From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from hr2.samba.org (hr2.samba.org [144.76.82.148]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 07DC233372B; Thu, 13 Nov 2025 10:42:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=144.76.82.148 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763030578; cv=none; b=ZH4yWrLOQ35Giu+DqxjLOEvoS1K5Uu1Es0sLotsMrwWnj0g8ilkVjHM0xLCHXMFOJkqLs2snZj5y+CinJxOUyYwesq3RnwKKgCbsdgX46S8sSIQzRs9ymBzZlCSgOP600pbc/loeS3wA+xTUAmkmCjsHZB0us6a2vdJo7EQQyzc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763030578; c=relaxed/simple; bh=whj3n/T6PmORVK4JkoSl9VDuMOzvpKT7dQnUXWT4W6A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=La5H5mwSL6f6o+EVTZKf3WCbANlDzn88QXDBu3JjReB95OHTIYu6GOkwia8t9Ovf0528mZrOfDGabnfp04Ef0ZCWPrmGaXNpHNg3yv/qMcXeePIAfQx9VDCda0K6+VXgeH7AV+/J2PvOq1X2qT+ZHpPl4y7+JKEW0m2zWuj6idQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=samba.org; spf=pass smtp.mailfrom=samba.org; dkim=pass (3072-bit key) header.d=samba.org header.i=@samba.org header.b=CqVnzDbL; arc=none smtp.client-ip=144.76.82.148 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=samba.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samba.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (3072-bit key) header.d=samba.org header.i=@samba.org header.b="CqVnzDbL" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42; h=From:Cc:To:Date:Message-ID; bh=f9OxqO8l4QrhVxX8ILnh3s0jiplaB1n16XfpK4pLU4Q=; b=CqVnzDbLyEUvbB/oQl8ruP/pmC D4m0lRwx4V6Xv6YMuUHJHGxjXgl03q2OJ9M5Kx46giMn7P2FPkks9fQdUyjtOXDJfBF91pwszyrHh asLDYHKTgnKfiJ4p6TupJmGT2qd8HqeeKOcLYmFXGueIcCcgAmWph1sTpnPBoC5t14RCAqR4LiKAy 6kmOPH+mjW6JdczOT/+YCNROJMAd2fJrZh6UdksUwEQbZ6OswZj9UzUpeJQwvJFw1vZM5hNa5aADM NfKJMUm/oYtdOk+HS7fBuTSy8bOy9g45Z5Nhb14qgsD/I1dDtxEZipE6ztUruTHnUh/41ouVt8w3Y xJmfO490mWavSz8iF0Sf/9EZZRdNyI/jiKDYAZCFLQbVMJAMi3EqNk3v6gUCmIPmYhPY65JkYhUxj KAI+113ijOEs1wJ/6gjHInn4GFbZqwzYtibpc0sLgH8NlqU8rf09IWJylYbGgjl2RB+nZn6Uf/qGk k7n0VhiPsjpvTVv+zf9eDth0; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.3:ECDHE_SECP256R1__ECDSA_SECP256R1_SHA256__CHACHA20_POLY1305:256) (Exim) id 1vJUmz-00DtLT-2N; Thu, 13 Nov 2025 10:42:53 +0000 Message-ID: <944b9487-059f-4c9b-b383-3ae4e359e01b@samba.org> Date: Thu, 13 Nov 2025 11:42:53 +0100 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/5] io_uring: bpf: add buffer support for IORING_OP_BPF To: Ming Lei , Jens Axboe , io-uring@vger.kernel.org Cc: Caleb Sander Mateos , Akilesh Kailash , bpf@vger.kernel.org, Alexei Starovoitov References: <20251104162123.1086035-1-ming.lei@redhat.com> <20251104162123.1086035-5-ming.lei@redhat.com> Content-Language: en-US From: Stefan Metzmacher In-Reply-To: <20251104162123.1086035-5-ming.lei@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Am 04.11.25 um 17:21 schrieb Ming Lei: > Add support for passing 0-2 buffers to BPF operations through > IORING_OP_BPF. Buffer types are encoded in sqe->bpf_op_flags > using dedicated 3-bit fields for each buffer. > > Buffer 1 can be: > - None (no buffer) > - Plain user buffer (addr=sqe->addr, len=sqe->len) > - Fixed/registered buffer (index=sqe->buf_index, offset=sqe->addr, > len=sqe->len) > > Buffer 2 can be: > - None (no buffer) > - Plain user buffer (addr=sqe->addr3, len=sqe->optlen) > > The sqe->bpf_op_flags layout (32 bits): > Bits 31-24: BPF operation ID (8 bits) > Bits 23-21: Buffer 1 type (3 bits) > Bits 20-18: Buffer 2 type (3 bits) > Bits 17-0: Custom BPF flags (18 bits) > > Using 3-bit encoding for each buffer type allows for future > expansion to 8 types (0-7). Currently types 0-2 are defined > (none/plain/fixed) and 3-7 are reserved for future use. > > Buffer 2 currently only supports none/plain types because the > io_uring framework can only handle one fixed buffer per request > (via req->buf_index). The 3-bit encoding