1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Devmem TCP 4 * 5 * Authors: Mina Almasry <almasrymina@google.com> 6 * Willem de Bruijn <willemdebruijn.kernel@gmail.com> 7 * Kaiyuan Zhang <kaiyuanz@google.com 8 */ 9 10 #include <linux/dma-buf.h> 11 #include <linux/genalloc.h> 12 #include <linux/mm.h> 13 #include <linux/netdevice.h> 14 #include <linux/types.h> 15 #include <net/netdev_queues.h> 16 #include <net/netdev_rx_queue.h> 17 #include <net/page_pool/helpers.h> 18 #include <net/page_pool/memory_provider.h> 19 #include <net/sock.h> 20 #include <trace/events/page_pool.h> 21 22 #include "devmem.h" 23 #include "mp_dmabuf_devmem.h" 24 #include "page_pool_priv.h" 25 26 /* Device memory support */ 27 28 static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1); 29 30 static const struct memory_provider_ops dmabuf_devmem_ops; 31 32 bool net_is_devmem_iov(struct net_iov *niov) 33 { 34 return niov->type == NET_IOV_DMABUF; 35 } 36 37 static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool, 38 struct gen_pool_chunk *chunk, 39 void *not_used) 40 { 41 struct dmabuf_genpool_chunk_owner *owner = chunk->owner; 42 43 kvfree(owner->area.niovs); 44 kfree(owner); 45 } 46 47 static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov) 48 { 49 struct dmabuf_genpool_chunk_owner *owner; 50 51 owner = net_devmem_iov_to_chunk_owner(niov); 52 return owner->base_dma_addr + 53 ((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT); 54 } 55 56 void __net_devmem_dmabuf_binding_free(struct work_struct *wq) 57 { 58 struct net_devmem_dmabuf_binding *binding = container_of(wq, typeof(*binding), unbind_w); 59 60 size_t size, avail; 61 62 gen_pool_for_each_chunk(binding->chunk_pool, 63 net_devmem_dmabuf_free_chunk_owner, NULL); 64 65 size = gen_pool_size(binding->chunk_pool); 66 avail = gen_pool_avail(binding->chunk_pool); 67 68 if (!WARN(size != avail, "can't destroy genpool. size=%zu, avail=%zu", 69 size, avail)) 70 gen_pool_destroy(binding->chunk_pool); 71 72 dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, 73 binding->direction); 74 dma_buf_detach(binding->dmabuf, binding->attachment); 75 dma_buf_put(binding->dmabuf); 76 xa_destroy(&binding->bound_rxqs); 77 kvfree(binding->tx_vec); 78 kfree(binding); 79 } 80 81 struct net_iov * 82 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) 83 { 84 struct dmabuf_genpool_chunk_owner *owner; 85 unsigned long dma_addr; 86 struct net_iov *niov; 87 ssize_t offset; 88 ssize_t index; 89 90 dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE, 91 (void **)&owner); 92 if (!dma_addr) 93 return NULL; 94 95 offset = dma_addr - owner->base_dma_addr; 96 index = offset / PAGE_SIZE; 97 niov = &owner->area.niovs[index]; 98 99 niov->pp_magic = 0; 100 niov->pp = NULL; 101 atomic_long_set(&niov->pp_ref_count, 0); 102 103 return niov; 104 } 105 106 void net_devmem_free_dmabuf(struct net_iov *niov) 107 { 108 struct net_devmem_dmabuf_binding *binding = net_devmem_iov_binding(niov); 109 unsigned long dma_addr = net_devmem_get_dma_addr(niov); 110 111 if (WARN_ON(!gen_pool_has_addr(binding->chunk_pool, dma_addr, 112 PAGE_SIZE))) 113 return; 114 115 gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE); 116 } 117 118 void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) 119 { 120 struct netdev_rx_queue *rxq; 121 unsigned long xa_idx; 122 unsigned int rxq_idx; 123 124 xa_erase(&net_devmem_dmabuf_bindings, binding->id); 125 126 /* Ensure no tx net_devmem_lookup_dmabuf() are in flight after the 127 * erase. 