[dpdk-dev] [PATCH] net/bnxt: fix missing barriers in completion handling

[Lance Richardson]

Ensure that Rx/Tx/Async completion entry fields are accessed
only after the completion's valid flag has been loaded and
verified. This is needed for correct operation on systems that
use relaxed memory consistency models.

Fixes: 2eb53b134aae ("net/bnxt: add initial Rx code")
Fixes: 6eb3cc2294fd ("net/bnxt: add initial Tx code")
Cc: stable at dpdk.org
Signed-off-by: Lance Richardson <lance.richardson at broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde at broadcom.com>
---
 drivers/net/bnxt/bnxt_cpr.h           | 36 ++++++++++++++++++++++++---
 drivers/net/bnxt/bnxt_ethdev.c        | 16 ++++++------
 drivers/net/bnxt/bnxt_irq.c           |  7 +++---
 drivers/net/bnxt/bnxt_rxr.c           |  9 ++++---
 drivers/net/bnxt/bnxt_rxtx_vec_avx2.c |  2 +-
 drivers/net/bnxt/bnxt_rxtx_vec_neon.c |  2 +-
 drivers/net/bnxt/bnxt_rxtx_vec_sse.c  |  2 +-
 drivers/net/bnxt/bnxt_txr.c           |  2 +-
 8 files changed, 54 insertions(+), 22 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_cpr.h b/drivers/net/bnxt/bnxt_cpr.h
index 2a56ec52c..3ee6b74bc 100644
--- a/drivers/net/bnxt/bnxt_cpr.h
+++ b/drivers/net/bnxt/bnxt_cpr.h
@@ -8,13 +8,10 @@
 #include <stdbool.h>
 
 #include <rte_io.h>
+#include "hsi_struct_def_dpdk.h"
 
 struct bnxt_db_info;
 
-#define CMP_VALID(cmp, raw_cons, ring)					\
-	(!!(rte_le_to_cpu_32(((struct cmpl_base *)(cmp))->info3_v) &	\
-	    CMPL_BASE_V) == !((raw_cons) & ((ring)->ring_size)))
-
 #define CMP_TYPE(cmp)						\
 	(((struct cmpl_base *)cmp)->type & CMPL_BASE_TYPE_MASK)
 
@@ -121,4 +118,35 @@ bool bnxt_is_recovery_enabled(struct bnxt *bp);
 bool bnxt_is_master_func(struct bnxt *bp);
 
 void bnxt_stop_rxtx(struct bnxt *bp);
+
+/**
+ * Check validity of a completion ring entry. If the entry is valid, include a
+ * C11 __ATOMIC_ACQUIRE fence to ensure that subsequent loads of fields in the
+ * completion are not hoisted by the compiler or by the CPU to come before the
+ * loading of the "valid" field.
+ *
+ * Note: the caller must not access any fields in the specified completion
+ * entry prior to calling this function.
+ *
+ * @param cmp
+ *   Pointer to an entry in the completion ring.
+ * @param raw_cons
+ *   Raw consumer index of entry in completion ring.
+ * @param ring_size
+ *   Size of completion ring.
+ */
+static __rte_always_inline bool
+bnxt_cpr_cmp_valid(const void *cmpl, uint32_t raw_cons, uint32_t ring_size)
+{
+	const struct cmpl_base *c = cmpl;
+	bool expected, valid;
+
+	expected = !(raw_cons & ring_size);
+	valid = !!(rte_le_to_cpu_32(c->info3_v) & CMPL_BASE_V);
+	if (valid == expected) {
+		rte_atomic_thread_fence(__ATOMIC_ACQUIRE);
+		return true;
+	}
+	return false;
+}
 #endif
diff --git a/drivers/net/bnxt/bnxt_ethdev.c b/drivers/net/bnxt/bnxt_ethdev.c
index ed09f1bf5..ee6929692 100644
--- a/drivers/net/bnxt/bnxt_ethdev.c
+++ b/drivers/net/bnxt/bnxt_ethdev.c
@@ -3126,7 +3126,7 @@ bnxt_rx_queue_count_op(struct rte_eth_dev *dev, uint16_t rx_queue_id)
 {
 	struct bnxt *bp = (struct bnxt *)dev->data->dev_private;
 	struct bnxt_cp_ring_info *cpr;
-	uint32_t desc = 0, raw_cons;
+	uint32_t desc = 0, raw_cons, cp_ring_size;
 	struct bnxt_rx_queue *rxq;
 	struct rx_pkt_cmpl *rxcmp;
 	int rc;
@@ -3138,6 +3138,7 @@ bnxt_rx_queue_count_op(struct rte_eth_dev *dev, uint16_t rx_queue_id)
 	rxq = dev->data->rx_queues[rx_queue_id];
 	cpr = rxq->cp_ring;
 	raw_cons = cpr->cp_raw_cons;
+	cp_ring_size = cpr->cp_ring_struct->ring_size;
 
