subprojects/libvduse/libvduse.c

   1 /*
   2  * VDUSE (vDPA Device in Userspace) library
   3  *
   4  * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
   5  *   Portions of codes and concepts borrowed from libvhost-user.c, so:
   6  *     Copyright IBM, Corp. 2007
   7  *     Copyright (c) 2016 Red Hat, Inc.
   8  *
   9  * Author:
  10  *   Xie Yongji <xieyongji@bytedance.com>
  11  *   Anthony Liguori <aliguori@us.ibm.com>
  12  *   Marc-André Lureau <mlureau@redhat.com>
  13  *   Victor Kaplansky <victork@redhat.com>
  14  *
  15  * This work is licensed under the terms of the GNU GPL, version 2 or
  16  * later.  See the COPYING file in the top-level directory.
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <stdbool.h>
  22 #include <stddef.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <assert.h>
  26 #include <endian.h>
  27 #include <unistd.h>
  28 #include <limits.h>
  29 #include <fcntl.h>
  30 #include <inttypes.h>
  31
  32 #include <sys/ioctl.h>
  33 #include <sys/eventfd.h>
  34 #include <sys/mman.h>
  35
  36 #include "include/atomic.h"
  37 #include "linux-headers/linux/virtio_ring.h"
  38 #include "linux-headers/linux/virtio_config.h"
  39 #include "linux-headers/linux/vduse.h"
  40 #include "libvduse.h"
  41
  42 #define VDUSE_VQ_ALIGN 4096
  43 #define MAX_IOVA_REGIONS 256
  44
  45 #define LOG_ALIGNMENT 64
  46
  47 /* Round number down to multiple */
  48 #define ALIGN_DOWN(n, m) ((n) / (m) * (m))
  49
  50 /* Round number up to multiple */
  51 #define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
  52
  53 #ifndef unlikely
  54 #define unlikely(x)   __builtin_expect(!!(x), 0)
  55 #endif
  56
  57 typedef struct VduseDescStateSplit {
  58     uint8_t inflight;
  59     uint8_t padding[5];
  60     uint16_t next;
  61     uint64_t counter;
  62 } VduseDescStateSplit;
  63
  64 typedef struct VduseVirtqLogInflight {
  65     uint64_t features;
  66     uint16_t version;
  67     uint16_t desc_num;
  68     uint16_t last_batch_head;
  69     uint16_t used_idx;
  70     VduseDescStateSplit desc[];
  71 } VduseVirtqLogInflight;
  72
  73 typedef struct VduseVirtqLog {
  74     VduseVirtqLogInflight inflight;
  75 } VduseVirtqLog;
  76
  77 typedef struct VduseVirtqInflightDesc {
  78     uint16_t index;
  79     uint64_t counter;
  80 } VduseVirtqInflightDesc;
  81
  82 typedef struct VduseRing {
  83     unsigned int num;
  84     uint64_t desc_addr;
  85     uint64_t avail_addr;
  86     uint64_t used_addr;
  87     struct vring_desc *desc;
  88     struct vring_avail *avail;
  89     struct vring_used *used;
  90 } VduseRing;
  91
  92 struct VduseVirtq {
  93     VduseRing vring;
  94     uint16_t last_avail_idx;
  95     uint16_t shadow_avail_idx;
  96     uint16_t used_idx;
  97     uint16_t signalled_used;
  98     bool signalled_used_valid;
  99     int index;
 100     int inuse;
 101     bool ready;
 102     int fd;
 103     VduseDev *dev;
 104     VduseVirtqInflightDesc *resubmit_list;
 105     uint16_t resubmit_num;
 106     uint64_t counter;
 107     VduseVirtqLog *log;
 108 };
 109
 110 typedef struct VduseIovaRegion {
 111     uint64_t iova;
 112     uint64_t size;
 113     uint64_t mmap_offset;
 114     uint64_t mmap_addr;
 115 } VduseIovaRegion;
 116
 117 struct VduseDev {
 118     VduseVirtq *vqs;
 119     VduseIovaRegion regions[MAX_IOVA_REGIONS];
 120     int num_regions;
 121     char *name;
 122     uint32_t device_id;
 123     uint32_t vendor_id;
 124     uint16_t num_queues;
 125     uint16_t queue_size;
 126     uint64_t features;
 127     const VduseOps *ops;
 128     int fd;
 129     int ctrl_fd;
 130     void *priv;
 131     void *log;
 132 };
 133
 134 static inline size_t vduse_vq_log_size(uint16_t queue_size)
 135 {
 136     return ALIGN_UP(sizeof(VduseDescStateSplit) * queue_size +
 137                     sizeof(VduseVirtqLogInflight), LOG_ALIGNMENT);
 138 }
 139
 140 static void *vduse_log_get(const char *filename, size_t size)
 141 {
 142     void *ptr = MAP_FAILED;
 143     int fd;
 144
 145     fd = open(filename, O_RDWR | O_CREAT, 0600);
 146     if (fd == -1) {
 147         return MAP_FAILED;
 148     }
 149
 150     if (ftruncate(fd, size) == -1) {
 151         goto out;
 152     }
 153
 154     ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 155
 156 out:
 157     close(fd);
 158     return ptr;
 159 }
 160
 161 static inline bool has_feature(uint64_t features, unsigned int fbit)
 162 {
 163     assert(fbit < 64);
 164     return !!(features & (1ULL << fbit));
 165 }
 166
 167 static inline bool vduse_dev_has_feature(VduseDev *dev, unsigned int fbit)
 168 {
 169     return has_feature(dev->features, fbit);
 170 }
 171
 172 uint64_t vduse_get_virtio_features(void)
 173 {
 174     return (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
 175            (1ULL << VIRTIO_F_VERSION_1) |
 176            (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 177            (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 178            (1ULL << VIRTIO_RING_F_INDIRECT_DESC);
