109c434b8SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2f87d0fbbSRusty Russell /* 3f87d0fbbSRusty Russell * Helpers for the host side of a virtio ring. 4f87d0fbbSRusty Russell * 5f87d0fbbSRusty Russell * Since these may be in userspace, we use (inline) accessors. 6f87d0fbbSRusty Russell */ 79d1b972fSMark Rutland #include <linux/compiler.h> 8f558a845SDave Jones #include <linux/module.h> 9f87d0fbbSRusty Russell #include <linux/vringh.h> 10f87d0fbbSRusty Russell #include <linux/virtio_ring.h> 11f87d0fbbSRusty Russell #include <linux/kernel.h> 12f87d0fbbSRusty Russell #include <linux/ratelimit.h> 13f87d0fbbSRusty Russell #include <linux/uaccess.h> 14f87d0fbbSRusty Russell #include <linux/slab.h> 15f87d0fbbSRusty Russell #include <linux/export.h> 169ad9c49cSJason Wang #include <linux/bvec.h> 179ad9c49cSJason Wang #include <linux/highmem.h> 189ad9c49cSJason Wang #include <linux/vhost_iotlb.h> 19b9f7ac8cSMichael S. Tsirkin #include <uapi/linux/virtio_config.h> 20f87d0fbbSRusty Russell 21f87d0fbbSRusty Russell static __printf(1,2) __cold void vringh_bad(const char *fmt, ...) 22f87d0fbbSRusty Russell { 23f87d0fbbSRusty Russell static DEFINE_RATELIMIT_STATE(vringh_rs, 24f87d0fbbSRusty Russell DEFAULT_RATELIMIT_INTERVAL, 25f87d0fbbSRusty Russell DEFAULT_RATELIMIT_BURST); 26f87d0fbbSRusty Russell if (__ratelimit(&vringh_rs)) { 27f87d0fbbSRusty Russell va_list ap; 28f87d0fbbSRusty Russell va_start(ap, fmt); 29f87d0fbbSRusty Russell printk(KERN_NOTICE "vringh:"); 30f87d0fbbSRusty Russell vprintk(fmt, ap); 31f87d0fbbSRusty Russell va_end(ap); 32f87d0fbbSRusty Russell } 33f87d0fbbSRusty Russell } 34f87d0fbbSRusty Russell 35f87d0fbbSRusty Russell /* Returns vring->num if empty, -ve on error. */ 36f87d0fbbSRusty Russell static inline int __vringh_get_head(const struct vringh *vrh, 37b9f7ac8cSMichael S. Tsirkin int (*getu16)(const struct vringh *vrh, 38b9f7ac8cSMichael S. Tsirkin u16 *val, const __virtio16 *p), 39f87d0fbbSRusty Russell u16 *last_avail_idx) 40f87d0fbbSRusty Russell { 41f87d0fbbSRusty Russell u16 avail_idx, i, head; 42f87d0fbbSRusty Russell int err; 43f87d0fbbSRusty Russell 44b9f7ac8cSMichael S. Tsirkin err = getu16(vrh, &avail_idx, &vrh->vring.avail->idx); 45f87d0fbbSRusty Russell if (err) { 46f87d0fbbSRusty Russell vringh_bad("Failed to access avail idx at %p", 47f87d0fbbSRusty Russell &vrh->vring.avail->idx); 48f87d0fbbSRusty Russell return err; 49f87d0fbbSRusty Russell } 50f87d0fbbSRusty Russell 51f87d0fbbSRusty Russell if (*last_avail_idx == avail_idx) 52f87d0fbbSRusty Russell return vrh->vring.num; 53f87d0fbbSRusty Russell 54f87d0fbbSRusty Russell /* Only get avail ring entries after they have been exposed by guest. */ 55f87d0fbbSRusty Russell virtio_rmb(vrh->weak_barriers); 56f87d0fbbSRusty Russell 57f87d0fbbSRusty Russell i = *last_avail_idx & (vrh->vring.num - 1); 58f87d0fbbSRusty Russell 59b9f7ac8cSMichael S. Tsirkin err = getu16(vrh, &head, &vrh->vring.avail->ring[i]); 60f87d0fbbSRusty Russell if (err) { 61f87d0fbbSRusty Russell vringh_bad("Failed to read head: idx %d address %p", 62f87d0fbbSRusty Russell *last_avail_idx, &vrh->vring.avail->ring[i]); 63f87d0fbbSRusty Russell return err; 64f87d0fbbSRusty Russell } 65f87d0fbbSRusty Russell 66f87d0fbbSRusty Russell if (head >= vrh->vring.num) { 67f87d0fbbSRusty Russell vringh_bad("Guest says index %u > %u is available", 68f87d0fbbSRusty Russell head, vrh->vring.num); 69f87d0fbbSRusty Russell return -EINVAL; 70f87d0fbbSRusty Russell } 71f87d0fbbSRusty Russell 72f87d0fbbSRusty Russell (*last_avail_idx)++; 73f87d0fbbSRusty Russell return head; 74f87d0fbbSRusty Russell } 75f87d0fbbSRusty Russell 76f87d0fbbSRusty Russell /* Copy some bytes to/from the iovec. Returns num copied. */ 779ad9c49cSJason Wang static inline ssize_t vringh_iov_xfer(struct vringh *vrh, 789ad9c49cSJason Wang struct vringh_kiov *iov, 79f87d0fbbSRusty Russell void *ptr, size_t len, 809ad9c49cSJason Wang int (*xfer)(const struct vringh *vrh, 819ad9c49cSJason Wang void *addr, void *ptr, 82f87d0fbbSRusty Russell size_t len)) 83f87d0fbbSRusty Russell { 84f87d0fbbSRusty Russell int err, done = 0; 85f87d0fbbSRusty Russell 86f87d0fbbSRusty Russell while (len && iov->i < iov->used) { 87f87d0fbbSRusty Russell size_t partlen; 88f87d0fbbSRusty Russell 89f87d0fbbSRusty Russell partlen = min(iov->iov[iov->i].iov_len, len); 909ad9c49cSJason Wang err = xfer(vrh, iov->iov[iov->i].iov_base, ptr, partlen); 91f87d0fbbSRusty Russell if (err) 92f87d0fbbSRusty Russell return err; 93f87d0fbbSRusty Russell done += partlen; 94f87d0fbbSRusty Russell len -= partlen; 95f87d0fbbSRusty Russell ptr += partlen; 96f87d0fbbSRusty Russell iov->consumed += partlen; 97f87d0fbbSRusty Russell iov->iov[iov->i].iov_len -= partlen; 98f87d0fbbSRusty Russell iov->iov[iov->i].iov_base += partlen; 99f87d0fbbSRusty Russell 100f87d0fbbSRusty Russell if (!iov->iov[iov->i].iov_len) { 101f87d0fbbSRusty Russell /* Fix up old iov element then increment. */ 102f87d0fbbSRusty Russell iov->iov[iov->i].iov_len = iov->consumed; 103f87d0fbbSRusty Russell iov->iov[iov->i].iov_base -= iov->consumed; 104f87d0fbbSRusty Russell 1059ad9c49cSJason Wang 106f87d0fbbSRusty Russell iov->consumed = 0; 107f87d0fbbSRusty Russell iov->i++; 108f87d0fbbSRusty Russell } 109f87d0fbbSRusty Russell } 110f87d0fbbSRusty Russell return done; 111f87d0fbbSRusty Russell } 112f87d0fbbSRusty Russell 113f87d0fbbSRusty Russell /* May reduce *len if range is shorter. */ 114f87d0fbbSRusty Russell static inline bool range_check(struct vringh *vrh, u64 addr, size_t *len, 115f87d0fbbSRusty Russell struct vringh_range *range, 116f87d0fbbSRusty Russell bool (*getrange)(struct vringh *, 117f87d0fbbSRusty Russell u64, struct vringh_range *)) 118f87d0fbbSRusty Russell { 119f87d0fbbSRusty Russell if (addr < range->start || addr > range->end_incl) { 120f87d0fbbSRusty Russell if (!getrange(vrh, addr, range)) 121f87d0fbbSRusty Russell return false; 122f87d0fbbSRusty Russell } 123f87d0fbbSRusty Russell BUG_ON(addr < range->start || addr > range->end_incl); 124f87d0fbbSRusty Russell 125f87d0fbbSRusty Russell /* To end of memory? */ 126f87d0fbbSRusty Russell if (unlikely(addr + *len == 0)) { 127f87d0fbbSRusty Russell if (range->end_incl == -1ULL) 128f87d0fbbSRusty Russell return true; 129f87d0fbbSRusty Russell goto truncate; 130f87d0fbbSRusty Russell } 131f87d0fbbSRusty Russell 132f87d0fbbSRusty Russell /* Otherwise, don't wrap. */ 133f87d0fbbSRusty Russell if (addr + *len < addr) { 134f87d0fbbSRusty Russell vringh_bad("Wrapping descriptor %zu@0x%llx", 135f87d0fbbSRusty Russell *len, (unsigned long long)addr); 136f87d0fbbSRusty Russell return false; 137f87d0fbbSRusty Russell } 138f87d0fbbSRusty Russell 139f87d0fbbSRusty Russell if (unlikely(addr + *len - 1 > range->end_incl)) 140f87d0fbbSRusty Russell goto truncate; 141f87d0fbbSRusty Russell return true; 142f87d0fbbSRusty Russell 143f87d0fbbSRusty Russell truncate: 144f87d0fbbSRusty Russell *len = range->end_incl + 1 - addr; 145f87d0fbbSRusty Russell return true; 146f87d0fbbSRusty Russell } 147f87d0fbbSRusty Russell 148f87d0fbbSRusty Russell static inline bool no_range_check(struct vringh *vrh, u64 addr, size_t *len, 149f87d0fbbSRusty Russell struct vringh_range *range, 150f87d0fbbSRusty Russell bool (*getrange)(struct vringh *, 151f87d0fbbSRusty Russell u64, struct vringh_range *)) 152f87d0fbbSRusty Russell { 153f87d0fbbSRusty Russell return true; 154f87d0fbbSRusty Russell } 155f87d0fbbSRusty Russell 156f87d0fbbSRusty Russell /* No reason for this code to be inline. */ 157b9f7ac8cSMichael S. Tsirkin static int move_to_indirect(const struct vringh *vrh, 158b9f7ac8cSMichael S. Tsirkin int *up_next, u16 *i, void *addr, 159f87d0fbbSRusty Russell const struct vring_desc *desc, 160f87d0fbbSRusty Russell struct vring_desc **descs, int *desc_max) 161f87d0fbbSRusty Russell { 162b9f7ac8cSMichael S. Tsirkin u32 len; 163b9f7ac8cSMichael S. Tsirkin 164f87d0fbbSRusty Russell /* Indirect tables can't have indirect. */ 165f87d0fbbSRusty Russell if (*up_next != -1) { 166f87d0fbbSRusty Russell vringh_bad("Multilevel indirect %u->%u", *up_next, *i); 167f87d0fbbSRusty Russell return -EINVAL; 168f87d0fbbSRusty Russell } 169f87d0fbbSRusty Russell 170b9f7ac8cSMichael S. Tsirkin len = vringh32_to_cpu(vrh, desc->len); 171b9f7ac8cSMichael S. Tsirkin if (unlikely(len % sizeof(struct vring_desc))) { 172f87d0fbbSRusty Russell vringh_bad("Strange indirect len %u", desc->len); 173f87d0fbbSRusty Russell return -EINVAL; 174f87d0fbbSRusty Russell } 175f87d0fbbSRusty Russell 176f87d0fbbSRusty Russell /* We will check this when we follow it! */ 177b9f7ac8cSMichael S. Tsirkin if (desc->flags & cpu_to_vringh16(vrh, VRING_DESC_F_NEXT)) 178b9f7ac8cSMichael S. Tsirkin *up_next = vringh16_to_cpu(vrh, desc->next); 179f87d0fbbSRusty Russell else 180f87d0fbbSRusty Russell *up_next = -2; 181f87d0fbbSRusty Russell *descs = addr; 182b9f7ac8cSMichael S. Tsirkin *desc_max = len / sizeof(struct vring_desc); 183f87d0fbbSRusty Russell 184f87d0fbbSRusty Russell /* Now, start at the first indirect. */ 185f87d0fbbSRusty