128 */ 129 synchronize_net(); 130 131 if (binding->list.next) 132 list_del(&binding->list); 133 134 xa_for_each(&binding->bound_rxqs, xa_idx, rxq) { 135 const struct pp_memory_provider_params mp_params = { 136 .mp_priv = binding, 137 .mp_ops = &dmabuf_devmem_ops, 138 }; 139 140 rxq_idx = get_netdev_rx_queue_index(rxq); 141 142 __net_mp_close_rxq(binding->dev, rxq_idx, &mp_params); 143 } 144 145 net_devmem_dmabuf_binding_put(binding); 146 } 147 148 int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 149 struct net_devmem_dmabuf_binding *binding, 150 struct netlink_ext_ack *extack) 151 { 152 struct pp_memory_provider_params mp_params = { 153 .mp_priv = binding, 154 .mp_ops = &dmabuf_devmem_ops, 155 }; 156 struct netdev_rx_queue *rxq; 157 u32 xa_idx; 158 int err; 159 160 err = __net_mp_open_rxq(dev, rxq_idx, &mp_params, extack); 161 if (err) 162 return err; 163 164 rxq = __netif_get_rx_queue(dev, rxq_idx); 165 err = xa_alloc(&binding->bound_rxqs, &xa_idx, rxq, xa_limit_32b, 166 GFP_KERNEL); 167 if (err) 168 goto err_close_rxq; 169 170 return 0; 171 172 err_close_rxq: 173 __net_mp_close_rxq(dev, rxq_idx, &mp_params); 174 return err; 175 } 176 177 struct net_devmem_dmabuf_binding * 178 net_devmem_bind_dmabuf(struct net_device *dev, 179 enum dma_data_direction direction, 180 unsigned int dmabuf_fd, struct netdev_nl_sock *priv, 181 struct netlink_ext_ack *extack) 182 { 183 struct net_devmem_dmabuf_binding *binding; 184 static u32 id_alloc_next; 185 struct scatterlist *sg; 186 struct dma_buf *dmabuf; 187 unsigned int sg_idx, i; 188 unsigned long virtual; 189 int err; 190 191 dmabuf = dma_buf_get(dmabuf_fd); 192 if (IS_ERR(dmabuf)) 193 return ERR_CAST(dmabuf); 194 195 binding = kzalloc_node(sizeof(*binding), GFP_KERNEL, 196 dev_to_node(&dev->dev)); 197 if (!binding) { 198 err = -ENOMEM; 199 goto err_put_dmabuf; 200 } 201 202 binding->dev = dev; 203 xa_init_flags(&binding->bound_rxqs, XA_FLAGS_ALLOC); 204 205 refcount_set(&binding->ref, 1); 206 207 mutex_init(&binding->lock); 208 209 binding->dmabuf = dmabuf; 210 binding->direction = direction; 211 212 binding->attachment = dma_buf_attach(binding->dmabuf, dev->dev.parent); 213 if (IS_ERR(binding->attachment)) { 214 err = PTR_ERR(binding->attachment); 215 NL_SET_ERR_MSG(extack, "Failed to bind dmabuf to device"); 216 goto err_free_binding; 217 } 218 219 binding->sgt = dma_buf_map_attachment_unlocked(binding->attachment, 220 direction); 221 if (IS_ERR(binding->sgt)) { 222 err = PTR_ERR(binding->sgt); 223 NL_SET_ERR_MSG(extack, "Failed to map dmabuf attachment"); 224 goto err_detach; 225 } 226 227 if (direction == DMA_TO_DEVICE) { 228 binding->tx_vec = kvmalloc_array(dmabuf->size / PAGE_SIZE, 229 sizeof(struct net_iov *), 230 GFP_KERNEL); 231 if (!binding->tx_vec) { 232 err = -ENOMEM; 233 goto err_unmap; 234 } 235 } 236 237 /* For simplicity we expect to make PAGE_SIZE allocations, but the 238 * binding can be much more flexible than that. We may be able to 239 * allocate MTU sized chunks here. Leave that for future work... 240 */ 241 binding->chunk_pool = gen_pool_create(PAGE_SHIFT, 242 dev_to_node(&dev->dev)); 243 if (!binding->chunk_pool) { 244 err = -ENOMEM; 245 goto