue is hairpin queue.
> + *
> + * @param dev
> + *  Pointer to the selected device.
> + * @param queue_id
> + *  The selected queue.
> + *
> + * @return
> + *   - (1) if the queue is hairpin queue, 0 otherwise.
> + */
> +static inline int

I think the function should return bool (and stdbool.h should be included).
Return value description should be updated.

> +rte_eth_dev_is_rx_hairpin_queue(struct rte_eth_dev *dev, uint16_t queue_id)
> +{
> +	if (dev->data->rx_queue_state[queue_id] ==
> +	    RTE_ETH_QUEUE_STATE_HAIRPIN)
> +		return 1;
> +	return 0;
> +}
> +
> +
> +/**
> + * @internal
> + * Check if the selected Tx queue is hairpin queue.
> + *
> + * @param dev
> + *  Pointer to the selected device.
> + * @param queue_id
> + *  The selected queue.
> + *
> + * @return
> + *   - (1) if the queue is hairpin queue, 0 otherwise.
> + */
> +static inline int

Same here.

> +rte_eth_dev_is_tx_hairpin_queue(struct rte_eth_dev *dev, uint16_t queue_id)
> +{
> +	if (dev->data->tx_queue_state[queue_id] ==
> +	    RTE_ETH_QUEUE_STATE_HAIRPIN)
> +		return 1;
> +	return 0;
> +}
>   
>   /**
>    * @internal

[snip]
  
Ori Kam Oct. 24, 2019, 8:29 a.m. UTC | #2
Hi Andrew,

When writing the new function I thought about using bool, but 
I decided against it for the following reasons:
1. There is no use of bool any where in the code, and there is not special reason to add it now.
2. Other functions of this kind already returns int. for example (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)

Thanks,
Ori

> -----Original Message-----
> From: Andrew Rybchenko <arybchenko@solarflare.com>
> Sent: Thursday, October 24, 2019 10:55 AM
> To: Ori Kam <orika@mellanox.com>; Thomas Monjalon
> <thomas@monjalon.net>; Ferruh Yigit <ferruh.yigit@intel.com>
> Cc: dev@dpdk.org; jingjing.wu@intel.com; stephen@networkplumber.org
> Subject: Re: [dpdk-dev] [PATCH v5 02/15] ethdev: add support for hairpin queue
> 
> Hi Ori,
> 
> thanks for review notes applied. Please, see below.
> 
> On 10/23/19 4:37 PM, Ori Kam wrote:
> > This commit introduce hairpin queue type.
> >
> > The hairpin queue in build from Rx queue binded to Tx queue.
> > It is used to offload traffic coming from the wire and redirect it back
> > to the wire.
> >
> > There are 3 new functions:
> > - rte_eth_dev_hairpin_capability_get
> > - rte_eth_rx_hairpin_queue_setup
> > - rte_eth_tx_hairpin_queue_setup
> >
> > In order to use the queue, there is a need to create rte_flow
> > with queue / RSS action that targets one or more of the Rx queues.
> >
> > Signed-off-by: Ori Kam <orika@mellanox.com>
> 
> Just a bit below
> Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
> 
> [snip]
> 
> > diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> > index 78da293..199e96e 100644
> > --- a/lib/librte_ethdev/rte_ethdev.c
> > +++ b/lib/librte_ethdev/rte_ethdev.c
> > @@ -923,6 +923,13 @@ struct rte_eth_dev *
> >
> >   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_start, -
> ENOTSUP);
> >
> > +	if (rte_eth_dev_is_rx_hairpin_queue(dev, rx_queue_id) == 1) {
> 
> I think the function should return bool and it results should be
> used as is without == 1 or something like this.
> Everyrwhere in the patch.
> 
> [snip]
> 
> > diff --git a/lib/librte_ethdev/rte_ethdev_driver.h
> b/lib/librte_ethdev/rte_ethdev_driver.h
> > index c404f17..98023d7 100644
> > --- a/lib/librte_ethdev/rte_ethdev_driver.h
> > +++ b/lib/librte_ethdev/rte_ethdev_driver.h
> > @@ -26,6 +26,50 @@
> >    */
> >   #define RTE_ETH_QUEUE_STATE_STOPPED 0
> >   #define RTE_ETH_QUEUE_STATE_STARTED 1
> > +#define RTE_ETH_QUEUE_STATE_HAIRPIN 2
> > +
> > +/**
> > + * @internal
> > + * Check if the selected Rx queue is hairpin queue.
> > + *
> > + * @param dev
> > + *  Pointer to the selected device.
> > + * @param queue_id
> > + *  The selected queue.
> > + *
> > + * @return
> > + *   - (1) if the queue is hairpin queue, 0 otherwise.
> > + */
> > +static inline int
> 
> I think the function should return bool (and stdbool.h should be included).
> Return value description should be updated.
> 
> > +rte_eth_dev_is_rx_hairpin_queue(struct rte_eth_dev *dev, uint16_t
> queue_id)
> > +{
> > +	if (dev->data->rx_queue_state[queue_id] ==
> > +	    RTE_ETH_QUEUE_STATE_HAIRPIN)
> > +		return 1;
> > +	return 0;
> > +}
> > +
> > +
> > +/**
> > + * @internal
> > + * Check if the selected Tx queue is hairpin queue.
> > + *
> > + * @param dev
> > + *  Pointer to the selected device.
> > + * @param queue_id
> > + *  The selected queue.
> > + *
> > + * @return
> > + *   - (1) if the queue is hairpin queue, 0 otherwise.
> > + */
> > +static inline int
> 
> Same here.
> 
> > +rte_eth_dev_is_tx_hairpin_queue(struct rte_eth_dev *dev, uint16_t
> queue_id)
> > +{
> > +	if (dev->data->tx_queue_state[queue_id] ==
> > +	    RTE_ETH_QUEUE_STATE_HAIRPIN)
> > +		return 1;
> > +	return 0;
> > +}
> >
> >   /**
> >    * @internal
> 
> [snip]
  