Russell *i = 0; 186f87d0fbbSRusty Russell return 0; 187f87d0fbbSRusty Russell } 188f87d0fbbSRusty Russell 189f87d0fbbSRusty Russell static int resize_iovec(struct vringh_kiov *iov, gfp_t gfp) 190f87d0fbbSRusty Russell { 191f87d0fbbSRusty Russell struct kvec *new; 192f87d0fbbSRusty Russell unsigned int flag, new_num = (iov->max_num & ~VRINGH_IOV_ALLOCATED) * 2; 193f87d0fbbSRusty Russell 194f87d0fbbSRusty Russell if (new_num < 8) 195f87d0fbbSRusty Russell new_num = 8; 196f87d0fbbSRusty Russell 197f87d0fbbSRusty Russell flag = (iov->max_num & VRINGH_IOV_ALLOCATED); 198f87d0fbbSRusty Russell if (flag) 199f87d0fbbSRusty Russell new = krealloc(iov->iov, new_num * sizeof(struct iovec), gfp); 200f87d0fbbSRusty Russell else { 2016da2ec56SKees Cook new = kmalloc_array(new_num, sizeof(struct iovec), gfp); 202f87d0fbbSRusty Russell if (new) { 203f87d0fbbSRusty Russell memcpy(new, iov->iov, 204f87d0fbbSRusty Russell iov->max_num * sizeof(struct iovec)); 205f87d0fbbSRusty Russell flag = VRINGH_IOV_ALLOCATED; 206f87d0fbbSRusty Russell } 207f87d0fbbSRusty Russell } 208f87d0fbbSRusty Russell if (!new) 209f87d0fbbSRusty Russell return -ENOMEM; 210f87d0fbbSRusty Russell iov->iov = new; 211f87d0fbbSRusty Russell iov->max_num = (new_num | flag); 212f87d0fbbSRusty Russell return 0; 213f87d0fbbSRusty Russell } 214f87d0fbbSRusty Russell 215f87d0fbbSRusty Russell static u16 __cold return_from_indirect(const struct vringh *vrh, int *up_next, 216f87d0fbbSRusty Russell struct vring_desc **descs, int *desc_max) 217f87d0fbbSRusty Russell { 218f87d0fbbSRusty Russell u16 i = *up_next; 219f87d0fbbSRusty Russell 220f87d0fbbSRusty Russell *up_next = -1; 221f87d0fbbSRusty Russell *descs = vrh->vring.desc; 222f87d0fbbSRusty Russell *desc_max = vrh->vring.num; 223f87d0fbbSRusty Russell return i; 224f87d0fbbSRusty Russell } 225f87d0fbbSRusty Russell 226f87d0fbbSRusty Russell static int slow_copy(struct vringh *vrh, void *dst, const void *src, 227f87d0fbbSRusty Russell bool (*rcheck)(struct vringh *vrh, u64 addr, size_t *len, 228f87d0fbbSRusty Russell struct vringh_range *range, 229f87d0fbbSRusty Russell bool (*getrange)(struct vringh *vrh, 230f87d0fbbSRusty Russell u64, 231f87d0fbbSRusty Russell struct vringh_range *)), 232f87d0fbbSRusty Russell bool (*getrange)(struct vringh *vrh, 233f87d0fbbSRusty Russell u64 addr, 234f87d0fbbSRusty Russell struct vringh_range *r), 235f87d0fbbSRusty Russell struct vringh_range *range, 2369ad9c49cSJason Wang int (*copy)(const struct vringh *vrh, 2379ad9c49cSJason Wang void *dst, const void *src, size_t len)) 238f87d0fbbSRusty Russell { 239f87d0fbbSRusty Russell size_t part, len = sizeof(struct vring_desc); 240f87d0fbbSRusty Russell 241f87d0fbbSRusty Russell do { 242f87d0fbbSRusty Russell u64 addr; 243f87d0fbbSRusty Russell int err; 244f87d0fbbSRusty Russell 245f87d0fbbSRusty Russell part = len; 246f87d0fbbSRusty Russell addr = (u64)(unsigned long)src - range->offset; 247f87d0fbbSRusty Russell 248f87d0fbbSRusty Russell if (!rcheck(vrh, addr, &part, range, getrange)) 249f87d0fbbSRusty Russell return -EINVAL; 250f87d0fbbSRusty Russell 2519ad9c49cSJason Wang err = copy(vrh, dst, src, part); 252f87d0fbbSRusty Russell if (err) 253f87d0fbbSRusty Russell return err; 254f87d0fbbSRusty Russell 255f87d0fbbSRusty Russell dst += part; 256f87d0fbbSRusty Russell src += part; 257f87d0fbbSRusty Russell len -= part; 258f87d0fbbSRusty Russell } while (len); 259f87d0fbbSRusty Russell return 0; 260f87d0fbbSRusty Russell } 261f87d0fbbSRusty Russell 262f87d0fbbSRusty Russell static inline int 263f87d0fbbSRusty Russell __vringh_iov(struct vringh *vrh, u16 i, 264f87d0fbbSRusty Russell struct vringh_kiov *riov, 265f87d0fbbSRusty Russell struct vringh_kiov *wiov, 266f87d0fbbSRusty Russell bool (*rcheck)(struct vringh *vrh, u64 addr, size_t *len, 267f87d0fbbSRusty Russell struct vringh_range *range, 268f87d0fbbSRusty Russell bool (*getrange)(struct vringh *, u64, 269f87d0fbbSRusty Russell struct vringh_range *)), 270f87d0fbbSRusty Russell bool (*getrange)(struct vringh *, u64, struct vringh_range *), 271f87d0fbbSRusty Russell gfp_t gfp, 2729ad9c49cSJason Wang int (*copy)(const struct vringh *vrh, 2739ad9c49cSJason Wang void *dst, const void *src, size_t len)) 274f87d0fbbSRusty Russell { 275f87d0fbbSRusty Russell int err, count = 0, up_next, desc_max; 276f87d0fbbSRusty Russell struct vring_desc desc, *descs; 277f87d0fbbSRusty Russell struct vringh_range range = { -1ULL, 0 }, slowrange; 278f87d0fbbSRusty Russell bool slow = false; 279f87d0fbbSRusty Russell 280f87d0fbbSRusty Russell /* We start traversing vring's descriptor table. */ 281f87d0fbbSRusty Russell descs = vrh->vring.desc; 282f87d0fbbSRusty Russell desc_max = vrh->vring.num; 283f87d0fbbSRusty Russell up_next = -1; 284f87d0fbbSRusty Russell 285f87d0fbbSRusty Russell if (riov) 286f87d0fbbSRusty Russell riov->i = riov->used = 0; 287f87d0fbbSRusty Russell else if (wiov) 288f87d0fbbSRusty Russell wiov->i = wiov->used = 0; 289f87d0fbbSRusty Russell else 290f87d0fbbSRusty Russell /* You must want something! */ 291f87d0fbbSRusty Russell BUG(); 292f87d0fbbSRusty Russell 293f87d0fbbSRusty Russell for (;;) { 294f87d0fbbSRusty Russell void *addr; 295f87d0fbbSRusty Russell struct vringh_kiov *iov; 296f87d0fbbSRusty Russell size_t len; 297f87d0fbbSRusty Russell 298f87d0fbbSRusty Russell if (unlikely(slow)) 299f87d0fbbSRusty Russell err = slow_copy(vrh, &desc, &descs[i], rcheck, getrange, 300f87d0fbbSRusty Russell &slowrange, copy); 301f87d0fbbSRusty Russell else 3029ad9c49cSJason Wang err = copy(vrh, &desc, &descs[i], sizeof(desc)); 303f87d0fbbSRusty Russell if (unlikely(err)) 304f87d0fbbSRusty Russell goto fail; 305f87d0fbbSRusty Russell 306b9f7ac8cSMichael S. Tsirkin if (unlikely(desc.flags & 307b9f7ac8cSMichael S. Tsirkin cpu_to_vringh16(vrh, VRING_DESC_F_INDIRECT))) { 308b9f7ac8cSMichael S. Tsirkin u64 a = vringh64_to_cpu(vrh, desc.addr); 309b9f7ac8cSMichael S. Tsirkin 310f87d0fbbSRusty Russell /* Make sure it's OK, and get offset. */ 311b9f7ac8cSMichael S. Tsirkin len = vringh32_to_cpu(vrh, desc.len); 312b9f7ac8cSMichael S. Tsirkin if (!rcheck(vrh, a, &len, &range, getrange)) { 313f87d0fbbSRusty Russell err = -EINVAL; 314f87d0fbbSRusty Russell goto fail; 315f87d0fbbSRusty Russell } 316f87d0fbbSRusty Russell 317b9f7ac8cSMichael S. Tsirkin if (unlikely(len != vringh32_to_cpu(vrh, desc.len))) { 318f87d0fbbSRusty Russell slow = true; 319f87d0fbbSRusty Russell /* We need to save this range to use offset */ 320f87d0fbbSRusty Russell slowrange = range; 321f87d0fbbSRusty Russell } 322f87d0fbbSRusty Russell 323b9f7ac8cSMichael S. Tsirkin addr = (void *)(long)(a + range.offset); 324b9f7ac8cSMichael S. Tsirkin err = move_to_indirect(vrh, &up_next, &i, addr, &desc, 325f87d0fbbSRusty Russell &descs, &desc_max); 326f87d0fbbSRusty Russell if (err) 327f87d0fbbSRusty Russell goto fail; 328f87d0fbbSRusty Russell continue; 329f87d0fbbSRusty Russell } 330f87d0fbbSRusty Russell 331f87d0fbbSRusty Russell if (count++ == vrh->vring.num) { 332f87d0fbbSRusty Russell vringh_bad("Descriptor loop in %p", descs); 333f87d0fbbSRusty Russell err = -ELOOP; 334f87d0fbbSRusty Russell goto fail; 335f87d0fbbSRusty Russell } 336f87d0fbbSRusty Russell 337b9f7ac8cSMichael S. Tsirkin if (desc.flags & cpu_to_vringh16(vrh, VRING_DESC_F_WRITE)) 338f87d0fbbSRusty Russell iov = wiov; 339f87d0fbbSRusty Russell else { 340f87d0fbbSRusty Russell iov = riov; 341f87d0fbbSRusty Russell if (unlikely(wiov && wiov->i)) { 342f87d0fbbSRusty Russell vringh_bad("Readable desc %p after writable", 343f87d0fbbSRusty Russell &descs[i]); 344f87d0fbbSRusty Russell err = -EINVAL; 345f87d0fbbSRusty Russell goto fail; 346f87d0fbbSRusty Russell } 347f87d0fbbSRusty Russell } 348f87d0fbbSRusty Russell 349f87d0fbbSRusty Russell if (!iov) { 350f87d0fbbSRusty Russell vringh_bad("Unexpected %s desc", 351f87d0fbbSRusty Russell !wiov ? "writable" : "readable"); 352f87d0fbbSRusty Russell err = -EPROTO; 353f87d0fbbSRusty Russell goto fail; 354f87d0fbbSRusty Russell } 355f87d0fbbSRusty Russell 356f87d0fbbSRusty Russell again: 357f87d0fbbSRusty Russell /* Make sure it's OK, and get offset. */ 358b9f7ac8cSMichael S. Tsirkin len = vringh32_to_cpu(vrh, desc.len); 359b9f7ac8cSMichael S. Tsirkin if (!rcheck(vrh, vringh64_to_cpu(vrh, desc.addr), &len, &range, 360b9f7ac8cSMichael S. Tsirkin getrange)) { 361f87d0fbbSRusty Russell err = -EINVAL; 362f87d0fbbSRusty Russell goto fail; 363f87d0fbbSRusty Russell } 364b9f7ac8cSMichael S. Tsirkin addr = (void *)(unsigned long)(vringh64_to_cpu(vrh, desc.addr) + 365b9f7ac8cSMichael S. Tsirkin range.offset); 366f87d0fbbSRusty Russell 367f87d0fbbSRusty Russell if (unlikely(iov->used == (iov->max_num & ~VRINGH_IOV_ALLOCATED))) { 368f87d0fbbSRusty Russell err = resize_iovec(iov, gfp); 369f87d0fbbSRusty Russell if (err) 370f87d0fbbSRusty Russell goto fail; 371f87d0fbbSRusty Russell } 372f87d0fbbSRusty Russell 373f87d0fbbSRusty Russell iov->iov[iov->used].iov_base = addr; 374f87d0fbbSRusty Russell iov->iov[iov->used].iov_len = len; 375f87d0fbbSRusty Russell iov->used++; 