 179 }
 180
 181 VduseDev *vduse_queue_get_dev(VduseVirtq *vq)
 182 {
 183     return vq->dev;
 184 }
 185
 186 int vduse_queue_get_fd(VduseVirtq *vq)
 187 {
 188     return vq->fd;
 189 }
 190
 191 void *vduse_dev_get_priv(VduseDev *dev)
 192 {
 193     return dev->priv;
 194 }
 195
 196 VduseVirtq *vduse_dev_get_queue(VduseDev *dev, int index)
 197 {
 198     return &dev->vqs[index];
 199 }
 200
 201 int vduse_dev_get_fd(VduseDev *dev)
 202 {
 203     return dev->fd;
 204 }
 205
 206 static int vduse_inject_irq(VduseDev *dev, int index)
 207 {
 208     return ioctl(dev->fd, VDUSE_VQ_INJECT_IRQ, &index);
 209 }
 210
 211 static int inflight_desc_compare(const void *a, const void *b)
 212 {
 213     VduseVirtqInflightDesc *desc0 = (VduseVirtqInflightDesc *)a,
 214                            *desc1 = (VduseVirtqInflightDesc *)b;
 215
 216     if (desc1->counter > desc0->counter &&
 217         (desc1->counter - desc0->counter) < VIRTQUEUE_MAX_SIZE * 2) {
 218         return 1;
 219     }
 220
 221     return -1;
 222 }
 223
 224 static int vduse_queue_check_inflights(VduseVirtq *vq)
 225 {
 226     int i = 0;
 227     VduseDev *dev = vq->dev;
 228
 229     vq->used_idx = le16toh(vq->vring.used->idx);
 230     vq->resubmit_num = 0;
 231     vq->resubmit_list = NULL;
 232     vq->counter = 0;
 233
 234     if (unlikely(vq->log->inflight.used_idx != vq->used_idx)) {
 235         if (vq->log->inflight.last_batch_head > VIRTQUEUE_MAX_SIZE) {
 236             return -1;
 237         }
 238
 239         vq->log->inflight.desc[vq->log->inflight.last_batch_head].inflight = 0;
 240
 241         barrier();
 242
 243         vq->log->inflight.used_idx = vq->used_idx;
 244     }
 245
 246     for (i = 0; i < vq->log->inflight.desc_num; i++) {
 247         if (vq->log->inflight.desc[i].inflight == 1) {
 248             vq->inuse++;
 249         }
 250     }
 251
 252     vq->shadow_avail_idx = vq->last_avail_idx = vq->inuse + vq->used_idx;
 253
 254     if (vq->inuse) {
 255         vq->resubmit_list = calloc(vq->inuse, sizeof(VduseVirtqInflightDesc));
 256         if (!vq->resubmit_list) {
 257             return -1;
 258         }
 259
 260         for (i = 0; i < vq->log->inflight.desc_num; i++) {
 261             if (vq->log->inflight.desc[i].inflight) {
 262                 vq->resubmit_list[vq->resubmit_num].index = i;
 263                 vq->resubmit_list[vq->resubmit_num].counter =
 264                                         vq->log->inflight.desc[i].counter;
 265                 vq->resubmit_num++;
 266             }
 267         }
 268
 269         if (vq->resubmit_num > 1) {
 270             qsort(vq->resubmit_list, vq->resubmit_num,
 271                   sizeof(VduseVirtqInflightDesc), inflight_desc_compare);
 272         }
 273         vq->counter = vq->resubmit_list[0].counter + 1;
 274     }
 275
 276     vduse_inject_irq(dev, vq->index);
 277
 278     return 0;
 279 }
 280
 281 static int vduse_queue_inflight_get(VduseVirtq *vq, int desc_idx)
 282 {
 283     vq->log->inflight.desc[desc_idx].counter = vq->counter++;
 284
 285     barrier();
 286
 287     vq->log->inflight.desc[desc_idx].inflight = 1;
 288
 289     return 0;
 290 }
 291
 292 static int vduse_queue_inflight_pre_put(VduseVirtq *vq, int desc_idx)
 293 {
 294     vq->log->inflight.last_batch_head = desc_idx;
 295
 296     return 0;
 297 }
 298
 299 static int vduse_queue_inflight_post_put(VduseVirtq *vq, int desc_idx)
 300 {
 301     vq->log->inflight.desc[desc_idx].inflight = 0;
 302
 303     barrier();
 304
 305     vq->log->inflight.used_idx = vq->used_idx;
 306
 307     return 0;
 308 }
 309
 310 static void vduse_iova_remove_region(VduseDev *dev, uint64_t start,
 311                                      uint64_t last)
 312 {
 313     int i;
 314
 315     if (last == start) {
 316         return;
 317     }
 318
 319     for (i = 0; i < MAX_IOVA_REGIONS; i++) {
 320         if (!dev->regions[i].mmap_addr) {
 321             continue;
 322         }
 323
 324         if (start <= dev->regions[i].iova &&
 325             last >= (dev->regions[i].iova + dev->regions[i].size - 1)) {
 326             munmap((void *)(uintptr_t)dev->regions[i].mmap_addr,
 327                    dev->regions[i].mmap_offset + dev->regions[i].size);
 328             dev->regions[i].mmap_addr = 0;
 329             dev->num_regions--;
 330         }
 331     }
 332 }
 333
 334 static int vduse_iova_add_region(VduseDev *dev, int fd,
 335                                  uint64_t offset, uint64_t start,
 336                                  uint64_t last, int prot)
 337 {
 338     int i;
 339     uint64_t size = last - start + 1;
 340     void *mmap_addr = mmap(0, size + offset, prot, MAP_SHARED, fd, 0);
 341
 342     if (mmap_addr == MAP_FAILED) {
 343         close(fd);
 344         return -EINVAL;
 345     }
 346
 347     for (i = 0; i < MAX_IOVA_REGIONS; i++) {
 348         if (!dev->regions[i].mmap_addr) {
