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" |
| 16 | |
| 17 | #define XDP_UMEM_MIN_FRAME_SIZE 2048 |
| 18 | |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 19 | static void xdp_umem_unpin_pages(struct xdp_umem *umem) |
| 20 | { |
| 21 | unsigned int i; |
| 22 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 23 | for (i = 0; i < umem->npgs; i++) { |
| 24 | struct page *page = umem->pgs[i]; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 25 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 26 | set_page_dirty_lock(page); |
| 27 | put_page(page); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 28 | } |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 29 | |
| 30 | kfree(umem->pgs); |
| 31 | umem->pgs = NULL; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 32 | } |
| 33 | |
| 34 | static void xdp_umem_unaccount_pages(struct xdp_umem *umem) |
| 35 | { |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 36 | atomic_long_sub(umem->npgs, &umem->user->locked_vm); |
| 37 | free_uid(umem->user); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 38 | } |
| 39 | |
| 40 | static void xdp_umem_release(struct xdp_umem *umem) |
| 41 | { |
| 42 | struct task_struct *task; |
| 43 | struct mm_struct *mm; |
| 44 | |
Magnus Karlsson | 423f383 | 2018-05-02 13:01:24 +0200 | [diff] [blame] | 45 | if (umem->fq) { |
| 46 | xskq_destroy(umem->fq); |
| 47 | umem->fq = NULL; |
| 48 | } |
| 49 | |
Magnus Karlsson | fe23083 | 2018-05-02 13:01:31 +0200 | [diff] [blame] | 50 | if (umem->cq) { |
| 51 | xskq_destroy(umem->cq); |
| 52 | umem->cq = NULL; |
| 53 | } |
| 54 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 55 | xdp_umem_unpin_pages(umem); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 56 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 57 | task = get_pid_task(umem->pid, PIDTYPE_PID); |
| 58 | put_pid(umem->pid); |
| 59 | if (!task) |
| 60 | goto out; |
| 61 | mm = get_task_mm(task); |
| 62 | put_task_struct(task); |
| 63 | if (!mm) |
| 64 | goto out; |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 65 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 66 | mmput(mm); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 67 | xdp_umem_unaccount_pages(umem); |
| 68 | out: |
| 69 | kfree(umem); |
| 70 | } |
| 71 | |
| 72 | static void xdp_umem_release_deferred(struct work_struct *work) |
| 73 | { |
| 74 | struct xdp_umem *umem = container_of(work, struct xdp_umem, work); |
| 75 | |
| 76 | xdp_umem_release(umem); |
| 77 | } |
| 78 | |
| 79 | void xdp_get_umem(struct xdp_umem *umem) |
| 80 | { |
Björn Töpel | d3b42f1 | 2018-05-22 09:35:03 +0200 | [diff] [blame^] | 81 | refcount_inc(&umem->users); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 82 | } |
| 83 | |
| 84 | void xdp_put_umem(struct xdp_umem *umem) |
| 85 | { |
| 86 | if (!umem) |
| 87 | return; |
| 88 | |
Björn Töpel | d3b42f1 | 2018-05-22 09:35:03 +0200 | [diff] [blame^] | 89 | if (refcount_dec_and_test(&umem->users)) { |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 90 | INIT_WORK(&umem->work, xdp_umem_release_deferred); |
| 91 | schedule_work(&umem->work); |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | static int xdp_umem_pin_pages(struct xdp_umem *umem) |
| 96 | { |
| 97 | unsigned int gup_flags = FOLL_WRITE; |
| 98 | long npgs; |
| 99 | int err; |
| 100 | |
| 101 | umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL); |
| 102 | if (!umem->pgs) |
| 103 | return -ENOMEM; |
| 104 | |
| 105 | down_write(¤t->mm->mmap_sem); |
| 106 | npgs = get_user_pages(umem->address, umem->npgs, |
| 107 | gup_flags, &umem->pgs[0], NULL); |
| 108 | up_write(¤t->mm->mmap_sem); |
| 109 | |
| 110 | if (npgs != umem->npgs) { |
| 111 | if (npgs >= 0) { |
| 112 | umem->npgs = npgs; |
| 113 | err = -ENOMEM; |
| 114 | goto out_pin; |
| 115 | } |
| 116 | err = npgs; |
| 117 | goto out_pgs; |
| 118 | } |
| 119 | return 0; |
| 120 | |
| 121 | out_pin: |
| 122 | xdp_umem_unpin_pages(umem); |
| 123 | out_pgs: |
| 124 | kfree(umem->pgs); |
| 125 | umem->pgs = NULL; |
| 126 | return err; |
| 127 | } |
| 128 | |
| 129 | static int xdp_umem_account_pages(struct xdp_umem *umem) |
| 130 | { |
| 131 | unsigned long lock_limit, new_npgs, old_npgs; |
| 132 | |
| 133 | if (capable(CAP_IPC_LOCK)) |