376f87d0fbbSRusty Russell 377b9f7ac8cSMichael S. Tsirkin if (unlikely(len != vringh32_to_cpu(vrh, desc.len))) { 378b9f7ac8cSMichael S. Tsirkin desc.len = cpu_to_vringh32(vrh, 379b9f7ac8cSMichael S. Tsirkin vringh32_to_cpu(vrh, desc.len) - len); 380b9f7ac8cSMichael S. Tsirkin desc.addr = cpu_to_vringh64(vrh, 381b9f7ac8cSMichael S. Tsirkin vringh64_to_cpu(vrh, desc.addr) + len); 382f87d0fbbSRusty Russell goto again; 383f87d0fbbSRusty Russell } 384f87d0fbbSRusty Russell 385b9f7ac8cSMichael S. Tsirkin if (desc.flags & cpu_to_vringh16(vrh, VRING_DESC_F_NEXT)) { 386b9f7ac8cSMichael S. Tsirkin i = vringh16_to_cpu(vrh, desc.next); 387f87d0fbbSRusty Russell } else { 388f87d0fbbSRusty Russell /* Just in case we need to finish traversing above. */ 389f87d0fbbSRusty Russell if (unlikely(up_next > 0)) { 390f87d0fbbSRusty Russell i = return_from_indirect(vrh, &up_next, 391f87d0fbbSRusty Russell &descs, &desc_max); 392f87d0fbbSRusty Russell slow = false; 393f87d0fbbSRusty Russell } else 394f87d0fbbSRusty Russell break; 395f87d0fbbSRusty Russell } 396f87d0fbbSRusty Russell 397f87d0fbbSRusty Russell if (i >= desc_max) { 398f87d0fbbSRusty Russell vringh_bad("Chained index %u > %u", i, desc_max); 399f87d0fbbSRusty Russell err = -EINVAL; 400f87d0fbbSRusty Russell goto fail; 401f87d0fbbSRusty Russell } 402f87d0fbbSRusty Russell } 403f87d0fbbSRusty Russell 404f87d0fbbSRusty Russell return 0; 405f87d0fbbSRusty Russell 406f87d0fbbSRusty Russell fail: 407f87d0fbbSRusty Russell return err; 408f87d0fbbSRusty Russell } 409f87d0fbbSRusty Russell 410f87d0fbbSRusty Russell static inline int __vringh_complete(struct vringh *vrh, 411f87d0fbbSRusty Russell const struct vring_used_elem *used, 412f87d0fbbSRusty Russell unsigned int num_used, 413b9f7ac8cSMichael S. Tsirkin int (*putu16)(const struct vringh *vrh, 414b9f7ac8cSMichael S. Tsirkin __virtio16 *p, u16 val), 4159ad9c49cSJason Wang int (*putused)(const struct vringh *vrh, 4169ad9c49cSJason Wang struct vring_used_elem *dst, 417f87d0fbbSRusty Russell const struct vring_used_elem 418f87d0fbbSRusty Russell *src, unsigned num)) 419f87d0fbbSRusty Russell { 420f87d0fbbSRusty Russell struct vring_used *used_ring; 421f87d0fbbSRusty Russell int err; 422f87d0fbbSRusty Russell u16 used_idx, off; 423f87d0fbbSRusty Russell 424f87d0fbbSRusty Russell used_ring = vrh->vring.used; 425f87d0fbbSRusty Russell used_idx = vrh->last_used_idx + vrh->completed; 426f87d0fbbSRusty Russell 427f87d0fbbSRusty Russell off = used_idx % vrh->vring.num; 428f87d0fbbSRusty Russell 429f87d0fbbSRusty Russell /* Compiler knows num_used == 1 sometimes, hence extra check */ 430f87d0fbbSRusty Russell if (num_used > 1 && unlikely(off + num_used >= vrh->vring.num)) { 431f87d0fbbSRusty Russell u16 part = vrh->vring.num - off; 4329ad9c49cSJason Wang err = putused(vrh, &used_ring->ring[off], used, part); 433f87d0fbbSRusty Russell if (!err) 4349ad9c49cSJason Wang err = putused(vrh, &used_ring->ring[0], used + part, 435f87d0fbbSRusty Russell num_used - part); 436f87d0fbbSRusty Russell } else 4379ad9c49cSJason Wang err = putused(vrh, &used_ring->ring[off], used, num_used); 438f87d0fbbSRusty Russell 439f87d0fbbSRusty Russell if (err) { 440f87d0fbbSRusty Russell vringh_bad("Failed to write %u used entries %u at %p", 441f87d0fbbSRusty Russell num_used, off, &used_ring->ring[off]); 442f87d0fbbSRusty Russell return err; 443f87d0fbbSRusty Russell } 444f87d0fbbSRusty Russell 445f87d0fbbSRusty Russell /* Make sure buffer is written before we update index. */ 446f87d0fbbSRusty Russell virtio_wmb(vrh->weak_barriers); 447f87d0fbbSRusty Russell 448b9f7ac8cSMichael S. Tsirkin err = putu16(vrh, &vrh->vring.used->idx, used_idx + num_used); 449f87d0fbbSRusty Russell if (err) { 450f87d0fbbSRusty Russell vringh_bad("Failed to update used index at %p", 451f87d0fbbSRusty Russell &vrh->vring.used->idx); 452f87d0fbbSRusty Russell return err; 453f87d0fbbSRusty Russell } 454f87d0fbbSRusty Russell 455f87d0fbbSRusty Russell vrh->completed += num_used; 456f87d0fbbSRusty Russell return 0; 457f87d0fbbSRusty Russell } 458f87d0fbbSRusty Russell 459f87d0fbbSRusty Russell 460f87d0fbbSRusty Russell static inline int __vringh_need_notify(struct vringh *vrh, 461b9f7ac8cSMichael S. Tsirkin int (*getu16)(const struct vringh *vrh, 462b9f7ac8cSMichael S. Tsirkin u16 *val, 463b9f7ac8cSMichael S. Tsirkin const __virtio16 *p)) 464f87d0fbbSRusty Russell { 465f87d0fbbSRusty Russell bool notify; 466f87d0fbbSRusty Russell u16 used_event; 467f87d0fbbSRusty Russell int err; 468f87d0fbbSRusty Russell 469f87d0fbbSRusty Russell /* Flush out used index update. This is paired with the 470f87d0fbbSRusty Russell * barrier that the Guest executes when enabling 471f87d0fbbSRusty Russell * interrupts. */ 472f87d0fbbSRusty Russell virtio_mb(vrh->weak_barriers); 473f87d0fbbSRusty Russell 474f87d0fbbSRusty Russell /* Old-style, without event indices. */ 475f87d0fbbSRusty Russell if (!vrh->event_indices) { 476f87d0fbbSRusty Russell u16 flags; 477b9f7ac8cSMichael S. Tsirkin err = getu16(vrh, &flags, &vrh->vring.avail->flags); 478f87d0fbbSRusty Russell if (err) { 479f87d0fbbSRusty Russell vringh_bad("Failed to get flags at %p", 480f87d0fbbSRusty Russell &vrh->vring.avail->flags); 481f87d0fbbSRusty Russell return err; 482f87d0fbbSRusty Russell } 483f87d0fbbSRusty Russell return (!(flags & VRING_AVAIL_F_NO_INTERRUPT)); 484f87d0fbbSRusty Russell } 485f87d0fbbSRusty Russell 486f87d0fbbSRusty Russell /* Modern: we know when other side wants to know. */ 487b9f7ac8cSMichael S. Tsirkin err = getu16(vrh, &used_event, &vring_used_event(&vrh->vring)); 488f87d0fbbSRusty Russell if (err) { 489f87d0fbbSRusty Russell vringh_bad("Failed to get used event idx at %p", 490f87d0fbbSRusty Russell &vring_used_event(&vrh->vring)); 491f87d0fbbSRusty Russell return err; 492f87d0fbbSRusty Russell } 493f87d0fbbSRusty Russell 494f87d0fbbSRusty Russell /* Just in case we added so many that we wrap. */ 495f87d0fbbSRusty Russell if (unlikely(vrh->completed > 0xffff)) 496f87d0fbbSRusty Russell notify = true; 497f87d0fbbSRusty Russell else 498f87d0fbbSRusty Russell notify = vring_need_event(used_event, 499f87d0fbbSRusty Russell vrh->last_used_idx + vrh->completed, 500f87d0fbbSRusty Russell vrh->last_used_idx); 501f87d0fbbSRusty Russell 502f87d0fbbSRusty Russell vrh->last_used_idx += vrh->completed; 503f87d0fbbSRusty Russell vrh->completed = 0; 504f87d0fbbSRusty Russell return notify; 505f87d0fbbSRusty Russell } 506f87d0fbbSRusty Russell 507f87d0fbbSRusty Russell static inline bool __vringh_notify_enable(struct vringh *vrh, 508b9f7ac8cSMichael S. Tsirkin int (*getu16)(const struct vringh *vrh, 509b9f7ac8cSMichael S. Tsirkin u16 *val, const __virtio16 *p), 510b9f7ac8cSMichael S. Tsirkin int (*putu16)(const struct vringh *vrh, 511b9f7ac8cSMichael S. Tsirkin __virtio16 *p, u16 val)) 512f87d0fbbSRusty Russell { 513f87d0fbbSRusty Russell u16 avail; 514f87d0fbbSRusty Russell 515f87d0fbbSRusty Russell if (!vrh->event_indices) { 516f87d0fbbSRusty Russell /* Old-school; update flags. */ 517b9f7ac8cSMichael S. Tsirkin if (putu16(vrh, &vrh->vring.used->flags, 0) != 0) { 518f87d0fbbSRusty Russell vringh_bad("Clearing used flags %p", 519f87d0fbbSRusty Russell &vrh->vring.used->flags); 520f87d0fbbSRusty Russell return true; 521f87d0fbbSRusty Russell } 522f87d0fbbSRusty Russell } else { 523b9f7ac8cSMichael S. Tsirkin if (putu16(vrh, &vring_avail_event(&vrh->vring), 524f87d0fbbSRusty Russell vrh->last_avail_idx) != 0) { 525f87d0fbbSRusty Russell vringh_bad("Updating avail event index %p", 526f87d0fbbSRusty Russell &vring_avail_event(&vrh->vring)); 527f87d0fbbSRusty Russell return true; 528f87d0fbbSRusty Russell } 529f87d0fbbSRusty Russell } 530f87d0fbbSRusty Russell 531f87d0fbbSRusty Russell /* They could have slipped one in as we were doing that: make 532f87d0fbbSRusty Russell * sure it's written, then check again. */ 533f87d0fbbSRusty Russell virtio_mb(vrh->weak_barriers); 534f87d0fbbSRusty Russell 535b9f7ac8cSMichael S. Tsirkin if (getu16(vrh, &avail, &vrh->vring.avail->idx) != 0) { 536f87d0fbbSRusty Russell vringh_bad("Failed to check avail idx at %p", 537f87d0fbbSRusty Russell &vrh->vring.avail->idx); 538f87d0fbbSRusty Russell return true; 539f87d0fbbSRusty Russell } 540f87d0fbbSRusty Russell 541f87d0fbbSRusty Russell /* This is unlikely, so we just leave notifications enabled 542f87d0fbbSRusty Russell * (if we're using event_indices, we'll only get one 543f87d0fbbSRusty Russell * notification anyway). */ 544f87d0fbbSRusty Russell return avail == vrh->last_avail_idx; 545f87d0fbbSRusty Russell } 546f87d0fbbSRusty Russell 547f87d0fbbSRusty Russell static inline void __vringh_notify_disable(struct vringh *vrh, 548b9f7ac8cSMichael S. Tsirkin int (*putu16)(const struct vringh *vrh, 549b9f7ac8cSMichael S. Tsirkin __virtio16 *p, u16 val)) 550f87d0fbbSRusty Russell { 551f87d0fbbSRusty Russell if (!vrh->event_indices) { 552f87d0fbbSRusty Russell /* Old-school; update flags. */ 553b9f7ac8cSMichael S. Tsirkin if (putu16(vrh, &vrh->vring.used->flags, 554b9f7ac8cSMichael S. Tsirkin