Re: [dpdk-dev] [PATCH] net/ixgbe: fix vlan insert parameter type and its use

[Scott Daniels <daniels@research.att.com>]

------------------------------------------------------------------------
E. Scott Daniels
PMTS - Cloud Software Research
AT&T Labs - Research
daniels@research.att.com
440.389.0011


On Wed, 19 Oct 2016, Lu, Wenzhuo wrote:

> Hi Daniels,
>
>
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of E. Scott Daniels
>> Sent: Wednesday, October 19, 2016 3:13 AM
>> To: Zhang, Helin; Iremonger, Bernard
>> Cc: dev@dpdk.org; az5157@att.com; E. Scott Daniels
>> Subject: [dpdk-dev] [PATCH] net/ixgbe: fix vlan insert parameter type and its use
>>
>> The final parameter to rte_pmd_ixgbe_set_vf_vlan_insert is uint8_t and treated
>> as a binary flag when it needs to be a uint16_t and treated as a VLAN id.  The
>> data sheet (sect 8.2.3.27.13) describes the right most 16 bits as the VLAN id that
>> is to be inserted; the
>> 16.11  code is accepting only a 1 or 0 thus effectively only allowing the VLAN id 1
>> to be inserted (0 disables the insertion setting).
>>
>> This patch changes the final parm name to represent the data that is being
>> accepted (vlan_id), changes the type to permit all valid VLAN ids, and validates
>> the parameter based on the range of 0 to 4095. Corresponding changes to
>> prototype and documentation in the .h file.
>>
>> Fixes:  49e248223e9f71 ("net/ixgbe: add API for VF management")
>>
>> Signed-off-by: E. Scott Daniels <daniels@research.att.com>
>> ---
>>  drivers/net/ixgbe/ixgbe_ethdev.c  | 8 ++++----
>> drivers/net/ixgbe/rte_pmd_ixgbe.h | 9 +++++----
>>  2 files changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
>> index 4ca5747..316af73 100644
>> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
>> @@ -4727,7 +4727,7 @@ rte_pmd_ixgbe_set_vf_mac_anti_spoof(uint8_t port,
>> uint16_t vf, uint8_t on)  }
>>
>>  int
>> -rte_pmd_ixgbe_set_vf_vlan_insert(uint8_t port, uint16_t vf, uint8_t on)
>> +rte_pmd_ixgbe_set_vf_vlan_insert(uint8_t port, uint16_t vf, uint16_t
>> +vlan_id)
>>  {
>>  	struct ixgbe_hw *hw;
>>  	uint32_t ctrl;
>> @@ -4742,13 +4742,13 @@ rte_pmd_ixgbe_set_vf_vlan_insert(uint8_t port,
>> uint16_t vf, uint8_t on)
>>  	if (vf >= dev_info.max_vfs)
>>  		return -EINVAL;
>>
>> -	if (on > 1)
>> +	if (vlan_id > 4095)
>>  		return -EINVAL;
>>
>>  	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>  	ctrl = IXGBE_READ_REG(hw, IXGBE_VMVIR(vf));
>> -	if (on) {
>> -		ctrl = on;
>> +	if (vlan_id) {
>> +		ctrl = vlan_id;
> I believe this patch is a good idea of an enhancement. But you cannot leverage the existing code like this.
> The register IXGBE_VMVIR is only for enable/disable. We cannot write the VLAN ID into it.
> If you want to merge the 2 things, enabling/disabling and setting VLAN ID together. I think we need a totally new implementation. So NACK.
>

I'm a bit confused.  According to the data sheet (section 8.2.3.27.13) 
this register accepts the "port VLAN tag to insert if the VLANA field = 
01b" in the right most 16 bits.  This allows the given tag to be inserted 
in outgoing packets.  The current implementation always sets this bit (via 
the IXGBE_VMVIR_VLANA_DEFAULT constant) which causes the tag in the right 
most bits to be inserted.

The current code, which I belive is broken, only ever inserts a 1 or 0 
into the right most bits as it takes the value passed in and ORs it with 
the constant, effectively only allowing the VLAN tag of 1 to be 
inserted.  The value passed in is not being used to set/reset the 
always/never insert VLAN action bit.

The only way to insert VLAN tags 2 through 4095 is to modify the code to 
accept the tag and insert it as described in the patch.

Scott


>>  		ctrl |= IXGBE_VMVIR_VLANA_DEFAULT;
>>  	} else {
>>  		ctrl = 0;
>> diff --git a/drivers/net/ixgbe/rte_pmd_ixgbe.h
>> b/drivers/net/ixgbe/rte_pmd_ixgbe.h
>> index 2fdf530..c2fb826 100644
>> --- a/drivers/net/ixgbe/rte_pmd_ixgbe.h
>> +++ b/drivers/net/ixgbe/rte_pmd_ixgbe.h
>> @@ -99,16 +99,17 @@ int rte_pmd_ixgbe_set_vf_mac_anti_spoof(uint8_t port,
>> uint16_t vf, uint8_t on);
>>   *    The port identifier of the Ethernet device.
>>   * @param vf
>>   *    ID specifying VF.
>> - * @param on
>> - *    1 - Enable VF's vlan insert.
>> - *    0 - Disable VF's vlan insert
>> + * @param vlan_id
>> + *    0 - Disable VF's vlan insert.
>> + *    n - Enable; n is inserted as the vlan id.
>>   *
>>   * @return
>>   *   - (0) if successful.
>>   *   - (-ENODEV) if *port* invalid.
>>   *   - (-EINVAL) if bad parameter.
>>   */
>> -int rte_pmd_ixgbe_set_vf_vlan_insert(uint8_t port, uint16_t vf, uint8_t on);
>> +int rte_pmd_ixgbe_set_vf_vlan_insert(uint8_t port, uint16_t vf,
>> +		uint16_t vlan_id);
>>
>>  /**
>>   * Enable/Disable tx loopback
>> --
>> 1.9.1
>
>