qemu/contrib/libvhost-user/libvhost-user.c
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   1/*
   2 * Vhost User library
   3 *
   4 * Copyright IBM, Corp. 2007
   5 * Copyright (c) 2016 Red Hat, Inc.
   6 *
   7 * Authors:
   8 *  Anthony Liguori <aliguori@us.ibm.com>
   9 *  Marc-André Lureau <mlureau@redhat.com>
  10 *  Victor Kaplansky <victork@redhat.com>
  11 *
  12 * This work is licensed under the terms of the GNU GPL, version 2 or
  13 * later.  See the COPYING file in the top-level directory.
  14 */
  15
  16/* this code avoids GLib dependency */
  17#include <stdlib.h>
  18#include <stdio.h>
  19#include <unistd.h>
  20#include <stdarg.h>
  21#include <errno.h>
  22#include <string.h>
  23#include <assert.h>
  24#include <inttypes.h>
  25#include <sys/types.h>
  26#include <sys/socket.h>
  27#include <sys/eventfd.h>
  28#include <sys/mman.h>
  29#include "qemu/compiler.h"
  30
  31#if defined(__linux__)
  32#include <sys/syscall.h>
  33#include <fcntl.h>
  34#include <sys/ioctl.h>
  35#include <linux/vhost.h>
  36
  37#ifdef __NR_userfaultfd
  38#include <linux/userfaultfd.h>
  39#endif
  40
  41#endif
  42
  43#include "qemu/atomic.h"
  44#include "qemu/osdep.h"
  45#include "qemu/memfd.h"
  46
  47#include "libvhost-user.h"
  48
  49/* usually provided by GLib */
  50#ifndef MIN
  51#define MIN(x, y) ({                            \
  52            typeof(x) _min1 = (x);              \
  53            typeof(y) _min2 = (y);              \
  54            (void) (&_min1 == &_min2);          \
  55            _min1 < _min2 ? _min1 : _min2; })
  56#endif
  57
  58/* Round number down to multiple */
  59#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
  60
  61/* Round number up to multiple */
  62#define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
  63
  64/* Align each region to cache line size in inflight buffer */
  65#define INFLIGHT_ALIGNMENT 64
  66
  67/* The version of inflight buffer */
  68#define INFLIGHT_VERSION 1
  69
  70#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
  71
  72/* The version of the protocol we support */
  73#define VHOST_USER_VERSION 1
  74#define LIBVHOST_USER_DEBUG 0
  75
  76#define DPRINT(...)                             \
  77    do {                                        \
  78        if (LIBVHOST_USER_DEBUG) {              \
  79            fprintf(stderr, __VA_ARGS__);        \
  80        }                                       \
  81    } while (0)
  82
  83static inline
  84bool has_feature(uint64_t features, unsigned int fbit)
  85{
  86    assert(fbit < 64);
  87    return !!(features & (1ULL << fbit));
  88}
  89
  90static inline
  91bool vu_has_feature(VuDev *dev,
  92                    unsigned int fbit)
  93{
  94    return has_feature(dev->features, fbit);
  95}
  96
  97static inline bool vu_has_protocol_feature(VuDev *dev, unsigned int fbit)
  98{
  99    return has_feature(dev->protocol_features, fbit);
 100}
 101
 102static const char *
 103vu_request_to_string(unsigned int req)
 104{
 105#define REQ(req) [req] = #req
 106    static const char *vu_request_str[] = {
 107        REQ(VHOST_USER_NONE),
 108        REQ(VHOST_USER_GET_FEATURES),
 109        REQ(VHOST_USER_SET_FEATURES),
 110        REQ(VHOST_USER_SET_OWNER),
 111        REQ(VHOST_USER_RESET_OWNER),
 112        REQ(VHOST_USER_SET_MEM_TABLE),
 113        REQ(VHOST_USER_SET_LOG_BASE),
 114        REQ(VHOST_USER_SET_LOG_FD),
 115        REQ(VHOST_USER_SET_VRING_NUM),
 116        REQ(VHOST_USER_SET_VRING_ADDR),
 117        REQ(VHOST_USER_SET_VRING_BASE),
 118        REQ(VHOST_USER_GET_VRING_BASE),
 119        REQ(VHOST_USER_SET_VRING_KICK),
 120        REQ(VHOST_USER_SET_VRING_CALL),
 121        REQ(VHOST_USER_SET_VRING_ERR),