VRING_USED_F_NO_NOTIFY)) { 555f87d0fbbSRusty Russell vringh_bad("Setting used flags %p", 556f87d0fbbSRusty Russell &vrh->vring.used->flags); 557f87d0fbbSRusty Russell } 558f87d0fbbSRusty Russell } 559f87d0fbbSRusty Russell } 560f87d0fbbSRusty Russell 561f87d0fbbSRusty Russell /* Userspace access helpers: in this case, addresses are really userspace. */ 562b9f7ac8cSMichael S. Tsirkin static inline int getu16_user(const struct vringh *vrh, u16 *val, const __virtio16 *p) 563f87d0fbbSRusty Russell { 564b9f7ac8cSMichael S. Tsirkin __virtio16 v = 0; 565b9f7ac8cSMichael S. Tsirkin int rc = get_user(v, (__force __virtio16 __user *)p); 566b9f7ac8cSMichael S. Tsirkin *val = vringh16_to_cpu(vrh, v); 567b9f7ac8cSMichael S. Tsirkin return rc; 568f87d0fbbSRusty Russell } 569f87d0fbbSRusty Russell 570b9f7ac8cSMichael S. Tsirkin static inline int putu16_user(const struct vringh *vrh, __virtio16 *p, u16 val) 571f87d0fbbSRusty Russell { 572b9f7ac8cSMichael S. Tsirkin __virtio16 v = cpu_to_vringh16(vrh, val); 573b9f7ac8cSMichael S. Tsirkin return put_user(v, (__force __virtio16 __user *)p); 574f87d0fbbSRusty Russell } 575f87d0fbbSRusty Russell 5769ad9c49cSJason Wang static inline int copydesc_user(const struct vringh *vrh, 5779ad9c49cSJason Wang void *dst, const void *src, size_t len) 578f87d0fbbSRusty Russell { 579f87d0fbbSRusty Russell return copy_from_user(dst, (__force void __user *)src, len) ? 580f87d0fbbSRusty Russell -EFAULT : 0; 581f87d0fbbSRusty Russell } 582f87d0fbbSRusty Russell 5839ad9c49cSJason Wang static inline int putused_user(const struct vringh *vrh, 5849ad9c49cSJason Wang struct vring_used_elem *dst, 585f87d0fbbSRusty Russell const struct vring_used_elem *src, 586f87d0fbbSRusty Russell unsigned int num) 587f87d0fbbSRusty Russell { 588f87d0fbbSRusty Russell return copy_to_user((__force void __user *)dst, src, 589f87d0fbbSRusty Russell sizeof(*dst) * num) ? -EFAULT : 0; 590f87d0fbbSRusty Russell } 591f87d0fbbSRusty Russell 5929ad9c49cSJason Wang static inline int xfer_from_user(const struct vringh *vrh, void *src, 5939ad9c49cSJason Wang void *dst, size_t len) 594f87d0fbbSRusty Russell { 595f87d0fbbSRusty Russell return copy_from_user(dst, (__force void __user *)src, len) ? 596f87d0fbbSRusty Russell -EFAULT : 0; 597f87d0fbbSRusty Russell } 598f87d0fbbSRusty Russell 5999ad9c49cSJason Wang static inline int xfer_to_user(const struct vringh *vrh, 6009ad9c49cSJason Wang void *dst, void *src, size_t len) 601f87d0fbbSRusty Russell { 602f87d0fbbSRusty Russell return copy_to_user((__force void __user *)dst, src, len) ? 603f87d0fbbSRusty Russell -EFAULT : 0; 604f87d0fbbSRusty Russell } 605f87d0fbbSRusty Russell 606f87d0fbbSRusty Russell /** 607f87d0fbbSRusty Russell * vringh_init_user - initialize a vringh for a userspace vring. 608f87d0fbbSRusty Russell * @vrh: the vringh to initialize. 609f87d0fbbSRusty Russell * @features: the feature bits for this ring. 610f87d0fbbSRusty Russell * @num: the number of elements. 611f87d0fbbSRusty Russell * @weak_barriers: true if we only need memory barriers, not I/O. 612f87d0fbbSRusty Russell * @desc: the userpace descriptor pointer. 613f87d0fbbSRusty Russell * @avail: the userpace avail pointer. 614f87d0fbbSRusty Russell * @used: the userpace used pointer. 615f87d0fbbSRusty Russell * 616f87d0fbbSRusty Russell * Returns an error if num is invalid: you should check pointers 617f87d0fbbSRusty Russell * yourself! 618f87d0fbbSRusty Russell */ 619b97a8a90SMichael S. Tsirkin int vringh_init_user(struct vringh *vrh, u64 features, 620f87d0fbbSRusty Russell unsigned int num, bool weak_barriers, 621f87d0fbbSRusty Russell struct vring_desc __user *desc, 622f87d0fbbSRusty Russell struct vring_avail __user *avail, 623f87d0fbbSRusty Russell struct vring_used __user *used) 624f87d0fbbSRusty Russell { 625f87d0fbbSRusty Russell /* Sane power of 2 please! */ 626f87d0fbbSRusty Russell if (!num || num > 0xffff || (num & (num - 1))) { 627f87d0fbbSRusty Russell vringh_bad("Bad ring size %u", num); 628f87d0fbbSRusty Russell return -EINVAL; 629f87d0fbbSRusty Russell } 630f87d0fbbSRusty Russell 631b9f7ac8cSMichael S. Tsirkin vrh->little_endian = (features & (1ULL << VIRTIO_F_VERSION_1)); 632f87d0fbbSRusty Russell vrh->event_indices = (features & (1 << VIRTIO_RING_F_EVENT_IDX)); 633f87d0fbbSRusty Russell vrh->weak_barriers = weak_barriers; 634f87d0fbbSRusty Russell vrh->completed = 0; 635f87d0fbbSRusty Russell vrh->last_avail_idx = 0; 636f87d0fbbSRusty Russell vrh->last_used_idx = 0; 637f87d0fbbSRusty Russell vrh->vring.num = num; 638f87d0fbbSRusty Russell /* vring expects kernel addresses, but only used via accessors. */ 639f87d0fbbSRusty Russell vrh->vring.desc = (__force struct vring_desc *)desc; 640f87d0fbbSRusty Russell vrh->vring.avail = (__force struct vring_avail *)avail; 641f87d0fbbSRusty Russell vrh->vring.used = (__force struct vring_used *)used; 642f87d0fbbSRusty Russell return 0; 643f87d0fbbSRusty Russell } 644f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_init_user); 645f87d0fbbSRusty Russell 646f87d0fbbSRusty Russell /** 647f87d0fbbSRusty Russell * vringh_getdesc_user - get next available descriptor from userspace ring. 648f87d0fbbSRusty Russell * @vrh: the userspace vring. 649f87d0fbbSRusty Russell * @riov: where to put the readable descriptors (or NULL) 650f87d0fbbSRusty Russell * @wiov: where to put the writable descriptors (or NULL) 651f87d0fbbSRusty Russell * @getrange: function to call to check ranges. 652f87d0fbbSRusty Russell * @head: head index we received, for passing to vringh_complete_user(). 653f87d0fbbSRusty Russell * 654f87d0fbbSRusty Russell * Returns 0 if there was no descriptor, 1 if there was, or -errno. 655f87d0fbbSRusty Russell * 656f87d0fbbSRusty Russell * Note that on error return, you can tell the difference between an 657f87d0fbbSRusty Russell * invalid ring and a single invalid descriptor: in the former case, 658f87d0fbbSRusty Russell * *head will be vrh->vring.num. You may be able to ignore an invalid 659f87d0fbbSRusty Russell * descriptor, but there's not much you can do with an invalid ring. 660f87d0fbbSRusty Russell * 661f87d0fbbSRusty Russell * Note that you may need to clean up riov and wiov, even on error! 662f87d0fbbSRusty Russell */ 663f87d0fbbSRusty Russell int vringh_getdesc_user(struct vringh *vrh, 664f87d0fbbSRusty Russell struct vringh_iov *riov, 665f87d0fbbSRusty Russell struct vringh_iov *wiov, 666f87d0fbbSRusty Russell bool (*getrange)(struct vringh *vrh, 667f87d0fbbSRusty Russell u64 addr, struct vringh_range *r), 668f87d0fbbSRusty Russell u16 *head) 669f87d0fbbSRusty Russell { 670f87d0fbbSRusty Russell int err; 671f87d0fbbSRusty Russell 672f87d0fbbSRusty Russell *head = vrh->vring.num; 673f87d0fbbSRusty Russell err = __vringh_get_head(vrh, getu16_user, &vrh->last_avail_idx); 674f87d0fbbSRusty Russell if (err < 0) 675f87d0fbbSRusty Russell return err; 676f87d0fbbSRusty Russell 677f87d0fbbSRusty Russell /* Empty... */ 678f87d0fbbSRusty Russell if (err == vrh->vring.num) 679f87d0fbbSRusty Russell return 0; 680f87d0fbbSRusty Russell 681f87d0fbbSRusty Russell /* We need the layouts to be the identical for this to work */ 682f87d0fbbSRusty Russell BUILD_BUG_ON(sizeof(struct vringh_kiov) != sizeof(struct vringh_iov)); 683f87d0fbbSRusty Russell BUILD_BUG_ON(offsetof(struct vringh_kiov, iov) != 684f87d0fbbSRusty Russell offsetof(struct vringh_iov, iov)); 685f87d0fbbSRusty Russell BUILD_BUG_ON(offsetof(struct vringh_kiov, i) != 686f87d0fbbSRusty Russell offsetof(struct vringh_iov, i)); 687f87d0fbbSRusty Russell BUILD_BUG_ON(offsetof(struct vringh_kiov, used) != 688f87d0fbbSRusty Russell offsetof(struct vringh_iov, used)); 689f87d0fbbSRusty Russell BUILD_BUG_ON(offsetof(struct vringh_kiov, max_num) != 690f87d0fbbSRusty Russell offsetof(struct vringh_iov, max_num)); 691f87d0fbbSRusty Russell BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); 692f87d0fbbSRusty Russell BUILD_BUG_ON(offsetof(struct iovec, iov_base) != 693f87d0fbbSRusty Russell offsetof(struct kvec, iov_base)); 694f87d0fbbSRusty Russell BUILD_BUG_ON(offsetof(struct iovec, iov_len) != 695f87d0fbbSRusty Russell offsetof(struct kvec, iov_len)); 696f87d0fbbSRusty Russell BUILD_BUG_ON(sizeof(((struct iovec *)NULL)->iov_base) 697f87d0fbbSRusty Russell != sizeof(((struct kvec *)NULL)->iov_base)); 698f87d0fbbSRusty Russell BUILD_BUG_ON(sizeof(((struct iovec *)NULL)->iov_len) 699f87d0fbbSRusty Russell != sizeof(((struct kvec *)NULL)->iov_len)); 700f87d0fbbSRusty Russell 701f87d0fbbSRusty Russell *head = err; 702f87d0fbbSRusty Russell err = __vringh_iov(vrh, *head, (struct vringh_kiov *)riov, 703f87d0fbbSRusty Russell (struct vringh_kiov *)wiov, 704f87d0fbbSRusty Russell range_check, getrange, GFP_KERNEL, copydesc_user); 705f87d0fbbSRusty Russell if (err) 706f87d0fbbSRusty Russell return err; 707f87d0fbbSRusty Russell 708f87d0fbbSRusty Russell return 1; 709f87d0fbbSRusty Russell } 710f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_getdesc_user); 711f87d0fbbSRusty Russell 712f87d0fbbSRusty Russell /** 713f87d0fbbSRusty Russell * vringh_iov_pull_user - copy bytes from vring_iov. 714f87d0fbbSRusty Russell * @riov: the riov as passed to vringh_getdesc_user() (updated as we consume) 715f87d0fbbSRusty Russell * @dst: the place to copy. 716f87d0fbbSRusty Russell * @len: the maximum length to copy. 717f87d0fbbSRusty Russell * 718f87d0fbbSRusty Russell * Returns the bytes copied <= len or a negative errno. 