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 #include <linux/vmalloc.h> 18 19 #include "xdp_umem.h" 20 #include "xsk_queue.h" 21 22 #define XDP_UMEM_MIN_CHUNK_SIZE 2048 23 24 static DEFINE_IDA(umem_ida); 25 26 void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) 27 { 28 unsigned long flags; 29 30 if (!xs->tx) 31 return; 32 33 spin_lock_irqsave(&umem->xsk_tx_list_lock, flags); 34 list_add_rcu(&xs->list, &umem->xsk_tx_list); 35 spin_unlock_irqrestore(&umem->xsk_tx_list_lock, flags); 36 } 37 38 void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) 39 { 40 unsigned long flags; 41 42 if (!xs->tx) 43 return; 44 45 spin_lock_irqsave(&umem->xsk_tx_list_lock, flags); 46 list_del_rcu(&xs->list); 47 spin_unlock_irqrestore(&umem->xsk_tx_list_lock, flags); 48 } 49 50 /* The umem is stored both in the _rx struct and the _tx struct as we do 51 * not know if the device has more tx queues than rx, or the opposite. 52 * This might also change during run time. 53 */ 54 static int xdp_reg_umem_at_qid(struct net_device *dev, struct xdp_umem *umem, 55 u16 queue_id) 56 { 57 if (queue_id >= max_t(unsigned int, 58 dev->real_num_rx_queues, 59 dev->real_num_tx_queues)) 60 return -EINVAL; 61 62 if (queue_id < dev->real_num_rx_queues) 63 dev->_rx[queue_id].umem = umem; 64 if (queue_id < dev->real_num_tx_queues) 65 dev->_tx[queue_id].umem = umem; 66 67 return 0; 68 } 69 70 struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev, 71 u16 queue_id) 72 { 73 if (queue_id < dev->real_num_rx_queues) 74 return dev->_rx[queue_id].umem; 75 if (queue_id < dev->real_num_tx_queues) 76 return dev->_tx[queue_id].umem; 77 78 return NULL; 79 } 80 EXPORT_SYMBOL(xdp_get_umem_from_qid); 81 82 static void xdp_clear_umem_at_qid(struct net_device *dev, u16 queue_id) 83 { 84 if (queue_id < dev->real_num_rx_queues) 85 dev->_rx[queue_id].umem = NULL; 86 if (queue_id < dev->real_num_tx_queues) 87 dev->_tx[queue_id].umem = NULL; 88 } 89 90 int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, 91 u16 queue_id, u16 flags) 92 { 93 bool force_zc, force_copy; 94 struct netdev_bpf bpf; 95 int err = 0; 96 97 ASSERT_RTNL(); 98 99 force_zc = flags & XDP_ZEROCOPY; 100 force_copy = flags & XDP_COPY; 101 102 if (force_zc && force_copy) 103 return -EINVAL; 104 105 if (xdp_get_umem_from_qid(dev, queue_id)) 106 return -EBUSY; 107 108 err = xdp_reg_umem_at_qid(dev, umem, queue_id); 109 if (err) 110 return err; 111 112 umem->dev = dev; 113 umem->queue_id = queue_id; 114 115 if (flags & XDP_USE_NEED_WAKEUP) { 116 umem->flags |= XDP_UMEM_USES_NEED_WAKEUP; 117 /* Tx needs to be explicitly woken up the first time. 118 * Also for supporting drivers that do not implement this 119 * feature. They will always have to call sendto(). 