Two aways to set mac address of SR-IOV VF

/**
 * igbvf_set_mac - Change the Ethernet Address of the NIC
 * @netdev: network interface device structure
 * @p: pointer to an address structure
 *
 * Returns 0 on success, negative on failure
 **/
static int igbvf_set_mac(struct net_device *netdev, void *p)
{
	struct igbvf_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	struct sockaddr *addr = p;

	if (!is_valid_ether_addr(addr->sa_data))
		return -EADDRNOTAVAIL;

	memcpy(hw->mac.addr, addr->sa_data, netdev->addr_len);

	hw->mac.ops.rar_set(hw, hw->mac.addr, 0); ///e1000_rar_set_vf

	if (memcmp(addr->sa_data, hw->mac.addr, 6))
		return -EADDRNOTAVAIL;

	memcpy(netdev->dev_addr, addr->sa_data, netdev->addr_len); 

	return 0;
}

/**
 *  e1000_rar_set_vf - set device MAC address
 *  @hw: pointer to the HW structure
 *  @addr: pointer to the receive address
 *  @index: receive address array register
 **/
static void e1000_rar_set_vf(struct e1000_hw *hw, u8 * addr, u32 index)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	u32 msgbuf[3];
	u8 *msg_addr = (u8 *)(&msgbuf[1]);
	s32 ret_val;

	memset(msgbuf, 0, 12);
	msgbuf[0] = E1000_VF_SET_MAC_ADDR;
	memcpy(msg_addr, addr, 6);
	ret_val = mbx->ops.write_posted(hw, msgbuf, 3);

	if (!ret_val)
		ret_val = mbx->ops.read_posted(hw, msgbuf, 3); ///e1000_read_posted_mbx

	msgbuf[0] &= ~E1000_VT_MSGTYPE_CTS;

	/* if nacked the address was rejected, use "perm_addr" */
	if (!ret_val &&
	    (msgbuf[0] == (E1000_VF_SET_MAC_ADDR | E1000_VT_MSGTYPE_NACK)))
		e1000_read_mac_addr_vf(hw);
}

/**
 *  e1000_read_mac_addr_vf - Read device MAC address
 *  @hw: pointer to the HW structure
 **/
static s32 e1000_read_mac_addr_vf(struct e1000_hw *hw)
{
	memcpy(hw->mac.addr, hw->mac.perm_addr, ETH_ALEN);

	return E1000_SUCCESS;
}

static void igb_rcv_msg_from_vf(struct igb_adapter *adapter, u32 vf)
{
///...
	retval = igb_read_mbx(hw, msgbuf, E1000_VFMAILBOX_SIZE, vf);

	switch ((msgbuf[0] & 0xFFFF)) {
	case E1000_VF_SET_MAC_ADDR:
		retval = -EINVAL;
		if (!(vf_data->flags & IGB_VF_FLAG_PF_SET_MAC))
			retval = igb_set_vf_mac_addr(adapter, msgbuf, vf);
		else
			dev_warn(&pdev->dev,
				 "VF %d attempted to override administratively set MAC address\nReload the VF driver to resume operations\n",
				 vf);
		break;

	msgbuf[0] |= E1000_VT_MSGTYPE_CTS;
out:
	/* notify the VF of the results of what it sent us */
	if (retval)
		msgbuf[0] |= E1000_VT_MSGTYPE_NACK; ///PF更新MAC失败
	else
		msgbuf[0] |= E1000_VT_MSGTYPE_ACK;

	igb_write_mbx(hw, msgbuf, 1, vf);
}

static int igb_set_vf_mac(struct igb_adapter *adapter,
			  int vf, unsigned char *mac_addr)
{
	struct e1000_hw *hw = &adapter->hw;
	/* VF MAC addresses start at end of receive addresses and moves
	 * towards the first, as a result a collision should not be possible
	 */
	int rar_entry = hw->mac.rar_entry_count - (vf + 1);

	memcpy(adapter->vf_data[vf].vf_mac_addresses, mac_addr, ETH_ALEN);

