Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2017-12-03

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Addition of a software model for BPF offloads in order to ease
   testing code changes in that area and make semantics more clear.
   This is implemented in a new driver called netdevsim, which can
   later also be extended for other offloads. SR-IOV support is added
   as well to netdevsim. BPF kernel selftests for offloading are
   added so we can track basic functionality as well as exercising
   all corner cases around BPF offloading, from Jakub.

2) Today drivers have to drop the reference on BPF progs they hold
   due to XDP on device teardown themselves. Change this in order
   to make XDP handling inside the drivers less error prone, and
   move disabling XDP to the core instead, also from Jakub.

3) Misc set of BPF verifier improvements and cleanups as preparatory
   work for upcoming BPF-to-BPF calls. Among others, this set also
   improves liveness marking such that pruning can be slightly more
   effective. Register and stack liveness information is now included
   in the verifier log as well, from Alexei.

4) nfp JIT improvements in order to identify load/store sequences in
   the BPF prog e.g. coming from memcpy lowering and optimizing them
   through the NPU's command push pull (CPP) instruction, from Jiong.

5) Cleanups to test_cgrp2_attach2.c BPF sample code in oder to remove
   bpf_prog_attach() magic values and replacing them with actual proper
   attach flag instead, from David.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 373 insertions, 0 deletions

diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c
new file mode 100644
index 000000000000..8e4398a50903
--- /dev/null
+++ b/drivers/net/netdevsim/bpf.c
@@ -0,0 +1,373 @@
+/*
+ * Copyright (C) 2017 Netronome Systems, Inc.
+ *
+ * This software is licensed under the GNU General License Version 2,
+ * June 1991 as shown in the file COPYING in the top-level directory of this
+ * source tree.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
+ * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
+ * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
+ * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+ */
+
+#include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/rtnetlink.h>
+#include <net/pkt_cls.h>
+
+#include "netdevsim.h"
+
+struct nsim_bpf_bound_prog {
+	struct netdevsim *ns;
+	struct bpf_prog *prog;
+	struct dentry *ddir;
+	const char *state;
+	bool is_loaded;
+	struct list_head l;
+};
+
+static int nsim_debugfs_bpf_string_read(struct seq_file *file, void *data)
+{
+	const char **str = file->private;
+
+	if (*str)
+		seq_printf(file, "%s\n", *str);
+
+	return 0;
+}
+
+static int nsim_debugfs_bpf_string_open(struct inode *inode, struct file *f)
+{
+	return single_open(f, nsim_debugfs_bpf_string_read, inode->i_private);
+}
+
+static const struct file_operations nsim_bpf_string_fops = {
+	.owner = THIS_MODULE,
+	.open = nsim_debugfs_bpf_string_open,
+	.release = single_release,
+	.read = seq_read,
+	.llseek = seq_lseek
+};
+
+static int
+nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn)
+{
+	struct nsim_bpf_bound_prog *state;
+
+	state = env->prog->aux->offload->dev_priv;
+	if (state->ns->bpf_bind_verifier_delay && !insn_idx)
+		msleep(state->ns->bpf_bind_verifier_delay);
+
+	return 0;
+}
+
+static const struct bpf_ext_analyzer_ops nsim_bpf_analyzer_ops = {
+	.insn_hook = nsim_bpf_verify_insn,
+};
+
+static bool nsim_xdp_offload_active(struct netdevsim *ns)
+{
+	return ns->xdp_prog_mode == XDP_ATTACHED_HW;
+}
+
+static void nsim_prog_set_loaded(struct bpf_prog *prog, bool loaded)
+{
+	struct nsim_bpf_bound_prog *state;
+
+	if (!prog || !prog->aux->offload)
+		return;
+
+	state = prog->aux->offload->dev_priv;
+	state->is_loaded = loaded;
+}
+
+static int
+nsim_bpf_offload(struct netdevsim *ns, struct bpf_prog *prog, bool oldprog)
+{
+	nsim_prog_set_loaded(ns->bpf_offloaded, false);
+
+	WARN(!!ns->bpf_offloaded != oldprog,
+	     "bad offload state, expected offload %sto be active",
+	     oldprog ? "" : "not ");
+	ns->bpf_offloaded = prog;
+	ns->bpf_offloaded_id = prog ? prog->aux->id : 0;
+	nsim_prog_set_loaded(prog, true);
+
+	return 0;
+}
+
+int nsim_bpf_setup_tc_block_cb(enum tc_setup_type type,
+			       void *type_data, void *cb_priv)
+{
+	struct tc_cls_bpf_offload *cls_bpf = type_data;
+	struct bpf_prog *prog = cls_bpf->prog;
+	struct netdevsim *ns = cb_priv;
+	bool skip_sw;
+
+	if (type != TC_SETUP_CLSBPF ||
+	    !tc_can_offload(ns->netdev) ||
+	    cls_bpf->common.protocol != htons(ETH_P_ALL) ||
+	    cls_bpf->common.chain_index)
+		return -EOPNOTSUPP;
+
+	skip_sw = cls_bpf->gen_flags & TCA_CLS_FLAGS_SKIP_SW;
+
+	if (nsim_xdp_offload_active(ns))
+		return -EBUSY;
+
+	if (!ns->bpf_tc_accept)
+		return -EOPNOTSUPP;
+	/* Note: progs without skip_sw will probably not be dev bound */
+	if (prog && !prog->aux->offload && !ns->bpf_tc_non_bound_accept)
+		return -EOPNOTSUPP;
+
+	switch (cls_bpf->command) {
+	case TC_CLSBPF_REPLACE:
+		return nsim_bpf_offload(ns, prog, true);
+	case TC_CLSBPF_ADD:
+		return nsim_bpf_offload(ns, prog, false);
+	case TC_CLSBPF_DESTROY:
+		return nsim_bpf_offload(ns, NULL, true);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+int nsim_bpf_disable_tc(struct netdevsim *ns)
+{
+	if (ns->bpf_offloaded && !nsim_xdp_offload_active(ns))
+		return -EBUSY;
+	return 0;
+}
+
+static int nsim_xdp_offload_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
+{
+	if (!nsim_xdp_offload_active(ns) && !bpf->prog)
+		return 0;
+	if (!nsim_xdp_offload_active(ns) && bpf->prog && ns->bpf_offloaded) {
+		NSIM_EA(bpf->extack, "TC program is already loaded");
+		return -EBUSY;
+	}
+
+	return nsim_bpf_offload(ns, bpf->prog, nsim_xdp_offload_active(ns));
+}
+
+static int nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf)
+{
+	int err;
+
+	if (ns->xdp_prog && (bpf->flags ^ ns->xdp_flags) & XDP_FLAGS_MODES) {
+		NSIM_EA(bpf->extack, "program loaded with different flags");
+		return -EBUSY;
+	}
+
+	if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) {
+		NSIM_EA(bpf->extack, "driver XDP disabled in DebugFS");
+		return -EOPNOTSUPP;
+	}
+	if (bpf->command == XDP_SETUP_PROG_HW && !ns->bpf_xdpoffload_accept) {
+		NSIM_EA(bpf->extack, "XDP offload disabled in DebugFS");
+		return -EOPNOTSUPP;
+	}
+
+	if (bpf->command == XDP_SETUP_PROG_HW) {
+		err = nsim_xdp_offload_prog(ns, bpf);