719f87d0fbbSRusty Russell */ 720f87d0fbbSRusty Russell ssize_t vringh_iov_pull_user(struct vringh_iov *riov, void *dst, size_t len) 721f87d0fbbSRusty Russell { 7229ad9c49cSJason Wang return vringh_iov_xfer(NULL, (struct vringh_kiov *)riov, 723f87d0fbbSRusty Russell dst, len, xfer_from_user); 724f87d0fbbSRusty Russell } 725f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_iov_pull_user); 726f87d0fbbSRusty Russell 727f87d0fbbSRusty Russell /** 728f87d0fbbSRusty Russell * vringh_iov_push_user - copy bytes into vring_iov. 729f87d0fbbSRusty Russell * @wiov: the wiov as passed to vringh_getdesc_user() (updated as we consume) 730f87d0fbbSRusty Russell * @dst: the place to copy. 731f87d0fbbSRusty Russell * @len: the maximum length to copy. 732f87d0fbbSRusty Russell * 733f87d0fbbSRusty Russell * Returns the bytes copied <= len or a negative errno. 734f87d0fbbSRusty Russell */ 735f87d0fbbSRusty Russell ssize_t vringh_iov_push_user(struct vringh_iov *wiov, 736f87d0fbbSRusty Russell const void *src, size_t len) 737f87d0fbbSRusty Russell { 7389ad9c49cSJason Wang return vringh_iov_xfer(NULL, (struct vringh_kiov *)wiov, 739f87d0fbbSRusty Russell (void *)src, len, xfer_to_user); 740f87d0fbbSRusty Russell } 741f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_iov_push_user); 742f87d0fbbSRusty Russell 743f87d0fbbSRusty Russell /** 744f87d0fbbSRusty Russell * vringh_abandon_user - we've decided not to handle the descriptor(s). 745f87d0fbbSRusty Russell * @vrh: the vring. 746f87d0fbbSRusty Russell * @num: the number of descriptors to put back (ie. num 747f87d0fbbSRusty Russell * vringh_get_user() to undo). 748f87d0fbbSRusty Russell * 749f87d0fbbSRusty Russell * The next vringh_get_user() will return the old descriptor(s) again. 750f87d0fbbSRusty Russell */ 751f87d0fbbSRusty Russell void vringh_abandon_user(struct vringh *vrh, unsigned int num) 752f87d0fbbSRusty Russell { 753f87d0fbbSRusty Russell /* We only update vring_avail_event(vr) when we want to be notified, 754f87d0fbbSRusty Russell * so we haven't changed that yet. */ 755f87d0fbbSRusty Russell vrh->last_avail_idx -= num; 756f87d0fbbSRusty Russell } 757f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_abandon_user); 758f87d0fbbSRusty Russell 759f87d0fbbSRusty Russell /** 760f87d0fbbSRusty Russell * vringh_complete_user - we've finished with descriptor, publish it. 761f87d0fbbSRusty Russell * @vrh: the vring. 762f87d0fbbSRusty Russell * @head: the head as filled in by vringh_getdesc_user. 763f87d0fbbSRusty Russell * @len: the length of data we have written. 764f87d0fbbSRusty Russell * 765f87d0fbbSRusty Russell * You should check vringh_need_notify_user() after one or more calls 766f87d0fbbSRusty Russell * to this function. 767f87d0fbbSRusty Russell */ 768f87d0fbbSRusty Russell int vringh_complete_user(struct vringh *vrh, u16 head, u32 len) 769f87d0fbbSRusty Russell { 770f87d0fbbSRusty Russell struct vring_used_elem used; 771f87d0fbbSRusty Russell 772b9f7ac8cSMichael S. Tsirkin used.id = cpu_to_vringh32(vrh, head); 773b9f7ac8cSMichael S. Tsirkin used.len = cpu_to_vringh32(vrh, len); 774f87d0fbbSRusty Russell return __vringh_complete(vrh, &used, 1, putu16_user, putused_user); 775f87d0fbbSRusty Russell } 776f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_complete_user); 777f87d0fbbSRusty Russell 778f87d0fbbSRusty Russell /** 779f87d0fbbSRusty Russell * vringh_complete_multi_user - we've finished with many descriptors. 780f87d0fbbSRusty Russell * @vrh: the vring. 781f87d0fbbSRusty Russell * @used: the head, length pairs. 782f87d0fbbSRusty Russell * @num_used: the number of used elements. 783f87d0fbbSRusty Russell * 784f87d0fbbSRusty Russell * You should check vringh_need_notify_user() after one or more calls 785f87d0fbbSRusty Russell * to this function. 786f87d0fbbSRusty Russell */ 787f87d0fbbSRusty Russell int vringh_complete_multi_user(struct vringh *vrh, 788f87d0fbbSRusty Russell const struct vring_used_elem used[], 789f87d0fbbSRusty Russell unsigned num_used) 790f87d0fbbSRusty Russell { 791f87d0fbbSRusty Russell return __vringh_complete(vrh, used, num_used, 792f87d0fbbSRusty Russell putu16_user, putused_user); 793f87d0fbbSRusty Russell } 794f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_complete_multi_user); 795f87d0fbbSRusty Russell 796f87d0fbbSRusty Russell /** 797f87d0fbbSRusty Russell * vringh_notify_enable_user - we want to know if something changes. 798f87d0fbbSRusty Russell * @vrh: the vring. 799f87d0fbbSRusty Russell * 800f87d0fbbSRusty Russell * This always enables notifications, but returns false if there are 801f87d0fbbSRusty Russell * now more buffers available in the vring. 802f87d0fbbSRusty Russell */ 803f87d0fbbSRusty Russell bool vringh_notify_enable_user(struct vringh *vrh) 804f87d0fbbSRusty Russell { 805f87d0fbbSRusty Russell return __vringh_notify_enable(vrh, getu16_user, putu16_user); 806f87d0fbbSRusty Russell } 807f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_notify_enable_user); 808f87d0fbbSRusty Russell 809f87d0fbbSRusty Russell /** 810f87d0fbbSRusty Russell * vringh_notify_disable_user - don't tell us if something changes. 811f87d0fbbSRusty Russell * @vrh: the vring. 812f87d0fbbSRusty Russell * 813f87d0fbbSRusty Russell * This is our normal running state: we disable and then only enable when 814f87d0fbbSRusty Russell * we're going to sleep. 815f87d0fbbSRusty Russell */ 816f87d0fbbSRusty Russell void vringh_notify_disable_user(struct vringh *vrh) 817f87d0fbbSRusty Russell { 818f87d0fbbSRusty Russell __vringh_notify_disable(vrh, putu16_user); 819f87d0fbbSRusty Russell } 820f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_notify_disable_user); 821f87d0fbbSRusty Russell 822f87d0fbbSRusty Russell /** 823f87d0fbbSRusty Russell * vringh_need_notify_user - must we tell the other side about used buffers? 824f87d0fbbSRusty Russell * @vrh: the vring we've called vringh_complete_user() on. 825f87d0fbbSRusty Russell * 826f87d0fbbSRusty Russell * Returns -errno or 0 if we don't need to tell the other side, 1 if we do. 827f87d0fbbSRusty Russell */ 828f87d0fbbSRusty Russell int vringh_need_notify_user(struct vringh *vrh) 829f87d0fbbSRusty Russell { 830f87d0fbbSRusty Russell return __vringh_need_notify(vrh, getu16_user); 831f87d0fbbSRusty Russell } 832f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_need_notify_user); 833f87d0fbbSRusty Russell 834f87d0fbbSRusty Russell /* Kernelspace access helpers. */ 835b9f7ac8cSMichael S. Tsirkin static inline int getu16_kern(const struct vringh *vrh, 836b9f7ac8cSMichael S. Tsirkin u16 *val, const __virtio16 *p) 837f87d0fbbSRusty Russell { 8389d1b972fSMark Rutland *val = vringh16_to_cpu(vrh, READ_ONCE(*p)); 839f87d0fbbSRusty Russell return 0; 840f87d0fbbSRusty Russell } 841f87d0fbbSRusty Russell 842b9f7ac8cSMichael S. Tsirkin static inline int putu16_kern(const struct vringh *vrh, __virtio16 *p, u16 val) 843f87d0fbbSRusty Russell { 8449d1b972fSMark Rutland WRITE_ONCE(*p, cpu_to_vringh16(vrh, val)); 845f87d0fbbSRusty Russell return 0; 846f87d0fbbSRusty Russell } 847f87d0fbbSRusty Russell 8489ad9c49cSJason Wang static inline int copydesc_kern(const struct vringh *vrh, 8499ad9c49cSJason Wang void *dst, const void *src, size_t len) 850f87d0fbbSRusty Russell { 851f87d0fbbSRusty Russell memcpy(dst, src, len); 852f87d0fbbSRusty Russell return 0; 853f87d0fbbSRusty Russell } 854f87d0fbbSRusty Russell 8559ad9c49cSJason Wang static inline int putused_kern(const struct vringh *vrh, 8569ad9c49cSJason Wang struct vring_used_elem *dst, 857f87d0fbbSRusty Russell const struct vring_used_elem *src, 858f87d0fbbSRusty Russell unsigned int num) 859f87d0fbbSRusty Russell { 860f87d0fbbSRusty Russell memcpy(dst, src, num * sizeof(*dst)); 861f87d0fbbSRusty Russell return 0; 862f87d0fbbSRusty Russell } 863f87d0fbbSRusty Russell 8649ad9c49cSJason Wang static inline int xfer_kern(const struct vringh *vrh, void *src, 8659ad9c49cSJason Wang void *dst, size_t len) 866f87d0fbbSRusty Russell { 867f87d0fbbSRusty Russell memcpy(dst, src, len); 868f87d0fbbSRusty Russell return 0; 869f87d0fbbSRusty Russell } 870f87d0fbbSRusty Russell 8719ad9c49cSJason Wang static inline int kern_xfer(const struct vringh *vrh, void *dst, 8729ad9c49cSJason Wang void *src, size_t len) 873b3683deeSJason Wang { 874b3683deeSJason Wang memcpy(dst, src, len); 875b3683deeSJason Wang return 0; 876b3683deeSJason Wang } 877b3683deeSJason Wang 878f87d0fbbSRusty Russell /** 879f87d0fbbSRusty Russell * vringh_init_kern - initialize a vringh for a kernelspace vring. 880f87d0fbbSRusty Russell * @vrh: the vringh to initialize. 881f87d0fbbSRusty Russell * @features: the feature bits for this ring. 882f87d0fbbSRusty Russell * @num: the number of elements. 