Commit 1cf1cae9 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

bpf: introduce BPF_PROG_TEST_RUN command 



development and testing of networking bpf programs is quite cumbersome.
Despite availability of user space bpf interpreters the kernel is
the ultimate authority and execution environment.
Current test frameworks for TC include creation of netns, veth,
qdiscs and use of various packet generators just to test functionality
of a bpf program. XDP testing is even more complicated, since
qemu needs to be started with gro/gso disabled and precise queue
configuration, transferring of xdp program from host into guest,
attaching to virtio/eth0 and generating traffic from the host
while capturing the results from the guest.

Moreover analyzing performance bottlenecks in XDP program is
impossible in virtio environment, since cost of running the program
is tiny comparing to the overhead of virtio packet processing,
so performance testing can only be done on physical nic
with another server generating traffic.

Furthermore ongoing changes to user space control plane of production
applications cannot be run on the test servers leaving bpf programs
stubbed out for testing.

Last but not least, the upstream llvm changes are validated by the bpf
backend testsuite which has no ability to test the code generated.

To improve this situation introduce BPF_PROG_TEST_RUN command
to test and performance benchmark bpf programs.

Joint work with Daniel Borkmann.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 98cd1552

include/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -169,6 +169,8 @@ struct bpf_verifier_ops { 
				  const struct bpf_insn *src,

				  struct bpf_insn *dst,

				  struct bpf_prog *prog);

	int (*test_run)(struct bpf_prog *prog, const union bpf_attr *kattr,

			union bpf_attr __user *uattr);

};



struct bpf_prog_type_list {
@@ -233,6 +235,11 @@ typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src, 
u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,

		     void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy);



int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,

			  union bpf_attr __user *uattr);

int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,

			  union bpf_attr __user *uattr);



#ifdef CONFIG_BPF_SYSCALL

DECLARE_PER_CPU(int, bpf_prog_active);

include/uapi/linux/bpf.h

+12 −0
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ enum bpf_cmd { 
	BPF_OBJ_GET,

	BPF_PROG_ATTACH,

	BPF_PROG_DETACH,

	BPF_PROG_TEST_RUN,

};



enum bpf_map_type {
@@ -189,6 +190,17 @@ union bpf_attr { 
		__u32		attach_type;

		__u32		attach_flags;

	};



	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */

		__u32		prog_fd;

		__u32		retval;

		__u32		data_size_in;

		__u32		data_size_out;

		__aligned_u64	data_in;

		__aligned_u64	data_out;

		__u32		repeat;

		__u32		duration;

	} test;

} __attribute__((aligned(8)));



/* BPF helper function descriptions:

kernel/bpf/syscall.c

+25 −2
Original line number Diff line number Diff line
@@ -973,6 +973,28 @@ static int bpf_prog_detach(const union bpf_attr *attr) 
}

#endif /* CONFIG_CGROUP_BPF */



#define BPF_PROG_TEST_RUN_LAST_FIELD test.duration



static int bpf_prog_test_run(const union bpf_attr *attr,

			     union bpf_attr __user *uattr)

{

	struct bpf_prog *prog;

	int ret = -ENOTSUPP;



	if (CHECK_ATTR(BPF_PROG_TEST_RUN))

		return -EINVAL;



	prog = bpf_prog_get(attr->test.prog_fd);

	if (IS_ERR(prog))

		return PTR_ERR(prog);



	if (prog->aux->ops->test_run)

		ret = prog->aux->ops->test_run(prog, attr, uattr);



	bpf_prog_put(prog);

	return ret;

}



SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)

{

	union bpf_attr attr = {};
@@ -1039,7 +1061,6 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz 
	case BPF_OBJ_GET:

		err = bpf_obj_get(&attr);

		break;



#ifdef CONFIG_CGROUP_BPF

	case BPF_PROG_ATTACH:

		err = bpf_prog_attach(&attr);
@@ -1048,7 +1069,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz 
		err = bpf_prog_detach(&attr);

		break;

#endif



	case BPF_PROG_TEST_RUN:

		err = bpf_prog_test_run(&attr, uattr);

		break;

	default:

		err = -EINVAL;

		break;

net/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ obj-$(CONFIG_NET) += $(tmp-y) 


# LLC has to be linked before the files in net/802/

obj-$(CONFIG_LLC)		+= llc/

obj-$(CONFIG_NET)		+= ethernet/ 802/ sched/ netlink/

obj-$(CONFIG_NET)		+= ethernet/ 802/ sched/ netlink/ bpf/

obj-$(CONFIG_NETFILTER)		+= netfilter/

obj-$(CONFIG_INET)		+= ipv4/

obj-$(CONFIG_XFRM)		+= xfrm/

net/bpf/Makefile

0 → 100644
+1 −0
Original line number Diff line number Diff line 
obj-y	:= test_run.o

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