 349             dev->regions[i].mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
 350             dev->regions[i].mmap_offset = offset;
 351             dev->regions[i].iova = start;
 352             dev->regions[i].size = size;
 353             dev->num_regions++;
 354             break;
 355         }
 356     }
 357     assert(i < MAX_IOVA_REGIONS);
 358     close(fd);
 359
 360     return 0;
 361 }
 362
 363 static int perm_to_prot(uint8_t perm)
 364 {
 365     int prot = 0;
 366
 367     switch (perm) {
 368     case VDUSE_ACCESS_WO:
 369         prot |= PROT_WRITE;
 370         break;
 371     case VDUSE_ACCESS_RO:
 372         prot |= PROT_READ;
 373         break;
 374     case VDUSE_ACCESS_RW:
 375         prot |= PROT_READ | PROT_WRITE;
 376         break;
 377     default:
 378         break;
 379     }
 380
 381     return prot;
 382 }
 383
 384 static inline void *iova_to_va(VduseDev *dev, uint64_t *plen, uint64_t iova)
 385 {
 386     int i, ret;
 387     struct vduse_iotlb_entry entry;
 388
 389     for (i = 0; i < MAX_IOVA_REGIONS; i++) {
 390         VduseIovaRegion *r = &dev->regions[i];
 391
 392         if (!r->mmap_addr) {
 393             continue;
 394         }
 395
 396         if ((iova >= r->iova) && (iova < (r->iova + r->size))) {
 397             if ((iova + *plen) > (r->iova + r->size)) {
 398                 *plen = r->iova + r->size - iova;
 399             }
 400             return (void *)(uintptr_t)(iova - r->iova +
 401                    r->mmap_addr + r->mmap_offset);
 402         }
 403     }
 404
 405     entry.start = iova;
 406     entry.last = iova + 1;
 407     ret = ioctl(dev->fd, VDUSE_IOTLB_GET_FD, &entry);
 408     if (ret < 0) {
 409         return NULL;
 410     }
 411
 412     if (!vduse_iova_add_region(dev, ret, entry.offset, entry.start,
 413                                entry.last, perm_to_prot(entry.perm))) {
 414         return iova_to_va(dev, plen, iova);
 415     }
 416
 417     return NULL;
 418 }
 419
 420 static inline uint16_t vring_avail_flags(VduseVirtq *vq)
 421 {
 422     return le16toh(vq->vring.avail->flags);
 423 }
 424
 425 static inline uint16_t vring_avail_idx(VduseVirtq *vq)
 426 {
 427     vq->shadow_avail_idx = le16toh(vq->vring.avail->idx);
 428
 429     return vq->shadow_avail_idx;
 430 }
 431
 432 static inline uint16_t vring_avail_ring(VduseVirtq *vq, int i)
 433 {
 434     return le16toh(vq->vring.avail->ring[i]);
 435 }
 436
 437 static inline uint16_t vring_get_used_event(VduseVirtq *vq)
 438 {
 439     return vring_avail_ring(vq, vq->vring.num);
 440 }
 441
 442 static bool vduse_queue_get_head(VduseVirtq *vq, unsigned int idx,
 443                                  unsigned int *head)
 444 {
 445     /*
 446      * Grab the next descriptor number they're advertising, and increment
 447      * the index we've seen.
 448      */
 449     *head = vring_avail_ring(vq, idx % vq->vring.num);
 450
 451     /* If their number is silly, that's a fatal mistake. */
 452     if (*head >= vq->vring.num) {
 453         fprintf(stderr, "Guest says index %u is available\n", *head);
 454         return false;
 455     }
 456
 457     return true;
 458 }
 459
 460 static int
 461 vduse_queue_read_indirect_desc(VduseDev *dev, struct vring_desc *desc,
 462                                uint64_t addr, size_t len)
 463 {
 464     struct vring_desc *ori_desc;
 465     uint64_t read_len;
 466
 467     if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc))) {
 468         return -1;
 469     }
 470
 471     if (len == 0) {
 472         return -1;
 473     }
 474
 475     while (len) {
 476         read_len = len;
 477         ori_desc = iova_to_va(dev, &read_len, addr);
 478         if (!ori_desc) {
 479             return -1;
 480         }
 481
 482         memcpy(desc, ori_desc, read_len);
 483         len -= read_len;
 484         addr += read_len;
 485         desc += read_len;
 486     }
 487
 488     return 0;
 489 }
 490
 491 enum {
 492     VIRTQUEUE_READ_DESC_ERROR = -1,
 493     VIRTQUEUE_READ_DESC_DONE = 0,   /* end of chain */
 494     VIRTQUEUE_READ_DESC_MORE = 1,   /* more buffers in chain */
 495 };
 496
 497 static int vduse_queue_read_next_desc(struct vring_desc *desc, int i,
 498                                       unsigned int max, unsigned int *next)
 499 {
 500     /* If this descriptor says it doesn't chain, we're done. */
 501     if (!(le16toh(desc[i].flags) & VRING_DESC_F_NEXT)) {
 502         return VIRTQUEUE_READ_DESC_DONE;
 503     }
 504
 505     /* Check they're not leading us off end of descriptors. */
 506     *next = desc[i].next;
 507     /* Make sure compiler knows to grab that: we don't want it changing! */
 508     smp_wmb();
 509
 510     if (*next >= max) {
 511         fprintf(stderr, "Desc next is %u\n", *next);
 512         return VIRTQUEUE_READ_DESC_ERROR;
 513     }
 514
 515     return VIRTQUEUE_READ_DESC_MORE;
 516 }
 517
 518 /*
 519  * Fetch avail_idx from VQ memory only when we really need to know if
 520  * guest has added some buffers.
