patch 'net/sfc: stop misuse of Rx ingress m-port metadata on EF100' has been queued to stable release 22.11.3

[Xueming Li <xuemingl@nvidia.com>]

Hi,

FYI, your patch has been queued to stable release 22.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 06/27/23. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://git.dpdk.org/dpdk-stable/log/?h=22.11-staging

This queued commit can be viewed at:
https://git.dpdk.org/dpdk-stable/commit/?h=22.11-staging&id=bd14912ab474e7dfb2b98f02a6f51ad4f58069cd

Thanks.

Xueming Li <xuemingl@nvidia.com>

---
From bd14912ab474e7dfb2b98f02a6f51ad4f58069cd Mon Sep 17 00:00:00 2001
From: Ivan Malov <ivan.malov@arknetworks.am>
Date: Wed, 12 Apr 2023 17:57:57 +0400
Subject: [PATCH] net/sfc: stop misuse of Rx ingress m-port metadata on EF100
Cc: Xueming Li <xuemingl@nvidia.com>

[ upstream commit 462c4f083c464e2d10391c78e7f67f178dbefb27 ]

The driver supports representor functionality. In it,
packets coming from VFs to the dedicated back-end Rx
queue get demultiplexed into front-end Rx queues of
representor ethdevs as per the per-packet metadata
indicating logical HW ingress ports. On transmit,
packets are provided with symmetrical metadata
by front-end Tx queues, and the back-end queue
transforms the data into so-called Tx override
descriptors. These let the packets bypass flow
lookup and go directly to the represented VFs.

However, in the Rx part, the driver extracts
the said metadata on every HW Rx queue, that
is, not just on the one used by representors.
Doing so leads to a buggy behaviour. It is
revealed by operating testpmd as follows:

dpdk-testpmd -a 0000:c6:00.0 -a 0000:c6:00.1 -- -i

testpmd> flow create 0 transfer pattern port_representor \
 port_id is 0 / end actions port_representor port_id 1 / end
Flow rule #0 created

testpmd> set fwd io
testpmd> start tx_first

testpmd> flow destroy 0 rule 0
Flow rule #0 destroyed

testpmd> stop

  ---------------------- Forward statistics for port 0  -----------------
  RX-packets: 19196498       RX-dropped: 0             RX-total: 19196498
  TX-packets: 19196535       TX-dropped: 0             TX-total: 19196535
  -----------------------------------------------------------------------

  ---------------------- Forward statistics for port 1  -----------------
  RX-packets: 19196503       RX-dropped: 0             RX-total: 19196503
  TX-packets: 19196530       TX-dropped: 0             TX-total: 19196530
  -----------------------------------------------------------------------

In this scenario, two physical functions of the adapter
do not have any corresponding "back-to-back" forwarder
on peer host. Packets transmitted from port 0 can only
be forwarded to port 1 by means of a special flow rule.

The flow rule indeed works, but destroying it does not
stop forwarding. Port statistics carry on incrementing.

Also, it is apparent that forwarding in the opposite
direction must not have worked in this case as the
flow is meant to target only one of the directions.

Because of the bug, the first 32 mbufs received
as a result of the flow rule operation have the
said metadata present. In io mode, testpmd does
not tamper with mbufs and passes them directly
to transmit path, so this data remains in them
instructing the PMD to override destinations
of the packets via Tx option descriptors.

Expected behaviour is as follows:

  ---------------------- Forward statistics for port 0  -----------------
  RX-packets: 0              RX-dropped: 0             RX-total: 0
  TX-packets: 15787496       TX-dropped: 0             TX-total: 15787496
  -----------------------------------------------------------------------

  ---------------------- Forward statistics for port 1  -----------------
  RX-packets: 15787464       RX-dropped: 0             RX-total: 15787464
  TX-packets: 32             TX-dropped: 0             TX-total: 32
  -----------------------------------------------------------------------

These figures show the rule work only for one direction.
Also, removing the flow shall cause forwarding to cease.

Provided patch fixes the bug accordingly.