 	while (1) {
 		uint32_t agg_cnt, cons, cmpl_type;
@@ -3145,7 +3146,7 @@ bnxt_rx_queue_count_op(struct rte_eth_dev *dev, uint16_t rx_queue_id)
 		cons = RING_CMP(cpr->cp_ring_struct, raw_cons);
 		rxcmp = (struct rx_pkt_cmpl *)&cpr->cp_desc_ring[cons];
 
-		if (!CMP_VALID(rxcmp, raw_cons, cpr->cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(rxcmp, raw_cons, cp_ring_size))
 			break;
 
 		cmpl_type = CMP_TYPE(rxcmp);
@@ -3189,7 +3190,7 @@ bnxt_rx_descriptor_status_op(void *rx_queue, uint16_t offset)
 	struct bnxt_rx_queue *rxq = rx_queue;
 	struct bnxt_cp_ring_info *cpr;
 	struct bnxt_rx_ring_info *rxr;
-	uint32_t desc, raw_cons;
+	uint32_t desc, raw_cons, cp_ring_size;
 	struct bnxt *bp = rxq->bp;
 	struct rx_pkt_cmpl *rxcmp;
 	int rc;
@@ -3203,6 +3204,7 @@ bnxt_rx_descriptor_status_op(void *rx_queue, uint16_t offset)
 
 	rxr = rxq->rx_ring;
 	cpr = rxq->cp_ring;
+	cp_ring_size = cpr->cp_ring_struct->ring_size;
 
 	/*
 	 * For the vector receive case, the completion at the requested
@@ -3219,7 +3221,7 @@ bnxt_rx_descriptor_status_op(void *rx_queue, uint16_t offset)
 		cons = RING_CMP(cpr->cp_ring_struct, raw_cons);
 		rxcmp = (struct rx_pkt_cmpl *)&cpr->cp_desc_ring[cons];
 
-		if (CMP_VALID(rxcmp, raw_cons, cpr->cp_ring_struct))
+		if (bnxt_cpr_cmp_valid(rxcmp, raw_cons, cp_ring_size))
 			return RTE_ETH_RX_DESC_DONE;
 
 		/* Check whether rx desc has an mbuf attached. */
@@ -3245,7 +3247,7 @@ bnxt_rx_descriptor_status_op(void *rx_queue, uint16_t offset)
 		cons = RING_CMP(cpr->cp_ring_struct, raw_cons);
 		rxcmp = (struct rx_pkt_cmpl *)&cpr->cp_desc_ring[cons];
 
-		if (!CMP_VALID(rxcmp, raw_cons, cpr->cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(rxcmp, raw_cons, cp_ring_size))
 			break;
 
 		cmpl_type = CMP_TYPE(rxcmp);
@@ -3299,7 +3301,6 @@ bnxt_tx_descriptor_status_op(void *tx_queue, uint16_t offset)
 	struct bnxt_tx_queue *txq = (struct bnxt_tx_queue *)tx_queue;
 	struct bnxt_cp_ring_info *cpr = txq->cp_ring;
 	uint32_t ring_mask, raw_cons, nb_tx_pkts = 0;
-	struct bnxt_ring *cp_ring_struct;
 	struct cmpl_base *cp_desc_ring;
 	int rc;
 
