1 // SPDX-License-Identifier: GPL-2.0 2 /* XDP user-space packet buffer 3 * Copyright(c) 2018 Intel Corporation. 4 */ 5 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> 13 #include <linux/mm.h> 14 #include <linux/netdevice.h> 15 #include <linux/rtnetlink.h> 16 #include <linux/idr.h> 17 18 #include "xdp_umem.h" 19 #include "xsk_queue.h" 20 21 #define XDP_UMEM_MIN_CHUNK_SIZE 2048 22 23 static DEFINE_IDA(umem_ida); 24 25 void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) 26 { 27 unsigned long flags; 28 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); 32 } 33 34 void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) 35 { 36 unsigned long flags; 37 38 spin_lock_irqsave(&umem->xsk_list_lock, flags); 39 list_del_rcu(&xs->list); 40 spin_unlock_irqrestore(&umem->xsk_list_lock, flags); 41 } 42 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. 46 */ 47 static int xdp_reg_umem_at_qid(struct net_device *dev, struct xdp_umem *umem, 48 u16 queue_id) 49 { 50 if (queue_id >= max_t(unsigned int, 51 dev->real_num_rx_queues, 52 dev->real_num_tx_queues)) 53 return -EINVAL; 54 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; 59 60 return 0; 61 } 62 63 struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev, 64 u16 queue_id) 65 { 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; 70 71 return NULL; 72 } 73 EXPORT_SYMBOL(xdp_get_umem_from_qid); 74 75 static void xdp_clear_umem_at_qid(struct net_device *dev, u16 queue_id) 76 { 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; 81 } 82 83 int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, 84 u16 queue_id, u16 flags) 85 { 86 bool force_zc, force_copy; 87 struct netdev_bpf bpf; 88 int err = 0; 89 90 ASSERT_RTNL(); 91 92 force_zc = flags & XDP_ZEROCOPY; 93 force_copy = flags & XDP_COPY; 94 95 if (force_zc && force_copy) 96 return -EINVAL; 97 98 if (xdp_get_umem_from_qid(dev, queue_id)) 99 return -EBUSY; 100 101 err = xdp_reg_umem_at_qid(dev, umem, queue_id); 102 if (err) 103 return err; 104 105 umem->dev = dev; 106 umem->queue_id = queue_id; 107 108 dev_hold(dev); 109 110 if (force_copy) 111 /* For copy-mode, we are done. */ 112 return 0; 113 114 if (!dev->netdev_ops->ndo_bpf || 115 !dev->netdev_ops->ndo_xsk_async_xmit) { 116 err = -EOPNOTSUPP; 117 goto err_unreg_umem; 118 } 119 120 bpf.command = XDP_SETUP_XSK_UMEM; 121 bpf.xsk.umem = umem; 122 bpf.xsk.queue_id = queue_id; 123 124 err = dev->netdev_ops->ndo_bpf(dev, &bpf); 125 if (err) 126 goto err_unreg_umem; 127 128 umem->zc = true; 129 return 0; 130 131 err_unreg_umem: 132 if (!force_zc) 133 err = 0; /* fallback to copy mode */ 134 if (err) 135 xdp_clear_umem_at_qid(dev, queue_id); 136 return err; 137 } 138 139 void xdp_umem_clear_dev(struct xdp_umem *umem) 140 { 141 struct netdev_bpf bpf; 142 int err; 143 144 ASSERT_RTNL(); 145 146 if (!umem->dev) 147 return; 148 149 if (umem->zc) { 150 bpf.command = XDP_SETUP_XSK_UMEM; 151 bpf.xsk.umem = NULL; 152 bpf.xsk.queue_id = umem->queue_id; 153 154 err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf); 155 156 if (err) 157 WARN(1, "failed to disable umem!\n"); 158 } 159 160 xdp_clear_umem_at_qid(umem->dev, umem->queue_id); 161 162 dev_put(umem->dev); 163 umem->dev = NULL; 164 umem->zc = false; 165 } 166 167 static void xdp_umem_unpin_pages(struct xdp_umem *umem) 168 { 169 unsigned int i; 170 171 for (i = 0; i < umem->npgs; i++) { 172 struct page *page = umem->pgs[i]; 173 174 set_page_dirty_lock(page); 175 put_page(page); 176 } 177 178 kfree(umem->pgs); 179 umem->pgs = NULL; 180 } 181 182 static void xdp_umem_unaccount_pages(struct xdp_umem *umem) 183 { 184 if (umem->user) { 185 atomic_long_sub(umem->npgs, &umem->user->locked_vm); 186 free_uid(umem->user); 187 } 188 } 189 190 static void xdp_umem_release(struct xdp_umem *umem) 191 { 192 rtnl_lock(); 193 xdp_umem_clear_dev(umem); 194 rtnl_unlock(); 195 196 ida_simple_remove(&umem_ida, umem->id); 197 198 if (umem->fq) { 199 xskq_destroy(umem->fq); 200 umem->fq = NULL; 201 } 202 203 if (umem->cq) { 204 xskq_destroy(umem->cq); 205 umem->cq = NULL; 206 } 207 208 xsk_reuseq_destroy(umem); 209 210 xdp_umem_unpin_pages(umem); 211 212 kfree(umem->pages); 213 umem->pages = NULL; 214 215 xdp_umem_unaccount_pages(umem); 216 kfree(umem); 217 } 218 219 static void xdp_umem_release_deferred(struct work_struct *work) 220 { 221 struct xdp_umem *umem = container_of(work, struct xdp_umem, work); 222 223 xdp_umem_release(umem); 