Subject: Re: [PATCH net-next v9 4/7] ixgbevf: Add a RETA query code

From: Vlad Zolotarov <[email-masked]>
Date: Mon, 30 Mar 2015 12:12:58 +0300

On 03/30/15 01:51, Alexander Duyck wrote:
> On 03/29/2015 09:11 AM, Vlad Zolotarov wrote:
>> We will currently support only 82599 and x540 deviced. Support for other devices
>> will be added later.
>>
>>     - Added a new API version support.
>>     - Added the query implementation in the ixgbevf.
>>
>> Signed-off-by: Vlad Zolotarov <[email-masked]>
>> ---
>> New in v9:
>>     - Reduce the support to 82599 and x540 devices only.
>>     - Improvements in RETA query code:
>>        - Implement a "compression" of VF's RETA contents: pass only 2 bits
>>          per-entry.
>>        - RETA querying is done in a single mailbox operation thanks to compression.
>>
>> New in v8:
>>     - Protect mailbox with a spinlock.
>>
>> New in v7:
>>     - Add ixgbe_mbox_api_12 case in ixgbevf_set_num_queues().
>>     - Properly expand HW RETA into the ethtool buffer.
>>
>> New in v6:
>>     - Add a proper return code when an operation is blocked by PF.
>>
>> New in v3:
>>     - Adjusted to the new interface IXGBE_VF_GET_RETA command.
>>     - Added a proper 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 ixgbevf_get_reta()).
>> ---
>>   drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |  5 +-
>>   drivers/net/ethernet/intel/ixgbevf/mbx.h          |  4 ++
>>   drivers/net/ethernet/intel/ixgbevf/vf.c           | 76 +++++++++++++++++++++++
>>   drivers/net/ethernet/intel/ixgbevf/vf.h           |  2 +
>>   4 files changed, 86 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> index 4ee15ad..a16d267 100644
>> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> @@ -2030,7 +2030,8 @@ static void ixgbevf_init_last_counter_stats(struct ixgbevf_adapter *adapter)
>>   static void ixgbevf_negotiate_api(struct ixgbevf_adapter *adapter)
>>   {
>>   	struct ixgbe_hw *hw = &adapter->hw;
>> -	int api[] = { ixgbe_mbox_api_11,
>> +	int api[] = { ixgbe_mbox_api_12,
>> +		      ixgbe_mbox_api_11,
>>   		      ixgbe_mbox_api_10,
>>   		      ixgbe_mbox_api_unknown };
>>   	int err = 0, idx = 0;
>> @@ -2332,6 +2333,7 @@ static void ixgbevf_set_num_queues(struct ixgbevf_adapter *adapter)
>>   
>>   		switch (hw->api_version) {
>>   		case ixgbe_mbox_api_11:
>> +		case ixgbe_mbox_api_12:
>>   			adapter->num_rx_queues = rss;
>>   			adapter->num_tx_queues = rss;
>>   		default:
>> @@ -3712,6 +3714,7 @@ static int ixgbevf_change_mtu(struct net_device *netdev, int new_mtu)
>>   
>>   	switch (adapter->hw.api_version) {
>>   	case ixgbe_mbox_api_11:
>> +	case ixgbe_mbox_api_12:
>>   		max_possible_frame = IXGBE_MAX_JUMBO_FRAME_SIZE;
>>   		break;
>>   	default:
>> diff --git a/drivers/net/ethernet/intel/ixgbevf/mbx.h b/drivers/net/ethernet/intel/ixgbevf/mbx.h
>> index 6253e93..66e138b 100644
>> --- a/drivers/net/ethernet/intel/ixgbevf/mbx.h
>> +++ b/drivers/net/ethernet/intel/ixgbevf/mbx.h
>> @@ -83,6 +83,7 @@ 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 */
>>   };
>> @@ -107,6 +108,9 @@ 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/ixgbevf/vf.c b/drivers/net/ethernet/intel/ixgbevf/vf.c
>> index 2614fd3..2676c0b 100644
>> --- a/drivers/net/ethernet/intel/ixgbevf/vf.c
>> +++ b/drivers/net/ethernet/intel/ixgbevf/vf.c
>> @@ -256,6 +256,81 @@ static s32 ixgbevf_set_uc_addr_vf(struct ixgbe_hw *hw, u32 index, u8 *addr)
>>   	return ret_val;
>>   }
>>   
>> +static inline int ixgbevf_get_reta_locked(struct ixgbe_hw *hw, u32 *msgbuf,
>> +					  u32 *reta)
>> +{
>> +	int err, i, j;
>> +	u32 *hw_reta = &msgbuf[1];
>> +
>> +	/* We have to use a mailbox for 82599 and x540 devices only.
>> +	 * For these devices RETA has 128 entries.
>> +	 * Also these VFs support up to 4 RSS queues. Therefore PF will compress
>> +	 * 16 RETA entries in each DWORD giving 2 bits to each entry.
>> +	 */
>> +	int dwords = 128 / 16;
>> +
>> +	msgbuf[0] = IXGBE_VF_GET_RETA;
>> +
>> +	err = hw->mbx.ops.write_posted(hw, msgbuf, 1);
>> +
>> +	if (err)
>> +		return err;
>> +
>> +	err = hw->mbx.ops.read_posted(hw, msgbuf, dwords + 1);
>> +
>> +	if (err)
>> +		return err;
>> +
>> +	msgbuf[0] &= ~IXGBE_VT_MSGTYPE_CTS;
>> +
>> +	/* If the operation has been refused by a PF return -EPERM */
>> +	if (msgbuf[0] == (IXGBE_VF_GET_RETA | IXGBE_VT_MSGTYPE_NACK))
>> +		return -EPERM;
>> +
>> +	/* If we didn't get an ACK there must have been
>> +	 * some sort of mailbox error so we should treat it
>> +	 * as such.
>> +	 */
>> +	if (msgbuf[0] != (IXGBE_VF_GET_RETA | IXGBE_VT_MSGTYPE_ACK))
>> +		return IXGBE_ERR_MBX;
>> +
>> +	for (i = 0; i < dwords; i++)
>> +		for (j = 0; j < 16; j++)
>> +			reta[i * 16 + j] = (hw_reta[i] >> (2 * j)) & 0x3;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * ixgbevf_get_reta - get the RSS redirection table (RETA) contents.
>> + * @adapter: pointer to the port handle
>> + * @reta: buffer to fill with RETA contents.
>> + *
>> + * The "reta" buffer should be big enough to contain 32 registers.
>> + *
>> + * Returns: 0 on success.
>> + *          if API doesn't support this operation - (-EPERM).
>> + */
>> +int ixgbevf_get_reta(struct ixgbevf_adapter *adapter, u32 *reta)
>> +{
>> +	int err;
>> +	u32 msgbuf[IXGBE_VFMAILBOX_SIZE];
>> +
>> +	/* We support the RSS querying for 82599 and x540 devices only.
>> +	 * Thus return an error if API doesn't support RETA querying or querying
>> +	 * is not supported for this device type.
>> +	 */
>> +	if (adapter->hw.api_version != ixgbe_mbox_api_12 ||
>> +	    adapter->hw.mac.type >= ixgbe_mac_X550_vf)
>> +		return -EPERM;