 122        REQ(VHOST_USER_GET_PROTOCOL_FEATURES),
 123        REQ(VHOST_USER_SET_PROTOCOL_FEATURES),
 124        REQ(VHOST_USER_GET_QUEUE_NUM),
 125        REQ(VHOST_USER_SET_VRING_ENABLE),
 126        REQ(VHOST_USER_SEND_RARP),
 127        REQ(VHOST_USER_NET_SET_MTU),
 128        REQ(VHOST_USER_SET_SLAVE_REQ_FD),
 129        REQ(VHOST_USER_IOTLB_MSG),
 130        REQ(VHOST_USER_SET_VRING_ENDIAN),
 131        REQ(VHOST_USER_GET_CONFIG),
 132        REQ(VHOST_USER_SET_CONFIG),
 133        REQ(VHOST_USER_POSTCOPY_ADVISE),
 134        REQ(VHOST_USER_POSTCOPY_LISTEN),
 135        REQ(VHOST_USER_POSTCOPY_END),
 136        REQ(VHOST_USER_GET_INFLIGHT_FD),
 137        REQ(VHOST_USER_SET_INFLIGHT_FD),
 138        REQ(VHOST_USER_GPU_SET_SOCKET),
 139        REQ(VHOST_USER_MAX),
 140    };
 141#undef REQ
 142
 143    if (req < VHOST_USER_MAX) {
 144        return vu_request_str[req];
 145    } else {
 146        return "unknown";
 147    }
 148}
 149
 150static void
 151vu_panic(VuDev *dev, const char *msg, ...)
 152{
 153    char *buf = NULL;
 154    va_list ap;
 155
 156    va_start(ap, msg);
 157    if (vasprintf(&buf, msg, ap) < 0) {
 158        buf = NULL;
 159    }
 160    va_end(ap);
 161
 162    dev->broken = true;
 163    dev->panic(dev, buf);
 164    free(buf);
 165
 166    /* FIXME: find a way to call virtio_error? */
 167}
 168
 169/* Translate guest physical address to our virtual address.  */
 170void *
 171vu_gpa_to_va(VuDev *dev, uint64_t *plen, uint64_t guest_addr)
 172{
 173    int i;
 174
 175    if (*plen == 0) {
 176        return NULL;
 177    }
 178
 179    /* Find matching memory region.  */
 180    for (i = 0; i < dev->nregions; i++) {
 181        VuDevRegion *r = &dev->regions[i];
 182
 183        if ((guest_addr >= r->gpa) && (guest_addr < (r->gpa + r->size))) {
 184            if ((guest_addr + *plen) > (r->gpa + r->size)) {
 185                *plen = r->gpa + r->size - guest_addr;
 186            }
 187            return (void *)(uintptr_t)
 188                guest_addr - r->gpa + r->mmap_addr + r->mmap_offset;
 189        }
 190    }
 191
 192    return NULL;
 193}
 194
 195/* Translate qemu virtual address to our virtual address.  */
 196static void *
 197qva_to_va(VuDev *dev, uint64_t qemu_addr)
 198{
 199    int i;
 200
 201    /* Find matching memory region.  */
 202    for (i = 0; i < dev->nregions; i++) {
 203        VuDevRegion *r = &dev->regions[i];
 204
 205        if ((qemu_addr >= r->qva) && (qemu_addr < (r->qva + r->size))) {
 206            return (void *)(uintptr_t)
 207                qemu_addr - r->qva + r->mmap_addr + r->mmap_offset;
 208        }
 209    }
 210
 211    return NULL;
 212}
 213
 214static void
 215vmsg_close_fds(VhostUserMsg *vmsg)
 216{
 217    int i;
 218
 219    for (i = 0; i < vmsg->fd_num; i++) {
 220        close(vmsg->fds[i]);
 221    }
 222}
 223
 224/* Set reply payload.u64 and clear request flags and fd_num */
 225static void vmsg_set_reply_u64(VhostUserMsg *vmsg, uint64_t val)
 226{
 227    vmsg->flags = 0; /* defaults will be set by vu_send_reply() */
 228    vmsg->size = sizeof(vmsg->payload.u64);
 229    vmsg->payload.u64 = val;
 230    vmsg->fd_num = 0;
 231}
 232
 233/* A test to see if we have userfault available */
 234static bool
 235have_userfault(void)
 236{
 237#if defined(__linux__) && defined(__NR_userfaultfd) &&\
 238        defined(UFFD_FEATURE_MISSING_SHMEM) &&\
 239        defined(UFFD_FEATURE_MISSING_HUGETLBFS)
 240    /* Now test the kernel we're running on really has the features */
 241    int ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
 242    struct uffdio_api api_struct;
 243    if (ufd < 0) {
 244        return false;
 245    }
 246
 247    api_struct.api = UFFD_API;
 248    api_struct.features = UFFD_FEATURE_MISSING_SHMEM |
