[PATCH bpf-next v2 15/15] nfp: bpf: implement bpf map offload

[Jakub Kicinski <jakub.kicinski@netronome.com>]

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>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c    |   1 +
 drivers/net/ethernet/netronome/nfp/bpf/main.h    |   4 +
 drivers/net/ethernet/netronome/nfp/bpf/offload.c | 104 +++++++++++++++++++++++
 3 files changed, 109 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.c b/drivers/net/ethernet/netronome/nfp/bpf/main.c
index 7d5cc59feb7e..8823c8360047 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/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);
 }
 
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index 59197535c465..b80e75a8ecda 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/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;
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/offload.c b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
index 6590228d3755..e2859b2e9c6a 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/offload.c
+++ b/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;
 	}
-- 
2.15.1