net/ixgbe: fix broadcast Rx on VF after promisc removal

[ upstream commit 8260929 ]

After a VF requested to remove the promiscuous flag on an interface, the
broadcast packets are not received anymore. This breaks some protocols
like ARP.

In ixgbe_update_vf_xcast_mode(), we should keep the IXGBE_VMOLR_BAM
bit (Broadcast Accept) on promiscuous removal. This flag is already set
by default in ixgbe_vf_reset_event() on VF reset.

A similar patch was accepted in Linux kernel (see link).
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=803e9895ea2b

Fixes: 0355c37 ("net/ixgbe: support VF promiscuous by PF driver")

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Wenjun Wu <wenjun1.wu@intel.com>

drivers/net/ixgbe/ixgbe_pf.c

@@ -747,9 +747,9 @@ ixgbe_set_vf_mc_promisc(struct rte_eth_dev *dev, uint32_t vf, uint32_t *msgbuf)
 
 	switch (xcast_mode) {
 	case IXGBEVF_XCAST_MODE_NONE:
-		disable = IXGBE_VMOLR_BAM | IXGBE_VMOLR_ROMPE |
+		disable = IXGBE_VMOLR_ROMPE |
 			  IXGBE_VMOLR_MPE | IXGBE_VMOLR_UPE | IXGBE_VMOLR_VPE;
-		enable = 0;
+		enable = IXGBE_VMOLR_BAM;
 		break;
 	case IXGBEVF_XCAST_MODE_MULTI:
 		disable = IXGBE_VMOLR_MPE | IXGBE_VMOLR_UPE | IXGBE_VMOLR_VPE;