@@ -3316,7 +3317,6 @@ bnxt_tx_descriptor_status_op(void *tx_queue, uint16_t offset)
 
 	raw_cons = cpr->cp_raw_cons;
 	cp_desc_ring = cpr->cp_desc_ring;
-	cp_ring_struct = cpr->cp_ring_struct;
 	ring_mask = cpr->cp_ring_struct->ring_mask;
 
 	/* Check to see if hw has posted a completion for the descriptor. */
@@ -3327,7 +3327,7 @@ bnxt_tx_descriptor_status_op(void *tx_queue, uint16_t offset)
 		cons = RING_CMPL(ring_mask, raw_cons);
 		txcmp = (struct tx_cmpl *)&cp_desc_ring[cons];
 
-		if (!CMP_VALID(txcmp, raw_cons, cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(txcmp, raw_cons, ring_mask + 1))
 			break;
 
 		if (CMP_TYPE(txcmp) == TX_CMPL_TYPE_TX_L2)
diff --git a/drivers/net/bnxt/bnxt_irq.c b/drivers/net/bnxt/bnxt_irq.c
index fd8b8fac9..ebdac8385 100644
--- a/drivers/net/bnxt/bnxt_irq.c
+++ b/drivers/net/bnxt/bnxt_irq.c
@@ -21,10 +21,10 @@ void bnxt_int_handler(void *param)
 {
 	struct rte_eth_dev *eth_dev = (struct rte_eth_dev *)param;
 	struct bnxt *bp = eth_dev->data->dev_private;
+	uint32_t cons, raw_cons, cp_ring_size;
 	struct bnxt_cp_ring_info *cpr;
 	struct cmpl_base *cmp;
-	uint32_t raw_cons;
-	uint32_t cons;
+
 
 	if (bp == NULL)
 		return;
@@ -33,6 +33,7 @@ void bnxt_int_handler(void *param)
 		return;
 
 	raw_cons = cpr->cp_raw_cons;
+	cp_ring_size = cpr->cp_ring_struct->ring_size;
 	pthread_mutex_lock(&bp->def_cp_lock);
 	while (1) {
 		if (!cpr || !cpr->cp_ring_struct || !cpr->cp_db.doorbell) {
@@ -48,7 +49,7 @@ void bnxt_int_handler(void *param)
 		cons = RING_CMP(cpr->cp_ring_struct, raw_cons);
 		cmp = &cpr->cp_desc_ring[cons];
 
-		if (!CMP_VALID(cmp, raw_cons, cpr->cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(cmp, raw_cons, cp_ring_size))
 			break;
 
 		bnxt_event_hwrm_resp_handler(bp, cmp);
diff --git a/drivers/net/bnxt/bnxt_rxr.c b/drivers/net/bnxt/bnxt_rxr.c
index 0dee73af8..aea71703d 100644
--- a/drivers/net/bnxt/bnxt_rxr.c
+++ b/drivers/net/bnxt/bnxt_rxr.c
@@ -297,7 +297,8 @@ static int bnxt_agg_bufs_valid(struct bnxt_cp_ring_info *cpr,
 	raw_cp_cons = ADV_RAW_CMP(raw_cp_cons, agg_bufs);
 	last_cp_cons = RING_CMP(cpr->cp_ring_struct, raw_cp_cons);
 	agg_cmpl = (struct rx_pkt_cmpl *)&cpr->cp_desc_ring[last_cp_cons];
-	return CMP_VALID(agg_cmpl, raw_cp_cons, cpr->cp_ring_struct);
+	return bnxt_cpr_cmp_valid(agg_cmpl, raw_cp_cons,
+				  cpr->cp_ring_struct->ring_size);
 }
 
 /* TPA consume agg buffer out of order, allocate connected data only */
@@ -892,7 +893,8 @@ static int bnxt_rx_pkt(struct rte_mbuf **rx_pkt,
 	cp_cons = RING_CMP(cpr->cp_ring_struct, tmp_raw_cons);
 	rxcmp1 = (struct rx_pkt_cmpl_hi *)&cpr->cp_desc_ring[cp_cons];
 