883f87d0fbbSRusty Russell * @weak_barriers: true if we only need memory barriers, not I/O. 884f87d0fbbSRusty Russell * @desc: the userpace descriptor pointer. 885f87d0fbbSRusty Russell * @avail: the userpace avail pointer. 886f87d0fbbSRusty Russell * @used: the userpace used pointer. 887f87d0fbbSRusty Russell * 888f87d0fbbSRusty Russell * Returns an error if num is invalid. 889f87d0fbbSRusty Russell */ 890b97a8a90SMichael S. Tsirkin int vringh_init_kern(struct vringh *vrh, u64 features, 891f87d0fbbSRusty Russell unsigned int num, bool weak_barriers, 892f87d0fbbSRusty Russell struct vring_desc *desc, 893f87d0fbbSRusty Russell struct vring_avail *avail, 894f87d0fbbSRusty Russell struct vring_used *used) 895f87d0fbbSRusty Russell { 896f87d0fbbSRusty Russell /* Sane power of 2 please! */ 897f87d0fbbSRusty Russell if (!num || num > 0xffff || (num & (num - 1))) { 898f87d0fbbSRusty Russell vringh_bad("Bad ring size %u", num); 899f87d0fbbSRusty Russell return -EINVAL; 900f87d0fbbSRusty Russell } 901f87d0fbbSRusty Russell 902b9f7ac8cSMichael S. Tsirkin vrh->little_endian = (features & (1ULL << VIRTIO_F_VERSION_1)); 903f87d0fbbSRusty Russell vrh->event_indices = (features & (1 << VIRTIO_RING_F_EVENT_IDX)); 904f87d0fbbSRusty Russell vrh->weak_barriers = weak_barriers; 905f87d0fbbSRusty Russell vrh->completed = 0; 906f87d0fbbSRusty Russell vrh->last_avail_idx = 0; 907f87d0fbbSRusty Russell vrh->last_used_idx = 0; 908f87d0fbbSRusty Russell vrh->vring.num = num; 909f87d0fbbSRusty Russell vrh->vring.desc = desc; 910f87d0fbbSRusty Russell vrh->vring.avail = avail; 911f87d0fbbSRusty Russell vrh->vring.used = used; 912f87d0fbbSRusty Russell return 0; 913f87d0fbbSRusty Russell } 914f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_init_kern); 915f87d0fbbSRusty Russell 916f87d0fbbSRusty Russell /** 917f87d0fbbSRusty Russell * vringh_getdesc_kern - get next available descriptor from kernelspace ring. 918f87d0fbbSRusty Russell * @vrh: the kernelspace vring. 919f87d0fbbSRusty Russell * @riov: where to put the readable descriptors (or NULL) 920f87d0fbbSRusty Russell * @wiov: where to put the writable descriptors (or NULL) 921f87d0fbbSRusty Russell * @head: head index we received, for passing to vringh_complete_kern(). 922f87d0fbbSRusty Russell * @gfp: flags for allocating larger riov/wiov. 923f87d0fbbSRusty Russell * 924f87d0fbbSRusty Russell * Returns 0 if there was no descriptor, 1 if there was, or -errno. 925f87d0fbbSRusty Russell * 926f87d0fbbSRusty Russell * Note that on error return, you can tell the difference between an 927f87d0fbbSRusty Russell * invalid ring and a single invalid descriptor: in the former case, 928f87d0fbbSRusty Russell * *head will be vrh->vring.num. You may be able to ignore an invalid 929f87d0fbbSRusty Russell * descriptor, but there's not much you can do with an invalid ring. 930f87d0fbbSRusty Russell * 931f87d0fbbSRusty Russell * Note that you may need to clean up riov and wiov, even on error! 932f87d0fbbSRusty Russell */ 933f87d0fbbSRusty Russell int vringh_getdesc_kern(struct vringh *vrh, 934f87d0fbbSRusty Russell struct vringh_kiov *riov, 935f87d0fbbSRusty Russell struct vringh_kiov *wiov, 936f87d0fbbSRusty Russell u16 *head, 937f87d0fbbSRusty Russell gfp_t gfp) 938f87d0fbbSRusty Russell { 939f87d0fbbSRusty Russell int err; 940f87d0fbbSRusty Russell 941f87d0fbbSRusty Russell err = __vringh_get_head(vrh, getu16_kern, &vrh->last_avail_idx); 942f87d0fbbSRusty Russell if (err < 0) 943f87d0fbbSRusty Russell return err; 944f87d0fbbSRusty Russell 945f87d0fbbSRusty Russell /* Empty... */ 946f87d0fbbSRusty Russell if (err == vrh->vring.num) 947f87d0fbbSRusty Russell return 0; 948f87d0fbbSRusty Russell 949f87d0fbbSRusty Russell *head = err; 950f87d0fbbSRusty Russell err = __vringh_iov(vrh, *head, riov, wiov, no_range_check, NULL, 951f87d0fbbSRusty Russell gfp, copydesc_kern); 952f87d0fbbSRusty Russell if (err) 953f87d0fbbSRusty Russell return err; 954f87d0fbbSRusty Russell 955f87d0fbbSRusty Russell return 1; 956f87d0fbbSRusty Russell } 957f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_getdesc_kern); 958f87d0fbbSRusty Russell 959f87d0fbbSRusty Russell /** 960f87d0fbbSRusty Russell * vringh_iov_pull_kern - copy bytes from vring_iov. 961f87d0fbbSRusty Russell * @riov: the riov as passed to vringh_getdesc_kern() (updated as we consume) 962f87d0fbbSRusty Russell * @dst: the place to copy. 963f87d0fbbSRusty Russell * @len: the maximum length to copy. 964f87d0fbbSRusty Russell * 965f87d0fbbSRusty Russell * Returns the bytes copied <= len or a negative errno. 966f87d0fbbSRusty Russell */ 967f87d0fbbSRusty Russell ssize_t vringh_iov_pull_kern(struct vringh_kiov *riov, void *dst, size_t len) 968f87d0fbbSRusty Russell { 9699ad9c49cSJason Wang return vringh_iov_xfer(NULL, riov, dst, len, xfer_kern); 970f87d0fbbSRusty Russell } 971f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_iov_pull_kern); 972f87d0fbbSRusty Russell 973f87d0fbbSRusty Russell /** 974f87d0fbbSRusty Russell * vringh_iov_push_kern - copy bytes into vring_iov. 975f87d0fbbSRusty Russell * @wiov: the wiov as passed to vringh_getdesc_kern() (updated as we consume) 976f87d0fbbSRusty Russell * @dst: the place to copy. 977f87d0fbbSRusty Russell * @len: the maximum length to copy. 978f87d0fbbSRusty Russell * 979f87d0fbbSRusty Russell * Returns the bytes copied <= len or a negative errno. 980f87d0fbbSRusty Russell */ 981f87d0fbbSRusty Russell ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov, 982f87d0fbbSRusty Russell const void *src, size_t len) 983f87d0fbbSRusty Russell { 9849ad9c49cSJason Wang return vringh_iov_xfer(NULL, wiov, (void *)src, len, kern_xfer); 985f87d0fbbSRusty Russell } 986f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_iov_push_kern); 987f87d0fbbSRusty Russell 988f87d0fbbSRusty Russell /** 989f87d0fbbSRusty Russell * vringh_abandon_kern - we've decided not to handle the descriptor(s). 990f87d0fbbSRusty Russell * @vrh: the vring. 991f87d0fbbSRusty Russell * @num: the number of descriptors to put back (ie. num 992f87d0fbbSRusty Russell * vringh_get_kern() to undo). 993f87d0fbbSRusty Russell * 994f87d0fbbSRusty Russell * The next vringh_get_kern() will return the old descriptor(s) again. 995f87d0fbbSRusty Russell */ 996f87d0fbbSRusty Russell void vringh_abandon_kern(struct vringh *vrh, unsigned int num) 997f87d0fbbSRusty Russell { 998f87d0fbbSRusty Russell /* We only update vring_avail_event(vr) when we want to be notified, 999f87d0fbbSRusty Russell * so we haven't changed that yet. */ 1000f87d0fbbSRusty Russell vrh->last_avail_idx -= num; 1001f87d0fbbSRusty Russell } 1002f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_abandon_kern); 1003f87d0fbbSRusty Russell 1004f87d0fbbSRusty Russell /** 1005f87d0fbbSRusty Russell * vringh_complete_kern - we've finished with descriptor, publish it. 1006f87d0fbbSRusty Russell * @vrh: the vring. 1007f87d0fbbSRusty Russell * @head: the head as filled in by vringh_getdesc_kern. 1008f87d0fbbSRusty Russell * @len: the length of data we have written. 1009f87d0fbbSRusty Russell * 1010f87d0fbbSRusty Russell * You should check vringh_need_notify_kern() after one or more calls 1011f87d0fbbSRusty Russell * to this function. 1012f87d0fbbSRusty Russell */ 1013f87d0fbbSRusty Russell int vringh_complete_kern(struct vringh *vrh, u16 head, u32 len) 1014f87d0fbbSRusty Russell { 1015f87d0fbbSRusty Russell struct vring_used_elem used; 1016f87d0fbbSRusty Russell 1017b9f7ac8cSMichael S. Tsirkin used.id = cpu_to_vringh32(vrh, head); 1018b9f7ac8cSMichael S. Tsirkin used.len = cpu_to_vringh32(vrh, len); 1019f87d0fbbSRusty Russell 1020f87d0fbbSRusty Russell return __vringh_complete(vrh, &used, 1, putu16_kern, putused_kern); 1021f87d0fbbSRusty Russell } 1022f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_complete_kern); 1023f87d0fbbSRusty Russell 1024f87d0fbbSRusty Russell /** 1025f87d0fbbSRusty Russell * vringh_notify_enable_kern - we want to know if something changes. 1026f87d0fbbSRusty Russell * @vrh: the vring. 1027f87d0fbbSRusty Russell * 1028f87d0fbbSRusty Russell * This always enables notifications, but returns false if there are 1029f87d0fbbSRusty Russell * now more buffers available in the vring. 1030f87d0fbbSRusty Russell */ 1031f87d0fbbSRusty Russell bool vringh_notify_enable_kern(struct vringh *vrh) 1032f87d0fbbSRusty Russell { 1033f87d0fbbSRusty Russell return __vringh_notify_enable(vrh, getu16_kern, putu16_kern); 1034f87d0fbbSRusty Russell } 1035f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_notify_enable_kern); 1036f87d0fbbSRusty Russell 1037f87d0fbbSRusty Russell /** 1038f87d0fbbSRusty Russell * vringh_notify_disable_kern - don't tell us if something changes. 1039f87d0fbbSRusty Russell * @vrh: the vring. 1040f87d0fbbSRusty Russell * 1041f87d0fbbSRusty Russell * This is our normal running state: we disable and then only enable when 1042f87d0fbbSRusty Russell * we're going to sleep. 