linux-gen: socket_xdp: try to detect XDP shadow queue using drivers at startup

With some NICs and drivers (e.g. Mellanox), using XDP in zero-copy mode
will result in "shadow queues" on top of regular queue indices. This
makes it impossible to programmatically setup the NIC RSS so that
packets would end up to the XDP queues.

Try to detect this when packet I/O is opened and warn users about this.
RSS will need to be manually configured in this case.

The existing `ODP_PKTIO_XDP_PARAMS` environment variable configuration is
also removed as part of this and queue binding is now automatically done
starting from the first shadow queue.

Signed-off-by: Tuomas Taipale <tuomas.taipale@nokia.com>
Reviewed-by: Matias Elo <matias.elo@nokia.com>

1 files changed, 38 insertions, 47 deletions

diff --git a/platform/linux-generic/pktio/socket_xdp.c b/platform/linux-generic/pktio/socket_xdp.c
index 30bc78d3b..806fde977 100644
--- a/platform/linux-generic/pktio/socket_xdp.c
+++ b/platform/linux-generic/pktio/socket_xdp.c
@@ -67,6 +67,10 @@ static const char * const internal_stats_strs[] = {
 
 #define MAX_INTERNAL_STATS _ODP_ARRAY_SIZE(internal_stats_strs)
 
+static const char * const shadow_q_driver_strs[] = {
+	"mlx",
+};
+
 typedef struct {
 	uint64_t rx_dropped;
 	uint64_t rx_inv_descs;
@@ -128,6 +132,7 @@ typedef struct {
 	uint32_t bind_q;
 	odp_bool_t lockless_rx;
 	odp_bool_t lockless_tx;
+	odp_bool_t is_shadow_q;
 } xdp_sock_info_t;
 
 typedef struct {
@@ -161,47 +166,6 @@ static inline xdp_sock_info_t *pkt_priv(pktio_entry_t *pktio_entry)
 	return (xdp_sock_info_t *)(uintptr_t)(pktio_entry->pkt_priv);
 }
 
-static uint32_t get_bind_queue_index(const char *devname)
-{
-	const char *param = getenv("ODP_PKTIO_XDP_PARAMS");
-	char *tmp_str;
-	char *tmp;
-	char *if_str;
-	int idx = 0;
-
-	if (param == NULL)
-		goto out;
-
-	tmp_str = strdup(param);
-
-	if (tmp_str == NULL)
-		goto out;
-
-	tmp = strtok(tmp_str, IF_DELIM);
-
-	if (tmp == NULL)
-		goto out_str;
-
-	while (tmp) {
-		if_str = strchr(tmp, Q_DELIM);
-
-		if (if_str != NULL && if_str != &tmp[strlen(tmp) - 1U]) {
-			if (strncmp(devname, tmp, (uint64_t)(uintptr_t)(if_str - tmp)) == 0) {
-				idx = _ODP_MAX(atoi(++if_str), 0);
-				break;
-			}
-		}
-
-		tmp = strtok(NULL, IF_DELIM);
-	}
-
-out_str:
-	free(tmp_str);
-
-out:
-	return idx;
-}
-
 static odp_bool_t get_nic_queue_count(int fd, const char *devname, drv_channels_t *cur_channels)
 {
 	struct ethtool_channels channels;
@@ -249,6 +213,34 @@ static odp_bool_t get_nic_rss_indir_count(int fd, const char *devname, uint32_t
 	return true;
 }
 
+static odp_bool_t is_shadow_q_driver(int fd, const char *devname)
+{
+	struct ethtool_drvinfo info;
+	struct ifreq ifr;
+	int ret;
+
+	memset(&info, 0, sizeof(struct ethtool_drvinfo));
+	info.cmd = ETHTOOL_GDRVINFO;
+	snprintf(ifr.ifr_name, IF_NAMESIZE, "%s", devname);
+	ifr.ifr_data = (char *)&info;
+	ret = ioctl(fd, SIOCETHTOOL, &ifr);
+
+	if (ret == -1) {
+		_ODP_DBG("Unable to query NIC driver information: %s\n", strerror(errno));
+		return false;
+	}
+
+	for (uint32_t i = 0U; i < _ODP_ARRAY_SIZE(shadow_q_driver_strs); ++i) {
+		if (strstr(info.driver, shadow_q_driver_strs[i]) != NULL) {
+			_ODP_PRINT("Driver with XDP shadow queues in use: %s, manual RSS"
+				   " configuration likely required\n", info.driver);
+			return true;
+		}
+	}
+
+	return false;
+}
+
 static void parse_options(xdp_umem_info_t *umem_info)
 {
 	if (!_odp_libconfig_lookup_ext_int(CONF_BASE_STR, NULL, RX_DESCS_STR,
@@ -320,12 +312,11 @@ static int sock_xdp_open(odp_pktio_t pktio, pktio_entry_t *pktio_entry, const ch
 		_ODP_PRINT("Warning: Unable to query NIC queue count/RSS, manual cleanup"
 			   " required\n");
 
-	priv->bind_q = get_bind_queue_index(pktio_entry->name);
+	priv->is_shadow_q = is_shadow_q_driver(priv->helper_sock, pktio_entry->name);
 	parse_options(priv->umem_info);
 	_ODP_DBG("Socket xdp interface (%s):\n", pktio_entry->name);
 	_ODP_DBG("  num_rx_desc: %d\n", priv->umem_info->num_rx_desc);
 	_ODP_DBG("  num_tx_desc: %d\n", priv->umem_info->num_tx_desc);
-	_ODP_DBG("  starting bind queue: %u\n", priv->bind_q);
 
 	return 0;
 
@@ -388,7 +379,7 @@ static int sock_xdp_close(pktio_entry_t *pktio_entry)
 		(void)set_nic_queue_count(priv->helper_sock, pktio_entry->name,
 					  &priv->q_num_conf.drv_channels);
 
-	if (priv->q_num_conf.drv_num_rss != 0U)
+	if (priv->q_num_conf.drv_num_rss != 0U && !priv->is_shadow_q)
 		(void)set_nic_rss_indir(priv->helper_sock, pktio_entry->name, &indir);
 
 	close(priv->helper_sock);
@@ -548,18 +539,18 @@ static int sock_xdp_start(pktio_entry_t *pktio_entry)
 
 	priv->q_num_conf.num_qs = _ODP_MAX(priv->q_num_conf.num_in_conf_qs,
 					   priv->q_num_conf.num_out_conf_qs);
+	priv->bind_q = priv->is_shadow_q ? priv->q_num_conf.num_qs : 0U;
 	channels.combined = priv->q_num_conf.num_qs;
 
 	if (!set_nic_queue_count(priv->helper_sock, pktio_entry->name, &channels))
 		_ODP_PRINT("Warning: Unable to configure NIC queue count, manual configuration"
 			   " required\n");
 
-	if (priv->q_num_conf.num_in_conf_qs > 0U) {
+	if (priv->q_num_conf.num_in_conf_qs > 0U && !priv->is_shadow_q) {
 		indir->indir_size = priv->q_num_conf.drv_num_rss;
 
 		for (uint32_t i = 0U; i < indir->indir_size; ++i)
-			indir->rss_config[i] = (i % priv->q_num_conf.num_in_conf_qs)
-					       + priv->bind_q;
+			indir->rss_config[i] = (i % priv->q_num_conf.num_in_conf_qs);
 
 		if (!set_nic_rss_indir(priv->helper_sock, pktio_entry->name, indir))
 			_ODP_PRINT("Warning: Unable to configure NIC RSS, manual configuration"