 521  */
 522 static bool vduse_queue_empty(VduseVirtq *vq)
 523 {
 524     if (unlikely(!vq->vring.avail)) {
 525         return true;
 526     }
 527
 528     if (vq->shadow_avail_idx != vq->last_avail_idx) {
 529         return false;
 530     }
 531
 532     return vring_avail_idx(vq) == vq->last_avail_idx;
 533 }
 534
 535 static bool vduse_queue_should_notify(VduseVirtq *vq)
 536 {
 537     VduseDev *dev = vq->dev;
 538     uint16_t old, new;
 539     bool v;
 540
 541     /* We need to expose used array entries before checking used event. */
 542     smp_mb();
 543
 544     /* Always notify when queue is empty (when feature acknowledge) */
 545     if (vduse_dev_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
 546         !vq->inuse && vduse_queue_empty(vq)) {
 547         return true;
 548     }
 549
 550     if (!vduse_dev_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
 551         return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
 552     }
 553
 554     v = vq->signalled_used_valid;
 555     vq->signalled_used_valid = true;
 556     old = vq->signalled_used;
 557     new = vq->signalled_used = vq->used_idx;
 558     return !v || vring_need_event(vring_get_used_event(vq), new, old);
 559 }
 560
 561 void vduse_queue_notify(VduseVirtq *vq)
 562 {
 563     VduseDev *dev = vq->dev;
 564
 565     if (unlikely(!vq->vring.avail)) {
 566         return;
 567     }
 568
 569     if (!vduse_queue_should_notify(vq)) {
 570         return;
 571     }
 572
 573     if (vduse_inject_irq(dev, vq->index) < 0) {
 574         fprintf(stderr, "Error inject irq for vq %d: %s\n",
 575                 vq->index, strerror(errno));
 576     }
 577 }
 578
 579 static inline void vring_set_avail_event(VduseVirtq *vq, uint16_t val)
 580 {
 581     *((uint16_t *)&vq->vring.used->ring[vq->vring.num]) = htole16(val);
 582 }
 583
 584 static bool vduse_queue_map_single_desc(VduseVirtq *vq, unsigned int *p_num_sg,
 585                                    struct iovec *iov, unsigned int max_num_sg,
 586                                    bool is_write, uint64_t pa, size_t sz)
 587 {
 588     unsigned num_sg = *p_num_sg;
 589     VduseDev *dev = vq->dev;
 590
 591     assert(num_sg <= max_num_sg);
 592
 593     if (!sz) {
 594         fprintf(stderr, "virtio: zero sized buffers are not allowed\n");
 595         return false;
 596     }
 597
 598     while (sz) {
 599         uint64_t len = sz;
 600
 601         if (num_sg == max_num_sg) {
 602             fprintf(stderr,
 603                     "virtio: too many descriptors in indirect table\n");
 604             return false;
 605         }
 606
 607         iov[num_sg].iov_base = iova_to_va(dev, &len, pa);
 608         if (iov[num_sg].iov_base == NULL) {
 609             fprintf(stderr, "virtio: invalid address for buffers\n");
 610             return false;
 611         }
 612         iov[num_sg++].iov_len = len;
 613         sz -= len;
 614         pa += len;
 615     }
 616
 617     *p_num_sg = num_sg;
 618     return true;
 619 }
 620
 621 static void *vduse_queue_alloc_element(size_t sz, unsigned out_num,
 622                                        unsigned in_num)
 623 {
 624     VduseVirtqElement *elem;
 625     size_t in_sg_ofs = ALIGN_UP(sz, __alignof__(elem->in_sg[0]));
 626     size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
 627     size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
 628
 629     assert(sz >= sizeof(VduseVirtqElement));
 630     elem = malloc(out_sg_end);
 631     if (!elem) {
 632         return NULL;
 633     }
 634     elem->out_num = out_num;
 635     elem->in_num = in_num;
 636     elem->in_sg = (void *)elem + in_sg_ofs;
 637     elem->out_sg = (void *)elem + out_sg_ofs;
 638     return elem;
 639 }
 640
 641 static void *vduse_queue_map_desc(VduseVirtq *vq, unsigned int idx, size_t sz)
 642 {
 643     struct vring_desc *desc = vq->vring.desc;
 644     VduseDev *dev = vq->dev;
 645     uint64_t desc_addr, read_len;
 646     unsigned int desc_len;
 647     unsigned int max = vq->vring.num;
 648     unsigned int i = idx;
 649     VduseVirtqElement *elem;
 650     struct iovec iov[VIRTQUEUE_MAX_SIZE];
 651     struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
 652     unsigned int out_num = 0, in_num = 0;
 653     int rc;
 654
 655     if (le16toh(desc[i].flags) & VRING_DESC_F_INDIRECT) {
 656         if (le32toh(desc[i].len) % sizeof(struct vring_desc)) {
 657             fprintf(stderr, "Invalid size for indirect buffer table\n");
 658             return NULL;
 659         }
 660
 661         /* loop over the indirect descriptor table */
 662         desc_addr = le64toh(desc[i].addr);
 663         desc_len = le32toh(desc[i].len);
 664         max = desc_len / sizeof(struct vring_desc);
 665         read_len = desc_len;
 666         desc = iova_to_va(dev, &read_len, desc_addr);
 667         if (unlikely(desc && read_len != desc_len)) {
 668             /* Failed to use zero copy */
 669             desc = NULL;
 670             if (!vduse_queue_read_indirect_desc(dev, desc_buf,
 671                                                 desc_addr,
 672                                                 desc_len)) {
 673                 desc = desc_buf;
 674             }
 675         }
 676         if (!desc) {
 677             fprintf(stderr, "Invalid indirect buffer table\n");