Andrew Rybchenko Oct. 24, 2019, 2:47 p.m. UTC | #3
On 10/24/19 11:29 AM, Ori Kam wrote:
> Hi Andrew,
>
> When writing the new function I thought about using bool, but
> I decided against it for the following reasons:
> 1. There is no use of bool any where in the code, and there is not special reason to add it now.

rte_ethdev.c includes stdbool.h and uses bool

> 2. Other functions of this kind already returns int. for example (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)
>
> Thanks,
> Ori
>
>> -----Original Message-----
>> From: Andrew Rybchenko <arybchenko@solarflare.com>
>> Sent: Thursday, October 24, 2019 10:55 AM
>> To: Ori Kam <orika@mellanox.com>; Thomas Monjalon
>> <thomas@monjalon.net>; Ferruh Yigit <ferruh.yigit@intel.com>
>> Cc: dev@dpdk.org; jingjing.wu@intel.com; stephen@networkplumber.org
>> Subject: Re: [dpdk-dev] [PATCH v5 02/15] ethdev: add support for hairpin queue
>>
>> Hi Ori,
>>
>> thanks for review notes applied. Please, see below.
>>
>> On 10/23/19 4:37 PM, Ori Kam wrote:
>>> This commit introduce hairpin queue type.
>>>
>>> The hairpin queue in build from Rx queue binded to Tx queue.
>>> It is used to offload traffic coming from the wire and redirect it back
>>> to the wire.
>>>
>>> There are 3 new functions:
>>> - rte_eth_dev_hairpin_capability_get
>>> - rte_eth_rx_hairpin_queue_setup
>>> - rte_eth_tx_hairpin_queue_setup
>>>
>>> In order to use the queue, there is a need to create rte_flow
>>> with queue / RSS action that targets one or more of the Rx queues.
>>>
>>> Signed-off-by: Ori Kam <orika@mellanox.com>
>> Just a bit below
>> Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
>>
>> [snip]
>>
>>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>>> index 78da293..199e96e 100644
>>> --- a/lib/librte_ethdev/rte_ethdev.c
>>> +++ b/lib/librte_ethdev/rte_ethdev.c
>>> @@ -923,6 +923,13 @@ struct rte_eth_dev *
>>>
>>>    	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_start, -
>> ENOTSUP);
>>> +	if (rte_eth_dev_is_rx_hairpin_queue(dev, rx_queue_id) == 1) {
>> I think the function should return bool and it results should be
>> used as is without == 1 or something like this.
>> Everyrwhere in the patch.
>>
>> [snip]
>>
>>> diff --git a/lib/librte_ethdev/rte_ethdev_driver.h
>> b/lib/librte_ethdev/rte_ethdev_driver.h
>>> index c404f17..98023d7 100644
>>> --- a/lib/librte_ethdev/rte_ethdev_driver.h
>>> +++ b/lib/librte_ethdev/rte_ethdev_driver.h
>>> @@ -26,6 +26,50 @@
>>>     */
>>>    #define RTE_ETH_QUEUE_STATE_STOPPED 0
>>>    #define RTE_ETH_QUEUE_STATE_STARTED 1
>>> +#define RTE_ETH_QUEUE_STATE_HAIRPIN 2
>>> +
>>> +/**
>>> + * @internal
>>> + * Check if the selected Rx queue is hairpin queue.
>>> + *
>>> + * @param dev
>>> + *  Pointer to the selected device.
>>> + * @param queue_id
>>> + *  The selected queue.
>>> + *
>>> + * @return
>>> + *   - (1) if the queue is hairpin queue, 0 otherwise.
>>> + */
>>> +static inline int
>> I think the function should return bool (and stdbool.h should be included).
>> Return value description should be updated.
>>
>>> +rte_eth_dev_is_rx_hairpin_queue(struct rte_eth_dev *dev, uint16_t
>> queue_id)
>>> +{
>>> +	if (dev->data->rx_queue_state[queue_id] ==
>>> +	    RTE_ETH_QUEUE_STATE_HAIRPIN)
>>> +		return 1;
>>> +	return 0;
>>> +}
>>> +
>>> +
>>> +/**
>>> + * @internal
>>> + * Check if the selected Tx queue is hairpin queue.
>>> + *
>>> + * @param dev
>>> + *  Pointer to the selected device.
>>> + * @param queue_id
>>> + *  The selected queue.
>>> + *
>>> + * @return
>>> + *   - (1) if the queue is hairpin queue, 0 otherwise.
>>> + */
>>> +static inline int
>> Same here.
>>
>>> +rte_eth_dev_is_tx_hairpin_queue(struct rte_eth_dev *dev, uint16_t
>> queue_id)
>>> +{
>>> +	if (dev->data->tx_queue_state[queue_id] ==
>>> +	    RTE_ETH_QUEUE_STATE_HAIRPIN)
>>> +		return 1;
>>> +	return 0;
>>> +}
>>>
>>>    /**
>>>     * @internal
>> [snip]
  
Thomas Monjalon Oct. 24, 2019, 3:17 p.m. UTC | #4
24/10/2019 16:47, Andrew Rybchenko:
> On 10/24/19 11:29 AM, Ori Kam wrote:
> > Hi Andrew,
> >
> > When writing the new function I thought about using bool, but
> > I decided against it for the following reasons:
> > 1. There is no use of bool any where in the code, and there is not special reason to add it now.
> 
> rte_ethdev.c includes stdbool.h and uses bool
> 
> > 2. Other functions of this kind already returns int. for example (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)

I agree with Ori here for 2 reasons:
1. It is better to be consistent in the API
2. I remember having some issues with some drivers when introducing stdbool in the API.

I think it may be nice to convert all such API to bool in one patch,
and check if there are some remaining issues with bool usage in drivers or with PPC.
But I suggest to do such API change in DPDK 20.11.
  
