Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* XDP user-space packet buffer |
| 3 | * Copyright(c) 2018 Intel Corporation. |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 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 | |
| 15 | #include "xdp_umem.h" |
Björn Töpel | e61e62b9 | 2018-06-04 14:05:51 +0200 | [diff] [blame] | 16 | #include "xsk_queue.h" |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 17 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 18 | #define XDP_UMEM_MIN_CHUNK_SIZE 2048 |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 19 | |
Magnus Karlsson | ac98d8a | 2018-06-04 14:05:57 +0200 | [diff] [blame] | 20 | void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) |
| 21 | { |
| 22 | unsigned long flags; |
| 23 | |
| 24 | spin_lock_irqsave(&umem->xsk_list_lock, flags); |
| 25 | list_add_rcu(&xs->list, &umem->xsk_list); |
| 26 | spin_unlock_irqrestore(&umem->xsk_list_lock, flags); |
| 27 | } |
| 28 | |
| 29 | void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs) |
| 30 | { |
| 31 | unsigned long flags; |
| 32 | |
| 33 | if (xs->dev) { |
| 34 | spin_lock_irqsave(&umem->xsk_list_lock, flags); |
| 35 | list_del_rcu(&xs->list); |
| 36 | spin_unlock_irqrestore(&umem->xsk_list_lock, flags); |
| 37 | |
| 38 | if (umem->zc) |
| 39 | synchronize_net(); |
| 40 | } |
| 41 | } |
| 42 | |
Björn Töpel | 173d3ad | 2018-06-04 14:05:55 +0200 | [diff] [blame] | 43 | int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev, |
| 44 | u32 queue_id, u16 flags) |
| 45 | { |
| 46 | bool force_zc, force_copy; |
| 47 | struct netdev_bpf bpf; |
| 48 | int err; |
| 49 | |
| 50 | force_zc = flags & XDP_ZEROCOPY; |
| 51 | force_copy = flags & XDP_COPY; |
| 52 | |
| 53 | if (force_zc && force_copy) |
| 54 | return -EINVAL; |
| 55 | |
| 56 | if (force_copy) |
| 57 | return 0; |
| 58 | |
| 59 | dev_hold(dev); |
| 60 | |
Magnus Karlsson | ac98d8a | 2018-06-04 14:05:57 +0200 | [diff] [blame] | 61 | if (dev->netdev_ops->ndo_bpf && dev->netdev_ops->ndo_xsk_async_xmit) { |
Björn Töpel | 173d3ad | 2018-06-04 14:05:55 +0200 | [diff] [blame] | 62 | bpf.command = XDP_QUERY_XSK_UMEM; |
| 63 | |
| 64 | rtnl_lock(); |
| 65 | err = dev->netdev_ops->ndo_bpf(dev, &bpf); |
| 66 | rtnl_unlock(); |
| 67 | |
| 68 | if (err) { |
| 69 | dev_put(dev); |
| 70 | return force_zc ? -ENOTSUPP : 0; |
| 71 | } |
| 72 | |
| 73 | bpf.command = XDP_SETUP_XSK_UMEM; |
| 74 | bpf.xsk.umem = umem; |
| 75 | bpf.xsk.queue_id = queue_id; |
| 76 | |
| 77 | rtnl_lock(); |
| 78 | err = dev->netdev_ops->ndo_bpf(dev, &bpf); |
| 79 | rtnl_unlock(); |
| 80 | |
| 81 | if (err) { |
| 82 | dev_put(dev); |
| 83 | return force_zc ? err : 0; /* fail or fallback */ |
| 84 | } |
| 85 | |
| 86 | umem->dev = dev; |
| 87 | umem->queue_id = queue_id; |
| 88 | umem->zc = true; |
| 89 | return 0; |
| 90 | } |
| 91 | |
| 92 | dev_put(dev); |
| 93 | return force_zc ? -ENOTSUPP : 0; /* fail or fallback */ |
| 94 | } |
| 95 | |
Magnus Karlsson | ac98d8a | 2018-06-04 14:05:57 +0200 | [diff] [blame] | 96 | static void xdp_umem_clear_dev(struct xdp_umem *umem) |
Björn Töpel | 173d3ad | 2018-06-04 14:05:55 +0200 | [diff] [blame] | 97 | { |
| 98 | struct netdev_bpf bpf; |
| 99 | int err; |
| 100 | |
| 101 | if (umem->dev) { |
| 102 | bpf.command = XDP_SETUP_XSK_UMEM; |
| 103 | bpf.xsk.umem = NULL; |
| 104 | bpf.xsk.queue_id = umem->queue_id; |
| 105 | |
| 106 | rtnl_lock(); |
| 107 | err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf); |