-	if (!CMP_VALID(rxcmp1, tmp_raw_cons, cpr->cp_ring_struct))
+	if (!bnxt_cpr_cmp_valid(rxcmp1, tmp_raw_cons,
+				cpr->cp_ring_struct->ring_size))
 		return -EBUSY;
 
 	if (cmp_type == RX_TPA_START_CMPL_TYPE_RX_TPA_START ||
@@ -1077,7 +1079,8 @@ uint16_t bnxt_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
 		cons = RING_CMP(cpr->cp_ring_struct, raw_cons);
 		rxcmp = (struct rx_pkt_cmpl *)&cpr->cp_desc_ring[cons];
 
-		if (!CMP_VALID(rxcmp, raw_cons, cpr->cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(rxcmp, raw_cons,
+					cpr->cp_ring_struct->ring_size))
 			break;
 		if (CMP_TYPE(rxcmp) == CMPL_BASE_TYPE_HWRM_DONE) {
 			PMD_DRV_LOG(ERR, "Rx flush done\n");
diff --git a/drivers/net/bnxt/bnxt_rxtx_vec_avx2.c b/drivers/net/bnxt/bnxt_rxtx_vec_avx2.c
index a06dfec90..d08854ff6 100644
--- a/drivers/net/bnxt/bnxt_rxtx_vec_avx2.c
+++ b/drivers/net/bnxt/bnxt_rxtx_vec_avx2.c
@@ -408,7 +408,7 @@ bnxt_handle_tx_cp_vec(struct bnxt_tx_queue *txq)
 		cons = RING_CMPL(ring_mask, raw_cons);
 		txcmp = (struct tx_cmpl *)&cp_desc_ring[cons];
 
-		if (!CMP_VALID(txcmp, raw_cons, cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(txcmp, raw_cons, ring_mask + 1))
 			break;
 
 		nb_tx_pkts += txcmp->opaque;
diff --git a/drivers/net/bnxt/bnxt_rxtx_vec_neon.c b/drivers/net/bnxt/bnxt_rxtx_vec_neon.c
index 263e6ec3c..13211060c 100644
--- a/drivers/net/bnxt/bnxt_rxtx_vec_neon.c
+++ b/drivers/net/bnxt/bnxt_rxtx_vec_neon.c
@@ -339,7 +339,7 @@ bnxt_handle_tx_cp_vec(struct bnxt_tx_queue *txq)
 		cons = RING_CMPL(ring_mask, raw_cons);
 		txcmp = (struct tx_cmpl *)&cp_desc_ring[cons];
 
-		if (!CMP_VALID(txcmp, raw_cons, cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(txcmp, raw_cons, ring_mask + 1))
 			break;
 
 		if (likely(CMP_TYPE(txcmp) == TX_CMPL_TYPE_TX_L2))
diff --git a/drivers/net/bnxt/bnxt_rxtx_vec_sse.c b/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
index 9a53d1fba..6e5630532 100644
--- a/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
+++ b/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
@@ -320,7 +320,7 @@ bnxt_handle_tx_cp_vec(struct bnxt_tx_queue *txq)
 		cons = RING_CMPL(ring_mask, raw_cons);
 		txcmp = (struct tx_cmpl *)&cp_desc_ring[cons];
 
-		if (!CMP_VALID(txcmp, raw_cons, cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(txcmp, raw_cons, ring_mask + 1))
 			break;
 
 		if (likely(CMP_TYPE(txcmp) == TX_CMPL_TYPE_TX_L2))
diff --git a/drivers/net/bnxt/bnxt_txr.c b/drivers/net/bnxt/bnxt_txr.c
index 9a6b96e04..47824334a 100644
--- a/drivers/net/bnxt/bnxt_txr.c
+++ b/drivers/net/bnxt/bnxt_txr.c
@@ -461,7 +461,7 @@ static int bnxt_handle_tx_cp(struct bnxt_tx_queue *txq)
 		cons = RING_CMPL(ring_mask, raw_cons);
 		txcmp = (struct tx_cmpl *)&cpr->cp_desc_ring[cons];
 
-		if (!CMP_VALID(txcmp, raw_cons, cp_ring_struct))
+		if (!bnxt_cpr_cmp_valid(txcmp, raw_cons, ring_mask + 1))
 			break;
 
 		opaque = rte_le_to_cpu_32(txcmp->opaque);
-- 
2.25.1