 678             return NULL;
 679         }
 680         i = 0;
 681     }
 682
 683     /* Collect all the descriptors */
 684     do {
 685         if (le16toh(desc[i].flags) & VRING_DESC_F_WRITE) {
 686             if (!vduse_queue_map_single_desc(vq, &in_num, iov + out_num,
 687                                              VIRTQUEUE_MAX_SIZE - out_num,
 688                                              true, le64toh(desc[i].addr),
 689                                              le32toh(desc[i].len))) {
 690                 return NULL;
 691             }
 692         } else {
 693             if (in_num) {
 694                 fprintf(stderr, "Incorrect order for descriptors\n");
 695                 return NULL;
 696             }
 697             if (!vduse_queue_map_single_desc(vq, &out_num, iov,
 698                                              VIRTQUEUE_MAX_SIZE, false,
 699                                              le64toh(desc[i].addr),
 700                                              le32toh(desc[i].len))) {
 701                 return NULL;
 702             }
 703         }
 704
 705         /* If we've got too many, that implies a descriptor loop. */
 706         if ((in_num + out_num) > max) {
 707             fprintf(stderr, "Looped descriptor\n");
 708             return NULL;
 709         }
 710         rc = vduse_queue_read_next_desc(desc, i, max, &i);
 711     } while (rc == VIRTQUEUE_READ_DESC_MORE);
 712
 713     if (rc == VIRTQUEUE_READ_DESC_ERROR) {
 714         fprintf(stderr, "read descriptor error\n");
 715         return NULL;
 716     }
 717
 718     /* Now copy what we have collected and mapped */
 719     elem = vduse_queue_alloc_element(sz, out_num, in_num);
 720     if (!elem) {
 721         fprintf(stderr, "read descriptor error\n");
 722         return NULL;
 723     }
 724     elem->index = idx;
 725     for (i = 0; i < out_num; i++) {
 726         elem->out_sg[i] = iov[i];
 727     }
 728     for (i = 0; i < in_num; i++) {
 729         elem->in_sg[i] = iov[out_num + i];
 730     }
 731
 732     return elem;
 733 }
 734
 735 void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
 736 {
 737     unsigned int head;
 738     VduseVirtqElement *elem;
 739     VduseDev *dev = vq->dev;
 740     int i;
 741
 742     if (unlikely(!vq->vring.avail)) {
 743         return NULL;
 744     }
 745
 746     if (unlikely(vq->resubmit_list && vq->resubmit_num > 0)) {
 747         i = (--vq->resubmit_num);
 748         elem = vduse_queue_map_desc(vq, vq->resubmit_list[i].index, sz);
 749
 750         if (!vq->resubmit_num) {
 751             free(vq->resubmit_list);
 752             vq->resubmit_list = NULL;
 753         }
 754
 755         return elem;
 756     }
 757
 758     if (vduse_queue_empty(vq)) {
 759         return NULL;
 760     }
 761     /* Needed after virtio_queue_empty() */
 762     smp_rmb();
 763
 764     if (vq->inuse >= vq->vring.num) {
 765         fprintf(stderr, "Virtqueue size exceeded: %d\n", vq->inuse);
 766         return NULL;
 767     }
 768
 769     if (!vduse_queue_get_head(vq, vq->last_avail_idx++, &head)) {
 770         return NULL;
 771     }
 772
 773     if (vduse_dev_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
 774         vring_set_avail_event(vq, vq->last_avail_idx);
 775     }
 776
 777     elem = vduse_queue_map_desc(vq, head, sz);
 778
 779     if (!elem) {
 780         return NULL;
 781     }
 782
 783     vq->inuse++;
 784
 785     vduse_queue_inflight_get(vq, head);
 786
 787     return elem;
 788 }
 789
 790 static inline void vring_used_write(VduseVirtq *vq,
 791                                     struct vring_used_elem *uelem, int i)
 792 {
 793     struct vring_used *used = vq->vring.used;
 794
 795     used->ring[i] = *uelem;
 796 }
 797
 798 static void vduse_queue_fill(VduseVirtq *vq, const VduseVirtqElement *elem,
 799                              unsigned int len, unsigned int idx)
 800 {
 801     struct vring_used_elem uelem;
 802
 803     if (unlikely(!vq->vring.used)) {
 804         return;
 805     }
 806
 807     idx = (idx + vq->used_idx) % vq->vring.num;
 808
 809     uelem.id = htole32(elem->index);
 810     uelem.len = htole32(len);
 811     vring_used_write(vq, &uelem, idx);
 812 }
 813
 814 static inline void vring_used_idx_set(VduseVirtq *vq, uint16_t val)
 815 {
 816     vq->vring.used->idx = htole16(val);
 817     vq->used_idx = val;
 818 }
 819
 820 static void vduse_queue_flush(VduseVirtq *vq, unsigned int count)
 821 {
 822     uint16_t old, new;
 823
 824     if (unlikely(!vq->vring.used)) {
 825         return;
 826     }
 827
 828     /* Make sure buffer is written before we update index. */
 829     smp_wmb();
 830
 831     old = vq->used_idx;
 832     new = old + count;
 833     vring_used_idx_set(vq, new);
 834     vq->inuse -= count;
 835     if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) {
 836         vq->signalled_used_valid = false;
 837     }
 838 }
 839
 840 void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
 841                       unsigned int len)
 842 {
 843     vduse_queue_fill(vq, elem, len, 0);
 844     vduse_queue_inflight_pre_put(vq, elem->index);
 845     vduse_queue_flush(vq, 1);
 846     vduse_queue_inflight_post_put(vq, elem->index);
 847 }
 848
 849 static int vduse_queue_update_vring(VduseVirtq *vq, uint64_t desc_addr,