| 108 | rtnl_unlock(); |
| 109 | |
| 110 | if (err) |
| 111 | WARN(1, "failed to disable umem!\n"); |
| 112 | |
| 113 | dev_put(umem->dev); |
| 114 | umem->dev = NULL; |
| 115 | } |
| 116 | } |
| 117 | |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 118 | static void xdp_umem_unpin_pages(struct xdp_umem *umem) |
| 119 | { |
| 120 | unsigned int i; |
| 121 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 122 | for (i = 0; i < umem->npgs; i++) { |
| 123 | struct page *page = umem->pgs[i]; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 124 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 125 | set_page_dirty_lock(page); |
| 126 | put_page(page); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 127 | } |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 128 | |
| 129 | kfree(umem->pgs); |
| 130 | umem->pgs = NULL; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | static void xdp_umem_unaccount_pages(struct xdp_umem *umem) |
| 134 | { |
Daniel Borkmann | c09290c | 2018-06-08 00:06:01 +0200 | [diff] [blame] | 135 | if (umem->user) { |
| 136 | atomic_long_sub(umem->npgs, &umem->user->locked_vm); |
| 137 | free_uid(umem->user); |
| 138 | } |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 139 | } |
| 140 | |
| 141 | static void xdp_umem_release(struct xdp_umem *umem) |
| 142 | { |
| 143 | struct task_struct *task; |
| 144 | struct mm_struct *mm; |
| 145 | |
Björn Töpel | 173d3ad | 2018-06-04 14:05:55 +0200 | [diff] [blame] | 146 | xdp_umem_clear_dev(umem); |
| 147 | |
Magnus Karlsson | 423f383 | 2018-05-02 13:01:24 +0200 | [diff] [blame] | 148 | if (umem->fq) { |
| 149 | xskq_destroy(umem->fq); |
| 150 | umem->fq = NULL; |
| 151 | } |
| 152 | |
Magnus Karlsson | fe23083 | 2018-05-02 13:01:31 +0200 | [diff] [blame] | 153 | if (umem->cq) { |
| 154 | xskq_destroy(umem->cq); |
| 155 | umem->cq = NULL; |
| 156 | } |
| 157 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 158 | xdp_umem_unpin_pages(umem); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 159 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 160 | task = get_pid_task(umem->pid, PIDTYPE_PID); |
| 161 | put_pid(umem->pid); |
| 162 | if (!task) |
| 163 | goto out; |
| 164 | mm = get_task_mm(task); |
| 165 | put_task_struct(task); |
| 166 | if (!mm) |
| 167 | goto out; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 168 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 169 | mmput(mm); |
Björn Töpel | 8aef734 | 2018-06-04 14:05:52 +0200 | [diff] [blame] | 170 | kfree(umem->pages); |
| 171 | umem->pages = NULL; |
| 172 | |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 173 | xdp_umem_unaccount_pages(umem); |
| 174 | out: |
| 175 | kfree(umem); |
| 176 | } |
| 177 | |
| 178 | static void xdp_umem_release_deferred(struct work_struct *work) |
| 179 | { |
| 180 | struct xdp_umem *umem = container_of(work, struct xdp_umem, work); |
| 181 | |
| 182 | xdp_umem_release(umem); |
| 183 | } |
| 184 | |
| 185 | void xdp_get_umem(struct xdp_umem *umem) |
| 186 | { |
Björn Töpel | d3b42f1 | 2018-05-22 09:35:03 +0200 | [diff] [blame] | 187 | refcount_inc(&umem->users); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 188 | } |
| 189 | |
| 190 | void xdp_put_umem(struct xdp_umem *umem) |
| 191 | { |
| 192 | if (!umem) |
| 193 | return; |
| 194 | |