Fixes: d0f981a3efd8 ("net/sfc: handle ingress mport in EF100 Rx prefix")

Signed-off-by: Ivan Malov <ivan.malov@arknetworks.am>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/sfc/sfc_dp_rx.h    |  1 +
 drivers/net/sfc/sfc_ef100_rx.c | 18 ++++++++++++++----
 drivers/net/sfc/sfc_rx.c       |  3 +++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/net/sfc/sfc_dp_rx.h b/drivers/net/sfc/sfc_dp_rx.h
index 246adbd87c..8a504bdcf1 100644
--- a/drivers/net/sfc/sfc_dp_rx.h
+++ b/drivers/net/sfc/sfc_dp_rx.h
@@ -69,6 +69,7 @@ struct sfc_dp_rx_qcreate_info {
 	/** Receive queue flags initializer */
 	unsigned int		flags;
 #define SFC_RXQ_FLAG_RSS_HASH	0x1
+#define SFC_RXQ_FLAG_INGRESS_MPORT	0x2
 
 	/** Rx queue size */
 	unsigned int		rxq_entries;
diff --git a/drivers/net/sfc/sfc_ef100_rx.c b/drivers/net/sfc/sfc_ef100_rx.c
index 16cd8524d3..37b754fa33 100644
--- a/drivers/net/sfc/sfc_ef100_rx.c
+++ b/drivers/net/sfc/sfc_ef100_rx.c
@@ -810,6 +810,9 @@ sfc_ef100_rx_qcreate(uint16_t port_id, uint16_t queue_id,
 	if (rxq->nic_dma_info->nb_regions > 0)
 		rxq->flags |= SFC_EF100_RXQ_NIC_DMA_MAP;
 
+	if (info->flags & SFC_RXQ_FLAG_INGRESS_MPORT)
+		rxq->flags |= SFC_EF100_RXQ_INGRESS_MPORT;
+
 	sfc_ef100_rx_debug(rxq, "RxQ doorbell is %p", rxq->doorbell);
 
 	*dp_rxqp = &rxq->dp;
@@ -876,11 +879,18 @@ sfc_ef100_rx_qstart(struct sfc_dp_rxq *dp_rxq, unsigned int evq_read_ptr,
 	else
 		rxq->flags &= ~SFC_EF100_RXQ_USER_MARK;
 
+
+	/*
+	 * At the moment, this feature is used only
+	 * by the representor proxy Rx queue and is
+	 * essential for representor support, so if
+	 * it has been requested but is unsupported,
+	 * point this inconsistency out to the user.
+	 */
 	if ((unsup_rx_prefix_fields &
-	     (1U << EFX_RX_PREFIX_FIELD_INGRESS_MPORT)) == 0)
-		rxq->flags |= SFC_EF100_RXQ_INGRESS_MPORT;
-	else
-		rxq->flags &= ~SFC_EF100_RXQ_INGRESS_MPORT;
+	     (1U << EFX_RX_PREFIX_FIELD_INGRESS_MPORT)) &&
+	    (rxq->flags & SFC_EF100_RXQ_INGRESS_MPORT))
+		return ENOTSUP;
 
 	rxq->prefix_size = pinfo->erpl_length;
 	rxq->rearm_data = sfc_ef100_mk_mbuf_rearm_data(rxq->dp.dpq.port_id,
diff --git a/drivers/net/sfc/sfc_rx.c b/drivers/net/sfc/sfc_rx.c
index 5ea98187c3..edd0f0c038 100644
--- a/drivers/net/sfc/sfc_rx.c
+++ b/drivers/net/sfc/sfc_rx.c
@@ -1225,6 +1225,9 @@ sfc_rx_qinit(struct sfc_adapter *sa, sfc_sw_index_t sw_index,
 	else
 		rxq_info->rxq_flags = 0;
 
+	if (rxq_info->type_flags & EFX_RXQ_FLAG_INGRESS_MPORT)
+		rxq_info->rxq_flags |= SFC_RXQ_FLAG_INGRESS_MPORT;
+
 	rxq->buf_size = buf_size;
 
 	rc = sfc_dma_alloc(sa, "rxq", sw_index, EFX_NIC_DMA_ADDR_RX_RING,
-- 
2.25.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2023-06-25 14:31:59.254805500 +0800
+++ 0027-net-sfc-stop-misuse-of-Rx-ingress-m-port-metadata-on.patch	2023-06-25 14:31:58.305773900 +0800
@@ -1 +1 @@
-From 462c4f083c464e2d10391c78e7f67f178dbefb27 Mon Sep 17 00:00:00 2001
+From bd14912ab474e7dfb2b98f02a6f51ad4f58069cd Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl@nvidia.com>
+
+[ upstream commit 462c4f083c464e2d10391c78e7f67f178dbefb27 ]
@@ -85 +87,0 @@
-Cc: stable@dpdk.org