// SPDX-License-Identifier: GPL-2.0 /* XDP user-space packet buffer * Copyright(c) 2018 Intel Corporation. */ #include <linux/init.h> #include <linux/sched/mm.h> #include <linux/sched/signal.h> #include <linux/sched/task.h> #include <linux/uaccess.h> #include <linux/slab.h> #include <linux/bpf.h> #include <linux/mm.h> #include <linux/netdevice.h> #include <linux/rtnetlink.h> #include <linux/idr.h> #include "xdp_umem.h" #include "xsk_queue.h" #define XDP_UMEM_MIN_CHUNK_SIZE 2048 static DEFINE_IDA(umem_ida); void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) { unsigned long flags; spin_lock_irqsave(&umem->xsk_list_lock, flags); list_add_rcu(&xs->list, &umem->xsk_list); spin_unlock_irqrestore(&umem->xsk_list_lock, flags); } void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) { unsigned long flags; spin_lock_irqsave(&umem->xsk_list_lock, flags); list_del_rcu(&xs->list); spin_unlock_irqrestore(&umem->xsk_list_lock, flags); } /* The umem is stored both in the _rx struct and the _tx struct as we do * not know if the device has more tx queues than rx, or the opposite. * This might also change during run time. */ static int xdp_reg_umem_at_qid(struct net_device *dev, struct xdp_umem *umem, u16 queue_id) { if (queue_id >= max_t(unsigned int, dev->real_num_rx_queues, dev->real_num_tx_queues)) return -EINVAL; if (queue_id < dev->real_num_rx_queues) dev->_rx[queue_id].umem = umem; if (queue_id < dev->real_num_tx_queues) dev->_tx[queue_id].umem = umem; return 0; } struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev, u16 queue_id) { if (queue_id < dev->real_num_rx_queues) return dev->_rx[queue_id].umem; if (queue_id < dev->real_num_tx_queues) return dev->_tx[queue_id].umem; return NULL; } EXPORT_SYMBOL(xdp_get_umem_from_qid); static void xdp_clear_umem_at_qid(struct net_device *dev, u16 queue_id) { if (queue_id < dev->real_num_rx_queues) dev->_rx[queue_id].umem = NULL; if (queue_id < dev->real_num_tx_queues) dev->_tx[queue_id].umem = NULL; } int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, u16 queue_id, u16 flags) { bool force_zc, force_copy; struct netdev_bpf bpf; int err = 0; ASSERT_RTNL(); force_zc = flags & XDP_ZEROCOPY; force_copy = flags & XDP_COPY; if (force_zc && force_copy) return -EINVAL; if (xdp_get_umem_from_qid(dev, queue_id)) return -EBUSY; err = xdp_reg_umem_at_qid(dev, umem, queue_id); if (err) return err; umem->dev = dev; umem->queue_id = queue_id; dev_hold(dev); if (force_copy) /* For copy-mode, we are done. */ return 0; if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_async_xmit) { err = -EOPNOTSUPP; goto err_unreg_umem; } bpf.command = XDP_SETUP_XSK_UMEM; bpf.xsk.umem = umem; bpf.xsk.queue_id = queue_id; err = dev->netdev_ops->ndo_bpf(dev, &bpf); if (err) goto err_unreg_umem; umem->zc = true; return 0; err_unreg_umem: if (!force_zc) err = 0; /* fallback to copy mode */ if (err) xdp_clear_umem_at_qid(dev, queue_id); return err; } void xdp_umem_clear_dev(struct xdp_umem *umem) { struct netdev_bpf bpf; int err; ASSERT_RTNL(); if (!umem->dev) return; if (umem->zc) { bpf.command = XDP_SETUP_XSK_UMEM; bpf.xsk.umem = NULL; bpf.xsk.queue_id = umem->queue_id; err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf); if (err) WARN(1, "failed to disable umem!\n"); } xdp_clear_umem_at_qid(umem->dev, umem->queue_id); dev_put(umem->dev); umem->dev = NULL; umem->zc = false; } static void xdp_umem_unpin_pages(struct xdp_umem *umem) { unsigned int i; for (i = 0; i < umem->npgs; i++) { struct page *page = umem->pgs[i]; set_page_dirty_lock(page); put_page(page); } kfree(umem->pgs); umem->pgs = NULL; } static void xdp_umem_unaccount_pages(struct xdp_umem *umem) { if (umem->user) { atomic_long_sub(umem->npgs, &umem->user->locked_vm); free_uid(umem->user); } } static void xdp_umem_release(struct xdp_umem *umem) { rtnl_lock(); xdp_umem_clear_dev(umem); rtnl_unlock(); ida_simple_remove(&umem_ida, umem->id); if (umem->fq) { xskq_destroy(umem->fq); umem->fq = NULL; } if (umem->cq) { xskq_destroy(umem->cq); umem->cq = NULL; } xsk_reuseq_destroy(umem); xdp_umem_unpin_pages(umem); kfree(umem->pages); umem->pages = NULL; xdp_umem_unaccount_pages(umem); kfree(umem); } static void xdp_umem_release_deferred(struct work_struct *work) { struct xdp_umem *umem = container_of(work, struct xdp_umem, work); xdp_umem_release(umem); } void xdp_get_umem(struct xdp_umem *umem) { refcount_inc(&umem->users); } void xdp_put_umem(struct xdp_umem *umem) { if (!umem) return; if (refcount_dec_and_test(&umem->users)) { INIT_WORK(&umem->work, xdp_umem_release_deferred); schedule_work(&umem->work); } } static int xdp_umem_pin_pages(struct xdp_umem *umem) { unsigned int gup_flags = FOLL_WRITE; long npgs; int err; umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL | __GFP_NOWARN); if (!umem->pgs) return -ENOMEM; down_read(¤t->mm->mmap_sem); npgs = get_user_pages(umem->address, umem->npgs, gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL); up_read(¤t->mm->mmap_sem); if (npgs != umem->npgs) { if (npgs >= 0) { umem->npgs = npgs; err = -ENOMEM; goto out_pin; } err = npgs; goto out_pgs; } return 0; out_pin: xdp_umem_unpin_pages(umem); out_pgs: kfree(umem->pgs); umem->pgs = NULL; return err; } static int xdp_umem_account_pages(struct xdp_umem *umem) { unsigned long lock_limit, new_npgs, old_npgs; if (capable(CAP_IPC_LOCK)) return 0; lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; umem->user = get_uid(current_user()); do { old_npgs = atomic_long_read(&umem->user->locked_vm); new_npgs = old_npgs + umem->npgs; if (new_npgs > lock_limit) { free_uid(umem->user); umem->user = NULL; return -ENOBUFS; } } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs, new_npgs) != old_npgs); return 0; } static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) { u32 chunk_size = mr->chunk_size, headroom = mr->headroom; unsigned int chunks, chunks_per_page; u64 addr = mr->addr, size = mr->len; int size_chk, err, i; if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { /* Strictly speaking we could support this, if: * - huge pages, or* * - using an IOMMU, or * - making sure the memory area is consecutive * but for now, we simply say "computer says no". */ return -EINVAL; } if (!is_power_of_2(chunk_size)) return -EINVAL; if (!PAGE_ALIGNED(addr)) { /* Memory area has to be page size aligned. For * simplicity, this might change. */ return -EINVAL; } if ((addr + size) < addr) return -EINVAL; chunks = (unsigned int)div_u64(size, chunk_size); if (chunks == 0) return -EINVAL; chunks_per_page = PAGE_SIZE / chunk_size; if (chunks < chunks_per_page || chunks % chunks_per_page) return -EINVAL; headroom = ALIGN(headroom, 64); size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM; if (size_chk < 0) return -EINVAL; umem->address = (unsigned long)addr; umem->chunk_mask = ~((u64)chunk_size - 1); umem->size = size; umem->headroom = headroom; umem->chunk_size_nohr = chunk_size - headroom; umem->npgs = size / PAGE_SIZE; umem->pgs = NULL; umem->user = NULL; INIT_LIST_HEAD(&umem->xsk_list); spin_lock_init(&umem->xsk_list_lock); refcount_set(&umem->users, 1); err = xdp_umem_account_pages(umem); if (err) return err; err = xdp_umem_pin_pages(umem); if (err) goto out_account; umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL); if (!umem->pages) { err = -ENOMEM; goto out_account; } for (i = 0; i < umem->npgs; i++) umem->pages[i].addr = page_address(umem->pgs[i]); return 0; out_account: xdp_umem_unaccount_pages(umem); return err; } struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr) { struct xdp_umem *umem; int err; umem = kzalloc(sizeof(*umem), GFP_KERNEL); if (!umem) return ERR_PTR(-ENOMEM); err = ida_simple_get(&umem_ida, 0, 0, GFP_KERNEL); if (err < 0) { kfree(umem); return ERR_PTR(err); } umem->id = err; err = xdp_umem_reg(umem, mr); if (err) { ida_simple_remove(&umem_ida, umem->id); kfree(umem); return ERR_PTR(err); } return umem; } bool xdp_umem_validate_queues(struct xdp_umem *umem) { return umem->fq && umem->cq; }