	igb_rar_set_qsel(adapter, mac_addr, rar_entry, vf);

	return 0;
}

static int igb_ndo_set_vf_mac(struct net_device *netdev, int vf, u8 *mac)
{
	struct igb_adapter *adapter = netdev_priv(netdev);
	if (!is_valid_ether_addr(mac) || (vf >= adapter->vfs_allocated_count))
		return -EINVAL;
	adapter->vf_data[vf].flags |= IGB_VF_FLAG_PF_SET_MAC;
	dev_info(&adapter->pdev->dev, "setting MAC %pM on VF %d\n", mac, vf);
	dev_info(&adapter->pdev->dev,
		 "Reload the VF driver to make this change effective.");
	if (test_bit(__IGB_DOWN, &adapter->state)) {
		dev_warn(&adapter->pdev->dev,
			 "The VF MAC address has been set, but the PF device is not up.\n");
		dev_warn(&adapter->pdev->dev,
			 "Bring the PF device up before attempting to use the VF device.\n");
	}
	return igb_set_vf_mac(adapter, vf, mac);
}

static int igbvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
///...
	/*reset the controller to put the device in a known good state */
	err = hw->mac.ops.reset_hw(hw);
	if (err) {
		dev_info(&pdev->dev,
			 "PF still in reset state. Is the PF interface up?\n");
	} else {
		err = hw->mac.ops.read_mac_addr(hw); ///read MAC from PF
		if (err)
			dev_info(&pdev->dev, "Error reading MAC address.\n");
		else if (is_zero_ether_addr(adapter->hw.mac.addr))
			dev_info(&pdev->dev, "MAC address not assigned by administrator.\n");
		memcpy(netdev->dev_addr, adapter->hw.mac.addr, ///set MAC address
		       netdev->addr_len);
	}

///...
}

static void igbvf_reset(struct igbvf_adapter *adapter)
{
	struct e1000_mac_info *mac = &adapter->hw.mac;
	struct net_device *netdev = adapter->netdev;
	struct e1000_hw *hw = &adapter->hw;

	/* Allow time for pending master requests to run */
	if (mac->ops.reset_hw(hw)) ///e1000_reset_hw_vf
		dev_err(&adapter->pdev->dev, "PF still resetting\n");

	mac->ops.init_hw(hw);///e1000_init_hw_vf

	if (is_valid_ether_addr(adapter->hw.mac.addr)) {
		memcpy(netdev->dev_addr, adapter->hw.mac.addr, ///set net_device MAC
		       netdev->addr_len);
		memcpy(netdev->perm_addr, adapter->hw.mac.addr,
		       netdev->addr_len);
	}

	adapter->last_reset = jiffies;
}

static s32 e1000_reset_hw_vf(struct e1000_hw *hw)
{
	if (timeout) {
		/* mailbox timeout can now become active */
		mbx->timeout = E1000_VF_MBX_INIT_TIMEOUT;

		/* notify pf of vf reset completion */
		msgbuf[0] = E1000_VF_RESET;
		mbx->ops.write_posted(hw, msgbuf, 1);

		msleep(10);

		/* set our "perm_addr" based on info provided by PF */
		ret_val = mbx->ops.read_posted(hw, msgbuf, 3);
		if (!ret_val) {
			if (msgbuf[0] == (E1000_VF_RESET | E1000_VT_MSGTYPE_ACK))
				memcpy(hw->mac.perm_addr, addr, 6); ///保存MAC
			else
				ret_val = -E1000_ERR_MAC_INIT;
		}
	}

static s32 e1000_init_hw_vf(struct e1000_hw *hw)
{
	/* attempt to set and restore our mac address */
	e1000_rar_set_vf(hw, hw->mac.addr, 0); ///上面已经分析

	return E1000_SUCCESS;
}

void igbvf_down(struct igbvf_adapter *adapter)
{

///...
	igbvf_reset(adapter);
	igbvf_clean_tx_ring(adapter->tx_ring);
	igbvf_clean_rx_ring(adapter->rx_ring);
}