Subject: Re: [PATCH net-next v9 3/7] ixgbe: Add a RETA query command to VF-PF channel API

From: Vlad Zolotarov <[email-masked]>
Date: Mon, 30 Mar 2015 11:24:24 +0300

On 03/30/15 01:45, Alexander Duyck wrote:
> On 03/29/2015 09:11 AM, Vlad Zolotarov wrote:
>> Add this new command for 82599 and x540 devices only. Support for other devices
>> will be added later.
>>
>> 82599 and x540 VFs and PF share the same RSS redirection table (RETA). Therefore we
>> just return it for all VFs.
>>
>> For 82599 and x540 RETA table is an array of 32 registers (128 bytes) and the maximum number of
>> registers that may be delivered in a single VF-PF channel command is 15. Therefore
>> we will deliver the whole table in 3 steps: 12, 12 and 8 registers in each
>> step correspondingly.
>>
>> Thus this patch does the following:
>>
>>    - Adds a new API version (to specify a new commands set).
>>    - Adds the IXGBE_VF_GET_RETA command to the VF-PF commands set.
>>
>> Signed-off-by: Vlad Zolotarov <[email-masked]>
>> ---
>> New in v9:
>>     - Reduce the support to 82599 and x540 devices only.
>>     - Improvements in query RETA VF-PF command implementation:
>>        - Use the cached RETA contents.
>>        - Compress the mailbox message.
>>
>> New in v5:
>>     - Use the newly added netdev op to allow/prevent the RETA query on a per-VF basis.
>>
>> New in v4:
>>     - Deleted an empty line in ixgbe_get_vf_reta() switch-case.
>>
>> New in v3:
>>     - Pass the number of dwords and offset in RETA in the IXGBE_VF_GET_RETA request message.
>>       This allows to reduce the added command set to a single command.
>>     - Added a support for all devices supported by the ixgbe driver that have
>>       SR-IOV functions support: 82599, x540 and x550. The original code supported
>>       only 82599 and x540.
>>     - Added the masking of the RETA entries according to the PSRTYPE[n].RQPL
>>       value.
>>
>> New in v1 (compared to RFC):
>>     - Use "if-else" statement instead of a "switch-case" for a single option case
>>       (in ixgbe_get_vf_reta()).
>> ---
>>   drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h   |  4 +++
>>   drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 49 ++++++++++++++++++++++++++
>>   2 files changed, 53 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
>> index a5cb755..3522f53 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h
>> @@ -73,6 +73,7 @@ enum ixgbe_pfvf_api_rev {
>>   	ixgbe_mbox_api_10,	/* API version 1.0, linux/freebsd VF driver */
>>   	ixgbe_mbox_api_20,	/* API version 2.0, solaris Phase1 VF driver */
>>   	ixgbe_mbox_api_11,	/* API version 1.1, linux/freebsd VF driver */
>> +	ixgbe_mbox_api_12,	/* API version 1.2, linux/freebsd VF driver */
>>   	/* This value should always be last */
>>   	ixgbe_mbox_api_unknown,	/* indicates that API version is not known */
>>   };
>> @@ -97,6 +98,9 @@ enum ixgbe_pfvf_api_rev {
>>   #define IXGBE_VF_TRANS_VLAN	3	/* Indication of port vlan */
>>   #define IXGBE_VF_DEF_QUEUE	4	/* Default queue offset */
>>   
>> +/* mailbox API, version 1.2 VF requests */
>> +#define IXGBE_VF_GET_RETA	0x0a	/* VF request for RETA */
>> +
>>   /* length of permanent address message returned from PF */
>>   #define IXGBE_VF_PERMADDR_MSG_LEN 4
>>   /* word in permanent address message with the current multicast type */
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
>> index f08672a..8424e7f 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
>> @@ -433,6 +433,7 @@ static s32 ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
>>   #endif /* CONFIG_FCOE */
>>   		switch (adapter->vfinfo[vf].vf_api) {
>>   		case ixgbe_mbox_api_11:
>> +		case ixgbe_mbox_api_12:
>>   			/*
>>   			 * Version 1.1 supports jumbo frames on VFs if PF has
>>   			 * jumbo frames enabled which means legacy VFs are
>> @@ -900,6 +901,7 @@ static int ixgbe_negotiate_vf_api(struct ixgbe_adapter *adapter,
>>   	switch (api) {
>>   	case ixgbe_mbox_api_10:
>>   	case ixgbe_mbox_api_11:
>> +	case ixgbe_mbox_api_12:
>>   		adapter->vfinfo[vf].vf_api = api;
>>   		return 0;
>>   	default:
>> @@ -923,6 +925,7 @@ static int ixgbe_get_vf_queues(struct ixgbe_adapter *adapter,
>>   	switch (adapter->vfinfo[vf].vf_api) {
>>   	case ixgbe_mbox_api_20:
>>   	case ixgbe_mbox_api_11:
>> +	case ixgbe_mbox_api_12:
>>   		break;
>>   	default:
>>   		return -1;
>> @@ -950,6 +953,49 @@ static int ixgbe_get_vf_queues(struct ixgbe_adapter *adapter,
>>   	return 0;
>>   }
>>   
>> +static int ixgbe_get_vf_reta(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
>> +{
>> +	struct ixgbe_hw *hw = &adapter->hw;
>> +	u32 i, j;
>> +	u32 *out_buf = &msgbuf[1];
>> +	const u8 *reta = adapter->rss_indir_tbl;
>> +	u8 mask = 0;
>> +	u32 psrtype;
>> +	u32 reta_size = ixgbe_rss_indir_tbl_entries(adapter);
>> +
>> +	/* 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;
>> +
>> +	psrtype = IXGBE_READ_REG(hw, IXGBE_PSRTYPE(vf));
>> +
>> +	/* The redirection table is composed as follows:
>> +	 * 82598: 128 (8 bit wide) entries containing pair of 4 bit RSS indices
>> +	 * 82599/X540: 128 (8 bit wide) entries containing 4 bit RSS index
>> +	 *
>> +	 * PSRTYPE[n].RQPL defines if 0, 1 or 2 bits from the redirection table
>> +	 * value should be used.
>> +	 */
>> +
>> +	if ((psrtype & (1 << 29)) == (1 << 29))
>> +		mask = 0x01;
>> +	else if ((psrtype & (2 << 29)) == (2 << 29))
>> +		mask = 0x03;
>> +
> The psrtype and mask should be dropped.  Any masking should happen on
> the VF end as the VF controls the psrtype register and the value could
> change depending on the VF settings.  You should just be using 0x3 as
> the mask always since you are encoding 2 bits per entry in the buffer.

