From 423f38329d267969130fb6f2c685f73d72687558 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 2 May 2018 13:01:24 +0200 Subject: [PATCH] xsk: add umem fill queue support and mmap Here, we add another setsockopt for registered user memory (umem) called XDP_UMEM_FILL_QUEUE. Using this socket option, the process can ask the kernel to allocate a queue (ring buffer) and also mmap it (XDP_UMEM_PGOFF_FILL_QUEUE) into the process. The queue is used to explicitly pass ownership of umem frames from the user process to the kernel. These frames will in a later patch be filled in with Rx packet data by the kernel. v2: Fixed potential crash in xsk_mmap. Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov --- include/uapi/linux/if_xdp.h | 15 +++++++++ net/xdp/Makefile | 2 +- net/xdp/xdp_umem.c | 5 +++ net/xdp/xdp_umem.h | 2 ++ net/xdp/xsk.c | 65 ++++++++++++++++++++++++++++++++++++- net/xdp/xsk_queue.c | 58 +++++++++++++++++++++++++++++++++ net/xdp/xsk_queue.h | 38 ++++++++++++++++++++++ 7 files changed, 183 insertions(+), 2 deletions(-) create mode 100644 net/xdp/xsk_queue.c create mode 100644 net/xdp/xsk_queue.h diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h index 41252135a0fe..975661e1baca 100644 --- a/include/uapi/linux/if_xdp.h +++ b/include/uapi/linux/if_xdp.h @@ -23,6 +23,7 @@ /* XDP socket options */ #define XDP_UMEM_REG 3 +#define XDP_UMEM_FILL_RING 4 struct xdp_umem_reg { __u64 addr; /* Start of packet data area */ @@ -31,4 +32,18 @@ struct xdp_umem_reg { __u32 frame_headroom; /* Frame head room */ }; +/* Pgoff for mmaping the rings */ +#define XDP_UMEM_PGOFF_FILL_RING 0x100000000 + +struct xdp_ring { + __u32 producer __attribute__((aligned(64))); + __u32 consumer __attribute__((aligned(64))); +}; + +/* Used for the fill and completion queues for buffers */ +struct xdp_umem_ring { + struct xdp_ring ptrs; + __u32 desc[0] __attribute__((aligned(64))); +}; + #endif /* _LINUX_IF_XDP_H */ diff --git a/net/xdp/Makefile b/net/xdp/Makefile index a5d736640a0f..074fb2b2d51c 100644 --- a/net/xdp/Makefile +++ b/net/xdp/Makefile @@ -1,2 +1,2 @@ -obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o +obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o xsk_queue.o diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index ec8b3552be44..e1f627d0cc1c 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -65,6 +65,11 @@ static void xdp_umem_release(struct xdp_umem *umem) struct task_struct *task; struct mm_struct *mm; + if (umem->fq) { + xskq_destroy(umem->fq); + umem->fq = NULL; + } + if (umem->pgs) { xdp_umem_unpin_pages(umem); diff --git a/net/xdp/xdp_umem.h b/net/xdp/xdp_umem.h index 4597ae81a221..25634b8a5c6f 100644 --- a/net/xdp/xdp_umem.h +++ b/net/xdp/xdp_umem.h @@ -19,9 +19,11 @@ #include #include +#include "xsk_queue.h" #include "xdp_umem_props.h" struct xdp_umem { + struct xsk_queue *fq; struct page **pgs; struct xdp_umem_props props; u32 npgs; diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 84e0e867febb..da67a3c5c1c9 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -32,6 +32,7 @@ #include #include +#include "xsk_queue.h" #include "xdp_umem.h" static struct xdp_sock *xdp_sk(struct sock *sk) @@ -39,6 +40,21 @@ static struct xdp_sock *xdp_sk(struct sock *sk) return (struct xdp_sock *)sk; } +static int xsk_init_queue(u32 entries, struct xsk_queue **queue) +{ + struct xsk_queue *q; + + if (entries == 0 || *queue || !is_power_of_2(entries)) + return -EINVAL; + + q = xskq_create(entries); + if (!q) + return -ENOMEM; + + *queue = q; + return 0; +} + static int xsk_release(struct socket *sock) { struct sock *sk = sock->sk; @@ -101,6 +117,23 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, mutex_unlock(&xs->mutex); return 0; } + case XDP_UMEM_FILL_RING: + { + struct xsk_queue **q; + int entries; + + if (!xs->umem) + return -EINVAL; + + if (copy_from_user(&entries, optval, sizeof(entries))) + return -EFAULT; + + mutex_lock(&xs->mutex); + q = &xs->umem->fq; + err = xsk_init_queue(entries, q); + mutex_unlock(&xs->mutex); + return err; + } default: break; } @@ -108,6 +141,36 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, return -ENOPROTOOPT; } +static int xsk_mmap(struct file *file, struct socket *sock, + struct vm_area_struct *vma) +{ + unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; + unsigned long size = vma->vm_end - vma->vm_start; + struct xdp_sock *xs = xdp_sk(sock->sk); + struct xsk_queue *q = NULL; + unsigned long pfn; + struct page *qpg; + + if (!xs->umem) + return -EINVAL; + + if (offset == XDP_UMEM_PGOFF_FILL_RING) + q = xs->umem->fq; + else + return -EINVAL; + + if (!q) + return -EINVAL; + + qpg = virt_to_head_page(q->ring); + if (size > (PAGE_SIZE << compound_order(qpg))) + return -EINVAL; + + pfn = virt_to_phys(q->ring) >> PAGE_SHIFT; + return remap_pfn_range(vma, vma->vm_start, pfn, + size, vma->vm_page_prot); +} + static struct proto xsk_proto = { .name = "XDP", .owner = THIS_MODULE, @@ -131,7 +194,7 @@ static const struct proto_ops xsk_proto_ops = { .getsockopt = sock_no_getsockopt, .sendmsg = sock_no_sendmsg, .recvmsg = sock_no_recvmsg, - .mmap = sock_no_mmap, + .mmap = xsk_mmap, .sendpage = sock_no_sendpage, }; diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c new file mode 100644 index 000000000000..23da4f29d3fb --- /dev/null +++ b/net/xdp/xsk_queue.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 +/* XDP user-space ring structure + * Copyright(c) 2018 Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include + +#include "xsk_queue.h" + +static u32 xskq_umem_get_ring_size(struct xsk_queue *q) +{ + return sizeof(struct xdp_umem_ring) + q->nentries * sizeof(u32); +} + +struct xsk_queue *xskq_create(u32 nentries) +{ + struct xsk_queue *q; + gfp_t gfp_flags; + size_t size; + + q = kzalloc(sizeof(*q), GFP_KERNEL); + if (!q) + return NULL; + + q->nentries = nentries; + q->ring_mask = nentries - 1; + + gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | + __GFP_COMP | __GFP_NORETRY; + size = xskq_umem_get_ring_size(q); + + q->ring = (struct xdp_ring *)__get_free_pages(gfp_flags, + get_order(size)); + if (!q->ring) { + kfree(q); + return NULL; + } + + return q; +} + +void xskq_destroy(struct xsk_queue *q) +{ + if (!q) + return; + + page_frag_free(q->ring); + kfree(q); +} diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h new file mode 100644 index 000000000000..7eb556bf73be --- /dev/null +++ b/net/xdp/xsk_queue.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0 + * XDP user-space ring structure + * Copyright(c) 2018 Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#ifndef _LINUX_XSK_QUEUE_H +#define _LINUX_XSK_QUEUE_H + +#include +#include + +#include "xdp_umem_props.h" + +struct xsk_queue { + struct xdp_umem_props umem_props; + u32 ring_mask; + u32 nentries; + u32 prod_head; + u32 prod_tail; + u32 cons_head; + u32 cons_tail; + struct xdp_ring *ring; + u64 invalid_descs; +}; + +struct xsk_queue *xskq_create(u32 nentries); +void xskq_destroy(struct xsk_queue *q); + +#endif /* _LINUX_XSK_QUEUE_H */