120 */ 121 xsk_set_tx_need_wakeup(umem); 122 } 123 124 dev_hold(dev); 125 126 if (force_copy) 127 /* For copy-mode, we are done. */ 128 return 0; 129 130 if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_wakeup) { 131 err = -EOPNOTSUPP; 132 goto err_unreg_umem; 133 } 134 135 bpf.command = XDP_SETUP_XSK_UMEM; 136 bpf.xsk.umem = umem; 137 bpf.xsk.queue_id = queue_id; 138 139 err = dev->netdev_ops->ndo_bpf(dev, &bpf); 140 if (err) 141 goto err_unreg_umem; 142 143 umem->zc = true; 144 return 0; 145 146 err_unreg_umem: 147 if (!force_zc) 148 err = 0; /* fallback to copy mode */ 149 if (err) 150 xdp_clear_umem_at_qid(dev, queue_id); 151 return err; 152 } 153 154 void xdp_umem_clear_dev(struct xdp_umem *umem) 155 { 156 struct netdev_bpf bpf; 157 int err; 158 159 ASSERT_RTNL(); 160 161 if (!umem->dev) 162 return; 163 164 if (umem->zc) { 165 bpf.command = XDP_SETUP_XSK_UMEM; 166 bpf.xsk.umem = NULL; 167 bpf.xsk.queue_id = umem->queue_id; 168 169 err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf); 170 171 if (err) 172 WARN(1, "failed to disable umem!\n"); 173 } 174 175 xdp_clear_umem_at_qid(umem->dev, umem->queue_id); 176 177 dev_put(umem->dev); 178 umem->dev = NULL; 179 umem->zc = false; 180 } 181 182 static void xdp_umem_unpin_pages(struct xdp_umem *umem) 183 { 184 unpin_user_pages_dirty_lock(umem->pgs, umem->npgs, true); 185 186 kfree(umem->pgs); 187 umem->pgs = NULL; 188 } 189 190 static void xdp_umem_unaccount_pages(struct xdp_umem *umem) 191 { 192 if (umem->user) { 193 atomic_long_sub(umem->npgs, &umem->user->locked_vm); 194 free_uid(umem->user); 195 } 196 } 197 198 static void xdp_umem_release(struct xdp_umem *umem) 199 { 200 rtnl_lock(); 201 xdp_umem_clear_dev(umem); 202 rtnl_unlock(); 203 204 ida_simple_remove(&umem_ida, umem->id); 205 206 if (umem->fq) { 207 xskq_destroy(umem->fq); 208 umem->fq = NULL; 209 } 210 211 if (umem->cq) { 212 xskq_destroy(umem->cq); 213 umem->cq = NULL; 214 } 215 216 xp_destroy(umem->pool); 217 xdp_umem_unpin_pages(umem); 218 219 xdp_umem_unaccount_pages(umem); 220 kfree(umem); 221 } 222 223 static void xdp_umem_release_deferred(struct work_struct *work) 224 { 225 struct xdp_umem *umem = container_of(work, struct xdp_umem, work); 226 227 xdp_umem_release(umem); 228 } 229 230 void xdp_get_umem(struct xdp_umem *umem) 231 { 232 refcount_inc(&umem->users); 233 } 234 235 void xdp_put_umem(struct xdp_umem *umem) 236 { 237 if (!umem) 238 return; 239 240 if (refcount_dec_and_test(&umem->users)) { 241 INIT_WORK(&umem->work, xdp_umem_release_deferred); 242 schedule_work(&umem->work); 243 } 244 } 245 246 static int xdp_umem_pin_pages(struct xdp_umem *umem, unsigned long address) 247 { 248 unsigned int gup_flags = FOLL_WRITE; 249 long npgs; 250 int err; 251 252 umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), 253 GFP_KERNEL | __GFP_NOWARN); 254 if (!umem->pgs) 255 return -ENOMEM; 256 257 mmap_read_lock(current->mm); 258 npgs = pin_user_pages(address, umem->npgs, 259 gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL); 260 mmap_read_unlock(current->mm); 261 262 if (npgs != umem->npgs) { 263 if (npgs >= 0) { 264 umem->npgs = npgs; 265 err = -ENOMEM; 266 goto out_pin; 267 } 268 err = npgs; 269 goto out_pgs; 270 } 271 return 0; 272 273 out_pin: 274 xdp_umem_unpin_pages(umem); 275 out_pgs: 276 kfree(umem->pgs); 277 umem->pgs = NULL; 278 return err; 279 } 280 281 static int xdp_umem_account_pages(struct xdp_umem *umem) 282 { 283 unsigned long lock_limit, new_npgs, old_npgs; 284 285 if (capable(CAP_IPC_LOCK)) 286 return 0; 287 288 