err_tx_vec; 246 } 247 248 virtual = 0; 249 for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx) { 250 dma_addr_t dma_addr = sg_dma_address(sg); 251 struct dmabuf_genpool_chunk_owner *owner; 252 size_t len = sg_dma_len(sg); 253 struct net_iov *niov; 254 255 owner = kzalloc_node(sizeof(*owner), GFP_KERNEL, 256 dev_to_node(&dev->dev)); 257 if (!owner) { 258 err = -ENOMEM; 259 goto err_free_chunks; 260 } 261 262 owner->area.base_virtual = virtual; 263 owner->base_dma_addr = dma_addr; 264 owner->area.num_niovs = len / PAGE_SIZE; 265 owner->binding = binding; 266 267 err = gen_pool_add_owner(binding->chunk_pool, dma_addr, 268 dma_addr, len, dev_to_node(&dev->dev), 269 owner); 270 if (err) { 271 kfree(owner); 272 err = -EINVAL; 273 goto err_free_chunks; 274 } 275 276 owner->area.niovs = kvmalloc_array(owner->area.num_niovs, 277 sizeof(*owner->area.niovs), 278 GFP_KERNEL); 279 if (!owner->area.niovs) { 280 err = -ENOMEM; 281 goto err_free_chunks; 282 } 283 284 for (i = 0; i < owner->area.num_niovs; i++) { 285 niov = &owner->area.niovs[i]; 286 niov->type = NET_IOV_DMABUF; 287 niov->owner = &owner->area; 288 page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), 289 net_devmem_get_dma_addr(niov)); 290 if (direction == DMA_TO_DEVICE) 291 binding->tx_vec[owner->area.base_virtual / PAGE_SIZE + i] = niov; 292 } 293 294 virtual += len; 295 } 296 297 err = xa_alloc_cyclic(&net_devmem_dmabuf_bindings, &binding->id, 298 binding, xa_limit_32b, &id_alloc_next, 299 GFP_KERNEL); 300 if (err < 0) 301 goto err_free_chunks; 302 303 list_add(&binding->list, &priv->bindings); 304 305 return binding; 306 307 err_free_chunks: 308 gen_pool_for_each_chunk(binding->chunk_pool, 309 net_devmem_dmabuf_free_chunk_owner, NULL); 310 gen_pool_destroy(binding->chunk_pool); 311 err_tx_vec: 312 kvfree(binding->tx_vec); 313 err_unmap: 314 dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, 315 direction); 316 err_detach: 317 dma_buf_detach(dmabuf, binding->attachment); 318 err_free_binding: 319 kfree(binding); 320 err_put_dmabuf: 321 dma_buf_put(dmabuf); 322 return ERR_PTR(err); 323 } 324 325 struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id) 326 { 327 struct net_devmem_dmabuf_binding *binding; 328 329 rcu_read_lock(); 330 binding = xa_load(&net_devmem_dmabuf_bindings, id); 331 if (binding) { 332 if (!net_devmem_dmabuf_binding_get(binding)) 333 binding = NULL; 334 } 335 rcu_read_unlock(); 336 337 return binding; 338 } 339 340 void net_devmem_get_net_iov(struct net_iov *niov) 341 { 342 net_devmem_dmabuf_binding_get(net_devmem_iov_binding(niov)); 343 } 344 345 void net_devmem_put_net_iov(struct net_iov *niov) 346 { 347 net_devmem_dmabuf_binding_put(net_devmem_iov_binding(niov)); 348 } 349 350 struct net_devmem_dmabuf_binding *net_devmem_get_binding(struct sock *sk, 351 unsigned int dmabuf_id) 352 { 353 struct net_devmem_dmabuf_binding *binding; 354 struct dst_entry *dst = __sk_dst_get(sk); 355 int err = 0; 356 357 binding = net_devmem_lookup_dmabuf(dmabuf_id); 358 if (!binding || !binding->tx_vec) { 359 err = -EINVAL; 360 goto out_err; 361 } 362 363 /* The dma-addrs in this binding are only reachable to the corresponding 364 * net_device. 