1043f87d0fbbSRusty Russell */ 1044f87d0fbbSRusty Russell void vringh_notify_disable_kern(struct vringh *vrh) 1045f87d0fbbSRusty Russell { 1046f87d0fbbSRusty Russell __vringh_notify_disable(vrh, putu16_kern); 1047f87d0fbbSRusty Russell } 1048f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_notify_disable_kern); 1049f87d0fbbSRusty Russell 1050f87d0fbbSRusty Russell /** 1051f87d0fbbSRusty Russell * vringh_need_notify_kern - must we tell the other side about used buffers? 1052f87d0fbbSRusty Russell * @vrh: the vring we've called vringh_complete_kern() on. 1053f87d0fbbSRusty Russell * 1054f87d0fbbSRusty Russell * Returns -errno or 0 if we don't need to tell the other side, 1 if we do. 1055f87d0fbbSRusty Russell */ 1056f87d0fbbSRusty Russell int vringh_need_notify_kern(struct vringh *vrh) 1057f87d0fbbSRusty Russell { 1058f87d0fbbSRusty Russell return __vringh_need_notify(vrh, getu16_kern); 1059f87d0fbbSRusty Russell } 1060f87d0fbbSRusty Russell EXPORT_SYMBOL(vringh_need_notify_kern); 1061f558a845SDave Jones 10629ad9c49cSJason Wang static int iotlb_translate(const struct vringh *vrh, 10639ad9c49cSJason Wang u64 addr, u64 len, struct bio_vec iov[], 10649ad9c49cSJason Wang int iov_size, u32 perm) 10659ad9c49cSJason Wang { 10669ad9c49cSJason Wang struct vhost_iotlb_map *map; 10679ad9c49cSJason Wang struct vhost_iotlb *iotlb = vrh->iotlb; 10689ad9c49cSJason Wang int ret = 0; 10699ad9c49cSJason Wang u64 s = 0; 10709ad9c49cSJason Wang 10719ad9c49cSJason Wang while (len > s) { 10729ad9c49cSJason Wang u64 size, pa, pfn; 10739ad9c49cSJason Wang 10749ad9c49cSJason Wang if (unlikely(ret >= iov_size)) { 10759ad9c49cSJason Wang ret = -ENOBUFS; 10769ad9c49cSJason Wang break; 10779ad9c49cSJason Wang } 10789ad9c49cSJason Wang 10799ad9c49cSJason Wang map = vhost_iotlb_itree_first(iotlb, addr, 10809ad9c49cSJason Wang addr + len - 1); 10819ad9c49cSJason Wang if (!map || map->start > addr) { 10829ad9c49cSJason Wang ret = -EINVAL; 10839ad9c49cSJason Wang break; 10849ad9c49cSJason Wang } else if (!(map->perm & perm)) { 10859ad9c49cSJason Wang ret = -EPERM; 10869ad9c49cSJason Wang break; 10879ad9c49cSJason Wang } 10889ad9c49cSJason Wang 10899ad9c49cSJason Wang size = map->size - addr + map->start; 10909ad9c49cSJason Wang pa = map->addr + addr - map->start; 10919ad9c49cSJason Wang pfn = pa >> PAGE_SHIFT; 10929ad9c49cSJason Wang iov[ret].bv_page = pfn_to_page(pfn); 10939ad9c49cSJason Wang iov[ret].bv_len = min(len - s, size); 10949ad9c49cSJason Wang iov[ret].bv_offset = pa & (PAGE_SIZE - 1); 10959ad9c49cSJason Wang s += size; 10969ad9c49cSJason Wang addr += size; 10979ad9c49cSJason Wang ++ret; 10989ad9c49cSJason Wang } 10999ad9c49cSJason Wang 11009ad9c49cSJason Wang return ret; 11019ad9c49cSJason Wang } 11029ad9c49cSJason Wang 11039ad9c49cSJason Wang static inline int copy_from_iotlb(const struct vringh *vrh, void *dst, 11049ad9c49cSJason Wang void *src, size_t len) 11059ad9c49cSJason Wang { 11069ad9c49cSJason Wang struct iov_iter iter; 11079ad9c49cSJason Wang struct bio_vec iov[16]; 11089ad9c49cSJason Wang int ret; 11099ad9c49cSJason Wang 11109ad9c49cSJason Wang ret = iotlb_translate(vrh, (u64)(uintptr_t)src, 11119ad9c49cSJason Wang len, iov, 16, VHOST_MAP_RO); 11129ad9c49cSJason Wang if (ret < 0) 11139ad9c49cSJason Wang return ret; 11149ad9c49cSJason Wang 11159ad9c49cSJason Wang iov_iter_bvec(&iter, READ, iov, ret, len); 11169ad9c49cSJason Wang 11179ad9c49cSJason Wang ret = copy_from_iter(dst, len, &iter); 11189ad9c49cSJason Wang 11199ad9c49cSJason Wang return ret; 11209ad9c49cSJason Wang } 11219ad9c49cSJason Wang 11229ad9c49cSJason Wang static inline int copy_to_iotlb(const struct vringh *vrh, void *dst, 11239ad9c49cSJason Wang void *src, size_t len) 11249ad9c49cSJason Wang { 11259ad9c49cSJason Wang struct iov_iter iter; 11269ad9c49cSJason Wang struct bio_vec iov[16]; 11279ad9c49cSJason Wang int ret; 11289ad9c49cSJason Wang 11299ad9c49cSJason Wang ret = iotlb_translate(vrh, (u64)(uintptr_t)dst, 11309ad9c49cSJason Wang len, iov, 16, VHOST_MAP_WO); 11319ad9c49cSJason Wang if (ret < 0) 11329ad9c49cSJason Wang return ret; 11339ad9c49cSJason Wang 11349ad9c49cSJason Wang iov_iter_bvec(&iter, WRITE, iov, ret, len); 11359ad9c49cSJason Wang 11369ad9c49cSJason Wang return copy_to_iter(src, len, &iter); 11379ad9c49cSJason Wang } 11389ad9c49cSJason Wang 11399ad9c49cSJason Wang static inline int getu16_iotlb(const struct vringh *vrh, 11409ad9c49cSJason Wang u16 *val, const __virtio16 *p) 11419ad9c49cSJason Wang { 11429ad9c49cSJason Wang struct bio_vec iov; 11439ad9c49cSJason Wang void *kaddr, *from; 11449ad9c49cSJason Wang int ret; 11459ad9c49cSJason Wang 11469ad9c49cSJason Wang /* Atomic read is needed for getu16 */ 11479ad9c49cSJason Wang ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), 11489ad9c49cSJason Wang &iov, 1, VHOST_MAP_RO); 11499ad9c49cSJason Wang if (ret < 0) 11509ad9c49cSJason Wang return ret; 11519ad9c49cSJason Wang 11529ad9c49cSJason Wang kaddr = kmap_atomic(iov.bv_page); 11539ad9c49cSJason Wang from = kaddr + iov.bv_offset; 11549ad9c49cSJason Wang *val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from)); 11559ad9c49cSJason Wang kunmap_atomic(kaddr); 11569ad9c49cSJason Wang 11579ad9c49cSJason Wang return 0; 11589ad9c49cSJason Wang } 11599ad9c49cSJason Wang 11609ad9c49cSJason Wang static inline int putu16_iotlb(const struct vringh *vrh, 11619ad9c49cSJason Wang __virtio16 *p, u16 val) 11629ad9c49cSJason Wang { 11639ad9c49cSJason Wang struct bio_vec iov; 11649ad9c49cSJason Wang void *kaddr, *to; 11659ad9c49cSJason Wang int ret; 11669ad9c49cSJason Wang 11679ad9c49cSJason Wang /* Atomic write is needed for putu16 */ 11689ad9c49cSJason Wang ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), 11699ad9c49cSJason Wang &iov, 1, VHOST_MAP_WO); 11709ad9c49cSJason Wang if (ret < 0) 11719ad9c49cSJason Wang return ret; 11729ad9c49cSJason Wang 11739ad9c49cSJason Wang kaddr = kmap_atomic(iov.bv_page); 11749ad9c49cSJason Wang to = kaddr + iov.bv_offset; 11759ad9c49cSJason Wang WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val)); 11769ad9c49cSJason Wang kunmap_atomic(kaddr); 11779ad9c49cSJason Wang 11789ad9c49cSJason Wang return 0; 11799ad9c49cSJason Wang } 11809ad9c49cSJason Wang 11819ad9c49cSJason Wang static inline int copydesc_iotlb(const struct vringh *vrh, 11829ad9c49cSJason Wang void *dst, const void *src, size_t len) 11839ad9c49cSJason Wang { 11849ad9c49cSJason Wang int ret; 11859ad9c49cSJason Wang 11869ad9c49cSJason Wang ret = copy_from_iotlb(vrh, dst, (void *)src, len); 11879ad9c49cSJason Wang if (ret != len) 11889ad9c49cSJason Wang return -EFAULT; 11899ad9c49cSJason Wang 11909ad9c49cSJason Wang return 0; 11919ad9c49cSJason Wang } 11929ad9c49cSJason Wang 11939ad9c49cSJason Wang static inline int xfer_from_iotlb(const struct vringh *vrh, void *src, 11949ad9c49cSJason Wang void *dst, size_t len) 11959ad9c49cSJason Wang { 11969ad9c49cSJason Wang int ret; 11979ad9c49cSJason Wang 11989ad9c49cSJason Wang ret = copy_from_iotlb(vrh, dst, src, len); 11999ad9c49cSJason Wang if (ret != len) 12009ad9c49cSJason Wang return -EFAULT; 12019ad9c49cSJason Wang 12029ad9c49cSJason Wang return 0; 12039ad9c49cSJason Wang } 12049ad9c49cSJason Wang 12059ad9c49cSJason Wang static inline int xfer_to_iotlb(const struct vringh *vrh, 12069ad9c49cSJason Wang void *dst, void *src, size_t len) 12079ad9c49cSJason Wang { 12089ad9c49cSJason Wang int ret; 12099ad9c49cSJason Wang 12109ad9c49cSJason Wang ret = copy_to_iotlb(vrh, dst, src, len); 12119ad9c49cSJason Wang if (ret != len) 12129ad9c49cSJason Wang return -EFAULT; 12139ad9c49cSJason Wang 12149ad9c49cSJason Wang return 0; 12159ad9c49cSJason Wang } 12169ad9c49cSJason Wang 12179ad9c49cSJason Wang static inline int putused_iotlb(const struct vringh *vrh, 12189ad9c49cSJason Wang struct vring_used_elem *dst, 12199ad9c49cSJason Wang const struct vring_used_elem *src, 12209ad9c49cSJason Wang unsigned int num) 12219ad9c49cSJason Wang { 12229ad9c49cSJason Wang int size = num * sizeof(*dst); 12239ad9c49cSJason Wang int ret; 12249ad9c49cSJason Wang 12259ad9c49cSJason Wang ret = copy_to_iotlb(vrh, dst, (void *)src, num * sizeof(*dst)); 12269ad9c49cSJason Wang if (ret != size) 12279ad9c49cSJason Wang return -EFAULT; 12289ad9c49cSJason Wang 12299ad9c49cSJason Wang return 0; 12309ad9c49cSJason Wang } 12319ad9c49cSJason Wang 12329ad9c49cSJason Wang /** 12339ad9c49cSJason Wang * vringh_init_iotlb - initialize a vringh for a ring with IOTLB. 12349ad9c49cSJason Wang * @vrh: the vringh to initialize. 12359ad9c49cSJason Wang * @features: the feature bits for this ring. 12369ad9c49cSJason Wang * @num: the number of elements. 12379ad9c49cSJason Wang * @weak_barriers: true if we only need memory barriers, not I/O. 12389ad9c49cSJason Wang * @desc: the userpace descriptor pointer. 12399ad9c49cSJason Wang * @avail: the userpace avail pointer. 12409ad9c49cSJason Wang * @used: the userpace used pointer. 12419ad9c49cSJason Wang * 12429ad9c49cSJason Wang * Returns an error if num is invalid. 