ixgbe: disallow IPsec Tx offload when in SR-IOV mode

[ Upstream commit 47b6f50077e68bcd544f657526dad4bfdce7e87d ]

There seems to be a problem in the x540's internal switch wherein if SR-IOV
mode is enabled and an offloaded IPsec packet is sent to a local VF,
the packet is silently dropped.  This might never be a problem as it is
somewhat a corner case, but if someone happens to be using IPsec offload
from the PF to a VF that just happens to get migrated to the local box,
communication will mysteriously fail.

Not good.

A simple way to protect from this is to simply not allow any IPsec offloads
for outgoing packets when num_vfs != 0.  This doesn't help any offloads that
were created before SR-IOV was enabled, but we'll get to that later.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
index da4322e..add124e 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
@@ -676,6 +676,9 @@ static int ixgbe_ipsec_add_sa(struct xfrm_state *xs)
        } else {
                struct tx_sa tsa;
 
+               if (adapter->num_vfs)
+                       return -EOPNOTSUPP;
+
                /* find the first unused index */
                ret = ixgbe_ipsec_find_empty_idx(ipsec, false);
                if (ret < 0) {