365 */ 366 if (!dst || !dst->dev || dst->dev->ifindex != binding->dev->ifindex) { 367 err = -ENODEV; 368 goto out_err; 369 } 370 371 return binding; 372 373 out_err: 374 if (binding) 375 net_devmem_dmabuf_binding_put(binding); 376 377 return ERR_PTR(err); 378 } 379 380 struct net_iov * 381 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, 382 size_t virt_addr, size_t *off, size_t *size) 383 { 384 if (virt_addr >= binding->dmabuf->size) 385 return NULL; 386 387 *off = virt_addr % PAGE_SIZE; 388 *size = PAGE_SIZE - *off; 389 390 return binding->tx_vec[virt_addr / PAGE_SIZE]; 391 } 392 393 /*** "Dmabuf devmem memory provider" ***/ 394 395 int mp_dmabuf_devmem_init(struct page_pool *pool) 396 { 397 struct net_devmem_dmabuf_binding *binding = pool->mp_priv; 398 399 if (!binding) 400 return -EINVAL; 401 402 /* dma-buf dma addresses do not need and should not be used with 403 * dma_sync_for_cpu/device. Force disable dma_sync. 404 */ 405 pool->dma_sync = false; 406 pool->dma_sync_for_cpu = false; 407 408 if (pool->p.order != 0) 409 return -E2BIG; 410 411 net_devmem_dmabuf_binding_get(binding); 412 return 0; 413 } 414 415 netmem_ref mp_dmabuf_devmem_alloc_netmems(struct page_pool *pool, gfp_t gfp) 416 { 417 struct net_devmem_dmabuf_binding *binding = pool->mp_priv; 418 struct net_iov *niov; 419 netmem_ref netmem; 420 421 niov = net_devmem_alloc_dmabuf(binding); 422 if (!niov) 423 return 0; 424 425 netmem = net_iov_to_netmem(niov); 426 427 page_pool_set_pp_info(pool, netmem); 428 429 pool->pages_state_hold_cnt++; 430 trace_page_pool_state_hold(pool, netmem, pool->pages_state_hold_cnt); 431 return netmem; 432 } 433 434 void mp_dmabuf_devmem_destroy(struct page_pool *pool) 435 { 436 struct net_devmem_dmabuf_binding *binding = pool->mp_priv; 437 438 net_devmem_dmabuf_binding_put(binding); 439 } 440 441 bool mp_dmabuf_devmem_release_page(struct page_pool *pool, netmem_ref netmem) 442 { 443 long refcount = atomic_long_read(netmem_get_pp_ref_count_ref(netmem)); 444 445 if (WARN_ON_ONCE(!netmem_is_net_iov(netmem))) 446 return false; 447 448 if (WARN_ON_ONCE(refcount != 1)) 449 return false; 450 451 page_pool_clear_pp_info(netmem); 452 453 net_devmem_free_dmabuf(netmem_to_net_iov(netmem)); 454 455 /* We don't want the page pool put_page()ing our net_iovs. */ 456 return false; 457 } 458 459 static int mp_dmabuf_devmem_nl_fill(void *mp_priv, struct sk_buff *rsp, 460 struct netdev_rx_queue *rxq) 461 { 462 const struct net_devmem_dmabuf_binding *binding = mp_priv; 463 int type = rxq ? NETDEV_A_QUEUE_DMABUF : NETDEV_A_PAGE_POOL_DMABUF; 464 465 return nla_put_u32(rsp, type, binding->id); 466 } 467 468 static void mp_dmabuf_devmem_uninstall(void *mp_priv, 469 struct netdev_rx_queue *rxq) 470 { 471 struct net_devmem_dmabuf_binding *binding = mp_priv; 472 struct netdev_rx_queue *bound_rxq; 473 unsigned long xa_idx; 474 475 xa_for_each(&binding->bound_rxqs, xa_idx, bound_rxq) { 476 if (bound_rxq == rxq) { 477 xa_erase(&binding->bound_rxqs, xa_idx); 478 if (xa_empty(&binding->bound_rxqs)) { 479 mutex_lock(&binding->lock); 480 binding->dev = NULL; 481 mutex_unlock(&binding->lock); 482 } 483 break; 484 } 485 } 486 } 487 488 static const struct memory_provider_ops dmabuf_devmem_ops = { 489 .init = mp_dmabuf_devmem_init, 490 .destroy = mp_dmabuf_devmem_destroy, 491 .alloc_netmems = mp_dmabuf_devmem_alloc_netmems, 492 .release_netmem = mp_dmabuf_devmem_release_page, 493 .nl_fill = mp_dmabuf_devmem_nl_fill, 494 .uninstall = mp_dmabuf_devmem_uninstall, 495 }; 496