On May 19, 2021, at 7:13 AM, Pavel Begunkov [off-list ref] wrote:

Draft a new program type BPF_PROG_TYPE_IOURING, which will be used by
io_uring to execute BPF-based requests.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c             | 21 +++++++++++++++++++++
include/linux/bpf_types.h |  2 ++
include/uapi/linux/bpf.h  |  1 +
kernel/bpf/syscall.c      |  1 +
kernel/bpf/verifier.c     |  5 ++++-
5 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1a4c9e513ac9..882b16b5e5eb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c

@@ -10201,6 +10201,27 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,

	return ret;
}

+static const struct bpf_func_proto *
+io_bpf_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	return bpf_base_func_proto(func_id);
+}
+
+static bool io_bpf_is_valid_access(int off, int size,
+				   enum bpf_access_type type,
+				   const struct bpf_prog *prog,
+				   struct bpf_insn_access_aux *info)
+{
+	return false;
+}
+
+const struct bpf_prog_ops bpf_io_uring_prog_ops = {};
+
+const struct bpf_verifier_ops bpf_io_uring_verifier_ops = {
+	.get_func_proto		= io_bpf_func_proto,
+	.is_valid_access	= io_bpf_is_valid_access,
+};
+
SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
		void __user *, arg, unsigned int, nr_args)
{

diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 99f7fd657d87..d0b7954887bd 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h

@@ -77,6 +77,8 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LSM, lsm,

	       void *, void *)
#endif /* CONFIG_BPF_LSM */
#endif
+BPF_PROG_TYPE(BPF_PROG_TYPE_IOURING, bpf_io_uring,
+	      void *, void *)

BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 4ba4ef0ff63a..de544f0fbeef 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h

@@ -206,6 +206,7 @@ enum bpf_prog_type {

	BPF_PROG_TYPE_EXT,
	BPF_PROG_TYPE_LSM,
	BPF_PROG_TYPE_SK_LOOKUP,
+	BPF_PROG_TYPE_IOURING,
};

enum bpf_attach_type {

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 250503482cda..6ef7a26f4dc3 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c

@@ -2041,6 +2041,7 @@ static bool is_net_admin_prog_type(enum bpf_prog_type prog_type)

	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
	case BPF_PROG_TYPE_CGROUP_SYSCTL:
	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_IOURING:
	case BPF_PROG_TYPE_EXT: /* extends any prog */
		return true;
	case BPF_PROG_TYPE_CGROUP_SKB:

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0399ac092b36..2a53f44618a7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c

@@ -8558,6 +8558,9 @@ static int check_return_code(struct bpf_verifier_env *env)

	case BPF_PROG_TYPE_SK_LOOKUP:
		range = tnum_range(SK_DROP, SK_PASS);
		break;
+	case BPF_PROG_TYPE_IOURING:
+		range = tnum_const(0);
+		break;
	case BPF_PROG_TYPE_EXT:
		/* freplace program can return anything as its return value
		 * depends on the to-be-replaced kernel func or bpf program.

@@ -12560,7 +12563,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)

	u64 key;

	if (prog->aux->sleepable && prog->type != BPF_PROG_TYPE_TRACING &&
-	    prog->type != BPF_PROG_TYPE_LSM) {
+	    prog->type != BPF_PROG_TYPE_LSM && prog->type != BPF_PROG_TYPE_IOURING) {