 850                                     uint64_t avail_addr, uint64_t used_addr)
 851 {
 852     struct VduseDev *dev = vq->dev;
 853     uint64_t len;
 854
 855     len = sizeof(struct vring_desc);
 856     vq->vring.desc = iova_to_va(dev, &len, desc_addr);
 857     if (len != sizeof(struct vring_desc)) {
 858         return -EINVAL;
 859     }
 860
 861     len = sizeof(struct vring_avail);
 862     vq->vring.avail = iova_to_va(dev, &len, avail_addr);
 863     if (len != sizeof(struct vring_avail)) {
 864         return -EINVAL;
 865     }
 866
 867     len = sizeof(struct vring_used);
 868     vq->vring.used = iova_to_va(dev, &len, used_addr);
 869     if (len != sizeof(struct vring_used)) {
 870         return -EINVAL;
 871     }
 872
 873     if (!vq->vring.desc || !vq->vring.avail || !vq->vring.used) {
 874         fprintf(stderr, "Failed to get vq[%d] iova mapping\n", vq->index);
 875         return -EINVAL;
 876     }
 877
 878     return 0;
 879 }
 880
 881 static void vduse_queue_enable(VduseVirtq *vq)
 882 {
 883     struct VduseDev *dev = vq->dev;
 884     struct vduse_vq_info vq_info;
 885     struct vduse_vq_eventfd vq_eventfd;
 886     int fd;
 887
 888     vq_info.index = vq->index;
 889     if (ioctl(dev->fd, VDUSE_VQ_GET_INFO, &vq_info)) {
 890         fprintf(stderr, "Failed to get vq[%d] info: %s\n",
 891                 vq->index, strerror(errno));
 892         return;
 893     }
 894
 895     if (!vq_info.ready) {
 896         return;
 897     }
 898
 899     vq->vring.num = vq_info.num;
 900     vq->vring.desc_addr = vq_info.desc_addr;
 901     vq->vring.avail_addr = vq_info.driver_addr;
 902     vq->vring.used_addr = vq_info.device_addr;
 903
 904     if (vduse_queue_update_vring(vq, vq_info.desc_addr,
 905                                  vq_info.driver_addr, vq_info.device_addr)) {
 906         fprintf(stderr, "Failed to update vring for vq[%d]\n", vq->index);
 907         return;
 908     }
 909
 910     fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
 911     if (fd < 0) {
 912         fprintf(stderr, "Failed to init eventfd for vq[%d]\n", vq->index);
 913         return;
 914     }
 915
 916     vq_eventfd.index = vq->index;
 917     vq_eventfd.fd = fd;
 918     if (ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &vq_eventfd)) {
 919         fprintf(stderr, "Failed to setup kick fd for vq[%d]\n", vq->index);
 920         close(fd);
 921         return;
 922     }
 923
 924     vq->fd = fd;
 925     vq->signalled_used_valid = false;
 926     vq->ready = true;
 927
 928     if (vduse_queue_check_inflights(vq)) {
 929         fprintf(stderr, "Failed to check inflights for vq[%d]\n", vq->index);
 930         close(fd);
 931         return;
 932     }
 933
 934     dev->ops->enable_queue(dev, vq);
 935 }
 936
 937 static void vduse_queue_disable(VduseVirtq *vq)
 938 {
 939     struct VduseDev *dev = vq->dev;
 940     struct vduse_vq_eventfd eventfd;
 941
 942     if (!vq->ready) {
 943         return;
 944     }
 945
 946     dev->ops->disable_queue(dev, vq);
 947
 948     eventfd.index = vq->index;
 949     eventfd.fd = VDUSE_EVENTFD_DEASSIGN;
 950     ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &eventfd);
 951     close(vq->fd);
 952
 953     assert(vq->inuse == 0);
 954
 955     vq->vring.num = 0;
 956     vq->vring.desc_addr = 0;
 957     vq->vring.avail_addr = 0;
 958     vq->vring.used_addr = 0;
 959     vq->vring.desc = 0;
 960     vq->vring.avail = 0;
 961     vq->vring.used = 0;
 962     vq->ready = false;
 963     vq->fd = -1;
 964 }
 965
 966 static void vduse_dev_start_dataplane(VduseDev *dev)
 967 {
 968     int i;
 969
 970     if (ioctl(dev->fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
 971         fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
 972         return;
 973     }
 974     assert(vduse_dev_has_feature(dev, VIRTIO_F_VERSION_1));
 975
 976     for (i = 0; i < dev->num_queues; i++) {
 977         vduse_queue_enable(&dev->vqs[i]);
 978     }
 979 }
 980
 981 static void vduse_dev_stop_dataplane(VduseDev *dev)
 982 {
 983     size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
 984     int i;
 985
 986     for (i = 0; i < dev->num_queues; i++) {
 987         vduse_queue_disable(&dev->vqs[i]);
 988     }
 989     if (dev->log) {
 990         memset(dev->log, 0, log_size);
 991     }
 992     dev->features = 0;
 993     vduse_iova_remove_region(dev, 0, ULONG_MAX);
 994 }
 995
 996 int vduse_dev_handler(VduseDev *dev)
 997 {
 998     struct vduse_dev_request req;
 999     struct vduse_dev_response resp = { 0 };
1000     VduseVirtq *vq;
1001     int i, ret;
1002
1003     ret = read(dev->fd, &req, sizeof(req));
1004     if (ret != sizeof(req)) {
1005         fprintf(stderr, "Read request error [%d]: %s\n",
1006                 ret, strerror(errno));
1007         return -errno;
1008     }
1009     resp.request_id = req.request_id;
1010
1011     switch (req.type) {
1012     case VDUSE_GET_VQ_STATE:
1013         vq = &dev->vqs[req.vq_state.index];
1014         resp.vq_state.split.avail_index = vq->last_avail_idx;
1015         resp.result = VDUSE_REQ_RESULT_OK;
1016         break;
1017     case VDUSE_SET_STATUS:
1018         if (req.s.status & VIRTIO_CONFIG_S_DRIVER_OK) {
1019             vduse_dev_start_dataplane(dev);
1020         } else if (req.s.status == 0) {
1021             vduse_dev_stop_dataplane(dev);