Andrew Rybchenko Oct. 24, 2019, 3:30 p.m. UTC | #5
On 10/24/19 6:17 PM, Thomas Monjalon wrote:
> 24/10/2019 16:47, Andrew Rybchenko:
>> On 10/24/19 11:29 AM, Ori Kam wrote:
>>> Hi Andrew,
>>>
>>> When writing the new function I thought about using bool, but
>>> I decided against it for the following reasons:
>>> 1. There is no use of bool any where in the code, and there is not special reason to add it now.
>> rte_ethdev.c includes stdbool.h and uses bool
>>
>>> 2. Other functions of this kind already returns int. for example (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)
> I agree with Ori here for 2 reasons:
> 1. It is better to be consistent in the API
> 2. I remember having some issues with some drivers when introducing stdbool in the API.
>
> I think it may be nice to convert all such API to bool in one patch,
> and check if there are some remaining issues with bool usage in drivers or with PPC.
> But I suggest to do such API change in DPDK 20.11.

OK, no problem. Does it prevent to avoid comparison == 1? Just to
avoid changes in these lines in the future.
  
Thomas Monjalon Oct. 24, 2019, 3:34 p.m. UTC | #6
24/10/2019 17:30, Andrew Rybchenko:
> On 10/24/19 6:17 PM, Thomas Monjalon wrote:
> > 24/10/2019 16:47, Andrew Rybchenko:
> >> On 10/24/19 11:29 AM, Ori Kam wrote:
> >>> Hi Andrew,
> >>>
> >>> When writing the new function I thought about using bool, but
> >>> I decided against it for the following reasons:
> >>> 1. There is no use of bool any where in the code, and there is not special reason to add it now.
> >> rte_ethdev.c includes stdbool.h and uses bool
> >>
> >>> 2. Other functions of this kind already returns int. for example (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)
> > I agree with Ori here for 2 reasons:
> > 1. It is better to be consistent in the API
> > 2. I remember having some issues with some drivers when introducing stdbool in the API.
> >
> > I think it may be nice to convert all such API to bool in one patch,
> > and check if there are some remaining issues with bool usage in drivers or with PPC.
> > But I suggest to do such API change in DPDK 20.11.
> 
> OK, no problem. Does it prevent to avoid comparison == 1? Just to
> avoid changes in these lines in the future.

Yes probably better to avoid explicit comparison, but prefer boolean operator (!).
  
Ori Kam Oct. 25, 2019, 7:01 p.m. UTC | #7
Hi Andrew, Thomas

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Thursday, October 24, 2019 6:35 PM
> To: Andrew Rybchenko <arybchenko@solarflare.com>
> Cc: dev@dpdk.org; Ori Kam <orika@mellanox.com>; Ferruh Yigit
> <ferruh.yigit@intel.com>; jingjing.wu@intel.com;
> stephen@networkplumber.org
> Subject: Re: [dpdk-dev] [PATCH v5 02/15] ethdev: add support for hairpin queue
> 
> 24/10/2019 17:30, Andrew Rybchenko:
> > On 10/24/19 6:17 PM, Thomas Monjalon wrote:
> > > 24/10/2019 16:47, Andrew Rybchenko:
> > >> On 10/24/19 11:29 AM, Ori Kam wrote:
> > >>> Hi Andrew,
> > >>>
> > >>> When writing the new function I thought about using bool, but
> > >>> I decided against it for the following reasons:
> > >>> 1. There is no use of bool any where in the code, and there is not special
> reason to add it now.
> > >> rte_ethdev.c includes stdbool.h and uses bool
> > >>
> > >>> 2. Other functions of this kind already returns int. for example
> (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)
> > > I agree with Ori here for 2 reasons:
> > > 1. It is better to be consistent in the API
> > > 2. I remember having some issues with some drivers when introducing
> stdbool in the API.
> > >
> > > I think it may be nice to convert all such API to bool in one patch,
> > > and check if there are some remaining issues with bool usage in drivers or
> with PPC.
> > > But I suggest to do such API change in DPDK 20.11.
> >
> > OK, no problem. Does it prevent to avoid comparison == 1? Just to
> > avoid changes in these lines in the future.
> 
> Yes probably better to avoid explicit comparison, but prefer boolean operator
> (!).
> 
> 

Thomas I understand your comments but from Andrew comment on my V2-01 patch:
"
>>> +	ret = (*dev->dev_ops->rx_hairpin_queue_setup)(dev, rx_queue_id,
>>> +						      nb_rx_desc, conf);
>>> +	if (!ret)
>> Please, compare with 0
>>
> Will do, but again just for my knowledge why?

https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdoc.dpdk.org%2Fguides%2Fcontributing%2Fcoding_style.html%23function-calls&amp;data=02%7C01%7Corika%40mellanox.com%7C022cd953964f4a20d50508d7508a259f%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C637066426584029629&amp;sdata=G8ZxEWFFsv1kLWc6L7sKT8O6CSiBcj5ZuwQqmK0Q6nY%3D&amp;reserved=0

"
I don't see any relevant info in the link, but maybe I'm missing something .
What are the rules? 
Thomas also keep in mind that in most cases the condition that is tested is the positive, meaning  it will look something like this:
if (rte_eth_dev_is_rx_hairpin_queue(dev, queue_id)) {     
        rte_errno = EINVAL;                               
        return NULL;                                      
}                                       

What do you think?
  
