1 // SPDX-License-Identifier: GPL-2.0
2 /* XDP user-space packet buffer
3 * Copyright(c) 2018 Intel Corporation.
6 #include <linux/init.h>
7 #include <linux/sched/mm.h>
8 #include <linux/sched/signal.h>
9 #include <linux/sched/task.h>
10 #include <linux/uaccess.h>
11 #include <linux/slab.h>
12 #include <linux/bpf.h>
14 #include <linux/netdevice.h>
15 #include <linux/rtnetlink.h>
16 #include <linux/idr.h>
19 #include "xsk_queue.h"
21 #define XDP_UMEM_MIN_CHUNK_SIZE 2048
23 static DEFINE_IDA(umem_ida);
25 void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
29 spin_lock_irqsave(&umem->xsk_list_lock, flags);
30 list_add_rcu(&xs->list, &umem->xsk_list);
31 spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
34 void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
38 spin_lock_irqsave(&umem->xsk_list_lock, flags);
39 list_del_rcu(&xs->list);
40 spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
43 /* The umem is stored both in the _rx struct and the _tx struct as we do
44 * not know if the device has more tx queues than rx, or the opposite.
45 * This might also change during run time.
47 static int xdp_reg_umem_at_qid(struct net_device *dev, struct xdp_umem *umem,
50 if (queue_id >= max_t(unsigned int,
51 dev->real_num_rx_queues,
52 dev->real_num_tx_queues))
55 if (queue_id < dev->real_num_rx_queues)
56 dev->_rx[queue_id].umem = umem;
57 if (queue_id < dev->real_num_tx_queues)
58 dev->_tx[queue_id].umem = umem;
63 struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev,
66 if (queue_id < dev->real_num_rx_queues)
67 return dev->_rx[queue_id].umem;
68 if (queue_id < dev->real_num_tx_queues)
69 return dev->_tx[queue_id].umem;
73 EXPORT_SYMBOL(xdp_get_umem_from_qid);
75 static void xdp_clear_umem_at_qid(struct net_device *dev, u16 queue_id)
77 if (queue_id < dev->real_num_rx_queues)
78 dev->_rx[queue_id].umem = NULL;
79 if (queue_id < dev->real_num_tx_queues)
80 dev->_tx[queue_id].umem = NULL;
83 int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
84 u16 queue_id, u16 flags)
86 bool force_zc, force_copy;
87 struct netdev_bpf bpf;
90 force_zc = flags & XDP_ZEROCOPY;
91 force_copy = flags & XDP_COPY;
93 if (force_zc && force_copy)
97 if (xdp_get_umem_from_qid(dev, queue_id)) {
102 err = xdp_reg_umem_at_qid(dev, umem, queue_id);
104 goto out_rtnl_unlock;
107 umem->queue_id = queue_id;
112 /* For copy-mode, we are done. */
113 goto out_rtnl_unlock;
115 if (!dev->netdev_ops->ndo_bpf ||
116 !dev->netdev_ops->ndo_xsk_async_xmit) {
121 bpf.command = XDP_SETUP_XSK_UMEM;
123 bpf.xsk.queue_id = queue_id;
125 err = dev->netdev_ops->ndo_bpf(dev, &bpf);
135 err = 0; /* fallback to copy mode */
137 xdp_clear_umem_at_qid(dev, queue_id);
143 void xdp_umem_clear_dev(struct xdp_umem *umem)
145 struct netdev_bpf bpf;
154 bpf.command = XDP_SETUP_XSK_UMEM;
156 bpf.xsk.queue_id = umem->queue_id;
158 err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf);
161 WARN(1, "failed to disable umem!\n");
164 xdp_clear_umem_at_qid(umem->dev, umem->queue_id);
171 static void xdp_umem_unpin_pages(struct xdp_umem *umem)
175 for (i = 0; i < umem->npgs; i++) {
176 struct page *page = umem->pgs[i];
178 set_page_dirty_lock(page);
186 static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
189 atomic_long_sub(umem->npgs, &umem->user->locked_vm);
190 free_uid(umem->user);
194 static void xdp_umem_release(struct xdp_umem *umem)
197 xdp_umem_clear_dev(umem);
