[PATCH] app/testpmd: skip stopped queues when forwarding

[Dmitry Kozlyuk <dkozlyuk@nvidia.com>]

After "port <port_id> rxq|txq <queue_id> stop"
the stopped queue was used in forwarding nonetheless,
which may cause undefined behavior in the PMD.

Record the configured queue state
and account for it when launching forwarding as follows:
+--------+---------+-----------------+---------------+
|RxQ     |TxQ      |Configured mode  |Launch routine |
+--------+---------+-----------------+---------------+
|stopped |stopped  |*                |-              |
|stopped |started  |txonly           |(configured)   |
|stopped |started  |*                |-              |
|started |stopped  |*                |rxonly         |
|started |started  |*                |(configured)   |
+--------+---------+-----------------+---------------+
Display stopped queues on "show port config rxtx".

Fixes: 5f4ec54f1d16 ("testpmd: queue start and stop")
Cc: jing.d.chen@intel.com
Cc: stable@dpdk.org

Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Reviewed-by: Raslan Darawsheh <rasland@nvidia.com>
---
 app/test-pmd/cmdline.c |  8 ++++++++
 app/test-pmd/config.c  |  6 ++++++
 app/test-pmd/testpmd.c | 18 ++++++++++++++++--
 app/test-pmd/testpmd.h | 10 ++++++++++
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
index e626b1c7d9..8b0920e23d 100644
--- a/app/test-pmd/cmdline.c
+++ b/app/test-pmd/cmdline.c
@@ -2702,6 +2702,14 @@ cmd_config_rxtx_queue_parsed(void *parsed_result,
 
 	if (ret == -ENOTSUP)
 		fprintf(stderr, "Function not supported in PMD\n");
+	if (ret == 0) {
+		struct rte_port *port;
+		struct queue_state *states;
+
+		port = &ports[res->portid];
+		states = isrx ? port->rxq_state : port->txq_state;
+		states[res->qid].stopped = !isstart;
+	}
 }
 
 cmdline_parse_token_string_t cmd_config_rxtx_queue_port =
diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 1722d6c8f8..7ce9cb483a 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -2817,6 +2817,9 @@ rxtx_config_display(void)
 				       rx_conf->share_qid);
 			printf("\n");
 		}
+		for (qid = 0; qid < nb_rxq; qid++)
+			if (ports[pid].rxq_state[qid].stopped)
+				printf("    RX queue %d is stopped\n", qid);
 
 		/* per tx queue config only for first queue to be less verbose */
 		for (qid = 0; qid < 1; qid++) {
@@ -2850,6 +2853,9 @@ rxtx_config_display(void)
 			printf("      TX offloads=0x%"PRIx64" - TX RS bit threshold=%d\n",
 				offloads_tmp, tx_rs_thresh_tmp);
 		}
+		for (qid = 0; qid < nb_txq; qid++)
+			if (ports[pid].txq_state[qid].stopped)
+				printf("    TX queue %d is stopped\n", qid);
 	}
 }
 
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 6c387bde84..36ff845181 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2152,6 +2152,8 @@ flush_fwd_rx_queues(void)
 		for (rxp = 0; rxp < cur_fwd_config.nb_fwd_ports; rxp++) {
 			for (rxq = 0; rxq < nb_rxq; rxq++) {
 				port_id = fwd_ports_ids[rxp];
+				if (ports[port_id].rxq_state[rxq].stopped)
+					continue;
 				/**
 				* testpmd can stuck in the below do while loop
 				* if rte_eth_rx_burst() always returns nonzero
@@ -2223,8 +2225,20 @@ run_pkt_fwd_on_lcore(struct fwd_lcore *fc, packet_fwd_t pkt_fwd)
 static int
 start_pkt_forward_on_core(void *fwd_arg)
 {
-	run_pkt_fwd_on_lcore((struct fwd_lcore *) fwd_arg,
-			     cur_fwd_config.fwd_eng->packet_fwd);
+	struct fwd_lcore *fc = fwd_arg;
+	struct fwd_stream *fsm = fwd_streams[fc->stream_idx];
+	struct queue_state *rxq = &ports[fsm->rx_port].rxq_state[fsm->rx_queue];
+	struct queue_state *txq = &ports[fsm->tx_port].txq_state[fsm->tx_queue];
+	struct fwd_engine *fwd_engine = cur_fwd_config.fwd_eng;
+	packet_fwd_t packet_fwd;
+
+	/* Check if there will ever be any packets to send. */
+	if (rxq->stopped && (txq->stopped || fwd_engine != &tx_only_engine))
+		return 0;
+	/* Force rxonly mode if RxQ is started, but TxQ is stopped. */
+	packet_fwd = !rxq->stopped && txq->stopped ? rx_only_engine.packet_fwd
+						   : fwd_engine->packet_fwd;
+	run_pkt_fwd_on_lcore(fc, packet_fwd);
 	return 0;
 }
 
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index 2149ecd93a..2744fa4d76 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -216,6 +216,12 @@ struct xstat_display_info {
 	bool	 allocated;
 };
 
+/** Application state of a queue. */
+struct queue_state {
+	/** The queue is stopped and should not be used. */
+	bool stopped;
+};
+
 /**
  * The data structure associated with each port.
  */
@@ -256,6 +262,10 @@ struct rte_port {
 	uint64_t		mbuf_dynf;
 	const struct rte_eth_rxtx_callback *tx_set_dynf_cb[RTE_MAX_QUEUES_PER_PORT+1];
 	struct xstat_display_info xstats_info;
+	/** Per-Rx-queue state. */
+	struct queue_state rxq_state[RTE_MAX_QUEUES_PER_PORT];
+	/** Per-Tx-queue state. */
+	struct queue_state txq_state[RTE_MAX_QUEUES_PER_PORT];
 };
 
 /**
-- 
2.25.1