Thomas Monjalon Oct. 25, 2019, 10:16 p.m. UTC | #8
25/10/2019 21:01, Ori Kam:
> From: Thomas Monjalon <thomas@monjalon.net>
> > 24/10/2019 17:30, Andrew Rybchenko:
> > > On 10/24/19 6:17 PM, Thomas Monjalon wrote:
> > > > 24/10/2019 16:47, Andrew Rybchenko:
> > > >> On 10/24/19 11:29 AM, Ori Kam wrote:
> > > >>> Hi Andrew,
> > > >>>
> > > >>> When writing the new function I thought about using bool, but
> > > >>> I decided against it for the following reasons:
> > > >>> 1. There is no use of bool any where in the code, and there is not special
> > reason to add it now.
> > > >> rte_ethdev.c includes stdbool.h and uses bool
> > > >>
> > > >>> 2. Other functions of this kind already returns int. for example
> > (rte_eth_dev_is_valid_port / rte_eth_is_valid_owner_id)
> > > > I agree with Ori here for 2 reasons:
> > > > 1. It is better to be consistent in the API
> > > > 2. I remember having some issues with some drivers when introducing
> > stdbool in the API.
> > > >
> > > > I think it may be nice to convert all such API to bool in one patch,
> > > > and check if there are some remaining issues with bool usage in drivers or
> > with PPC.
> > > > But I suggest to do such API change in DPDK 20.11.
> > >
> > > OK, no problem. Does it prevent to avoid comparison == 1? Just to
> > > avoid changes in these lines in the future.
> > 
> > Yes probably better to avoid explicit comparison, but prefer boolean operator
> > (!).
> > 
> > 
> 
> Thomas I understand your comments but from Andrew comment on my V2-01 patch:
> "
> >>> +	ret = (*dev->dev_ops->rx_hairpin_queue_setup)(dev, rx_queue_id,
> >>> +						      nb_rx_desc, conf);
> >>> +	if (!ret)
> >> Please, compare with 0
> >>
> > Will do, but again just for my knowledge why?
> 
> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdoc.dpdk.org%2Fguides%2Fcontributing%2Fcoding_style.html%23function-calls&amp;data=02%7C01%7Corika%40mellanox.com%7C022cd953964f4a20d50508d7508a259f%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C637066426584029629&amp;sdata=G8ZxEWFFsv1kLWc6L7sKT8O6CSiBcj5ZuwQqmK0Q6nY%3D&amp;reserved=0
> 
> "
> I don't see any relevant info in the link, but maybe I'm missing something .
> What are the rules? 
> Thomas also keep in mind that in most cases the condition that is tested is the positive, meaning  it will look something like this:
> if (rte_eth_dev_is_rx_hairpin_queue(dev, queue_id)) {     
>         rte_errno = EINVAL;                               
>         return NULL;                                      
> }                                       
> 
> What do you think?

I think for normal functions with error codes,
we should compare explictly with a value.
But for boolean-type functions like "is_hairpin_queue",
we should have implicit (natural) comparison. So yes, this is correct:
	if (rte_eth_dev_is_rx_hairpin_queue(dev, queue_id))
  

Patch

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 78da293..199e96e 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -923,6 +923,13 @@  struct rte_eth_dev *
 
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_start, -ENOTSUP);
 
+	if (rte_eth_dev_is_rx_hairpin_queue(dev, rx_queue_id) == 1) {
+		RTE_ETHDEV_LOG(INFO,
+			"Can't start Rx queue %"PRIu16" of device with port_id=%"PRIu16" is hairpin queue\n",
+			rx_queue_id, port_id);
+		return -EINVAL;
+	}
+
 	if (dev->data->rx_queue_state[rx_queue_id] != RTE_ETH_QUEUE_STATE_STOPPED) {
 		RTE_ETHDEV_LOG(INFO,
 			"Queue %"PRIu16" of device with port_id=%"PRIu16" already started\n",
@@ -950,6 +957,13 @@  struct rte_eth_dev *
 
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_stop, -ENOTSUP);
 
+	if (rte_eth_dev_is_rx_hairpin_queue(dev, rx_queue_id) == 1) {
+		RTE_ETHDEV_LOG(INFO,
+			"Can't stop Rx queue %"PRIu16" of device with port_id=%"PRIu16" is hairpin queue\n",
+			rx_queue_id, port_id);
+		return -EINVAL;
+	}
+
 	if (dev->data->rx_queue_state[rx_queue_id] == RTE_ETH_QUEUE_STATE_STOPPED) {
 		RTE_ETHDEV_LOG(INFO,
 			"Queue %"PRIu16" of device with port_id=%"PRIu16" already stopped\n",
@@ -983,6 +997,13 @@  struct rte_eth_dev *
 
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_queue_start, -ENOTSUP);
 
+	if (rte_eth_dev_is_tx_hairpin_queue(dev, tx_queue_id) == 1) {
+		RTE_ETHDEV_LOG(INFO,
+			"Can't start Tx queue %"PRIu16" of device with port_id=%"PRIu16" is hairpin queue\n",
+			tx_queue_id, port_id);
+		return -EINVAL;
+	}
+
 	if (dev->data->tx_queue_state[tx_queue_id] != RTE_ETH_QUEUE_STATE_STOPPED) {
 		RTE_ETHDEV_LOG(INFO,
 			"Queue %"PRIu16" of device with port_id=%"PRIu16" already started\n",
@@ -1008,6 +1029,13 @@  struct rte_eth_dev *
 
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_queue_stop, -ENOTSUP);
 
+	if (rte_eth_dev_is_tx_hairpin_queue(dev, tx_queue_id) == 1) {
+		RTE_ETHDEV_LOG(INFO,
+			"Can't stop Tx queue %"PRIu16" of device with port_id=%"PRIu16" is hairpin queue\n",
+			tx_queue_id, port_id);
+		return -EINVAL;
+	}
+
 	if (dev->data->tx_queue_state[tx_queue_id] == RTE_ETH_QUEUE_STATE_STOPPED) {
 		RTE_ETHDEV_LOG(INFO,
 			"Queue %"PRIu16" of device with port_id=%"PRIu16" already stopped\n",
@@ -1780,6 +1808,79 @@  struct rte_eth_dev *
 }
 
