ice: Check if unicast MAC exists before setting VF MAC

Currently if a unicast MAC is set via ndo_set_vf_mac, the PF driver will
set the VF's dflt_lan_addr.addr once some basic checks have passed. The
VF is then reset. During reset the PF driver will attempt to program the
VF's MAC from the dflt_lan_addr.addr field. This fails when the MAC
already exists on the PF's switch.

This is causing the VF to be completely disabled until removing/enabling
any VFs via sysfs.

Fix this by checking if the unicast MAC exists before triggering a VF
reset directly in ndo_set_vf_mac. Also, add a check if the unicast MAC
is set to the same value as before and return 0 if that is the case.

Signed-off-by: Brett Creeley <[email protected]>
Tested-by: Andrew Bowers <[email protected]>
Signed-off-by: Jeff Kirsher <[email protected]>

Author: bcreeley13

drivers/net/ethernet/intel/ice/ice_virtchnl_pf.c

@@ -3640,6 +3640,39 @@ ice_get_vf_cfg(struct net_device *netdev, int vf_id, struct ifla_vf_info *ivi)
 	return 0;
 }
 
+/**
+ * ice_unicast_mac_exists - check if the unicast MAC exists on the PF's switch
+ * @pf: PF used to reference the switch's rules
+ * @umac: unicast MAC to compare against existing switch rules
+ *
+ * Return true on the first/any match, else return false
+ */
+static bool ice_unicast_mac_exists(struct ice_pf *pf, u8 *umac)
+{
+	struct ice_sw_recipe *mac_recipe_list =
+		&pf->hw.switch_info->recp_list[ICE_SW_LKUP_MAC];
+	struct ice_fltr_mgmt_list_entry *list_itr;
+	struct list_head *rule_head;
+	struct mutex *rule_lock; /* protect MAC filter list access */
+
+	rule_head = &mac_recipe_list->filt_rules;
+	rule_lock = &mac_recipe_list->filt_rule_lock;
+
+	mutex_lock(rule_lock);
+	list_for_each_entry(list_itr, rule_head, list_entry) {
+		u8 *existing_mac = &list_itr->fltr_info.l_data.mac.mac_addr[0];
+
+		if (ether_addr_equal(existing_mac, umac)) {
+			mutex_unlock(rule_lock);
+			return true;
+		}
+	}
+
+	mutex_unlock(rule_lock);
+
+	return false;
+}
+
 /**
  * ice_set_vf_mac
  * @netdev: network interface device structure
@@ -3663,10 +3696,20 @@ int ice_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 	}
 
 	vf = &pf->vf[vf_id];
+	/* nothing left to do, unicast MAC already set */
+	if (ether_addr_equal(vf->dflt_lan_addr.addr, mac))
+		return 0;
+
 	ret = ice_check_vf_ready_for_cfg(vf);
 	if (ret)
 		return ret;
 
+	if (ice_unicast_mac_exists(pf, mac)) {
+		netdev_err(netdev, "Unicast MAC %pM already exists on this PF. Preventing setting VF %u unicast MAC address to %pM\n",
+			   mac, vf_id, mac);
+		return -EINVAL;
+	}
+
 	/* copy MAC into dflt_lan_addr and trigger a VF reset. The reset
 	 * flow will use the updated dflt_lan_addr and add a MAC filter
 	 * using ice_add_mac. Also set pf_set_mac to indicate that the PF has