 249                          UFFD_FEATURE_MISSING_HUGETLBFS;
 250    if (ioctl(ufd, UFFDIO_API, &api_struct)) {
 251        close(ufd);
 252        return false;
 253    }
 254    close(ufd);
 255    return true;
 256
 257#else
 258    return false;
 259#endif
 260}
 261
 262static bool
 263vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 264{
 265    char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
 266    struct iovec iov = {
 267        .iov_base = (char *)vmsg,
 268        .iov_len = VHOST_USER_HDR_SIZE,
 269    };
 270    struct msghdr msg = {
 271        .msg_iov = &iov,
 272        .msg_iovlen = 1,
 273        .msg_control = control,
 274        .msg_controllen = sizeof(control),
 275    };
 276    size_t fd_size;
 277    struct cmsghdr *cmsg;
 278    int rc;
 279
 280    do {
 281        rc = recvmsg(conn_fd, &msg, 0);
 282    } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
 283
 284    if (rc < 0) {
 285        vu_panic(dev, "Error while recvmsg: %s", strerror(errno));
 286        return false;
 287    }
 288
 289    vmsg->fd_num = 0;
 290    for (cmsg = CMSG_FIRSTHDR(&msg);
 291         cmsg != NULL;
 292         cmsg = CMSG_NXTHDR(&msg, cmsg))
 293    {
 294        if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
 295            fd_size = cmsg->cmsg_len - CMSG_LEN(0);
 296            vmsg->fd_num = fd_size / sizeof(int);
 297            memcpy(vmsg->fds, CMSG_DATA(cmsg), fd_size);
 298            break;
 299        }
 300    }
 301
 302    if (vmsg->size > sizeof(vmsg->payload)) {
 303        vu_panic(dev,
 304                 "Error: too big message request: %d, size: vmsg->size: %u, "
 305                 "while sizeof(vmsg->payload) = %zu\n",
 306                 vmsg->request, vmsg->size, sizeof(vmsg->payload));
 307        goto fail;
 308    }
 309
 310    if (vmsg->size) {
 311        do {
 312            rc = read(conn_fd, &vmsg->payload, vmsg->size);
 313        } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
 314
 315        if (rc <= 0) {
 316            vu_panic(dev, "Error while reading: %s", strerror(errno));
 317            goto fail;
 318        }
 319
 320        assert(rc == vmsg->size);
 321    }
 322
 323    return true;
 324
 325fail:
 326    vmsg_close_fds(vmsg);
 327
 328    return false;
 329}
 330
 331static bool
 332vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 333{
 334    int rc;
 335    uint8_t *p = (uint8_t *)vmsg;
 336    char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
 337    struct iovec iov = {
 338        .iov_base = (char *)vmsg,
 339        .iov_len = VHOST_USER_HDR_SIZE,
 340    };
 341    struct msghdr msg = {
 342        .msg_iov = &iov,
 343        .msg_iovlen = 1,
 344        .msg_control = control,
 345    };
 346    struct cmsghdr *cmsg;
 347
 348    memset(control, 0, sizeof(control));
 349    assert(vmsg->fd_num <= VHOST_MEMORY_MAX_NREGIONS);
 350    if (vmsg->fd_num > 0) {
 351        size_t fdsize = vmsg->fd_num * sizeof(int);
 352        msg.msg_controllen = CMSG_SPACE(fdsize);
 353        cmsg = CMSG_FIRSTHDR(&msg);
 354        cmsg->cmsg_len = CMSG_LEN(fdsize);
 355        cmsg->cmsg_level = SOL_SOCKET;
 356        cmsg->cmsg_type = SCM_RIGHTS;
 357        memcpy(CMSG_DATA(cmsg), vmsg->fds, fdsize);
 358    } else {
 359        msg.msg_controllen = 0;
 360    }
 361
 362    do {
 363        rc = sendmsg(conn_fd, &msg, 0);
 364    } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
 365
 366    if (vmsg->size) {
 367        do {
 368            if (vmsg->data) {
 369                rc = write(conn_fd, vmsg->data, vmsg->size);
 370            } else {
 371                rc = write(conn_fd, p + VHOST_USER_HDR_SIZE, vmsg->size);
 372            }