224 } 225 226 void xdp_get_umem(struct xdp_umem *umem) 227 { 228 refcount_inc(&umem->users); 229 } 230 231 void xdp_put_umem(struct xdp_umem *umem) 232 { 233 if (!umem) 234 return; 235 236 if (refcount_dec_and_test(&umem->users)) { 237 INIT_WORK(&umem->work, xdp_umem_release_deferred); 238 schedule_work(&umem->work); 239 } 240 } 241 242 static int xdp_umem_pin_pages(struct xdp_umem *umem) 243 { 244 unsigned int gup_flags = FOLL_WRITE; 245 long npgs; 246 int err; 247 248 umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), 249 GFP_KERNEL | __GFP_NOWARN); 250 if (!umem->pgs) 251 return -ENOMEM; 252 253 down_read(¤t->mm->mmap_sem); 254 npgs = get_user_pages(umem->address, umem->npgs, 255 gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL); 256 up_read(¤t->mm->mmap_sem); 257 258 if (npgs != umem->npgs) { 259 if (npgs >= 0) { 260 umem->npgs = npgs; 261 err = -ENOMEM; 262 goto out_pin; 263 } 264 err = npgs; 265 goto out_pgs; 266 } 267 return 0; 268 269 out_pin: 270 xdp_umem_unpin_pages(umem); 271 out_pgs: 272 kfree(umem->pgs); 273 umem->pgs = NULL; 274 return err; 275 } 276 277 static int xdp_umem_account_pages(struct xdp_umem *umem) 278 { 279 unsigned long lock_limit, new_npgs, old_npgs; 280 281 if (capable(CAP_IPC_LOCK)) 282 return 0; 283 284 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 285 umem->user = get_uid(current_user()); 286 287 do { 288 old_npgs = atomic_long_read(&umem->user->locked_vm); 289 new_npgs = old_npgs + umem->npgs; 290 if (new_npgs > lock_limit) { 291 free_uid(umem->user); 292 umem->user = NULL; 293 return -ENOBUFS; 294 } 295 } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs, 296 new_npgs) != old_npgs); 297 return 0; 298 } 299 300 static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) 301 { 302 u32 chunk_size = mr->chunk_size, headroom = mr->headroom; 303 unsigned int chunks, chunks_per_page; 304 u64 addr = mr->addr, size = mr->len; 305 int size_chk, err, i; 306 307 if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { 308 /* Strictly speaking we could support this, if: 309 * - huge pages, or* 310 * - using an IOMMU, or 311 * - making sure the memory area is consecutive 312 * but for now, we simply say "computer says no". 313 */ 314 return -EINVAL; 315 } 316 317 if (!is_power_of_2(chunk_size)) 318 return -EINVAL; 319 320 if (!PAGE_ALIGNED(addr)) { 321 /* Memory area has to be page size aligned. For 322 * simplicity, this might change. 323 */ 324 return -EINVAL; 325 } 326 327 if ((addr + size) < addr) 328 return -EINVAL; 329 330 chunks = (unsigned int)div_u64(size, chunk_size); 331 if (chunks == 0) 332 return -EINVAL; 333 334 chunks_per_page = PAGE_SIZE / chunk_size; 335 if (chunks < chunks_per_page || chunks % chunks_per_page) 336 return -EINVAL; 337 338 headroom = ALIGN(headroom, 64); 339 340 size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM; 341 if (size_chk < 0) 342 return -EINVAL; 343 344 umem->address = (unsigned long)addr; 345 umem->chunk_mask = ~((u64)chunk_size - 1); 346 umem->size = size; 347 umem->headroom = headroom; 348 umem->chunk_size_nohr = chunk_size - headroom; 349 umem->npgs = size / PAGE_SIZE; 350 umem->pgs = NULL; 351 umem->user = NULL; 352 INIT_LIST_HEAD(&umem->xsk_list); 353 spin_lock_init(&umem->xsk_list_lock); 354 355 refcount_set(&umem->users, 1); 356 357 err = xdp_umem_account_pages(umem); 358 if (err) 359 return err; 360 361 err = xdp_umem_pin_pages(umem); 362 if (err) 363 goto out_account; 364 365 umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL); 366 if (!umem->pages) { 367 err = -ENOMEM; 368 goto out_account; 369 } 370 371 for (i = 0; i < umem->npgs; i++) 372 umem->pages[i].addr = page_address(umem->pgs[i]); 373 374 return 0; 375 376 out_account: 377 xdp_umem_unaccount_pages(umem); 378 return err; 379 } 380 381 struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr) 382 { 383 struct xdp_umem *umem; 384 int err; 385 386 umem = kzalloc(sizeof(*umem), GFP_KERNEL); 387 if (!umem) 388 return ERR_PTR(-ENOMEM); 389 390 err = ida_simple_get(&umem_ida, 0, 0, GFP_KERNEL); 391 if (err < 0) { 392 kfree(umem); 393 return ERR_PTR(err); 394 } 395 umem->id = err; 396 397 err = xdp_umem_reg(umem, mr); 398 if (err) { 399 ida_simple_remove(&umem_ida, umem->id); 400 kfree(umem); 401 return ERR_PTR(err); 402 } 403 404 return umem; 405 } 406 407 bool xdp_umem_validate_queues(struct xdp_umem *umem) 408 { 409 return umem->fq && umem->cq; 410 } 411