By the way, since u've commented on the return codes in PATCH02 don't u 
think that we should return -EOPNOTSUPP here too?

>> +
>> +	spin_lock_bh(&adapter->mbx_lock);
>> +	err = ixgbevf_get_reta_locked(&adapter->hw, msgbuf, reta);
>> +	spin_unlock_bh(&adapter->mbx_lock);
>> +
>> +	return err;
>> +}
>> +
> You really shouldn't be pushing the lock down to this level.  The caller
> should be one to hold the mailbox lock.  Also the functions at this
> level are normally only passed the hardware struct, not the adapter
> struct as most of this code is meant to be usable in other OSes such as
> FreeBSD and the Linux spin_lock calls are not generic across OSes.
>
>>   /**
>>    *  ixgbevf_set_rar_vf - set device MAC address
>>    *  @hw: pointer to hardware structure
>> @@ -545,6 +620,7 @@ int ixgbevf_get_queues(struct ixgbe_hw *hw, unsigned int *num_tcs,
>>   	/* do nothing if API doesn't support ixgbevf_get_queues */
>>   	switch (hw->api_version) {
>>   	case ixgbe_mbox_api_11:
>> +	case ixgbe_mbox_api_12:
>>   		break;
>>   	default:
>>   		return 0;
>> diff --git a/drivers/net/ethernet/intel/ixgbevf/vf.h b/drivers/net/ethernet/intel/ixgbevf/vf.h
>> index 6688250..7944962 100644
>> --- a/drivers/net/ethernet/intel/ixgbevf/vf.h
>> +++ b/drivers/net/ethernet/intel/ixgbevf/vf.h
>> @@ -38,6 +38,7 @@
>>   #include "mbx.h"
>>   
>>   struct ixgbe_hw;
>> +struct ixgbevf_adapter;
>>   
>>   /* iterator type for walking multicast address lists */
>>   typedef u8* (*ixgbe_mc_addr_itr) (struct ixgbe_hw *hw, u8 **mc_addr_ptr,
>> @@ -210,4 +211,5 @@ void ixgbevf_rlpml_set_vf(struct ixgbe_hw *hw, u16 max_size);
>>   int ixgbevf_negotiate_api_version(struct ixgbe_hw *hw, int api);
>>   int ixgbevf_get_queues(struct ixgbe_hw *hw, unsigned int *num_tcs,
>>   		       unsigned int *default_tc);
>> +int ixgbevf_get_reta(struct ixgbevf_adapter *adapter, u32 *reta);
>>   #endif /* __IXGBE_VF_H__ */
>>