 373        } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
 374    }
 375
 376    if (rc <= 0) {
 377        vu_panic(dev, "Error while writing: %s", strerror(errno));
 378        return false;
 379    }
 380
 381    return true;
 382}
 383
 384static bool
 385vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 386{
 387    /* Set the version in the flags when sending the reply */
 388    vmsg->flags &= ~VHOST_USER_VERSION_MASK;
 389    vmsg->flags |= VHOST_USER_VERSION;
 390    vmsg->flags |= VHOST_USER_REPLY_MASK;
 391
 392    return vu_message_write(dev, conn_fd, vmsg);
 393}
 394
 395static bool
 396vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
 397{
 398    VhostUserMsg msg_reply;
 399
 400    if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) == 0) {
 401        return true;
 402    }
 403
 404    if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) {
 405        return false;
 406    }
 407
 408    if (msg_reply.request != vmsg->request) {
 409        DPRINT("Received unexpected msg type. Expected %d received %d",
 410               vmsg->request, msg_reply.request);
 411        return false;
 412    }
 413
 414    return msg_reply.payload.u64 == 0;
 415}
 416
 417/* Kick the log_call_fd if required. */
 418static void
 419vu_log_kick(VuDev *dev)
 420{
 421    if (dev->log_call_fd != -1) {
 422        DPRINT("Kicking the QEMU's log...\n");
 423        if (eventfd_write(dev->log_call_fd, 1) < 0) {
 424            vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
 425        }
 426    }
 427}
 428
 429static void
 430vu_log_page(uint8_t *log_table, uint64_t page)
 431{
 432    DPRINT("Logged dirty guest page: %"PRId64"\n", page);
 433    atomic_or(&log_table[page / 8], 1 << (page % 8));
 434}
 435
 436static void
 437vu_log_write(VuDev *dev, uint64_t address, uint64_t length)
 438{
 439    uint64_t page;
 440
 441    if (!(dev->features & (1ULL << VHOST_F_LOG_ALL)) ||
 442        !dev->log_table || !length) {
 443        return;
 444    }
 445
 446    assert(dev->log_size > ((address + length - 1) / VHOST_LOG_PAGE / 8));
 447
 448    page = address / VHOST_LOG_PAGE;
 449    while (page * VHOST_LOG_PAGE < address + length) {
 450        vu_log_page(dev->log_table, page);
 451        page += 1;
 452    }
 453
 454    vu_log_kick(dev);
 455}
 456
 457static void
 458vu_kick_cb(VuDev *dev, int condition, void *data)
 459{
 460    int index = (intptr_t)data;
 461    VuVirtq *vq = &dev->vq[index];
 462    int sock = vq->kick_fd;
 463    eventfd_t kick_data;
 464    ssize_t rc;
 465
 466    rc = eventfd_read(sock, &kick_data);
 467    if (rc == -1) {
 468        vu_panic(dev, "kick eventfd_read(): %s", strerror(errno));
 469        dev->remove_watch(dev, dev->vq[index].kick_fd);
 470    } else {
 471        DPRINT("Got kick_data: %016"PRIx64" handler:%p idx:%d\n",
 472               kick_data, vq->handler, index);
 473        if (vq->handler) {
 474            vq->handler(dev, index);
 475        }
 476    }
 477}
 478
 479static bool
 480vu_get_features_exec(VuDev *dev, VhostUserMsg *vmsg)
 481{
 482    vmsg->payload.u64 =
 483        1ULL << VHOST_F_LOG_ALL |
 484        1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
 485
 486    if (dev->iface->get_features) {
 487        vmsg->payload.u64 |= dev->iface->get_features(dev);
 488    }
 489
 490    vmsg->size = sizeof(vmsg->payload.u64);
 491    vmsg->fd_num = 0;
 492
 493    DPRINT("Sending back to guest u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
 494
 495    return true;
 496}
 497
 498static void
 499vu_set_enable_all_rings(VuDev *dev, bool enabled)
 500{
 501    uint16_t i;
 502
 503    for (i = 0; i < dev->max_queues; i++) {
 504        dev->vq[i].enable = enabled;
 505    }
 506}
 507
 508static bool