 int
+rte_eth_rx_hairpin_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
+			       uint16_t nb_rx_desc,
+			       const struct rte_eth_hairpin_conf *conf)
+{
+	int ret;
+	struct rte_eth_dev *dev;
+	struct rte_eth_hairpin_cap cap;
+	void **rxq;
+	int i;
+	int count = 0;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
+
+	dev = &rte_eth_devices[port_id];
+	if (rx_queue_id >= dev->data->nb_rx_queues) {
+		RTE_ETHDEV_LOG(ERR, "Invalid RX queue_id=%u\n", rx_queue_id);
+		return -EINVAL;
+	}
+	ret = rte_eth_dev_hairpin_capability_get(port_id, &cap);
+	if (ret != 0)
+		return ret;
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_hairpin_queue_setup,
+				-ENOTSUP);
+	/* Use default specified by driver, if nb_rx_desc is zero */
+	if (nb_rx_desc == 0)
+		nb_rx_desc = cap.max_nb_desc;
+	if (nb_rx_desc > cap.max_nb_desc) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid value for nb_rx_desc(=%hu), should be: <= %hu",
+			nb_rx_desc, cap.max_nb_desc);
+		return -EINVAL;
+	}
+	if (conf->peer_count > cap.max_rx_2_tx) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid value for number of peers for Rx queue(=%hu), should be: <= %hu",
+			conf->peer_count, cap.max_rx_2_tx);
+		return -EINVAL;
+	}
+	if (conf->peer_count == 0) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid value for number of peers for Rx queue(=%hu), should be: > 0",
+			conf->peer_count);
+		return -EINVAL;
+	}
+	if (cap.max_nb_queues != UINT16_MAX) {
+		for (i = 0; i < dev->data->nb_rx_queues; i++) {
+			if (rte_eth_dev_is_rx_hairpin_queue(dev, i) == 1)
+				count++;
+		}
+		if (count > cap.max_nb_queues) {
+			RTE_ETHDEV_LOG(ERR, "To many Rx hairpin queues %d",
+			count);
+			return -EINVAL;
+		}
+	}
+	if (dev->data->dev_started)
+		return -EBUSY;
+	rxq = dev->data->rx_queues;
+	if (rxq[rx_queue_id] != NULL) {
+		RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_release,
+					-ENOTSUP);
+		(*dev->dev_ops->rx_queue_release)(rxq[rx_queue_id]);
+		rxq[rx_queue_id] = NULL;
+	}
+	ret = (*dev->dev_ops->rx_hairpin_queue_setup)(dev, rx_queue_id,
+						      nb_rx_desc, conf);
+	if (ret == 0)
+		dev->data->rx_queue_state[rx_queue_id] =
+			RTE_ETH_QUEUE_STATE_HAIRPIN;
+	return eth_err(port_id, ret);
+}
+
+int
 rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
 		       uint16_t nb_tx_desc, unsigned int socket_id,
 		       const struct rte_eth_txconf *tx_conf)
@@ -1878,6 +1979,78 @@  struct rte_eth_dev *
 		       tx_queue_id, nb_tx_desc, socket_id, &local_conf));
 }
 
+int
+rte_eth_tx_hairpin_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
+			       uint16_t nb_tx_desc,
+			       const struct rte_eth_hairpin_conf *conf)
+{
+	struct rte_eth_dev *dev;
+	struct rte_eth_hairpin_cap cap;
+	void **txq;
+	int i;
+	int count = 0;
+	int ret;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
+	dev = &rte_eth_devices[port_id];
+	if (tx_queue_id >= dev->data->nb_tx_queues) {
+		RTE_ETHDEV_LOG(ERR, "Invalid TX queue_id=%u\n", tx_queue_id);
+		return -EINVAL;
+	}
+	ret = rte_eth_dev_hairpin_capability_get(port_id, &cap);
+	if (ret != 0)
+		return ret;
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_hairpin_queue_setup,
+				-ENOTSUP);
+	/* Use default specified by driver, if nb_tx_desc is zero */
+	if (nb_tx_desc == 0)
+		nb_tx_desc = cap.max_nb_desc;
+	if (nb_tx_desc > cap.max_nb_desc) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid value for nb_tx_desc(=%hu), should be: <= %hu",
+			nb_tx_desc, cap.max_nb_desc);
+		return -EINVAL;
+	}
+	if (conf->peer_count > cap.max_tx_2_rx) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid value for number of peers for Tx queue(=%hu), should be: <= %hu",
+			conf->peer_count, cap.max_tx_2_rx);
+		return -EINVAL;
+	}
+	if (conf->peer_count == 0) {
+		RTE_ETHDEV_LOG(ERR,
+			"Invalid value for number of peers for Tx queue(=%hu), should be: > 0",
+			conf->peer_count);
+		return -EINVAL;
+	}
+	if (cap.max_nb_queues != UINT16_MAX) {
+		for (i = 0; i < dev->data->nb_tx_queues; i++) {
+			if (rte_eth_dev_is_tx_hairpin_queue(dev, i) == 1)
+				count++;
+		}
+		if (count > cap.max_nb_queues) {
+			RTE_ETHDEV_LOG(ERR,
+				       "To many Tx hairpin queues %d", count);
+			return -EINVAL;
+		}
+	}
+	if (dev->data->dev_started)
+		return -EBUSY;
+	txq = dev->data->tx_queues;
+	if (txq[tx_queue_id] != NULL) {
+		RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_queue_release,
+					-ENOTSUP);
+		(*dev->dev_ops->tx_queue_release)(txq[tx_queue_id]);
+		txq[tx_queue_id] = NULL;
+	}
+	ret = (*dev->dev_ops->tx_hairpin_queue_setup)
+		(dev, tx_queue_id, nb_tx_desc, conf);
+	if (ret == 0)
+		dev->data->tx_queue_state[tx_queue_id] =
+			RTE_ETH_QUEUE_STATE_HAIRPIN;
+	return eth_err(port_id, ret);
+}
+
 void
 rte_eth_tx_buffer_drop_callback(struct rte_mbuf **pkts, uint16_t unsent,
 		void *userdata __rte_unused)
@@ -4007,12 +4180,19 @@  int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
 	rte_errno = ENOTSUP;
 	return NULL;
 #endif
+	struct rte_eth_dev *dev;
+
 	/* check input parameters */
 	if (!rte_eth_dev_is_valid_port(port_id) || fn == NULL ||
 		    queue_id >= rte_eth_devices[port_id].data->nb_rx_queues) {
 		rte_errno = EINVAL;
 		return NULL;
 	}
+	dev = &rte_eth_devices[port_id];
+	if (rte_eth_dev_is_rx_hairpin_queue(dev, queue_id) == 1) {
+		rte_errno = EINVAL;
+		return NULL;
+	}
 	struct rte_eth_rxtx_callback *cb = rte_zmalloc(NULL, sizeof(*cb), 0);
 
 	if (cb == NULL) {
@@ -4084,6 +4264,8 @@  int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
 	rte_errno = ENOTSUP;
 	return NULL;
 #endif
+	struct rte_eth_dev *dev;
+
 	/* check input parameters */
 	if (!rte_eth_dev_is_valid_port(port_id) || fn == NULL ||
 		    queue_id >= rte_eth_devices[port_id].data->nb_tx_queues) {
@@ -4091,6 +4273,12 @@  int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
 		return NULL;
 	}
 
