Subject: Re: [PATCH net-next v9 5/7] ixgbe: Add GET_RSS_KEY command to VF-PF channel commands set

From: Vlad Zolotarov <[email-masked]>
Date: Mon, 30 Mar 2015 13:08:15 +0300

On 03/30/15 01:04, Alexander Duyck wrote:
> On 03/29/2015 09:11 AM, Vlad Zolotarov wrote:
>> For 82599 and x540 VFs and PF share the same RSS Key. Therefore we will return
>> the same RSS key for all VFs.
>>
>> Support for other devices will be added later.
>>
>> Signed-off-by: Vlad Zolotarov <[email-masked]>
>> ---
>> New in v9:
>>     - Reduce the support to 82599 and x540 devices only.
>>     - Get rid of registers access in GET_VF_RSS_KEY flow:
>>        - Get the RSS HASH Key value from the PF's adapter->rss_key[].
>>
>> New in v5:
>>     - Use a newly added netdev op to allow/prevent the RSS Hash Key querying on a per-VF
>>       basis.
>>
>> New in v3:
>>     - Added a support for x550 devices.
>>
>> New in v1 (compared to RFC):
>>     - Use "if-else" statement instead of a "switch-case" for a single option case
>>       (in ixgbe_get_vf_rss_key()).
>> ---
>>   drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h   |  1 +
>>   drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 25 +++++++++++++++++++++++++
>>   2 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
>> index 3522f53..b1e4703 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
>> @@ -100,6 +100,7 @@ enum ixgbe_pfvf_api_rev {
>>   
>>   /* mailbox API, version 1.2 VF requests */
>>   #define IXGBE_VF_GET_RETA	0x0a	/* VF request for RETA */
>> +#define IXGBE_VF_GET_RSS_KEY	0x0b	/* get RSS key */
>>   
>>   /* length of permanent address message returned from PF */
>>   #define IXGBE_VF_PERMADDR_MSG_LEN 4
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
>> index 8424e7f..4d87458 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
>> @@ -996,6 +996,28 @@ static int ixgbe_get_vf_reta(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
>>   	return 0;
>>   }
>>   
>> +static int ixgbe_get_vf_rss_key(struct ixgbe_adapter *adapter,
>> +				u32 *msgbuf, u32 vf)
>> +{
>> +	struct ixgbe_hw *hw = &adapter->hw;
>> +	u32 *rss_key = &msgbuf[1];
>> +
>> +	/* verify the PF is supporting the correct API */
>> +	if (!adapter->vfinfo[vf].rss_query_enabled ||
>> +	    (adapter->vfinfo[vf].vf_api != ixgbe_mbox_api_12))
>> +		return -EPERM;
>> +
>> +	/* Read the RSS KEY.
>> +	 * We only support 82599 and x540 devices at the moment.
>> +	 */
>> +	if (hw->mac.type >= ixgbe_mac_X550)
>> +		return -1;
>> +
> The return should be not supported, not -1 since that is too ambiguous.

On the other hand - why this condition here at all? It will never return 
TRUE anyway since the operation will be blocked by 
adapter->vfinfo[vf].rss_query_enabled
check before since ixgbe_ndo_set_vf_rss_query_en() will prevent the 
rss_query_enabling for the devices newer than x540. So IMHO the right 
thing to do here should be to remove the last "if" at all and split the 
previous one in two so that we will return -EOPNOTSUPP for 
(adapter->vfinfo[vf].vf_api != ixgbe_mbox_api_12) condition.

>
>> +	memcpy(rss_key, adapter->rss_key, sizeof(adapter->rss_key));
>> +
>> +	return 0;
>> +}
>> +
>>   static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
>>   {
>>   	u32 mbx_size = IXGBE_VFMAILBOX_SIZE;
>> @@ -1055,6 +1077,9 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
>>   	case IXGBE_VF_GET_RETA:
>>   		retval = ixgbe_get_vf_reta(adapter, msgbuf, vf);
>>   		break;
>> +	case IXGBE_VF_GET_RSS_KEY:
>> +		retval = ixgbe_get_vf_rss_key(adapter, msgbuf, vf);
>> +		break;
>>   	default:
>>   		e_err(drv, "Unhandled Msg %8.8x\n", msgbuf[0]);
>>   		retval = IXGBE_ERR_MBX;
>>