Björn Töpel | d3b42f1 | 2018-05-22 09:35:03 +0200 | [diff] [blame] | 195 | if (refcount_dec_and_test(&umem->users)) { |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 196 | INIT_WORK(&umem->work, xdp_umem_release_deferred); |
| 197 | schedule_work(&umem->work); |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | static int xdp_umem_pin_pages(struct xdp_umem *umem) |
| 202 | { |
| 203 | unsigned int gup_flags = FOLL_WRITE; |
| 204 | long npgs; |
| 205 | int err; |
| 206 | |
Björn Töpel | a343993 | 2018-06-11 13:57:12 +0200 | [diff] [blame] | 207 | umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), |
| 208 | GFP_KERNEL | __GFP_NOWARN); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 209 | if (!umem->pgs) |
| 210 | return -ENOMEM; |
| 211 | |
| 212 | down_write(¤t->mm->mmap_sem); |
| 213 | npgs = get_user_pages(umem->address, umem->npgs, |
| 214 | gup_flags, &umem->pgs[0], NULL); |
| 215 | up_write(¤t->mm->mmap_sem); |
| 216 | |
| 217 | if (npgs != umem->npgs) { |
| 218 | if (npgs >= 0) { |
| 219 | umem->npgs = npgs; |
| 220 | err = -ENOMEM; |
| 221 | goto out_pin; |
| 222 | } |
| 223 | err = npgs; |
| 224 | goto out_pgs; |
| 225 | } |
| 226 | return 0; |
| 227 | |
| 228 | out_pin: |
| 229 | xdp_umem_unpin_pages(umem); |
| 230 | out_pgs: |
| 231 | kfree(umem->pgs); |
| 232 | umem->pgs = NULL; |
| 233 | return err; |
| 234 | } |
| 235 | |
| 236 | static int xdp_umem_account_pages(struct xdp_umem *umem) |
| 237 | { |
| 238 | unsigned long lock_limit, new_npgs, old_npgs; |
| 239 | |
| 240 | if (capable(CAP_IPC_LOCK)) |
| 241 | return 0; |
| 242 | |
| 243 | lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; |
| 244 | umem->user = get_uid(current_user()); |
| 245 | |
| 246 | do { |
| 247 | old_npgs = atomic_long_read(&umem->user->locked_vm); |
| 248 | new_npgs = old_npgs + umem->npgs; |
| 249 | if (new_npgs > lock_limit) { |
| 250 | free_uid(umem->user); |
| 251 | umem->user = NULL; |
| 252 | return -ENOBUFS; |
| 253 | } |
| 254 | } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs, |
| 255 | new_npgs) != old_npgs); |
| 256 | return 0; |
| 257 | } |
| 258 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 259 | static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 260 | { |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 261 | u32 chunk_size = mr->chunk_size, headroom = mr->headroom; |
| 262 | unsigned int chunks, chunks_per_page; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 263 | u64 addr = mr->addr, size = mr->len; |
Björn Töpel | 8aef734 | 2018-06-04 14:05:52 +0200 | [diff] [blame] | 264 | int size_chk, err, i; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 265 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 266 | if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 267 | /* Strictly speaking we could support this, if: |
| 268 | * - huge pages, or* |
| 269 | * - using an IOMMU, or |
| 270 | * - making sure the memory area is consecutive |
| 271 | * but for now, we simply say "computer says no". |
| 272 | */ |
| 273 | return -EINVAL; |
| 274 | } |
| 275 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 276 | if (!is_power_of_2(chunk_size)) |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 277 | return -EINVAL; |
| 278 | |
| 279 | if (!PAGE_ALIGNED(addr)) { |
| 280 | /* Memory area has to be page size aligned. For |
| 281 | * simplicity, this might change. |
| 282 | */ |
| 283 | return -EINVAL; |
| 284 | } |
| 285 | |
| 286 | if ((addr + size) < addr) |
| 287 | return -EINVAL; |