 509vu_set_features_exec(VuDev *dev, VhostUserMsg *vmsg)
 510{
 511    DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
 512
 513    dev->features = vmsg->payload.u64;
 514
 515    if (!(dev->features & VHOST_USER_F_PROTOCOL_FEATURES)) {
 516        vu_set_enable_all_rings(dev, true);
 517    }
 518
 519    if (dev->iface->set_features) {
 520        dev->iface->set_features(dev, dev->features);
 521    }
 522
 523    return false;
 524}
 525
 526static bool
 527vu_set_owner_exec(VuDev *dev, VhostUserMsg *vmsg)
 528{
 529    return false;
 530}
 531
 532static void
 533vu_close_log(VuDev *dev)
 534{
 535    if (dev->log_table) {
 536        if (munmap(dev->log_table, dev->log_size) != 0) {
 537            perror("close log munmap() error");
 538        }
 539
 540        dev->log_table = NULL;
 541    }
 542    if (dev->log_call_fd != -1) {
 543        close(dev->log_call_fd);
 544        dev->log_call_fd = -1;
 545    }
 546}
 547
 548static bool
 549vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg)
 550{
 551    vu_set_enable_all_rings(dev, false);
 552
 553    return false;
 554}
 555
 556static bool
 557vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
 558{
 559    int i;
 560    VhostUserMemory m = vmsg->payload.memory, *memory = &m;
 561    dev->nregions = memory->nregions;
 562
 563    DPRINT("Nregions: %d\n", memory->nregions);
 564    for (i = 0; i < dev->nregions; i++) {
 565        void *mmap_addr;
 566        VhostUserMemoryRegion *msg_region = &memory->regions[i];
 567        VuDevRegion *dev_region = &dev->regions[i];
 568
 569        DPRINT("Region %d\n", i);
 570        DPRINT("    guest_phys_addr: 0x%016"PRIx64"\n",
 571               msg_region->guest_phys_addr);
 572        DPRINT("    memory_size:     0x%016"PRIx64"\n",
 573               msg_region->memory_size);
 574        DPRINT("    userspace_addr   0x%016"PRIx64"\n",
 575               msg_region->userspace_addr);
 576        DPRINT("    mmap_offset      0x%016"PRIx64"\n",
 577               msg_region->mmap_offset);
 578
 579        dev_region->gpa = msg_region->guest_phys_addr;
 580        dev_region->size = msg_region->memory_size;
 581        dev_region->qva = msg_region->userspace_addr;
 582        dev_region->mmap_offset = msg_region->mmap_offset;
 583
 584        /* We don't use offset argument of mmap() since the
 585         * mapped address has to be page aligned, and we use huge
 586         * pages.
 587         * In postcopy we're using PROT_NONE here to catch anyone
 588         * accessing it before we userfault
 589         */
 590        mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
 591                         PROT_NONE, MAP_SHARED,
 592                         vmsg->fds[i], 0);
 593
 594        if (mmap_addr == MAP_FAILED) {
 595            vu_panic(dev, "region mmap error: %s", strerror(errno));
 596        } else {
 597            dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
 598            DPRINT("    mmap_addr:       0x%016"PRIx64"\n",
 599                   dev_region->mmap_addr);
 600        }
 601
 602        /* Return the address to QEMU so that it can translate the ufd
 603         * fault addresses back.
 604         */
 605        msg_region->userspace_addr = (uintptr_t)(mmap_addr +
 606                                                 dev_region->mmap_offset);
 607        close(vmsg->fds[i]);
 608    }
 609
 610    /* Send the message back to qemu with the addresses filled in */
 611    vmsg->fd_num = 0;
 612    if (!vu_send_reply(dev, dev->sock, vmsg)) {
 613        vu_panic(dev, "failed to respond to set-mem-table for postcopy");
 614        return false;
 615    }
 616
 617    /* Wait for QEMU to confirm that it's registered the handler for the
 618     * faults.
