net/bnxt: fix missing barriers in completion handling

[ upstream commit 5ed30db ]

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: 2eb53b1 ("net/bnxt: add initial Rx code")
Fixes: 6eb3cc2 ("net/bnxt: add initial Tx code")

Signed-off-by: Lance Richardson <lance.richardson@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

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 CMPL_VALID(cmp, v)						\
 	(!!(rte_le_to_cpu_32(((struct cmpl_base *)(cmp))->info3_v) &	\
 	    CMPL_BASE_V) == !(v))
@@ -131,4 +128,35 @@ 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 cmpl
+ *   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

drivers/net/bnxt/bnxt_ethdev.c

@@ -3041,7 +3041,7 @@ 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;
@@ -3053,14 +3053,15 @@ 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;
 
 		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);
@@ -3104,7 +3105,7 @@ 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;
@@ -3118,6 +3119,7 @@ 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
@@ -3134,7 +3136,7 @@ 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. */
@@ -3160,7 +3162,7 @@ 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);
@@ -3214,7 +3216,6 @@ 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;
 
@@ -3231,7 +3232,6 @@ 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. */
@@ -3242,7 +3242,7 @@ 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)

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);

drivers/net/bnxt/bnxt_rxr.c

@@ -242,7 +242,8 @@ static int bnxt_agg_bufs_valid(struct bnxt_cp_ring_info *cpr,
 	cpr->valid = FLIP_VALID(raw_cp_cons,
 				cpr->cp_ring_struct->ring_mask,
 				cpr->valid);
-	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 */
@@ -827,7 +828,8 @@ 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;
 
 	cpr->valid = FLIP_VALID(cp_cons,
@@ -1006,7 +1008,8 @@ 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;
 		cpr->valid = FLIP_VALID(cons,
 					cpr->cp_ring_struct->ring_mask,

drivers/net/bnxt/bnxt_rxtx_vec_neon.c

@@ -347,7 +347,7 @@ 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))

drivers/net/bnxt/bnxt_rxtx_vec_sse.c

@@ -329,7 +329,7 @@ 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))

drivers/net/bnxt/bnxt_txr.c

@@ -443,7 +443,7 @@ 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);