[net PATCH] octeontx2-pf: Fix ntuple rule creation to direct packet to VF with higher Rx queue than its PF

[Suman Ghosh <sumang@marvell.com>]

It is possible to add a ntuple rule which would like to direct packet to
a VF whose number of queues are greater/less than its PF's queue numbers.
For example a PF can have 2 Rx queues but a VF created on that PF can have
8 Rx queues. As of today, ntuple rule will reject rule because it is
checking the requested queue number against PF's number of Rx queues.
As a part of this fix if the action of a ntuple rule is to move a packet
to a VF's queue then the check is removed. Also, a debug information is
printed to aware user that it is user's responsibility to cross check if
the requested queue number on that VF is a valid one.

Fixes: f0a1913f8a6f ("octeontx2-pf: Add support for ethtool ntuple filters")
Signed-off-by: Suman Ghosh <sumang@marvell.com>
---
 .../marvell/octeontx2/nic/otx2_flows.c        | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_flows.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_flows.c
index 4762dbea64a1..4200f2d387f6 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_flows.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_flows.c
@@ -1088,6 +1088,7 @@ int otx2_add_flow(struct otx2_nic *pfvf, struct ethtool_rxnfc *nfc)
 	struct ethhdr *eth_hdr;
 	bool new = false;
 	int err = 0;
+	u64 vf_num;
 	u32 ring;
 
 	if (!flow_cfg->max_flows) {
@@ -1100,9 +1101,26 @@ int otx2_add_flow(struct otx2_nic *pfvf, struct ethtool_rxnfc *nfc)
 	if (!(pfvf->flags & OTX2_FLAG_NTUPLE_SUPPORT))
 		return -ENOMEM;
 
+	/* Number of queues on a VF can be greater or less than
+	 * the PF's queue. Hence no need to check for the
+	 * queue count. Hence no need to check queue count if PF
+	 * is installing for its VF. Below is the expected vf_num value
+	 * based on the ethtool commands.
+	 *
+	 * e.g.
+	 * 1. ethtool -U <netdev> ... action -1  ==> vf_num:255
+	 * 2. ethtool -U <netdev> ... action <queue_num>  ==> vf_num:0
+	 * 3. ethtool -U <netdev> ... vf <vf_idx> queue <queue_num>  ==>
+	 *    vf_num:vf_idx+1
+	 */
+	vf_num = ethtool_get_flow_spec_ring_vf(fsp->ring_cookie);
+	if (!is_otx2_vf(pfvf->pcifunc) && vf_num)
+		goto bypass_queue_check;
+
 	if (ring >= pfvf->hw.rx_queues && fsp->ring_cookie != RX_CLS_FLOW_DISC)
 		return -EINVAL;
 
+bypass_queue_check:
 	if (fsp->location >= otx2_get_maxflows(flow_cfg))
 		return -EINVAL;
 
@@ -1182,6 +1200,9 @@ int otx2_add_flow(struct otx2_nic *pfvf, struct ethtool_rxnfc *nfc)
 		flow_cfg->nr_flows++;
 	}
 
+	if (flow->is_vf)
+		netdev_info(pfvf->netdev,
+			    "Make sure that VF's queue number is within its queue limit\n");
 	return 0;
 }
 
-- 
2.25.1