+	dev = &rte_eth_devices[port_id];
+	if (rte_eth_dev_is_tx_hairpin_queue(dev, queue_id) == 1) {
+		rte_errno = EINVAL;
+		return NULL;
+	}
+
 	struct rte_eth_rxtx_callback *cb = rte_zmalloc(NULL, sizeof(*cb), 0);
 
 	if (cb == NULL) {
@@ -4204,6 +4392,13 @@  int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
 		return -EINVAL;
 	}
 
+	if (rte_eth_dev_is_rx_hairpin_queue(dev, queue_id) == 1) {
+		RTE_ETHDEV_LOG(INFO,
+			"Can't get queue info for Rx queue %"PRIu16" of device with port_id=%"PRIu16" is hairpin queue\n",
+			queue_id, port_id);
+		return -EINVAL;
+	}
+
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rxq_info_get, -ENOTSUP);
 
 	memset(qinfo, 0, sizeof(*qinfo));
@@ -4228,6 +4423,13 @@  int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
 		return -EINVAL;
 	}
 
+	if (rte_eth_dev_is_tx_hairpin_queue(dev, queue_id) == 1) {
+		RTE_ETHDEV_LOG(INFO,
+			"Can't get queue info for Tx queue %"PRIu16" of device with port_id=%"PRIu16" is hairpin queue\n",
+			queue_id, port_id);
+		return -EINVAL;
+	}
+
 	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->txq_info_get, -ENOTSUP);
 
 	memset(qinfo, 0, sizeof(*qinfo));
@@ -4600,6 +4802,21 @@  int rte_eth_set_queue_rate_limit(uint16_t port_id, uint16_t queue_idx,
 }
 
 int
+rte_eth_dev_hairpin_capability_get(uint16_t port_id,
+				   struct rte_eth_hairpin_cap *cap)
+{
+	struct rte_eth_dev *dev;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
+
+	dev = &rte_eth_devices[port_id];
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->hairpin_cap_get,
+				-ENOTSUP);
+	memset(cap, 0, sizeof(*cap));
+	return eth_err(port_id, (*dev->dev_ops->hairpin_cap_get)(dev, cap));
+}
+
+int
 rte_eth_dev_pool_ops_supported(uint16_t port_id, const char *pool)
 {
 	struct rte_eth_dev *dev;
diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
index 09c611a..24b7a3c 100644
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
@@ -839,6 +839,46 @@  struct rte_eth_txconf {
 };
 
 /**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * A structure used to return the hairpin capabilities that are supported.
+ */
+struct rte_eth_hairpin_cap {
+	/** The max number of hairpin queues (different bindings). */
+	uint16_t max_nb_queues;
+	/**< Max number of Rx queues to be connected to one Tx queue. */
+	uint16_t max_rx_2_tx;
+	/**< Max number of Tx queues to be connected to one Rx queue. */
+	uint16_t max_tx_2_rx;
+	uint16_t max_nb_desc; /**< The max num of descriptors. */
+};
+
+#define RTE_ETH_MAX_HAIRPIN_PEERS 32
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * A structure used to hold hairpin peer data.
+ */
+struct rte_eth_hairpin_peer {
+	uint16_t port; /**< Peer port. */
+	uint16_t queue; /**< Peer queue. */
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * A structure used to configure hairpin binding.
+ */
+struct rte_eth_hairpin_conf {
+	uint16_t peer_count; /**< The number of peers. */
+	struct rte_eth_hairpin_peer peers[RTE_ETH_MAX_HAIRPIN_PEERS];
+};
+
+/**
  * A structure contains information about HW descriptor ring limitations.
  */
 struct rte_eth_desc_lim {
@@ -1829,6 +1869,37 @@  int rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
 		struct rte_mempool *mb_pool);
 
 /**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Allocate and set up a hairpin receive queue for an Ethernet device.
+ *
+ * The function set up the selected queue to be used in hairpin.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param rx_queue_id
+ *   The index of the receive queue to set up.
+ *   The value must be in the range [0, nb_rx_queue - 1] previously supplied
+ *   to rte_eth_dev_configure().
+ * @param nb_rx_desc
+ *   The number of receive descriptors to allocate for the receive ring.
+ *   0 means the PMD will use default value.
+ * @param conf
+ *   The pointer to the hairpin configuration.
+ *
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if hardware doesn't support.
+ *   - (-EINVAL) if bad parameter.
+ *   - (-ENOMEM) if unable to allocate the resources.
+ */
+__rte_experimental
+int rte_eth_rx_hairpin_queue_setup
+	(uint16_t port_id, uint16_t rx_queue_id, uint16_t nb_rx_desc,
+	 const struct rte_eth_hairpin_conf *conf);
+
+/**
  * Allocate and set up a transmit queue for an Ethernet device.
  *
  * @param port_id
@@ -1881,6 +1952,35 @@  int rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
 		const struct rte_eth_txconf *tx_conf);
 
