nfp: bpf: implement bpf map offload

Plug in to the stack's map offload callbacks for BPF map offload.
Get next call needs some special handling on the FW side, since
we can't send a NULL pointer to the FW there is a get first entry
FW command.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

drivers/net/ethernet/netronome/nfp/bpf/main.c

@@ -381,6 +381,7 @@ static void nfp_bpf_clean(struct nfp_app *app)
 
 	WARN_ON(!skb_queue_empty(&bpf->cmsg_replies));
 	WARN_ON(!list_empty(&bpf->map_list));
+	WARN_ON(bpf->maps_in_use || bpf->map_elems_in_use);
 	kfree(bpf);
 }
 

drivers/net/ethernet/netronome/nfp/bpf/main.h

@@ -108,6 +108,8 @@ enum pkt_vec {
  * @cmsg_wq:		work queue for waiting for cmsg replies
  *
  * @map_list:		list of offloaded maps
+ * @maps_in_use:	number of currently offloaded maps
+ * @map_elems_in_use:	number of elements allocated to offloaded maps
  *
  * @adjust_head:	adjust head capability
  * @flags:		extra flags for adjust head
@@ -138,6 +140,8 @@ struct nfp_app_bpf {
 	struct wait_queue_head cmsg_wq;
 
 	struct list_head map_list;
+	unsigned int maps_in_use;
+	unsigned int map_elems_in_use;
 
 	struct nfp_bpf_cap_adjust_head {
 		u32 flags;

drivers/net/ethernet/netronome/nfp/bpf/offload.c

@@ -36,6 +36,9 @@
  * Netronome network device driver: TC offload functions for PF and VF
  */
 
+#define pr_fmt(fmt)	"NFP net bpf: " fmt
+
+#include <linux/bpf.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/pci.h>
@@ -153,6 +156,103 @@ static int nfp_bpf_destroy(struct nfp_net *nn, struct bpf_prog *prog)
 	return 0;
 }
 
+static int
+nfp_bpf_map_get_next_key(struct bpf_offloaded_map *offmap,
+			 void *key, void *next_key)
+{
+	if (!key)
+		return nfp_bpf_ctrl_getfirst_entry(offmap, next_key);
+	return nfp_bpf_ctrl_getnext_entry(offmap, key, next_key);
+}
+
+static int
+nfp_bpf_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
+{
+	return nfp_bpf_ctrl_del_entry(offmap, key);
+}
+
+static const struct bpf_map_dev_ops nfp_bpf_map_ops = {
+	.map_get_next_key	= nfp_bpf_map_get_next_key,
+	.map_lookup_elem	= nfp_bpf_ctrl_lookup_entry,
+	.map_update_elem	= nfp_bpf_ctrl_update_entry,
+	.map_delete_elem	= nfp_bpf_map_delete_elem,
+};
+
+static int
+nfp_bpf_map_alloc(struct nfp_app_bpf *bpf, struct bpf_offloaded_map *offmap)
+{
+	struct nfp_bpf_map *nfp_map;
+	long long int res;
+
+	if (!bpf->maps.types)
+		return -EOPNOTSUPP;
+
+	if (offmap->map.map_flags ||
+	    offmap->map.numa_node != NUMA_NO_NODE) {
+		pr_info("map flags are not supported\n");
+		return -EINVAL;
+	}
+
+	if (!(bpf->maps.types & 1 << offmap->map.map_type)) {
+		pr_info("map type not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (bpf->maps.max_maps == bpf->maps_in_use) {
+		pr_info("too many maps for a device\n");
+		return -ENOMEM;
+	}
+	if (bpf->maps.max_elems - bpf->map_elems_in_use <
+	    offmap->map.max_entries) {
+		pr_info("map with too many elements: %u, left: %u\n",
+			offmap->map.max_entries,
+			bpf->maps.max_elems - bpf->map_elems_in_use);
+		return -ENOMEM;
+	}
+	if (offmap->map.key_size > bpf->maps.max_key_sz ||
+	    offmap->map.value_size > bpf->maps.max_val_sz ||
+	    round_up(offmap->map.key_size, 8) +
+	    round_up(offmap->map.value_size, 8) > bpf->maps.max_elem_sz) {
+		pr_info("elements don't fit in device constraints\n");
+		return -ENOMEM;
+	}
+
+	nfp_map = kzalloc(sizeof(*nfp_map), GFP_USER);
+	if (!nfp_map)
+		return -ENOMEM;
+
+	offmap->dev_priv = nfp_map;
+	nfp_map->offmap = offmap;
+	nfp_map->bpf = bpf;
+
+	res = nfp_bpf_ctrl_alloc_map(bpf, &offmap->map);
+	if (res < 0) {
+		kfree(nfp_map);
+		return res;
+	}
+
+	nfp_map->tid = res;
+	offmap->dev_ops = &nfp_bpf_map_ops;
+	bpf->maps_in_use++;
+	bpf->map_elems_in_use += offmap->map.max_entries;
+	list_add_tail(&nfp_map->l, &bpf->map_list);
+
+	return 0;
+}
+
+static int
+nfp_bpf_map_free(struct nfp_app_bpf *bpf, struct bpf_offloaded_map *offmap)
+{
+	struct nfp_bpf_map *nfp_map = offmap->dev_priv;
+
+	nfp_bpf_ctrl_free_map(bpf, nfp_map);
+	list_del_init(&nfp_map->l);
+	bpf->map_elems_in_use -= offmap->map.max_entries;
+	bpf->maps_in_use--;
+	kfree(nfp_map);
+
+	return 0;
+}
+
 int nfp_ndo_bpf(struct nfp_app *app, struct nfp_net *nn, struct netdev_bpf *bpf)
 {
 	switch (bpf->command) {
@@ -162,6 +262,10 @@ int nfp_ndo_bpf(struct nfp_app *app, struct nfp_net *nn, struct netdev_bpf *bpf)
 		return nfp_bpf_translate(nn, bpf->offload.prog);
 	case BPF_OFFLOAD_DESTROY:
 		return nfp_bpf_destroy(nn, bpf->offload.prog);
+	case BPF_OFFLOAD_MAP_ALLOC:
+		return nfp_bpf_map_alloc(app->priv, bpf->offmap);
+	case BPF_OFFLOAD_MAP_FREE:
+		return nfp_bpf_map_free(app->priv, bpf->offmap);
 	default:
 		return -EINVAL;
 	}