200 ida_simple_remove(&umem_ida, umem->id);
203 xskq_destroy(umem->fq);
208 xskq_destroy(umem->cq);
212 xsk_reuseq_destroy(umem);
214 xdp_umem_unpin_pages(umem);
219 xdp_umem_unaccount_pages(umem);
223 static void xdp_umem_release_deferred(struct work_struct *work)
225 struct xdp_umem *umem = container_of(work, struct xdp_umem, work);
227 xdp_umem_release(umem);
230 void xdp_get_umem(struct xdp_umem *umem)
232 refcount_inc(&umem->users);
235 void xdp_put_umem(struct xdp_umem *umem)
240 if (refcount_dec_and_test(&umem->users)) {
241 INIT_WORK(&umem->work, xdp_umem_release_deferred);
242 schedule_work(&umem->work);
246 static int xdp_umem_pin_pages(struct xdp_umem *umem)
248 unsigned int gup_flags = FOLL_WRITE;
252 umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs),
253 GFP_KERNEL | __GFP_NOWARN);
257 down_read(¤t->mm->mmap_sem);
258 npgs = get_user_pages(umem->address, umem->npgs,
259 gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL);
260 up_read(¤t->mm->mmap_sem);
262 if (npgs != umem->npgs) {
274 xdp_umem_unpin_pages(umem);
281 static int xdp_umem_account_pages(struct xdp_umem *umem)
283 unsigned long lock_limit, new_npgs, old_npgs;
285 if (capable(CAP_IPC_LOCK))
288 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
289 umem->user = get_uid(current_user());
292 old_npgs = atomic_long_read(&umem->user->locked_vm);
293 new_npgs = old_npgs + umem->npgs;
294 if (new_npgs > lock_limit) {
295 free_uid(umem->user);
299 } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs,
300 new_npgs) != old_npgs);
304 static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
306 u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
307 unsigned int chunks, chunks_per_page;
308 u64 addr = mr->addr, size = mr->len;
309 int size_chk, err, i;
311 if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
312 /* Strictly speaking we could support this, if:
314 * - using an IOMMU, or
315 * - making sure the memory area is consecutive
316 * but for now, we simply say "computer says no".
321 if (!is_power_of_2(chunk_size))
324 if (!PAGE_ALIGNED(addr)) {
325 /* Memory area has to be page size aligned. For
326 * simplicity, this might change.
331 if ((addr + size) < addr)
334 chunks = (unsigned int)div_u64(size, chunk_size);
338 chunks_per_page = PAGE_SIZE / chunk_size;
339 if (chunks < chunks_per_page || chunks % chunks_per_page)
342 headroom = ALIGN(headroom, 64);
344 size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM;
348 umem->address = (unsigned long)addr;
349 umem->chunk_mask = ~((u64)chunk_size - 1);
351 umem->headroom = headroom;
352 umem->chunk_size_nohr = chunk_size - headroom;
353 umem->npgs = size / PAGE_SIZE;
356 INIT_LIST_HEAD(&umem->xsk_list);
357 spin_lock_init(&umem->xsk_list_lock);
359 refcount_set(&umem->users, 1);
361 err = xdp_umem_account_pages(umem);
365 err = xdp_umem_pin_pages(umem);
369 umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL);
375 for (i = 0; i < umem->npgs; i++)
376 umem->pages[i].addr = page_address(umem->pgs[i]);
381 xdp_umem_unaccount_pages(umem);
385 struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr)
387 struct xdp_umem *umem;
390 umem = kzalloc(sizeof(*umem), GFP_KERNEL);
392 return ERR_PTR(-ENOMEM);
394 err = ida_simple_get(&umem_ida, 0, 0, GFP_KERNEL);
401 err = xdp_umem_reg(umem, mr);
403 ida_simple_remove(&umem_ida, umem->id);
411 bool xdp_umem_validate_queues(struct xdp_umem *umem)
413 return umem->fq && umem->cq;