 /**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Allocate and set up a transmit hairpin queue for an Ethernet device.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param tx_queue_id
+ *   The index of the transmit queue to set up.
+ *   The value must be in the range [0, nb_tx_queue - 1] previously supplied
+ *   to rte_eth_dev_configure().
+ * @param nb_tx_desc
+ *   The number of transmit descriptors to allocate for the transmit ring.
+ *   0 to set default PMD value.
+ * @param conf
+ *   The hairpin configuration.
+ *
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if hardware doesn't support.
+ *   - (-EINVAL) if bad parameter.
+ *   - (-ENOMEM) if unable to allocate the resources.
+ */
+__rte_experimental
+int rte_eth_tx_hairpin_queue_setup
+	(uint16_t port_id, uint16_t tx_queue_id, uint16_t nb_tx_desc,
+	 const struct rte_eth_hairpin_conf *conf);
+
+/**
  * Return the NUMA socket to which an Ethernet device is connected
  *
  * @param port_id
@@ -1915,7 +2015,7 @@  int rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
  *   to rte_eth_dev_configure().
  * @return
  *   - 0: Success, the receive queue is started.
- *   - -EINVAL: The port_id or the queue_id out of range.
+ *   - -EINVAL: The port_id or the queue_id out of range or belong to hairpin.
  *   - -EIO: if device is removed.
  *   - -ENOTSUP: The function not supported in PMD driver.
  */
@@ -1932,7 +2032,7 @@  int rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
  *   to rte_eth_dev_configure().
  * @return
  *   - 0: Success, the receive queue is stopped.
- *   - -EINVAL: The port_id or the queue_id out of range.
+ *   - -EINVAL: The port_id or the queue_id out of range or belong to hairpin.
  *   - -EIO: if device is removed.
  *   - -ENOTSUP: The function not supported in PMD driver.
  */
@@ -1950,7 +2050,7 @@  int rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
  *   to rte_eth_dev_configure().
  * @return
  *   - 0: Success, the transmit queue is started.
- *   - -EINVAL: The port_id or the queue_id out of range.
+ *   - -EINVAL: The port_id or the queue_id out of range or belong to hairpin.
  *   - -EIO: if device is removed.
  *   - -ENOTSUP: The function not supported in PMD driver.
  */
@@ -1967,7 +2067,7 @@  int rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
  *   to rte_eth_dev_configure().
  * @return
  *   - 0: Success, the transmit queue is stopped.
- *   - -EINVAL: The port_id or the queue_id out of range.
+ *   - -EINVAL: The port_id or the queue_id out of range or belong to hairpin.
  *   - -EIO: if device is removed.
  *   - -ENOTSUP: The function not supported in PMD driver.
  */
@@ -3633,7 +3733,8 @@  int rte_eth_remove_tx_callback(uint16_t port_id, uint16_t queue_id,
  * @return
  *   - 0: Success
  *   - -ENOTSUP: routine is not supported by the device PMD.
- *   - -EINVAL:  The port_id or the queue_id is out of range.
+ *   - -EINVAL:  The port_id or the queue_id is out of range, or the queue
+ *               is hairpin queue.
  */
 int rte_eth_rx_queue_info_get(uint16_t port_id, uint16_t queue_id,
 	struct rte_eth_rxq_info *qinfo);
@@ -3653,7 +3754,8 @@  int rte_eth_rx_queue_info_get(uint16_t port_id, uint16_t queue_id,
  * @return
  *   - 0: Success
  *   - -ENOTSUP: routine is not supported by the device PMD.
- *   - -EINVAL:  The port_id or the queue_id is out of range.
+ *   - -EINVAL:  The port_id or the queue_id is out of range, or the queue
+ *               is hairpin queue.
  */
 int rte_eth_tx_queue_info_get(uint16_t port_id, uint16_t queue_id,
 	struct rte_eth_txq_info *qinfo);
@@ -4151,6 +4253,23 @@  int rte_eth_dev_adjust_nb_rx_tx_desc(uint16_t port_id,
 void *
 rte_eth_dev_get_sec_ctx(uint16_t port_id);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Query the device hairpin capabilities.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param cap
+ *   Pointer to a structure that will hold the hairpin capabilities.
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if hardware doesn't support.
+ */
+__rte_experimental
+int rte_eth_dev_hairpin_capability_get(uint16_t port_id,
+				       struct rte_eth_hairpin_cap *cap);
 
 #include <rte_ethdev_core.h>
 
@@ -4251,6 +4370,11 @@  int rte_eth_dev_adjust_nb_rx_tx_desc(uint16_t port_id,
 		RTE_ETHDEV_LOG(ERR, "Invalid RX queue_id=%u\n", queue_id);
 		return 0;
 	}
+	if (rte_eth_dev_is_rx_hairpin_queue(dev, queue_id) == 1) {
+		RTE_ETHDEV_LOG(ERR, "Rx burst failed, queue_id=%u is hairpin queue\n",
+			       queue_id);
+		return 0;
+	}
 #endif
 	nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
 				     rx_pkts, nb_pkts);
@@ -4517,6 +4641,11 @@  static inline int rte_eth_tx_descriptor_status(uint16_t port_id,
 		RTE_ETHDEV_LOG(ERR, "Invalid TX queue_id=%u\n", queue_id);
 		return 0;
 	}
+	if (rte_eth_dev_is_tx_hairpin_queue(dev, queue_id) == 1) {
+		RTE_ETHDEV_LOG(ERR, "Tx burst failed, queue_id=%u is hairpin queue\n",
+			       queue_id);
+		return 0;
+	}
 #endif
 
 #ifdef RTE_ETHDEV_RXTX_CALLBACKS
diff --git a/lib/librte_ethdev/rte_ethdev_core.h b/lib/librte_ethdev/rte_ethdev_core.h
index 392aea8..f215af7 100644
--- a/lib/librte_ethdev/rte_ethdev_core.h
+++ b/lib/librte_ethdev/rte_ethdev_core.h
@@ -509,6 +509,86 @@  typedef int (*eth_pool_ops_supported_t)(struct rte_eth_dev *dev,
 /**< @internal Test if a port supports specific mempool ops */
 