Namely no masking at all here. Sounds reasonable. I tried to drop 
PSRTYPE reading and then noticed that it's a VF that eventually changes 
it so I reverted it back.
U r right, I should have gone a one step further here.

>
>> +	/* Compress the RETA by saving only 2 bits from each entry. This way
>> +	 * we will be able to transfer the whole RETA in a single mailbox
>> +	 * operation.
>> +	 */
>> +	for (i = 0; i < reta_size / 16; i++) {
>> +		out_buf[i] = 0;
>> +		for (j = 0; j < 16; j++)
>> +			out_buf[i] |= (u32)(reta[16 * i + j] & mask) << (2 * j);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
>>   {
>>   	u32 mbx_size = IXGBE_VFMAILBOX_SIZE;
>> @@ -1006,6 +1052,9 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
>>   	case IXGBE_VF_GET_QUEUES:
>>   		retval = ixgbe_get_vf_queues(adapter, msgbuf, vf);
>>   		break;
>> +	case IXGBE_VF_GET_RETA:
>> +		retval = ixgbe_get_vf_reta(adapter, msgbuf, vf);
>> +		break;
>>   	default:
>>   		e_err(drv, "Unhandled Msg %8.8x\n", msgbuf[0]);
>>   		retval = IXGBE_ERR_MBX;
>>