+		if (err)
+			return err;
+	}
+
+	if (ns->xdp_prog)
+		bpf_prog_put(ns->xdp_prog);
+
+	ns->xdp_prog = bpf->prog;
+	ns->xdp_flags = bpf->flags;
+
+	if (!bpf->prog)
+		ns->xdp_prog_mode = XDP_ATTACHED_NONE;
+	else if (bpf->command == XDP_SETUP_PROG)
+		ns->xdp_prog_mode = XDP_ATTACHED_DRV;
+	else
+		ns->xdp_prog_mode = XDP_ATTACHED_HW;
+
+	return 0;
+}
+
+int nsim_bpf_create_prog(struct netdevsim *ns, struct bpf_prog *prog)
+{
+	struct nsim_bpf_bound_prog *state;
+	char name[16];
+	int err;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	state->ns = ns;
+	state->prog = prog;
+	state->state = "verify";
+
+	/* Program id is not populated yet when we create the state. */
+	sprintf(name, "%u", ns->prog_id_gen++);
+	state->ddir = debugfs_create_dir(name, ns->ddir_bpf_bound_progs);
+	if (IS_ERR(state->ddir)) {
+		err = PTR_ERR(state->ddir);
+		kfree(state);
+		return err;
+	}
+
+	debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id);
+	debugfs_create_file("state", 0400, state->ddir,
+			    &state->state, &nsim_bpf_string_fops);
+	debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded);
+
+	list_add_tail(&state->l, &ns->bpf_bound_progs);
+
+	prog->aux->offload->dev_priv = state;
+
+	return 0;
+}
+
+void nsim_bpf_destroy_prog(struct bpf_prog *prog)
+{
+	struct nsim_bpf_bound_prog *state;
+
+	state = prog->aux->offload->dev_priv;
+	WARN(state->is_loaded,
+	     "offload state destroyed while program still bound");
+	debugfs_remove_recursive(state->ddir);
+	list_del(&state->l);
+	kfree(state);
+}
+
+static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
+{
+	if (bpf->prog && bpf->prog->aux->offload) {
+		NSIM_EA(bpf->extack, "attempt to load offloaded prog to drv");
+		return -EINVAL;
+	}
+	if (ns->netdev->mtu > NSIM_XDP_MAX_MTU) {
+		NSIM_EA(bpf->extack, "MTU too large w/ XDP enabled");
+		return -EINVAL;
+	}
+	if (nsim_xdp_offload_active(ns)) {
+		NSIM_EA(bpf->extack, "xdp offload active, can't load drv prog");
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int
+nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
+{
+	struct nsim_bpf_bound_prog *state;
+
+	if (!bpf->prog)
+		return 0;
+
+	if (!bpf->prog->aux->offload) {
+		NSIM_EA(bpf->extack, "xdpoffload of non-bound program");
+		return -EINVAL;
+	}
+	if (bpf->prog->aux->offload->netdev != ns->netdev) {
+		NSIM_EA(bpf->extack, "program bound to different dev");
+		return -EINVAL;
+	}
+
+	state = bpf->prog->aux->offload->dev_priv;
+	if (WARN_ON(strcmp(state->state, "xlated"))) {
+		NSIM_EA(bpf->extack, "offloading program in bad state");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+	struct nsim_bpf_bound_prog *state;
+	int err;
+
+	ASSERT_RTNL();
+
+	switch (bpf->command) {
+	case BPF_OFFLOAD_VERIFIER_PREP:
+		if (!ns->bpf_bind_accept)
+			return -EOPNOTSUPP;
+
+		err = nsim_bpf_create_prog(ns, bpf->verifier.prog);
+		if (err)
+			return err;
+
+		bpf->verifier.ops = &nsim_bpf_analyzer_ops;
+		return 0;
+	case BPF_OFFLOAD_TRANSLATE:
+		state = bpf->offload.prog->aux->offload->dev_priv;
+
+		state->state = "xlated";
+		return 0;
+	case BPF_OFFLOAD_DESTROY:
+		nsim_bpf_destroy_prog(bpf->offload.prog);
+		return 0;
+	case XDP_QUERY_PROG:
+		bpf->prog_attached = ns->xdp_prog_mode;
+		bpf->prog_id = ns->xdp_prog ? ns->xdp_prog->aux->id : 0;
+		bpf->prog_flags = ns->xdp_prog ? ns->xdp_flags : 0;
+		return 0;
+	case XDP_SETUP_PROG:
+		err = nsim_setup_prog_checks(ns, bpf);
+		if (err)
+			return err;
+
+		return nsim_xdp_set_prog(ns, bpf);
+	case XDP_SETUP_PROG_HW:
+		err = nsim_setup_prog_hw_checks(ns, bpf);
+		if (err)
+			return err;
+
+		return nsim_xdp_set_prog(ns, bpf);
+	default:
+		return -EINVAL;
+	}
+}
+
+int nsim_bpf_init(struct netdevsim *ns)
+{
+	INIT_LIST_HEAD(&ns->bpf_bound_progs);
+
+	debugfs_create_u32("bpf_offloaded_id", 0400, ns->ddir,
+			   &ns->bpf_offloaded_id);
+
+	ns->bpf_bind_accept = true;
+	debugfs_create_bool("bpf_bind_accept", 0600, ns->ddir,
+			    &ns->bpf_bind_accept);
+	debugfs_create_u32("bpf_bind_verifier_delay", 0600, ns->ddir,
+			   &ns->bpf_bind_verifier_delay);
+	ns->ddir_bpf_bound_progs =
+		debugfs_create_dir("bpf_bound_progs", ns->ddir);
+
+	ns->bpf_tc_accept = true;
+	debugfs_create_bool("bpf_tc_accept", 0600, ns->ddir,
+			    &ns->bpf_tc_accept);
+	debugfs_create_bool("bpf_tc_non_bound_accept", 0600, ns->ddir,
+			    &ns->bpf_tc_non_bound_accept);
+	ns->bpf_xdpdrv_accept = true;
+	debugfs_create_bool("bpf_xdpdrv_accept", 0600, ns->ddir,
+			    &ns->bpf_xdpdrv_accept);
+	ns->bpf_xdpoffload_accept = true;
+	debugfs_create_bool("bpf_xdpoffload_accept", 0600, ns->ddir,
+			    &ns->bpf_xdpoffload_accept);
+
+	return 0;
+}
+
+void nsim_bpf_uninit(struct netdevsim *ns)
+{
+	WARN_ON(!list_empty(&ns->bpf_bound_progs));
+	WARN_ON(ns->xdp_prog);
+	WARN_ON(ns->bpf_offloaded);
+}