bnx2x: Enlarge the dorq threshold for VFs

A malicious VF might try to starve the other VFs & PF by creating
contineous doorbell floods. In order to negate this, HW has a threshold of
doorbells per client, which will stop the client doorbells from arriving
if crossed.

The threshold currently configured for VFs is too low - under extreme traffic
scenarios, it's possible for a VF to reach the threshold and thus for its
fastpath to stop working.
Signed-off-by: Ariel Elior <ariel.elior@qlogic.com>
Signed-off-by: Yuval Mintz <yuval.mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c

@@ -1071,8 +1071,10 @@ void bnx2x_iov_init_dq(struct bnx2x *bp)
 	REG_WR(bp, DORQ_REG_VF_TYPE_MIN_MCID_0, 0);
 	REG_WR(bp, DORQ_REG_VF_TYPE_MAX_MCID_0, 0x1ffff);
 
-	/* set the VF doorbell threshold */
-	REG_WR(bp, DORQ_REG_VF_USAGE_CT_LIMIT, 4);
+	/* set the VF doorbell threshold. This threshold represents the amount
+	 * of doorbells allowed in the main DORQ fifo for a specific VF.
+	 */
+	REG_WR(bp, DORQ_REG_VF_USAGE_CT_LIMIT, 64);
 }
 
 void bnx2x_iov_init_dmae(struct bnx2x *bp)