ixgbe: Enable jumbo frames support w/ SR-IOV

This change makes it so that we can have limited support for jumbo frames
when SR-IOV is enabled.  In order to accomplish this it is necessary to
disable all VFs when the PF has jumbo frames enabled.  If the VFs then
request the same maximum frame size as the PF they will be re-enabled.  A
follow on patch will add a means of identifying when a VF can support
spanning buffers and does not need to be worried about the actual supported
max frame size.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Tested-by: Robert Garrett <robertx.e.garrett@intel.com>
Tested-by: Sibai Li <Sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c

@@ -800,6 +800,10 @@ int ixgbe_fcoe_enable(struct net_device *netdev)
 		return -EINVAL;
 
 	e_info(drv, "Enabling FCoE offload features.\n");
+
+	if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)
+		e_warn(probe, "Enabling FCoE on PF will disable legacy VFs\n");
+
 	if (netif_running(netdev))
 		netdev->netdev_ops->ndo_stop(netdev);
 

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -3263,6 +3263,11 @@ static void ixgbe_set_rx_buffer_len(struct ixgbe_adapter *adapter)
 		max_frame = IXGBE_FCOE_JUMBO_FRAME_SIZE;
 
 #endif /* IXGBE_FCOE */
+
+	/* adjust max frame to be at least the size of a standard frame */
+	if (max_frame < (ETH_FRAME_LEN + ETH_FCS_LEN))
+		max_frame = (ETH_FRAME_LEN + ETH_FCS_LEN);
+
 	mhadd = IXGBE_READ_REG(hw, IXGBE_MHADD);
 	if (max_frame != (mhadd >> IXGBE_MHADD_MFS_SHIFT)) {
 		mhadd &= ~IXGBE_MHADD_MFS_MASK;
@@ -4828,14 +4833,14 @@ static int ixgbe_change_mtu(struct net_device *netdev, int new_mtu)
 		return -EINVAL;
 
 	/*
-	 * For 82599EB we cannot allow PF to change MTU greater than 1500
-	 * in SR-IOV mode as it may cause buffer overruns in guest VFs that
-	 * don't allocate and chain buffers correctly.
+	 * For 82599EB we cannot allow legacy VFs to enable their receive
+	 * paths when MTU greater than 1500 is configured.  So display a
+	 * warning that legacy VFs will be disabled.
 	 */
 	if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) &&
 	    (adapter->hw.mac.type == ixgbe_mac_82599EB) &&
 	    (max_frame > MAXIMUM_ETHERNET_VLAN_SIZE))
-			return -EINVAL;
+		e_warn(probe, "Setting MTU > 1500 will disable legacy VFs\n");
 
 	e_info(probe, "changing MTU from %d to %d\n", netdev->mtu, new_mtu);
 

drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c

@@ -150,16 +150,6 @@ void ixgbe_enable_sriov(struct ixgbe_adapter *adapter,
 		adapter->flags2 &= ~(IXGBE_FLAG2_RSC_CAPABLE |
 				     IXGBE_FLAG2_RSC_ENABLED);
 
-#ifdef IXGBE_FCOE
-		/*
-		 * When SR-IOV is enabled 82599 cannot support jumbo frames
-		 * so we must disable FCoE because we cannot support FCoE MTU.
-		 */
-		if (adapter->hw.mac.type == ixgbe_mac_82599EB)
-			adapter->flags &= ~(IXGBE_FLAG_FCOE_ENABLED |
-					    IXGBE_FLAG_FCOE_CAPABLE);
-#endif
-
 		/* enable spoof checking for all VFs */
 		for (i = 0; i < adapter->num_vfs; i++)
 			adapter->vfinfo[i].spoofchk_enabled = true;
@@ -353,31 +343,77 @@ static int ixgbe_set_vf_vlan(struct ixgbe_adapter *adapter, int add, int vid,
 	return adapter->hw.mac.ops.set_vfta(&adapter->hw, vid, vf, (bool)add);
 }
 
-static void ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 *msgbuf)
+static s32 ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
 {
 	struct ixgbe_hw *hw = &adapter->hw;
-	int new_mtu = msgbuf[1];
+	int max_frame = msgbuf[1];
 	u32 max_frs;
-	int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
 