provides room for > future enhancements. > > Buffer metadata (addresses, lengths) is stored in the extended > uring_bpf_data structure and is accessible to BPF programs with > readonly permissions. Buffer types can be extracted from the opf > field using IORING_BPF_BUF1_TYPE() and IORING_BPF_BUF2_TYPE() > macros. > > Valid buffer combinations: > - 0 buffers > - 1 plain buffer > - 1 fixed buffer > - 2 plain buffers > - 1 fixed buffer + 1 plain buffer > > Signed-off-by: Ming Lei > --- > include/uapi/linux/io_uring.h | 45 +++++++++++++++++++++++-- > io_uring/bpf.c | 63 ++++++++++++++++++++++++++++++++++- > io_uring/uring_bpf.h | 12 ++++++- > 3 files changed, 116 insertions(+), 4 deletions(-) > > diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h > index 94d2050131ac..950f4cfbbf86 100644 > --- a/include/uapi/linux/io_uring.h > +++ b/include/uapi/linux/io_uring.h > @@ -429,12 +429,53 @@ enum io_uring_op { > #define IORING_SEND_VECTORIZED (1U << 5) > > /* > - * sqe->bpf_op_flags top 8bits is for storing bpf op > - * The other 24bits are used for bpf prog > + * sqe->bpf_op_flags layout (32 bits total): > + * Bits 31-24: BPF operation ID (8 bits, 256 possible operations) > + * Bits 23-21: Buffer 1 type (3 bits: none/plain/fixed/reserved) > + * Bits 20-18: Buffer 2 type (3 bits: none/plain/reserved) > + * Bits 17-0: Custom BPF flags (18 bits, available for BPF programs) > + * > + * For IORING_OP_BPF, buffers are specified as follows: > + * Buffer 1 (plain): addr=sqe->addr, len=sqe->len > + * Buffer 1 (fixed): index=sqe->buf_index, offset=sqe->addr, len=sqe->len > + * Buffer 2 (plain): addr=sqe->addr3, len=sqe->optlen > + * > + * Note: Buffer 1 can be none/plain/fixed. Buffer 2 can only be none/plain. > + * 3-bit encoding for each buffer allows for future expansion to 8 types (0-7). > + * Currently only one fixed buffer per request is supported (buffer 1). > + * Valid combinations: 0 buffers, 1 plain, 1 fixed, 2 plain, 1 fixed + 1 plain. > */ > #define IORING_BPF_OP_BITS (8) > #define IORING_BPF_OP_SHIFT (24) > > +/* Buffer type encoding in sqe->bpf_op_flags */ > +#define IORING_BPF_BUF1_TYPE_SHIFT (21) > +#define IORING_BPF_BUF2_TYPE_SHIFT (18) > +#define IORING_BPF_BUF_TYPE_NONE (0) /* No buffer */ > +#define IORING_BPF_BUF_TYPE_PLAIN (1) /* Plain user buffer */ > +#define IORING_BPF_BUF_TYPE_FIXED (2) /* Fixed/registered buffer */ > +#define IORING_BPF_BUF_TYPE_MASK (7) /* 3-bit mask */ > + > +/* Helper macros to encode/decode buffer types */ > +#define IORING_BPF_BUF1_TYPE(flags) \ > + (((flags) >> IORING_BPF_BUF1_TYPE_SHIFT) & IORING_BPF_BUF_TYPE_MASK) > +#define IORING_BPF_BUF2_TYPE(flags) \ > + (((flags) >> IORING_BPF_BUF2_TYPE_SHIFT) & IORING_BPF_BUF_TYPE_MASK) > +#define IORING_BPF_SET_BUF1_TYPE(type) \ > + (((type) & IORING_BPF_BUF_TYPE_MASK) << IORING_BPF_BUF1_TYPE_SHIFT) > +#define IORING_BPF_SET_BUF2_TYPE(type) \ > + (((type) & IORING_BPF_BUF_TYPE_MASK) << IORING_BPF_BUF2_TYPE_SHIFT) > + > +/* Custom BPF flags mask (18 bits available, bits 17-0) */ > +#define IORING_BPF_CUSTOM_FLAGS_MASK ((1U << 18) - 1) > + > +/* Encode all components into sqe->bpf_op_flags */ > +#define IORING_BPF_OP_FLAGS(op, buf1_type, buf2_type, flags) \ > + (((op) << IORING_BPF_OP_SHIFT) | \ > + IORING_BPF_SET_BUF1_TYPE(buf1_type) | \ > + IORING_BPF_SET_BUF2_TYPE(buf2_type) | \ > + ((flags) & IORING_BPF_CUSTOM_FLAGS_MASK)) > + > /* > * cqe.res for IORING_CQE_F_NOTIF if > * IORING_SEND_ZC_REPORT_USAGE was requested > diff --git a/io_uring/bpf.c b/io_uring/bpf.c > index 8227be6d5a10..e837c3d57b96 100644 > --- a/io_uring/bpf.c > +++ b/io_uring/bpf.c > @@ -11,8 +11,10 @@ > #include > #include > #include > +#include > #include "io_uring.h" > #include "uring_bpf.h" > +#include "rsrc.h" > > #define MAX_BPF_OPS_COUNT (1 << IORING_BPF_OP_BITS) > > @@ -28,7 +30,7 @@ static inline