 /**
+ * @internal
+ * Get the hairpin capabilities.
+ *
+ * @param dev
+ *   ethdev handle of port.
+ * @param cap
+ *   returns the hairpin capabilities from the device.
+ *
+ * @return
+ *   Negative errno value on error, 0 on success.
+ *
+ * @retval 0
+ *   Success, hairpin is supported.
+ * @retval -ENOTSUP
+ *   Hairpin is not supported.
+ */
+typedef int (*eth_hairpin_cap_get_t)(struct rte_eth_dev *dev,
+				     struct rte_eth_hairpin_cap *cap);
+
+/**
+ * @internal
+ * Setup RX hairpin queue.
+ *
+ * @param dev
+ *   ethdev handle of port.
+ * @param rx_queue_id
+ *   the selected RX queue index.
+ * @param nb_rx_desc
+ *   the requested number of descriptors for this queue. 0 - use PMD default.
+ * @param conf
+ *   the RX hairpin configuration structure.
+ *
+ * @return
+ *   Negative errno value on error, 0 on success.
+ *
+ * @retval 0
+ *   Success, hairpin is supported.
+ * @retval -ENOTSUP
+ *   Hairpin is not supported.
+ * @retval -EINVAL
+ *   One of the parameters is invalid.
+ * @retval -ENOMEM
+ *   Unable to allocate resources.
+ */
+typedef int (*eth_rx_hairpin_queue_setup_t)
+	(struct rte_eth_dev *dev, uint16_t rx_queue_id,
+	 uint16_t nb_rx_desc,
+	 const struct rte_eth_hairpin_conf *conf);
+
+/**
+ * @internal
+ * Setup TX hairpin queue.
+ *
+ * @param dev
+ *   ethdev handle of port.
+ * @param tx_queue_id
+ *   the selected TX queue index.
+ * @param nb_tx_desc
+ *   the requested number of descriptors for this queue. 0 - use PMD default.
+ * @param conf
+ *   the TX hairpin configuration structure.
+ *
+ * @return
+ *   Negative errno value on error, 0 on success.
+ *
+ * @retval 0
+ *   Success, hairpin is supported.
+ * @retval -ENOTSUP
+ *   Hairpin is not supported.
+ * @retval -EINVAL
+ *   One of the parameters is invalid.
+ * @retval -ENOMEM
+ *   Unable to allocate resources.
+ */
+typedef int (*eth_tx_hairpin_queue_setup_t)
+	(struct rte_eth_dev *dev, uint16_t tx_queue_id,
+	 uint16_t nb_tx_desc,
+	 const struct rte_eth_hairpin_conf *hairpin_conf);
+
+/**
  * @internal A structure containing the functions exported by an Ethernet driver.
  */
 struct eth_dev_ops {
@@ -644,6 +724,13 @@  struct eth_dev_ops {
 
 	eth_pool_ops_supported_t pool_ops_supported;
 	/**< Test if a port supports specific mempool ops */
+
+	eth_hairpin_cap_get_t hairpin_cap_get;
+	/**< Returns the hairpin capabilities. */
+	eth_rx_hairpin_queue_setup_t rx_hairpin_queue_setup;
+	/**< Set up device RX hairpin queue. */
+	eth_tx_hairpin_queue_setup_t tx_hairpin_queue_setup;
+	/**< Set up device TX hairpin queue. */
 };
 
 /**
@@ -751,9 +838,9 @@  struct rte_eth_dev_data {
 		dev_started : 1,   /**< Device state: STARTED(1) / STOPPED(0). */
 		lro         : 1;   /**< RX LRO is ON(1) / OFF(0) */
 	uint8_t rx_queue_state[RTE_MAX_QUEUES_PER_PORT];
-			/**< Queues state: STARTED(1) / STOPPED(0). */
+		/**< Queues state: HAIRPIN(2) / STARTED(1) / STOPPED(0). */
 	uint8_t tx_queue_state[RTE_MAX_QUEUES_PER_PORT];
-			/**< Queues state: STARTED(1) / STOPPED(0). */
+		/**< Queues state: HAIRPIN(2) / STARTED(1) / STOPPED(0). */
 	uint32_t dev_flags;             /**< Capabilities. */
 	enum rte_kernel_driver kdrv;    /**< Kernel driver passthrough. */
 	int numa_node;                  /**< NUMA node connection. */
diff --git a/lib/librte_ethdev/rte_ethdev_driver.h b/lib/librte_ethdev/rte_ethdev_driver.h
index c404f17..98023d7 100644
--- a/lib/librte_ethdev/rte_ethdev_driver.h
+++ b/lib/librte_ethdev/rte_ethdev_driver.h
@@ -26,6 +26,50 @@ 
  */
 #define RTE_ETH_QUEUE_STATE_STOPPED 0
 #define RTE_ETH_QUEUE_STATE_STARTED 1
+#define RTE_ETH_QUEUE_STATE_HAIRPIN 2
+
+/**
+ * @internal
+ * Check if the selected Rx queue is hairpin queue.
+ *
+ * @param dev
+ *  Pointer to the selected device.
+ * @param queue_id
+ *  The selected queue.
+ *
+ * @return
+ *   - (1) if the queue is hairpin queue, 0 otherwise.
+ */
+static inline int
+rte_eth_dev_is_rx_hairpin_queue(struct rte_eth_dev *dev, uint16_t queue_id)
+{
+	if (dev->data->rx_queue_state[queue_id] ==
+	    RTE_ETH_QUEUE_STATE_HAIRPIN)
+		return 1;
+	return 0;
+}
+
+
+/**
+ * @internal
+ * Check if the selected Tx queue is hairpin queue.
+ *
+ * @param dev
+ *  Pointer to the selected device.
+ * @param queue_id
+ *  The selected queue.
+ *
+ * @return
+ *   - (1) if the queue is hairpin queue, 0 otherwise.
+ */
+static inline int
+rte_eth_dev_is_tx_hairpin_queue(struct rte_eth_dev *dev, uint16_t queue_id)
+{
+	if (dev->data->tx_queue_state[queue_id] ==
+	    RTE_ETH_QUEUE_STATE_HAIRPIN)
+		return 1;
+	return 0;
+}
 
 /**
  * @internal
diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
index e59d516..48b5389 100644
--- a/lib/librte_ethdev/rte_ethdev_version.map
+++ b/lib/librte_ethdev/rte_ethdev_version.map
@@ -288,4 +288,7 @@  EXPERIMENTAL {
 	rte_eth_rx_burst_mode_get;
 	rte_eth_tx_burst_mode_get;
 	rte_eth_burst_mode_option_name;
+	rte_eth_rx_hairpin_queue_setup;
+	rte_eth_tx_hairpin_queue_setup;
+	rte_eth_dev_hairpin_capability_get;
 };