| 288 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 289 | chunks = (unsigned int)div_u64(size, chunk_size); |
| 290 | if (chunks == 0) |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 291 | return -EINVAL; |
| 292 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 293 | chunks_per_page = PAGE_SIZE / chunk_size; |
| 294 | if (chunks < chunks_per_page || chunks % chunks_per_page) |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 295 | return -EINVAL; |
| 296 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 297 | headroom = ALIGN(headroom, 64); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 298 | |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 299 | size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 300 | if (size_chk < 0) |
| 301 | return -EINVAL; |
| 302 | |
| 303 | umem->pid = get_task_pid(current, PIDTYPE_PID); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 304 | umem->address = (unsigned long)addr; |
Björn Töpel | bbff2f3 | 2018-06-04 13:57:13 +0200 | [diff] [blame] | 305 | umem->props.chunk_mask = ~((u64)chunk_size - 1); |
| 306 | umem->props.size = size; |
| 307 | umem->headroom = headroom; |
| 308 | umem->chunk_size_nohr = chunk_size - headroom; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 309 | umem->npgs = size / PAGE_SIZE; |
| 310 | umem->pgs = NULL; |
| 311 | umem->user = NULL; |
Magnus Karlsson | ac98d8a | 2018-06-04 14:05:57 +0200 | [diff] [blame] | 312 | INIT_LIST_HEAD(&umem->xsk_list); |
| 313 | spin_lock_init(&umem->xsk_list_lock); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 314 | |
Björn Töpel | d3b42f1 | 2018-05-22 09:35:03 +0200 | [diff] [blame] | 315 | refcount_set(&umem->users, 1); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 316 | |
| 317 | err = xdp_umem_account_pages(umem); |
| 318 | if (err) |
| 319 | goto out; |
| 320 | |
| 321 | err = xdp_umem_pin_pages(umem); |
| 322 | if (err) |
| 323 | goto out_account; |
Björn Töpel | 8aef734 | 2018-06-04 14:05:52 +0200 | [diff] [blame] | 324 | |
| 325 | umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL); |
| 326 | if (!umem->pages) { |
| 327 | err = -ENOMEM; |
| 328 | goto out_account; |
| 329 | } |
| 330 | |
| 331 | for (i = 0; i < umem->npgs; i++) |
| 332 | umem->pages[i].addr = page_address(umem->pgs[i]); |
| 333 | |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 334 | return 0; |
| 335 | |
| 336 | out_account: |
| 337 | xdp_umem_unaccount_pages(umem); |
| 338 | out: |
| 339 | put_pid(umem->pid); |
| 340 | return err; |
| 341 | } |
Magnus Karlsson | 965a9909 | 2018-05-02 13:01:26 +0200 | [diff] [blame] | 342 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 343 | struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr) |
| 344 | { |
| 345 | struct xdp_umem *umem; |
| 346 | int err; |
| 347 | |
| 348 | umem = kzalloc(sizeof(*umem), GFP_KERNEL); |
| 349 | if (!umem) |
| 350 | return ERR_PTR(-ENOMEM); |
| 351 | |
| 352 | err = xdp_umem_reg(umem, mr); |
| 353 | if (err) { |
| 354 | kfree(umem); |
| 355 | return ERR_PTR(err); |
| 356 | } |
| 357 | |
| 358 | return umem; |
| 359 | } |
| 360 | |
Magnus Karlsson | 965a9909 | 2018-05-02 13:01:26 +0200 | [diff] [blame] | 361 | bool xdp_umem_validate_queues(struct xdp_umem *umem) |
| 362 | { |
Björn Töpel | da60cf0 | 2018-05-18 14:00:23 +0200 | [diff] [blame] | 363 | return umem->fq && umem->cq; |
Magnus Karlsson | 965a9909 | 2018-05-02 13:01:26 +0200 | [diff] [blame] | 364 | } |