unsigned char uring_bpf_get_op(unsigned int op_flags) > > static inline unsigned int uring_bpf_get_flags(unsigned int op_flags) > { > - return op_flags & ((1U << IORING_BPF_OP_SHIFT) - 1); > + return op_flags & IORING_BPF_CUSTOM_FLAGS_MASK; > } > > static inline struct uring_bpf_ops *uring_bpf_get_ops(struct uring_bpf_data *data) > @@ -36,18 +38,77 @@ static inline struct uring_bpf_ops *uring_bpf_get_ops(struct uring_bpf_data *dat > return &bpf_ops[uring_bpf_get_op(data->opf)]; > } > > +static int io_bpf_prep_buffers(struct io_kiocb *req, > + const struct io_uring_sqe *sqe, > + struct uring_bpf_data *data, > + unsigned int op_flags) > +{ > + u8 buf1_type, buf2_type; > + > + /* Extract buffer configuration from bpf_op_flags */ > + buf1_type = IORING_BPF_BUF1_TYPE(op_flags); > + buf2_type = IORING_BPF_BUF2_TYPE(op_flags); > + > + /* Prepare buffer 1 */ > + if (buf1_type == IORING_BPF_BUF_TYPE_PLAIN) { > + /* Plain user buffer: addr=sqe->addr, len=sqe->len */ > + data->buf1_addr = READ_ONCE(sqe->addr); > + data->buf1_len = READ_ONCE(sqe->len); > + } else if (buf1_type == IORING_BPF_BUF_TYPE_FIXED) { > + /* Fixed buffer: index=sqe->buf_index, offset=sqe->addr, len=sqe->len */ > + req->buf_index = READ_ONCE(sqe->buf_index); > + data->buf1_addr = READ_ONCE(sqe->addr); /* offset within fixed buffer */ > + data->buf1_len = READ_ONCE(sqe->len); > + > + /* Validate buffer index */ > + if (unlikely(!req->ctx->buf_table.nr)) > + return -EFAULT; > + if (unlikely(req->buf_index >= req->ctx->buf_table.nr)) > + return -EINVAL; > + } else if (buf1_type == IORING_BPF_BUF_TYPE_NONE) { > + data->buf1_addr = 0; > + data->buf1_len = 0; > + } else { > + return -EINVAL; > + } > + > + /* Prepare buffer 2 (plain only - io_uring only supports one fixed buffer) */ > + if (buf2_type == IORING_BPF_BUF_TYPE_PLAIN) { > + /* Plain user buffer: addr=sqe->addr3, len=sqe->optlen */ > + data->buf2_addr = READ_ONCE(sqe->addr3); > + data->buf2_len = READ_ONCE(sqe->optlen); > + } else if (buf2_type == IORING_BPF_BUF_TYPE_NONE) { > + data->buf2_addr = 0; > + data->buf2_len = 0; > + } else { > + return -EINVAL; > + } > + > + return 0; > +} > + > + > int io_uring_bpf_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) > { > struct uring_bpf_data *data = io_kiocb_to_cmd(req, struct uring_bpf_data); > unsigned int op_flags = READ_ONCE(sqe->bpf_op_flags); > struct uring_bpf_ops *ops; > + int ret; > > if (!(req->ctx->flags & IORING_SETUP_BPF)) > return -EACCES; > > + if (uring_bpf_get_flags(op_flags)) > + return -EINVAL; > + > data->opf = op_flags; > ops = &bpf_ops[uring_bpf_get_op(data->opf)]; > > + /* Prepare buffers based on buffer type flags */ > + ret = io_bpf_prep_buffers(req, sqe, data, op_flags); > + if (ret) > + return ret; > + > if (ops->prep_fn) > return ops->prep_fn(data, sqe); > return -EOPNOTSUPP; > diff --git a/io_uring/uring_bpf.h b/io_uring/uring_bpf.h > index c76eba887d22..c919931cb4b0 100644 > --- a/io_uring/uring_bpf.h > +++ b/io_uring/uring_bpf.h > @@ -7,8 +7,18 @@ struct uring_bpf_data { > struct file *file; > u32 opf; > > + /* Buffer 1 metadata - readable for bpf prog */ > + u32 buf1_len; /* buffer 1 length, bytes 12-15 */ > + u64 buf1_addr; /* buffer 1 address or offset, bytes 16-23 */ > + > + /* Buffer 2 metadata - readable for bpf prog (plain only) */ > + u64 buf2_addr; /* buffer 2 address, bytes 24-31 */ > + u32 buf2_len; /* buffer 2 length, bytes 32-35 */ > + u32 __pad; /* padding, bytes 36-39 */ I'm wondering if this should be in the generic struct uring_bpf_data at all. For io_uring_cmd we have helper functions like io_uring_cmd_import_fixed[_vec] which can be used by the implementation, but the layout on top of io_uring_cmd->pdu is up to the specific operation. Thinking about it, I'm wondering if the bpf operations could be implemented on top of io_uring_cmd. metze