-	/* Only X540 supports jumbo frames in IOV mode */
-	if (adapter->hw.mac.type != ixgbe_mac_X540)
-		return;
+	/*
+	 * For 82599EB we have to keep all PFs and VFs operating with
+	 * the same max_frame value in order to avoid sending an oversize
+	 * frame to a VF.  In order to guarantee this is handled correctly
+	 * for all cases we have several special exceptions to take into
+	 * account before we can enable the VF for receive
+	 */
+	if (adapter->hw.mac.type == ixgbe_mac_82599EB) {
+		struct net_device *dev = adapter->netdev;
+		int pf_max_frame = dev->mtu + ETH_HLEN;
+		u32 reg_offset, vf_shift, vfre;
+		s32 err = 0;
+
+#ifdef CONFIG_FCOE
+		if (dev->features & NETIF_F_FCOE_MTU)
+			pf_max_frame = max_t(int, pf_max_frame,
+					     IXGBE_FCOE_JUMBO_FRAME_SIZE);
+
+#endif /* CONFIG_FCOE */
+		/*
+		 * If the PF or VF are running w/ jumbo frames enabled we
+		 * need to shut down the VF Rx path as we cannot support
+		 * jumbo frames on legacy VFs
+		 */
+		if ((pf_max_frame > ETH_FRAME_LEN) ||
+		    (max_frame > (ETH_FRAME_LEN + ETH_FCS_LEN)))
+			err = -EINVAL;
+
+		/* determine VF receive enable location */
+		vf_shift = vf % 32;
+		reg_offset = vf / 32;
+
+		/* enable or disable receive depending on error */
+		vfre = IXGBE_READ_REG(hw, IXGBE_VFRE(reg_offset));
+		if (err)
+			vfre &= ~(1 << vf_shift);
+		else
+			vfre |= 1 << vf_shift;
+		IXGBE_WRITE_REG(hw, IXGBE_VFRE(reg_offset), vfre);
+
+		if (err) {
+			e_err(drv, "VF max_frame %d out of range\n", max_frame);
+			return err;
+		}
+	}
 
 	/* MTU < 68 is an error and causes problems on some kernels */
-	if ((new_mtu < 68) || (max_frame > IXGBE_MAX_JUMBO_FRAME_SIZE)) {
-		e_err(drv, "VF mtu %d out of range\n", new_mtu);
-		return;
+	if (max_frame > IXGBE_MAX_JUMBO_FRAME_SIZE) {
+		e_err(drv, "VF max_frame %d out of range\n", max_frame);
+		return -EINVAL;
 	}
 
-	max_frs = (IXGBE_READ_REG(hw, IXGBE_MAXFRS) &
-		   IXGBE_MHADD_MFS_MASK) >> IXGBE_MHADD_MFS_SHIFT;
-	if (max_frs < new_mtu) {
-		max_frs = new_mtu << IXGBE_MHADD_MFS_SHIFT;
+	/* pull current max frame size from hardware */
+	max_frs = IXGBE_READ_REG(hw, IXGBE_MAXFRS);
+	max_frs &= IXGBE_MHADD_MFS_MASK;
+	max_frs >>= IXGBE_MHADD_MFS_SHIFT;
+
+	if (max_frs < max_frame) {
+		max_frs = max_frame << IXGBE_MHADD_MFS_SHIFT;
 		IXGBE_WRITE_REG(hw, IXGBE_MAXFRS, max_frs);
 	}
 
-	e_info(hw, "VF requests change max MTU to %d\n", new_mtu);
+	e_info(hw, "VF requests change max MTU to %d\n", max_frame);
+
+	return 0;
 }
 
 static void ixgbe_set_vmolr(struct ixgbe_hw *hw, u32 vf, bool aupe)
@@ -532,11 +568,28 @@ static inline void ixgbe_vf_reset_msg(struct ixgbe_adapter *adapter, u32 vf)
 
 	/* enable transmit and receive for vf */
 	reg = IXGBE_READ_REG(hw, IXGBE_VFTE(reg_offset));
-	reg |= (reg | (1 << vf_shift));
+	reg |= 1 << vf_shift;
 	IXGBE_WRITE_REG(hw, IXGBE_VFTE(reg_offset), reg);
 
 	reg = IXGBE_READ_REG(hw, IXGBE_VFRE(reg_offset));
-	reg |= (reg | (1 << vf_shift));
+	reg |= 1 << vf_shift;
+	/*
+	 * The 82599 cannot support a mix of jumbo and non-jumbo PF/VFs.
+	 * For more info take a look at ixgbe_set_vf_lpe
+	 */
+	if (adapter->hw.mac.type == ixgbe_mac_82599EB) {
+		struct net_device *dev = adapter->netdev;
+		int pf_max_frame = dev->mtu + ETH_HLEN;
+
+#ifdef CONFIG_FCOE
+		if (dev->features & NETIF_F_FCOE_MTU)
+			pf_max_frame = max_t(int, pf_max_frame,
+					     IXGBE_FCOE_JUMBO_FRAME_SIZE);
+
+#endif /* CONFIG_FCOE */
+		if (pf_max_frame > ETH_FRAME_LEN)
+			reg &= ~(1 << vf_shift);
+	}
 	IXGBE_WRITE_REG(hw, IXGBE_VFRE(reg_offset), reg);
 
 	/* Enable counting of spoofed packets in the SSVPC register */
@@ -633,7 +686,7 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
 		                                 hash_list, vf);
 		break;
 	case IXGBE_VF_SET_LPE:
-		ixgbe_set_vf_lpe(adapter, msgbuf);
+		retval = ixgbe_set_vf_lpe(adapter, msgbuf, vf);
 		break;
 	case IXGBE_VF_SET_VLAN:
 		add = (msgbuf[0] & IXGBE_VT_MSGINFO_MASK)