| // 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 "xdp_umem.h" |
| #include "xsk_queue.h" |
| |
| #define XDP_UMEM_MIN_CHUNK_SIZE 2048 |
| |
| 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; |
| |
| if (xs->dev) { |
| spin_lock_irqsave(&umem->xsk_list_lock, flags); |
| list_del_rcu(&xs->list); |
| spin_unlock_irqrestore(&umem->xsk_list_lock, flags); |
| |
| if (umem->zc) |
| synchronize_net(); |
| } |
| } |
| |
| int xdp_umem_query(struct net_device *dev, u16 queue_id) |
| { |
| struct netdev_bpf bpf; |
| |
| ASSERT_RTNL(); |
| |
| memset(&bpf, 0, sizeof(bpf)); |
| bpf.command = XDP_QUERY_XSK_UMEM; |
| bpf.xsk.queue_id = queue_id; |
| |
| if (!dev->netdev_ops->ndo_bpf) |
| return 0; |
| return dev->netdev_ops->ndo_bpf(dev, &bpf) ?: !!bpf.xsk.umem; |
| } |
| |
| int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, |
| u32 queue_id, u16 flags) |
| { |
| bool force_zc, force_copy; |
| struct netdev_bpf bpf; |
| int err; |
| |
| force_zc = flags & XDP_ZEROCOPY; |
| force_copy = flags & XDP_COPY; |
| |
| if (force_zc && force_copy) |
| return -EINVAL; |
| |
| if (force_copy) |
| return 0; |
| |
| if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_async_xmit) |
| return force_zc ? -EOPNOTSUPP : 0; /* fail or fallback */ |
| |
| bpf.command = XDP_QUERY_XSK_UMEM; |
| |
| rtnl_lock(); |
| err = xdp_umem_query(dev, queue_id); |
| if (err) { |
| err = err < 0 ? -EOPNOTSUPP : -EBUSY; |
| goto err_rtnl_unlock; |
| } |
| |
| 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_rtnl_unlock; |
| rtnl_unlock(); |
| |
| dev_hold(dev); |
| umem->dev = dev; |
| umem->queue_id = queue_id; |
| umem->zc = true; |
| return 0; |
| |
| err_rtnl_unlock: |
| rtnl_unlock(); |
| return force_zc ? err : 0; /* fail or fallback */ |
| } |
| |
| static void xdp_umem_clear_dev(struct xdp_umem *umem) |
| { |
| struct netdev_bpf bpf; |
| int err; |
| |
| if (umem->dev) { |
| bpf.command = XDP_SETUP_XSK_UMEM; |
| bpf.xsk.umem = NULL; |
| bpf.xsk.queue_id = umem->queue_id; |
| |
| rtnl_lock(); |
| err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf); |
| rtnl_unlock(); |
| |
| if (err) |
| WARN(1, "failed to disable umem!\n"); |
| |
| dev_put(umem->dev); |
| umem->dev = NULL; |
| } |
| } |
| |
| 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) |
| { |
| struct task_struct *task; |
| struct mm_struct *mm; |
| |
| xdp_umem_clear_dev(umem); |
| |
| if (umem->fq) { |
| xskq_destroy(umem->fq); |
| umem->fq = NULL; |
| } |
| |
| if (umem->cq) { |
| xskq_destroy(umem->cq); |
| umem->cq = NULL; |
| } |
| |
| xdp_umem_unpin_pages(umem); |
| |
| task = get_pid_task(umem->pid, PIDTYPE_PID); |
| put_pid(umem->pid); |
| if (!task) |
| goto out; |
| mm = get_task_mm(task); |
| put_task_struct(task); |
| if (!mm) |
| goto out; |
| |
| mmput(mm); |
| kfree(umem->pages); |
| umem->pages = NULL; |
| |
| xdp_umem_unaccount_pages(umem); |
| out: |
| 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_write(¤t->mm->mmap_sem); |
| npgs = get_user_pages(umem->address, umem->npgs, |
| gup_flags, &umem->pgs[0], NULL); |
| up_write(¤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->pid = get_task_pid(current, PIDTYPE_PID); |
| umem->address = (unsigned long)addr; |
| umem->props.chunk_mask = ~((u64)chunk_size - 1); |
| umem->props.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) |
| goto out; |
| |
| 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); |
| out: |
| put_pid(umem->pid); |
| 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 = xdp_umem_reg(umem, mr); |
| if (err) { |
| kfree(umem); |
| return ERR_PTR(err); |
| } |
| |
| return umem; |
| } |
| |
| bool xdp_umem_validate_queues(struct xdp_umem *umem) |
| { |
| return umem->fq && umem->cq; |
| } |