nfp: bpf: parse global BPF ABI version capability

Up until now we only had per-vNIC BPF ABI version capabilities,
which are slightly awkward to use because bulk of the resources
and configuration does not relate to any particular vNIC.  Add
a new capability for global ABI version and check the per-vNIC
version are equal to it.  Assume the ABI version 2 if no explicit
version capability is present.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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

@@ -52,6 +52,7 @@ enum bpf_cap_tlv_type {
 	NFP_BPF_CAP_TYPE_RANDOM		= 4,
 	NFP_BPF_CAP_TYPE_QUEUE_SELECT	= 5,
 	NFP_BPF_CAP_TYPE_ADJUST_TAIL	= 6,
+	NFP_BPF_CAP_TYPE_ABI_VERSION	= 7,
 };
 
 struct nfp_bpf_cap_tlv_func {

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

@@ -54,11 +54,14 @@ const struct rhashtable_params nfp_bpf_maps_neutral_params = {
 static bool nfp_net_ebpf_capable(struct nfp_net *nn)
 {
 #ifdef __LITTLE_ENDIAN
-	if (nn->cap & NFP_NET_CFG_CTRL_BPF &&
-	    nn_readb(nn, NFP_NET_CFG_BPF_ABI) == NFP_NET_BPF_ABI)
-		return true;
-#endif
+	struct nfp_app_bpf *bpf = nn->app->priv;
+
+	return nn->cap & NFP_NET_CFG_CTRL_BPF &&
+	       bpf->abi_version &&
+	       nn_readb(nn, NFP_NET_CFG_BPF_ABI) == bpf->abi_version;
+#else
 	return false;
+#endif
 }
 
 static int
@@ -342,6 +345,26 @@ nfp_bpf_parse_cap_adjust_tail(struct nfp_app_bpf *bpf, void __iomem *value,
 	return 0;
 }
 
+static int
+nfp_bpf_parse_cap_abi_version(struct nfp_app_bpf *bpf, void __iomem *value,
+			      u32 length)
+{
+	if (length < 4) {
+		nfp_err(bpf->app->cpp, "truncated ABI version TLV: %d\n",
+			length);
+		return -EINVAL;
+	}
+
+	bpf->abi_version = readl(value);
+	if (bpf->abi_version != 2) {
+		nfp_warn(bpf->app->cpp, "unsupported BPF ABI version: %d\n",
+			 bpf->abi_version);
+		bpf->abi_version = 0;
+	}
+
+	return 0;
+}
+
 static int nfp_bpf_parse_capabilities(struct nfp_app *app)
 {
 	struct nfp_cpp *cpp = app->pf->cpp;
@@ -393,6 +416,11 @@ static int nfp_bpf_parse_capabilities(struct nfp_app *app)
 							  length))
 				goto err_release_free;
 			break;
+		case NFP_BPF_CAP_TYPE_ABI_VERSION:
+			if (nfp_bpf_parse_cap_abi_version(app->priv, value,
+							  length))
+				goto err_release_free;
+			break;
 		default:
 			nfp_dbg(cpp, "unknown BPF capability: %d\n", type);
 			break;
@@ -414,6 +442,11 @@ static int nfp_bpf_parse_capabilities(struct nfp_app *app)
 	return -EINVAL;
 }
 
+static void nfp_bpf_init_capabilities(struct nfp_app_bpf *bpf)
+{
+	bpf->abi_version = 2; /* Original BPF ABI version */
+}
+
 static int nfp_bpf_ndo_init(struct nfp_app *app, struct net_device *netdev)
 {
 	struct nfp_app_bpf *bpf = app->priv;
@@ -447,6 +480,8 @@ static int nfp_bpf_init(struct nfp_app *app)
 	if (err)
 		goto err_free_bpf;
 
+	nfp_bpf_init_capabilities(bpf);
+
 	err = nfp_bpf_parse_capabilities(app);
 	if (err)
 		goto err_free_neutral_maps;

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

@@ -127,6 +127,8 @@ enum pkt_vec {
  *
  * @maps_neutral:	hash table of offload-neutral maps (on pointer)
  *
+ * @abi_version:	global BPF ABI version
+ *
  * @adjust_head:	adjust head capability
  * @adjust_head.flags:		extra flags for adjust head
  * @adjust_head.off_min:	minimal packet offset within buffer required
@@ -170,6 +172,8 @@ struct nfp_app_bpf {
 
 	struct rhashtable maps_neutral;
 
+	u32 abi_version;
+
 	struct nfp_bpf_cap_adjust_head {
 		u32 flags;
 		int off_min;