| 134 | return 0; |
| 135 | |
| 136 | lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; |
| 137 | umem->user = get_uid(current_user()); |
| 138 | |
| 139 | do { |
| 140 | old_npgs = atomic_long_read(&umem->user->locked_vm); |
| 141 | new_npgs = old_npgs + umem->npgs; |
| 142 | if (new_npgs > lock_limit) { |
| 143 | free_uid(umem->user); |
| 144 | umem->user = NULL; |
| 145 | return -ENOBUFS; |
| 146 | } |
| 147 | } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs, |
| 148 | new_npgs) != old_npgs); |
| 149 | return 0; |
| 150 | } |
| 151 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 152 | 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] | 153 | { |
| 154 | u32 frame_size = mr->frame_size, frame_headroom = mr->frame_headroom; |
| 155 | u64 addr = mr->addr, size = mr->len; |
| 156 | unsigned int nframes, nfpp; |
| 157 | int size_chk, err; |
| 158 | |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 159 | if (frame_size < XDP_UMEM_MIN_FRAME_SIZE || frame_size > PAGE_SIZE) { |
| 160 | /* Strictly speaking we could support this, if: |
| 161 | * - huge pages, or* |
| 162 | * - using an IOMMU, or |
| 163 | * - making sure the memory area is consecutive |
| 164 | * but for now, we simply say "computer says no". |
| 165 | */ |
| 166 | return -EINVAL; |
| 167 | } |
| 168 | |
| 169 | if (!is_power_of_2(frame_size)) |
| 170 | return -EINVAL; |
| 171 | |
| 172 | if (!PAGE_ALIGNED(addr)) { |
| 173 | /* Memory area has to be page size aligned. For |
| 174 | * simplicity, this might change. |
| 175 | */ |
| 176 | return -EINVAL; |
| 177 | } |
| 178 | |
| 179 | if ((addr + size) < addr) |
| 180 | return -EINVAL; |
| 181 | |
Björn Töpel | ea7e343 | 2018-05-07 19:43:50 +0200 | [diff] [blame] | 182 | nframes = (unsigned int)div_u64(size, frame_size); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 183 | if (nframes == 0 || nframes > UINT_MAX) |
| 184 | return -EINVAL; |
| 185 | |
| 186 | nfpp = PAGE_SIZE / frame_size; |
| 187 | if (nframes < nfpp || nframes % nfpp) |
| 188 | return -EINVAL; |
| 189 | |
| 190 | frame_headroom = ALIGN(frame_headroom, 64); |
| 191 | |
| 192 | size_chk = frame_size - frame_headroom - XDP_PACKET_HEADROOM; |
| 193 | if (size_chk < 0) |
| 194 | return -EINVAL; |
| 195 | |
| 196 | umem->pid = get_task_pid(current, PIDTYPE_PID); |
| 197 | umem->size = (size_t)size; |
| 198 | umem->address = (unsigned long)addr; |
| 199 | umem->props.frame_size = frame_size; |
| 200 | umem->props.nframes = nframes; |
| 201 | umem->frame_headroom = frame_headroom; |
| 202 | umem->npgs = size / PAGE_SIZE; |
| 203 | umem->pgs = NULL; |
| 204 | umem->user = NULL; |
| 205 | |
| 206 | umem->frame_size_log2 = ilog2(frame_size); |
| 207 | umem->nfpp_mask = nfpp - 1; |
| 208 | umem->nfpplog2 = ilog2(nfpp); |
Björn Töpel | d3b42f1 | 2018-05-22 09:35:03 +0200 | [diff] [blame^] | 209 | refcount_set(&umem->users, 1); |
Björn Töpel | c0c77d8 | 2018-05-02 13:01:23 +0200 | [diff] [blame] | 210 | |
| 211 | err = xdp_umem_account_pages(umem); |
| 212 | if (err) |
| 213 | goto out; |
| 214 | |
| 215 | err = xdp_umem_pin_pages(umem); |
| 216 | if (err) |
| 217 | goto out_account; |
| 218 | return 0; |
| 219 | |
| 220 | out_account: |
| 221 | xdp_umem_unaccount_pages(umem); |
| 222 | out: |
| 223 | put_pid(umem->pid); |
| 224 | return err; |
| 225 | } |
Magnus Karlsson | 965a990 | 2018-05-02 13:01:26 +0200 | [diff] [blame] | 226 | |
Björn Töpel | a49049e | 2018-05-22 09:35:02 +0200 | [diff] [blame] | 227 | struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr) |
| 228 | { |
| 229 | struct xdp_umem *umem; |
| 230 | int err; |
| 231 | |
| 232 | umem = kzalloc(sizeof(*umem), GFP_KERNEL); |
| 233 | if (!umem) |
| 234 | return ERR_PTR(-ENOMEM); |
| 235 | |
| 236 | err = xdp_umem_reg(umem, mr); |
| 237 | if (err) { |
| 238 | kfree(umem); |
| 239 | return ERR_PTR(err); |
| 240 | } |
| 241 | |
| 242 | return umem; |
| 243 | } |
| 244 | |
Magnus Karlsson | 965a990 | 2018-05-02 13:01:26 +0200 | [diff] [blame] | 245 | bool xdp_umem_validate_queues(struct xdp_umem *umem) |
| 246 | { |
Björn Töpel | da60cf0 | 2018-05-18 14:00:23 +0200 | [diff] [blame] | 247 | return umem->fq && umem->cq; |
Magnus Karlsson | 965a990 | 2018-05-02 13:01:26 +0200 | [diff] [blame] | 248 | } |