1022         }
1023         resp.result = VDUSE_REQ_RESULT_OK;
1024         break;
1025     case VDUSE_UPDATE_IOTLB:
1026         /* The iova will be updated by iova_to_va() later, so just remove it */
1027         vduse_iova_remove_region(dev, req.iova.start, req.iova.last);
1028         for (i = 0; i < dev->num_queues; i++) {
1029             VduseVirtq *vq = &dev->vqs[i];
1030             if (vq->ready) {
1031                 if (vduse_queue_update_vring(vq, vq->vring.desc_addr,
1032                                              vq->vring.avail_addr,
1033                                              vq->vring.used_addr)) {
1034                     fprintf(stderr, "Failed to update vring for vq[%d]\n",
1035                             vq->index);
1036                 }
1037             }
1038         }
1039         resp.result = VDUSE_REQ_RESULT_OK;
1040         break;
1041     default:
1042         resp.result = VDUSE_REQ_RESULT_FAILED;
1043         break;
1044     }
1045
1046     ret = write(dev->fd, &resp, sizeof(resp));
1047     if (ret != sizeof(resp)) {
1048         fprintf(stderr, "Write request %d error [%d]: %s\n",
1049                 req.type, ret, strerror(errno));
1050         return -errno;
1051     }
1052     return 0;
1053 }
1054
1055 int vduse_dev_update_config(VduseDev *dev, uint32_t size,
1056                             uint32_t offset, char *buffer)
1057 {
1058     int ret;
1059     struct vduse_config_data *data;
1060
1061     data = malloc(offsetof(struct vduse_config_data, buffer) + size);
1062     if (!data) {
1063         return -ENOMEM;
1064     }
1065
1066     data->offset = offset;
1067     data->length = size;
1068     memcpy(data->buffer, buffer, size);
1069
1070     ret = ioctl(dev->fd, VDUSE_DEV_SET_CONFIG, data);
1071     free(data);
1072
1073     if (ret) {
1074         return -errno;
1075     }
1076
1077     if (ioctl(dev->fd, VDUSE_DEV_INJECT_CONFIG_IRQ)) {
1078         return -errno;
1079     }
1080
1081     return 0;
1082 }
1083
1084 int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size)
1085 {
1086     VduseVirtq *vq = &dev->vqs[index];
1087     struct vduse_vq_config vq_config = { 0 };
1088
1089     if (max_size > VIRTQUEUE_MAX_SIZE) {
1090         return -EINVAL;
1091     }
1092
1093     vq_config.index = vq->index;
1094     vq_config.max_size = max_size;
1095
1096     if (ioctl(dev->fd, VDUSE_VQ_SETUP, &vq_config)) {
1097         return -errno;
1098     }
1099
1100     vduse_queue_enable(vq);
1101
1102     return 0;
1103 }
1104
1105 int vduse_set_reconnect_log_file(VduseDev *dev, const char *filename)
1106 {
1107
1108     size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
1109     void *log;
1110     int i;
1111
1112     dev->log = log = vduse_log_get(filename, log_size);
1113     if (log == MAP_FAILED) {
1114         fprintf(stderr, "Failed to get vduse log\n");
1115         return -EINVAL;
1116     }
1117
1118     for (i = 0; i < dev->num_queues; i++) {
1119         dev->vqs[i].log = log;
1120         dev->vqs[i].log->inflight.desc_num = VIRTQUEUE_MAX_SIZE;
1121         log = (void *)((char *)log + vduse_vq_log_size(VIRTQUEUE_MAX_SIZE));
1122     }
1123
1124     return 0;
1125 }
1126
1127 static int vduse_dev_init_vqs(VduseDev *dev, uint16_t num_queues)
1128 {
1129     VduseVirtq *vqs;
1130     int i;
1131
1132     vqs = calloc(sizeof(VduseVirtq), num_queues);
1133     if (!vqs) {
1134         return -ENOMEM;
1135     }
1136
1137     for (i = 0; i < num_queues; i++) {
1138         vqs[i].index = i;
1139         vqs[i].dev = dev;
1140         vqs[i].fd = -1;
1141     }
1142     dev->vqs = vqs;
1143
1144     return 0;
1145 }
1146
1147 static int vduse_dev_init(VduseDev *dev, const char *name,
1148                           uint16_t num_queues, const VduseOps *ops,
1149                           void *priv)
1150 {
1151     char *dev_path, *dev_name;
1152     int ret, fd;
1153
1154     dev_path = malloc(strlen(name) + strlen("/dev/vduse/") + 1);
1155     if (!dev_path) {
1156         return -ENOMEM;
1157     }
1158     sprintf(dev_path, "/dev/vduse/%s", name);
1159
1160     fd = open(dev_path, O_RDWR);
1161     free(dev_path);
1162     if (fd < 0) {
1163         fprintf(stderr, "Failed to open vduse dev %s: %s\n",
1164                 name, strerror(errno));
1165         return -errno;
1166     }
1167
1168     if (ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
1169         fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
1170         close(fd);
1171         return -errno;
1172     }
1173
1174     dev_name = strdup(name);
1175     if (!dev_name) {
1176         close(fd);
1177         return -ENOMEM;
1178     }
1179
1180     ret = vduse_dev_init_vqs(dev, num_queues);
1181     if (ret) {
1182         free(dev_name);
1183         close(fd);
1184         return ret;
1185     }
1186
1187     dev->name = dev_name;
1188     dev->num_queues = num_queues;
1189     dev->fd = fd;
1190     dev->ops = ops;
1191     dev->priv = priv;
1192
1193     return 0;
1194 }
1195
1196 static inline bool vduse_name_is_invalid(const char *name)
1197 {
1198     return strlen(name) >= VDUSE_NAME_MAX || strstr(name, "..");
1199 }
1200
1201 VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
1202                                  const VduseOps *ops, void *priv)
1203 {
1204     VduseDev *dev;
1205     int ret;
1206
