ixgbe: fix large MTU request from VF

Check that the MTU value requested by the VF is in the supported
range of MTUs before attempting to set the VF large packet enable,
otherwise reject the request. This also avoids unnecessary
register updates in the case of the 82599 controller.

Fixes: 872844d ("ixgbe: Enable jumbo frames support w/ SR-IOV")
Co-developed-by: Piotr Skajewski <piotrx.skajewski@intel.com>
Signed-off-by: Piotr Skajewski <piotrx.skajewski@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Co-developed-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -467,12 +467,16 @@ static int ixgbe_set_vf_vlan(struct ixgbe_adapter *adapter, int add, int vid,
 	return err;
 }
 
-static s32 ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
+static int ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 max_frame, u32 vf)
 {
 	struct ixgbe_hw *hw = &adapter->hw;
-	int max_frame = msgbuf[1];
 	u32 max_frs;
 
+	if (max_frame < ETH_MIN_MTU || max_frame > IXGBE_MAX_JUMBO_FRAME_SIZE) {
+		e_err(drv, "VF max_frame %d out of range\n", max_frame);
+		return -EINVAL;
+	}
+
 	/*
 	 * For 82599EB we have to keep all PFs and VFs operating with
 	 * the same max_frame value in order to avoid sending an oversize
@@ -533,12 +537,6 @@ static s32 ixgbe_set_vf_lpe(struct ixgbe_adapter *adapter, u32 *msgbuf, u32 vf)
 		}
 	}
 
-	/* MTU < 68 is an error and causes problems on some kernels */
-	if (max_frame > IXGBE_MAX_JUMBO_FRAME_SIZE) {
-		e_err(drv, "VF max_frame %d out of range\n", max_frame);
-		return -EINVAL;
-	}
-
 	/* pull current max frame size from hardware */
 	max_frs = IXGBE_READ_REG(hw, IXGBE_MAXFRS);
 	max_frs &= IXGBE_MHADD_MFS_MASK;
@@ -1249,7 +1247,7 @@ static int ixgbe_rcv_msg_from_vf(struct ixgbe_adapter *adapter, u32 vf)
 		retval = ixgbe_set_vf_vlan_msg(adapter, msgbuf, vf);
 		break;
 	case IXGBE_VF_SET_LPE:
-		retval = ixgbe_set_vf_lpe(adapter, msgbuf, vf);
+		retval = ixgbe_set_vf_lpe(adapter, msgbuf[1], vf);
 		break;
 	case IXGBE_VF_SET_MACVLAN:
 		retval = ixgbe_set_vf_macvlan_msg(adapter, msgbuf, vf);