Merge branch 'bpf-and-netdevsim-test-updates'

Jakub Kicinski says:

====================
bpf and netdevsim test updates

A number of test improvements (delayed by merges).  Quentin provides
patches for checking printing to the verifier log from the drivers
and validating extack messages are propagated.  There is also a test
for replacing TC filters to avoid adding back the bug Daniel recently
fixed in net and stable.
====================

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netdevsim/Makefile

@@ -4,4 +4,8 @@ obj-$(CONFIG_NETDEVSIM) += netdevsim.o
 
 netdevsim-objs := \
 	netdev.o \
-	bpf.o \
+
+ifeq ($(CONFIG_BPF_SYSCALL),y)
+netdevsim-objs += \
+	bpf.o
+endif

drivers/net/netdevsim/bpf.c

@@ -23,6 +23,9 @@
 
 #include "netdevsim.h"
 
+#define pr_vlog(env, fmt, ...)	\
+	bpf_verifier_log_write(env, "[netdevsim] " fmt, ##__VA_ARGS__)
+
 struct nsim_bpf_bound_prog {
 	struct netdevsim *ns;
 	struct bpf_prog *prog;
@@ -77,6 +80,9 @@ nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn)
 	if (state->ns->bpf_bind_verifier_delay && !insn_idx)
 		msleep(state->ns->bpf_bind_verifier_delay);
 
+	if (insn_idx == env->prog->len - 1)
+		pr_vlog(env, "Hello from netdevsim!\n");
+
 	return 0;
 }
 
@@ -123,17 +129,35 @@ int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
 	struct netdevsim *ns = cb_priv;
 	struct bpf_prog *oldprog;
 
-	if (type != TC_SETUP_CLSBPF ||
-	    !tc_can_offload(ns->netdev) ||
-	    cls_bpf->common.protocol != htons(ETH_P_ALL) ||
-	    cls_bpf->common.chain_index)
+	if (type != TC_SETUP_CLSBPF) {
+		NSIM_EA(cls_bpf->common.extack,
+			"only offload of BPF classifiers supported");
 		return -EOPNOTSUPP;
+	}
 
-	if (!ns->bpf_tc_accept)
+	if (!tc_can_offload_extack(ns->netdev, cls_bpf->common.extack))
 		return -EOPNOTSUPP;
+
+	if (cls_bpf->common.protocol != htons(ETH_P_ALL)) {
+		NSIM_EA(cls_bpf->common.extack,
+			"only ETH_P_ALL supported as filter protocol");
+		return -EOPNOTSUPP;
+	}
+
+	if (cls_bpf->common.chain_index)
+		return -EOPNOTSUPP;
+
+	if (!ns->bpf_tc_accept) {
+		NSIM_EA(cls_bpf->common.extack,
+			"netdevsim configured to reject BPF TC offload");
+		return -EOPNOTSUPP;
+	}
 	/* Note: progs without skip_sw will probably not be dev bound */
-	if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept)
+	if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept) {
+		NSIM_EA(cls_bpf->common.extack,
+			"netdevsim configured to reject unbound programs");
 		return -EOPNOTSUPP;
+	}
 
 	if (cls_bpf->command != TC_CLSBPF_OFFLOAD)
 		return -EOPNOTSUPP;
@@ -145,8 +169,11 @@ int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
 		oldprog = NULL;
 		if (!cls_bpf->prog)
 			return 0;
-		if (ns->bpf_offloaded)
+		if (ns->bpf_offloaded) {
+			NSIM_EA(cls_bpf->common.extack,
+				"driver and netdev offload states mismatch");
 			return -EBUSY;
+		}
 	}
 
 	return nsim_bpf_offload(ns, cls_bpf->prog, oldprog);

drivers/net/netdevsim/netdevsim.h

@@ -68,12 +68,40 @@ struct netdevsim {
 
 extern struct dentry *nsim_ddir;
 
+#ifdef CONFIG_BPF_SYSCALL
 int nsim_bpf_init(struct netdevsim *ns);
 void nsim_bpf_uninit(struct netdevsim *ns);
 int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf);
 int nsim_bpf_disable_tc(struct netdevsim *ns);
 int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
 			       void *type_data, void *cb_priv);
+#else
+static inline int nsim_bpf_init(struct netdevsim *ns)
+{
+	return 0;
+}
+
+static inline void nsim_bpf_uninit(struct netdevsim *ns)
+{
+}
+
+static inline int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
+{
+	return bpf->command == XDP_QUERY_PROG ? 0 : -EOPNOTSUPP;
+}
+
+static inline int nsim_bpf_disable_tc(struct netdevsim *ns)
+{
+	return 0;
+}
+
+static inline int
+nsim_bpf_setup_tc_block_cb(enum tc_setup_type type, void *type_data,
+			   void *cb_priv)
+{
+	return -EOPNOTSUPP;
+}
+#endif
 
 static inline struct netdevsim *to_nsim(struct device *ptr)
 {