This patch introduces a new object in io_uring called an interface queue
(ifq) which contains:
* A pool region allocated by userspace and registered w/ io_uring where
Rx data is written to.
* A net device and one specific Rx queue in it that will be configured
for ZC Rx.
* A pair of shared ringbuffers w/ userspace, dubbed registered buf
(rbuf) rings. Each entry contains a pool region id and an offset + len
within that region. The kernel writes entries into the completion ring
to tell userspace where RX data is relative to the start of a region.
Userspace writes entries into the refill ring to tell the kernel when
it is done with the data.
For now, each io_uring instance has a single ifq, and each ifq has a
single pool region associated with one Rx queue.
Add a new opcode to io_uring_register that sets up an ifq. Size and
offsets of shared ringbuffers are returned to userspace for it to mmap.
The implementation will be added in a later patch.
Co-developed-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: David Wei <dw@xxxxxxxxxxx>
---
include/linux/io_uring_types.h | 6 +++
include/uapi/linux/io_uring.h | 50 +++++++++++++++++++++
io_uring/Makefile | 3 +-
io_uring/io_uring.c | 8 ++++
io_uring/kbuf.c | 27 ++++++++++++
io_uring/kbuf.h | 5 +++
io_uring/zc_rx.c | 79 ++++++++++++++++++++++++++++++++++
io_uring/zc_rx.h | 34 +++++++++++++++
8 files changed, 211 insertions(+), 1 deletion(-)
create mode 100644 io_uring/zc_rx.c
create mode 100644 io_uring/zc_rx.h
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 13d19b9be9f4..4f902e17b9c7 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -151,6 +151,10 @@ struct io_rings {
struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
};
+struct io_rbuf_ring {
+ struct io_uring rq, cq;
+};
+
struct io_restriction {
DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
@@ -336,6 +340,8 @@ struct io_ring_ctx {
struct io_rsrc_data *file_data;
struct io_rsrc_data *buf_data;
+ struct io_zc_rx_ifq *ifq;
+
/* protected by ->uring_lock */
struct list_head rsrc_ref_list;
struct io_alloc_cache rsrc_node_cache;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 8e61f8b7c2ce..84c82a789543 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -546,6 +546,9 @@ enum {
/* register a range of fixed file slots for automatic slot allocation */
IORING_REGISTER_FILE_ALLOC_RANGE = 25,
+ /* register a network interface queue for zerocopy */
+ IORING_REGISTER_ZC_RX_IFQ = 26,
+
/* this goes last */
IORING_REGISTER_LAST,
@@ -736,6 +739,53 @@ enum {
SOCKET_URING_OP_SIOCOUTQ,
};
+struct io_uring_rbuf_rqe {
+ __u32 off;
+ __u32 len;
+ __u16 region;
+ __u8 __pad[6];
+};
+
+struct io_uring_rbuf_cqe {
+ __u32 off;
+ __u32 len;
+ __u16 region;
+ __u8 flags;
+ __u8 __pad[3];
+};
+
+struct io_rbuf_rqring_offsets {
+ __u32 head;
+ __u32 tail;
+ __u32 rqes;
+ __u8 __pad[4];
+};
+
+struct io_rbuf_cqring_offsets {
+ __u32 head;
+ __u32 tail;
+ __u32 cqes;
+ __u8 __pad[4];
+};
+
+/*
+ * Argument for IORING_REGISTER_ZC_RX_IFQ
+ */
+struct io_uring_zc_rx_ifq_reg {
+ __u32 if_idx;
+ /* hw rx descriptor ring id */
+ __u32 if_rxq_id;
+ __u32 region_id;
+ __u32 rq_entries;
+ __u32 cq_entries;
+ __u32 flags;
+ __u16 cpu;
+
+ __u32 mmap_sz;
+ struct io_rbuf_rqring_offsets rq_off;
+ struct io_rbuf_cqring_offsets cq_off;
+};
+
#ifdef __cplusplus
}
#endif
diff --git a/io_uring/Makefile b/io_uring/Makefile
index 8cc8e5387a75..7818b015a1f2 100644
--- a/io_uring/Makefile
+++ b/io_uring/Makefile
@@ -7,5 +7,6 @@ obj-$(CONFIG_IO_URING) += io_uring.o xattr.o nop.o fs.o splice.o \
openclose.o uring_cmd.o epoll.o \
statx.o net.o msg_ring.o timeout.o \
sqpoll.o fdinfo.o tctx.o poll.o \
- cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o
+ cancel.o kbuf.o rsrc.o rw.o opdef.o \
+ notif.o zc_rx.o
obj-$(CONFIG_IO_WQ) += io-wq.o
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 783ed0fff71b..ae7f37aabe78 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -92,6 +92,7 @@
#include "cancel.h"
#include "net.h"
#include "notif.h"
+#include "zc_rx.h"
#include "timeout.h"
#include "poll.h"
@@ -3160,6 +3161,7 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
percpu_ref_kill(&ctx->refs);
xa_for_each(&ctx->personalities, index, creds)
io_unregister_personality(ctx, index);
+ io_unregister_zc_rx_ifq(ctx);
if (ctx->rings)
io_poll_remove_all(ctx, NULL, true);
mutex_unlock(&ctx->uring_lock);