12439ad9c49cSJason Wang */ 12449ad9c49cSJason Wang int vringh_init_iotlb(struct vringh *vrh, u64 features, 12459ad9c49cSJason Wang unsigned int num, bool weak_barriers, 12469ad9c49cSJason Wang struct vring_desc *desc, 12479ad9c49cSJason Wang struct vring_avail *avail, 12489ad9c49cSJason Wang struct vring_used *used) 12499ad9c49cSJason Wang { 12509ad9c49cSJason Wang return vringh_init_kern(vrh, features, num, weak_barriers, 12519ad9c49cSJason Wang desc, avail, used); 12529ad9c49cSJason Wang } 12539ad9c49cSJason Wang EXPORT_SYMBOL(vringh_init_iotlb); 12549ad9c49cSJason Wang 12559ad9c49cSJason Wang /** 12569ad9c49cSJason Wang * vringh_set_iotlb - initialize a vringh for a ring with IOTLB. 12579ad9c49cSJason Wang * @vrh: the vring 12589ad9c49cSJason Wang * @iotlb: iotlb associated with this vring 12599ad9c49cSJason Wang */ 12609ad9c49cSJason Wang void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb) 12619ad9c49cSJason Wang { 12629ad9c49cSJason Wang vrh->iotlb = iotlb; 12639ad9c49cSJason Wang } 12649ad9c49cSJason Wang EXPORT_SYMBOL(vringh_set_iotlb); 12659ad9c49cSJason Wang 12669ad9c49cSJason Wang /** 12679ad9c49cSJason Wang * vringh_getdesc_iotlb - get next available descriptor from ring with 12689ad9c49cSJason Wang * IOTLB. 12699ad9c49cSJason Wang * @vrh: the kernelspace vring. 12709ad9c49cSJason Wang * @riov: where to put the readable descriptors (or NULL) 12719ad9c49cSJason Wang * @wiov: where to put the writable descriptors (or NULL) 12729ad9c49cSJason Wang * @head: head index we received, for passing to vringh_complete_iotlb(). 12739ad9c49cSJason Wang * @gfp: flags for allocating larger riov/wiov. 12749ad9c49cSJason Wang * 12759ad9c49cSJason Wang * Returns 0 if there was no descriptor, 1 if there was, or -errno. 12769ad9c49cSJason Wang * 12779ad9c49cSJason Wang * Note that on error return, you can tell the difference between an 12789ad9c49cSJason Wang * invalid ring and a single invalid descriptor: in the former case, 12799ad9c49cSJason Wang * *head will be vrh->vring.num. You may be able to ignore an invalid 12809ad9c49cSJason Wang * descriptor, but there's not much you can do with an invalid ring. 12819ad9c49cSJason Wang * 12829ad9c49cSJason Wang * Note that you may need to clean up riov and wiov, even on error! 12839ad9c49cSJason Wang */ 12849ad9c49cSJason Wang int vringh_getdesc_iotlb(struct vringh *vrh, 12859ad9c49cSJason Wang struct vringh_kiov *riov, 12869ad9c49cSJason Wang struct vringh_kiov *wiov, 12879ad9c49cSJason Wang u16 *head, 12889ad9c49cSJason Wang gfp_t gfp) 12899ad9c49cSJason Wang { 12909ad9c49cSJason Wang int err; 12919ad9c49cSJason Wang 12929ad9c49cSJason Wang err = __vringh_get_head(vrh, getu16_iotlb, &vrh->last_avail_idx); 12939ad9c49cSJason Wang if (err < 0) 12949ad9c49cSJason Wang return err; 12959ad9c49cSJason Wang 12969ad9c49cSJason Wang /* Empty... */ 12979ad9c49cSJason Wang if (err == vrh->vring.num) 12989ad9c49cSJason Wang return 0; 12999ad9c49cSJason Wang 13009ad9c49cSJason Wang *head = err; 13019ad9c49cSJason Wang err = __vringh_iov(vrh, *head, riov, wiov, no_range_check, NULL, 13029ad9c49cSJason Wang gfp, copydesc_iotlb); 13039ad9c49cSJason Wang if (err) 13049ad9c49cSJason Wang return err; 13059ad9c49cSJason Wang 13069ad9c49cSJason Wang return 1; 13079ad9c49cSJason Wang } 13089ad9c49cSJason Wang EXPORT_SYMBOL(vringh_getdesc_iotlb); 13099ad9c49cSJason Wang 13109ad9c49cSJason Wang /** 13119ad9c49cSJason Wang * vringh_iov_pull_iotlb - copy bytes from vring_iov. 13129ad9c49cSJason Wang * @vrh: the vring. 13139ad9c49cSJason Wang * @riov: the riov as passed to vringh_getdesc_iotlb() (updated as we consume) 13149ad9c49cSJason Wang * @dst: the place to copy. 13159ad9c49cSJason Wang * @len: the maximum length to copy. 13169ad9c49cSJason Wang * 13179ad9c49cSJason Wang * Returns the bytes copied <= len or a negative errno. 13189ad9c49cSJason Wang */ 13199ad9c49cSJason Wang ssize_t vringh_iov_pull_iotlb(struct vringh *vrh, 13209ad9c49cSJason Wang struct vringh_kiov *riov, 13219ad9c49cSJason Wang void *dst, size_t len) 13229ad9c49cSJason Wang { 13239ad9c49cSJason Wang return vringh_iov_xfer(vrh, riov, dst, len, xfer_from_iotlb); 13249ad9c49cSJason Wang } 13259ad9c49cSJason Wang EXPORT_SYMBOL(vringh_iov_pull_iotlb); 13269ad9c49cSJason Wang 13279ad9c49cSJason Wang /** 13289ad9c49cSJason Wang * vringh_iov_push_iotlb - copy bytes into vring_iov. 13299ad9c49cSJason Wang * @vrh: the vring. 13309ad9c49cSJason Wang * @wiov: the wiov as passed to vringh_getdesc_iotlb() (updated as we consume) 13319ad9c49cSJason Wang * @dst: the place to copy. 13329ad9c49cSJason Wang * @len: the maximum length to copy. 13339ad9c49cSJason Wang * 13349ad9c49cSJason Wang * Returns the bytes copied <= len or a negative errno. 13359ad9c49cSJason Wang */ 13369ad9c49cSJason Wang ssize_t vringh_iov_push_iotlb(struct vringh *vrh, 13379ad9c49cSJason Wang struct vringh_kiov *wiov, 13389ad9c49cSJason Wang const void *src, size_t len) 13399ad9c49cSJason Wang { 13409ad9c49cSJason Wang return vringh_iov_xfer(vrh, wiov, (void *)src, len, xfer_to_iotlb); 13419ad9c49cSJason Wang } 13429ad9c49cSJason Wang EXPORT_SYMBOL(vringh_iov_push_iotlb); 13439ad9c49cSJason Wang 13449ad9c49cSJason Wang /** 13459ad9c49cSJason Wang * vringh_abandon_iotlb - we've decided not to handle the descriptor(s). 13469ad9c49cSJason Wang * @vrh: the vring. 13479ad9c49cSJason Wang * @num: the number of descriptors to put back (ie. num 13489ad9c49cSJason Wang * vringh_get_iotlb() to undo). 13499ad9c49cSJason Wang * 13509ad9c49cSJason Wang * The next vringh_get_iotlb() will return the old descriptor(s) again. 13519ad9c49cSJason Wang */ 13529ad9c49cSJason Wang void vringh_abandon_iotlb(struct vringh *vrh, unsigned int num) 13539ad9c49cSJason Wang { 13549ad9c49cSJason Wang /* We only update vring_avail_event(vr) when we want to be notified, 13559ad9c49cSJason Wang * so we haven't changed that yet. 13569ad9c49cSJason Wang */ 13579ad9c49cSJason Wang vrh->last_avail_idx -= num; 13589ad9c49cSJason Wang } 13599ad9c49cSJason Wang EXPORT_SYMBOL(vringh_abandon_iotlb); 13609ad9c49cSJason Wang 13619ad9c49cSJason Wang /** 13629ad9c49cSJason Wang * vringh_complete_iotlb - we've finished with descriptor, publish it. 13639ad9c49cSJason Wang * @vrh: the vring. 13649ad9c49cSJason Wang * @head: the head as filled in by vringh_getdesc_iotlb. 13659ad9c49cSJason Wang * @len: the length of data we have written. 13669ad9c49cSJason Wang * 13679ad9c49cSJason Wang * You should check vringh_need_notify_iotlb() after one or more calls 13689ad9c49cSJason Wang * to this function. 13699ad9c49cSJason Wang */ 13709ad9c49cSJason Wang int vringh_complete_iotlb(struct vringh *vrh, u16 head, u32 len) 13719ad9c49cSJason Wang { 13729ad9c49cSJason Wang struct vring_used_elem used; 13739ad9c49cSJason Wang 13749ad9c49cSJason Wang used.id = cpu_to_vringh32(vrh, head); 13759ad9c49cSJason Wang used.len = cpu_to_vringh32(vrh, len); 13769ad9c49cSJason Wang 13779ad9c49cSJason Wang return __vringh_complete(vrh, &used, 1, putu16_iotlb, putused_iotlb); 13789ad9c49cSJason Wang } 13799ad9c49cSJason Wang EXPORT_SYMBOL(vringh_complete_iotlb); 13809ad9c49cSJason Wang 13819ad9c49cSJason Wang /** 13829ad9c49cSJason Wang * vringh_notify_enable_iotlb - we want to know if something changes. 13839ad9c49cSJason Wang * @vrh: the vring. 13849ad9c49cSJason Wang * 13859ad9c49cSJason Wang * This always enables notifications, but returns false if there are 13869ad9c49cSJason Wang * now more buffers available in the vring. 13879ad9c49cSJason Wang */ 13889ad9c49cSJason Wang bool vringh_notify_enable_iotlb(struct vringh *vrh) 13899ad9c49cSJason Wang { 13909ad9c49cSJason Wang return __vringh_notify_enable(vrh, getu16_iotlb, putu16_iotlb); 13919ad9c49cSJason Wang } 13929ad9c49cSJason Wang EXPORT_SYMBOL(vringh_notify_enable_iotlb); 13939ad9c49cSJason Wang 13949ad9c49cSJason Wang /** 13959ad9c49cSJason Wang * vringh_notify_disable_iotlb - don't tell us if something changes. 13969ad9c49cSJason Wang * @vrh: the vring. 13979ad9c49cSJason Wang * 13989ad9c49cSJason Wang * This is our normal running state: we disable and then only enable when 13999ad9c49cSJason Wang * we're going to sleep. 14009ad9c49cSJason Wang */ 14019ad9c49cSJason Wang void vringh_notify_disable_iotlb(struct vringh *vrh) 14029ad9c49cSJason Wang { 14039ad9c49cSJason Wang __vringh_notify_disable(vrh, putu16_iotlb); 14049ad9c49cSJason Wang } 14059ad9c49cSJason Wang EXPORT_SYMBOL(vringh_notify_disable_iotlb); 14069ad9c49cSJason Wang 14079ad9c49cSJason Wang /** 14089ad9c49cSJason Wang * vringh_need_notify_iotlb - must we tell the other side about used buffers? 14099ad9c49cSJason Wang * @vrh: the vring we've called vringh_complete_iotlb() on. 14109ad9c49cSJason Wang * 14119ad9c49cSJason Wang * Returns -errno or 0 if we don't need to tell the other side, 1 if we do. 14129ad9c49cSJason Wang */ 14139ad9c49cSJason Wang int vringh_need_notify_iotlb(struct vringh *vrh) 14149ad9c49cSJason Wang { 14159ad9c49cSJason Wang return __vringh_need_notify(vrh, getu16_iotlb); 14169ad9c49cSJason Wang } 14179ad9c49cSJason Wang EXPORT_SYMBOL(vringh_need_notify_iotlb); 14189ad9c49cSJason Wang 14199ad9c49cSJason Wang 1420f558a845SDave Jones MODULE_LICENSE("GPL"); 1421