1207     if (!ops || !ops->enable_queue || !ops->disable_queue) {
1208         fprintf(stderr, "Invalid parameter for vduse\n");
1209         return NULL;
1210     }
1211
1212     dev = calloc(sizeof(VduseDev), 1);
1213     if (!dev) {
1214         fprintf(stderr, "Failed to allocate vduse device\n");
1215         return NULL;
1216     }
1217
1218     if (ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
1219         fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
1220         free(dev);
1221         return NULL;
1222     }
1223
1224     ret = vduse_dev_init_vqs(dev, num_queues);
1225     if (ret) {
1226         fprintf(stderr, "Failed to init vqs\n");
1227         free(dev);
1228         return NULL;
1229     }
1230
1231     dev->num_queues = num_queues;
1232     dev->fd = fd;
1233     dev->ops = ops;
1234     dev->priv = priv;
1235
1236     return dev;
1237 }
1238
1239 VduseDev *vduse_dev_create_by_name(const char *name, uint16_t num_queues,
1240                                    const VduseOps *ops, void *priv)
1241 {
1242     VduseDev *dev;
1243     int ret;
1244
1245     if (!name || vduse_name_is_invalid(name) || !ops ||
1246         !ops->enable_queue || !ops->disable_queue) {
1247         fprintf(stderr, "Invalid parameter for vduse\n");
1248         return NULL;
1249     }
1250
1251     dev = calloc(sizeof(VduseDev), 1);
1252     if (!dev) {
1253         fprintf(stderr, "Failed to allocate vduse device\n");
1254         return NULL;
1255     }
1256
1257     ret = vduse_dev_init(dev, name, num_queues, ops, priv);
1258     if (ret < 0) {
1259         fprintf(stderr, "Failed to init vduse device %s: %s\n",
1260                 name, strerror(-ret));
1261         free(dev);
1262         return NULL;
1263     }
1264
1265     return dev;
1266 }
1267
1268 VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
1269                            uint32_t vendor_id, uint64_t features,
1270                            uint16_t num_queues, uint32_t config_size,
1271                            char *config, const VduseOps *ops, void *priv)
1272 {
1273     VduseDev *dev;
1274     int ret, ctrl_fd;
1275     uint64_t version;
1276     struct vduse_dev_config *dev_config;
1277     size_t size = offsetof(struct vduse_dev_config, config);
1278
1279     if (!name || vduse_name_is_invalid(name) ||
1280         !has_feature(features,  VIRTIO_F_VERSION_1) || !config ||
1281         !config_size || !ops || !ops->enable_queue || !ops->disable_queue) {
1282         fprintf(stderr, "Invalid parameter for vduse\n");
1283         return NULL;
1284     }
1285
1286     dev = calloc(sizeof(VduseDev), 1);
1287     if (!dev) {
1288         fprintf(stderr, "Failed to allocate vduse device\n");
1289         return NULL;
1290     }
1291
1292     ctrl_fd = open("/dev/vduse/control", O_RDWR);
1293     if (ctrl_fd < 0) {
1294         fprintf(stderr, "Failed to open /dev/vduse/control: %s\n",
1295                 strerror(errno));
1296         goto err_ctrl;
1297     }
1298
1299     version = VDUSE_API_VERSION;
1300     if (ioctl(ctrl_fd, VDUSE_SET_API_VERSION, &version)) {
1301         fprintf(stderr, "Failed to set api version %" PRIu64 ": %s\n",
1302                 version, strerror(errno));
1303         goto err_dev;
1304     }
1305
1306     dev_config = calloc(size + config_size, 1);
1307     if (!dev_config) {
1308         fprintf(stderr, "Failed to allocate config space\n");
1309         goto err_dev;
1310     }
1311
1312     assert(!vduse_name_is_invalid(name));
1313     strcpy(dev_config->name, name);
1314     dev_config->device_id = device_id;
1315     dev_config->vendor_id = vendor_id;
1316     dev_config->features = features;
1317     dev_config->vq_num = num_queues;
1318     dev_config->vq_align = VDUSE_VQ_ALIGN;
1319     dev_config->config_size = config_size;
1320     memcpy(dev_config->config, config, config_size);
1321
1322     ret = ioctl(ctrl_fd, VDUSE_CREATE_DEV, dev_config);
1323     free(dev_config);
1324     if (ret && errno != EEXIST) {
1325         fprintf(stderr, "Failed to create vduse device %s: %s\n",
1326                 name, strerror(errno));
1327         goto err_dev;
1328     }
1329     dev->ctrl_fd = ctrl_fd;
1330
1331     ret = vduse_dev_init(dev, name, num_queues, ops, priv);
1332     if (ret < 0) {
1333         fprintf(stderr, "Failed to init vduse device %s: %s\n",
1334                 name, strerror(-ret));
1335         goto err;
1336     }
1337
1338     return dev;
1339 err:
1340     ioctl(ctrl_fd, VDUSE_DESTROY_DEV, name);
1341 err_dev:
1342     close(ctrl_fd);
1343 err_ctrl:
1344     free(dev);
1345
1346     return NULL;
1347 }
1348
1349 int vduse_dev_destroy(VduseDev *dev)
1350 {
1351     size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
1352     int i, ret = 0;
1353
1354     if (dev->log) {
1355         munmap(dev->log, log_size);
1356     }
1357     for (i = 0; i < dev->num_queues; i++) {
1358         free(dev->vqs[i].resubmit_list);
1359     }
1360     free(dev->vqs);
1361     if (dev->fd >= 0) {
1362         close(dev->fd);
1363         dev->fd = -1;
1364     }
1365     if (dev->ctrl_fd >= 0) {
1366         if (ioctl(dev->ctrl_fd, VDUSE_DESTROY_DEV, dev->name)) {
1367             ret = -errno;
1368         }
1369         close(dev->ctrl_fd);
1370         dev->ctrl_fd = -1;
1371     }
1372     free(dev->name);
1373     free(dev);
1374
1375     return ret;
1376 }