@@ -4536,6 +4538,12 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
break;
ret = io_register_file_alloc_range(ctx, arg);
break;
+ case IORING_REGISTER_ZC_RX_IFQ:
+ ret = -EINVAL;
+ if (!arg || nr_args != 1)
+ break;
+ ret = io_register_zc_rx_ifq(ctx, arg);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 556f4df25b0f..30c3e5b20ab3 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -630,3 +630,30 @@ void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
return bl->buf_ring;
}
+
+int io_allocate_rbuf_ring(struct io_zc_rx_ifq *ifq,
+ struct io_uring_zc_rx_ifq_reg *reg)
+{
+ gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
+ size_t off, size, rq_size, cq_size;
+ void *ptr;
+
+ off = sizeof(struct io_rbuf_ring);
+ rq_size = reg->rq_entries * sizeof(struct io_uring_rbuf_rqe);
+ cq_size = reg->cq_entries * sizeof(struct io_uring_rbuf_cqe);
+ size = off + rq_size + cq_size;
+ ptr = (void *) __get_free_pages(gfp, get_order(size));
+ if (!ptr)
+ return -ENOMEM;
+ ifq->ring = (struct io_rbuf_ring *)ptr;
+ ifq->rqes = (struct io_uring_rbuf_rqe *)((char *)ptr + off);
+ ifq->cqes = (struct io_uring_rbuf_cqe *)((char *)ifq->rqes + rq_size);
+
+ return 0;
+}
+
+void io_free_rbuf_ring(struct io_zc_rx_ifq *ifq)
+{
+ if (ifq->ring)
+ folio_put(virt_to_folio(ifq->ring));
+}
diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index d14345ef61fc..6c8afda93646 100644
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -4,6 +4,8 @@
#include <uapi/linux/io_uring.h>
+#include "zc_rx.h"
+
struct io_buffer_list {
/*
* If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
@@ -57,6 +59,9 @@ void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid);
+int io_allocate_rbuf_ring(struct io_zc_rx_ifq *ifq, struct io_uring_zc_rx_ifq_reg *reg);
+void io_free_rbuf_ring(struct io_zc_rx_ifq *ifq);
+
static inline void io_kbuf_recycle_ring(struct io_kiocb *req)
{
/*
diff --git a/io_uring/zc_rx.c b/io_uring/zc_rx.c
new file mode 100644
index 000000000000..45dab29fe0ae
--- /dev/null
+++ b/io_uring/zc_rx.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+#if defined(CONFIG_NET)
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "kbuf.h"
+#include "zc_rx.h"
+
+static struct io_zc_rx_ifq *io_zc_rx_ifq_alloc(struct io_ring_ctx *ctx)
+{
+ struct io_zc_rx_ifq *ifq;
+
+ ifq = kzalloc(sizeof(*ifq), GFP_KERNEL);
+ if (!ifq)
+ return NULL;
+
+ ifq->ctx = ctx;
+
+ return ifq;
+}
+
+static void io_zc_rx_ifq_free(struct io_zc_rx_ifq *ifq)
+{
+ io_free_rbuf_ring(ifq);
+ kfree(ifq);
+}
+
+int io_register_zc_rx_ifq(struct io_ring_ctx *ctx,
+ struct io_uring_zc_rx_ifq_reg __user *arg)
+{
+ struct io_uring_zc_rx_ifq_reg reg;
+ struct io_zc_rx_ifq *ifq;
+ int ret;
+
+ if (copy_from_user(®, arg, sizeof(reg)))
+ return -EFAULT;
+ if (ctx->ifq)
+ return -EBUSY;
+
+ ifq = io_zc_rx_ifq_alloc(ctx);
+ if (!ifq)
+ return -ENOMEM;
+
+ /* TODO: initialise network interface */
+
+ ret = io_allocate_rbuf_ring(ifq, ®);
+ if (ret)
+ goto err;
+
+ /* TODO: map zc region and initialise zc pool */
+
+ ifq->rq_entries = reg.rq_entries;
+ ifq->cq_entries = reg.cq_entries;
+ ifq->if_rxq_id = reg.if_rxq_id;
+ ctx->ifq = ifq;
+
+ return 0;
+err:
+ io_zc_rx_ifq_free(ifq);
+ return ret;
+}
+
+int io_unregister_zc_rx_ifq(struct io_ring_ctx *ctx)
+{
+ struct io_zc_rx_ifq *ifq = ctx->ifq;
+
+ if (!ifq)
+ return -EINVAL;
+
+ ctx->ifq = NULL;
+ io_zc_rx_ifq_free(ifq);
+ return 0;
+}
+#endif
diff --git a/io_uring/zc_rx.h b/io_uring/zc_rx.h
new file mode 100644
index 000000000000..5f6d80c1c2b8
--- /dev/null
+++ b/io_uring/zc_rx.h
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_ZC_RX_H
+#define IOU_ZC_RX_H
+
+struct io_zc_rx_ifq {
+ struct io_ring_ctx *ctx;
+ struct net_device *dev;
+ struct io_rbuf_ring *ring;
+ struct io_uring_rbuf_rqe *rqes;
+ struct io_uring_rbuf_cqe *cqes;
+ u32 rq_entries, cq_entries;
+ void *pool;
+
+ /* hw rx descriptor ring id */
+ u32 if_rxq_id;
+};
+
+#if defined(CONFIG_NET)
+int io_register_zc_rx_ifq(struct io_ring_ctx *ctx,
+ struct io_uring_zc_rx_ifq_reg __user *arg);
+int io_unregister_zc_rx_ifq(struct io_ring_ctx *ctx);
+#else
+static inline int io_register_zc_rx_ifq(struct io_ring_ctx *ctx,
+ struct io_uring_zc_rx_ifq_reg __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+static inline int io_unregister_zc_rx_ifq(struct io_ring_ctx *ctx)
+{
+ return -EOPNOTSUPP;
+}
+#endif
+
+#endif
--
2.39.3