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 289 umem->user = get_uid(current_user()); 290 291 do { 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); 296 umem->user = NULL; 297 return -ENOBUFS; 298 } 299 } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs, 300 new_npgs) != old_npgs); 301 return 0; 302 } 303 304 static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) 305 { 306 u32 npgs_rem, chunk_size = mr->chunk_size, headroom = mr->headroom; 307 bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG; 308 u64 npgs, addr = mr->addr, size = mr->len; 309 unsigned int chunks, chunks_rem; 310 int err; 311 312 if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { 313 /* Strictly speaking we could support this, if: 314 * - huge pages, or* 315 * - using an IOMMU, or 316 * - making sure the memory area is consecutive 317 * but for now, we simply say "computer says no". 318 */ 319 return -EINVAL; 320 } 321 322 if (mr->flags & ~(XDP_UMEM_UNALIGNED_CHUNK_FLAG | 323 XDP_UMEM_USES_NEED_WAKEUP)) 324 return -EINVAL; 325 326 if (!unaligned_chunks && !is_power_of_2(chunk_size)) 327 return -EINVAL; 328 329 if (!PAGE_ALIGNED(addr)) { 330 /* Memory area has to be page size aligned. For 331 * simplicity, this might change. 332 */ 333 return -EINVAL; 334 } 335 336 if ((addr + size) < addr) 337 return -EINVAL; 338 339 npgs = div_u64_rem(size, PAGE_SIZE, &npgs_rem); 340 if (npgs_rem) 341 npgs++; 342 if (npgs > U32_MAX) 343 return -EINVAL; 344 345 chunks = (unsigned int)div_u64_rem(size, chunk_size, &chunks_rem); 346 if (chunks == 0) 347 return -EINVAL; 348 349 if (!unaligned_chunks && chunks_rem) 350 return -EINVAL; 351 352 if (headroom >= chunk_size - XDP_PACKET_HEADROOM) 353 return -EINVAL; 354 355 umem->size = size; 356 umem->headroom = headroom; 357 umem->chunk_size = chunk_size; 358 umem->npgs = (u32)npgs; 359 umem->pgs = NULL; 360 umem->user = NULL; 361 umem->flags = mr->flags; 362 INIT_LIST_HEAD(&umem->xsk_tx_list); 363 spin_lock_init(&umem->xsk_tx_list_lock); 364 365 refcount_set(&umem->users, 1); 366 367 err = xdp_umem_account_pages(umem); 368 if (err) 369 return err; 370 371 err = xdp_umem_pin_pages(umem, (unsigned long)addr); 372 if (err) 373 goto out_account; 374 375 umem->pool = xp_create(umem->pgs, umem->npgs, chunks, chunk_size, 376 headroom, size, unaligned_chunks); 377 if (!umem->pool) { 378 err = -ENOMEM; 379 goto out_pin; 380 } 381 return 0; 382 383 out_pin: 384 xdp_umem_unpin_pages(umem); 385 out_account: 386 xdp_umem_unaccount_pages(umem); 387 return err; 388 } 389 390 struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr) 391 { 392 struct xdp_umem *umem; 393 int err; 394 395 umem = kzalloc(sizeof(*umem), GFP_KERNEL); 396 if (!umem) 397 return ERR_PTR(-ENOMEM); 398 399 err = ida_simple_get(&umem_ida, 0, 0, GFP_KERNEL); 400 if (err < 0) { 401 kfree(umem); 402 return ERR_PTR(err); 403 } 404 umem->id = err; 405 406 err = xdp_umem_reg(umem, mr); 407 if (err) { 408 ida_simple_remove(&umem_ida, umem->id); 409 kfree(umem); 410 return ERR_PTR(err); 411 } 412 413 return umem; 414 } 415 416 bool xdp_umem_validate_queues(struct xdp_umem *umem) 417 { 418 return umem->fq && umem->cq; 419 } 420