 619     */
 620    if (!vu_message_read(dev, dev->sock, vmsg) ||
 621        vmsg->size != sizeof(vmsg->payload.u64) ||
 622        vmsg->payload.u64 != 0) {
 623        vu_panic(dev, "failed to receive valid ack for postcopy set-mem-table");
 624        return false;
 625    }
 626
 627    /* OK, now we can go and register the memory and generate faults */
 628    for (i = 0; i < dev->nregions; i++) {
 629        VuDevRegion *dev_region = &dev->regions[i];
 630        int ret;
 631#ifdef UFFDIO_REGISTER
 632        /* We should already have an open ufd. Mark each memory
 633         * range as ufd.
 634         * Discard any mapping we have here; note I can't use MADV_REMOVE
 635         * or fallocate to make the hole since I don't want to lose
 636         * data that's already arrived in the shared process.
 637         * TODO: How to do hugepage
 638         */
 639        ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
 640                      dev_region->size + dev_region->mmap_offset,
 641                      MADV_DONTNEED);
 642        if (ret) {
 643            fprintf(stderr,
 644                    "%s: Failed to madvise(DONTNEED) region %d: %s\n",
 645                    __func__, i, strerror(errno));
 646        }
 647        /* Turn off transparent hugepages so we dont get lose wakeups
 648         * in neighbouring pages.
 649         * TODO: Turn this backon later.
 650         */
 651        ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
 652                      dev_region->size + dev_region->mmap_offset,
 653                      MADV_NOHUGEPAGE);
 654        if (ret) {
 655            /* Note: This can happen legally on kernels that are configured
 656             * without madvise'able hugepages
 657             */
 658            fprintf(stderr,
 659                    "%s: Failed to madvise(NOHUGEPAGE) region %d: %s\n",
 660                    __func__, i, strerror(errno));
 661        }
 662        struct uffdio_register reg_struct;
 663        reg_struct.range.start = (uintptr_t)dev_region->mmap_addr;
 664        reg_struct.range.len = dev_region->size + dev_region->mmap_offset;
 665        reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
 666
 667        if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER, &reg_struct)) {
 668            vu_panic(dev, "%s: Failed to userfault region %d "
 669                          "@%p + size:%zx offset: %zx: (ufd=%d)%s\n",
 670                     __func__, i,
 671                     dev_region->mmap_addr,
 672                     dev_region->size, dev_region->mmap_offset,
 673                     dev->postcopy_ufd, strerror(errno));
 674            return false;
 675        }
 676        if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) {
 677            vu_panic(dev, "%s Region (%d) doesn't support COPY",
 678                     __func__, i);
 679            return false;
 680        }
 681        DPRINT("%s: region %d: Registered userfault for %"
 682               PRIx64 " + %" PRIx64 "\n", __func__, i,
 683               (uint64_t)reg_struct.range.start,
 684               (uint64_t)reg_struct.range.len);
 685        /* Now it's registered we can let the client at it */
 686        if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
 687                     dev_region->size + dev_region->mmap_offset,
 688                     PROT_READ | PROT_WRITE)) {
 689            vu_panic(dev, "failed to mprotect region %d for postcopy (%s)",
 690                     i, strerror(errno));
 691            return false;
 692        }
 693        /* TODO: Stash 'zero' support flags somewhere */
 694#endif
 695    }
 696
 697    return false;
 698}
 699
 700static bool
 701vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
 702{
 703    int i;
 704    VhostUserMemory m = vmsg->payload.memory, *memory = &m;
 705
 706    for (i = 0; i < dev->nregions; i++) {
 707        VuDevRegion *r = &dev->regions[i];
 708        void *m = (void *) (uintptr_t) r->mmap_addr;
 709
 710        if (m) {
 711            munmap(m, r->size + r->mmap_offset);
 712        }
 713    }
 714    dev->nregions = memory->nregions;
 715
 716    if (dev->postcopy_listening) {
 717        return vu_set_mem_table_exec_postcopy(dev, vmsg);
 718    }
 719
 720    DPRINT("Nregions: %d\n", memory->nregions);
 721    for (i = 0; i < dev->nregions; i++) {
 722        void *mmap_addr;
 723        VhostUserMemoryRegion *msg_region = &memory->regions[i];
 724        VuDevRegion *dev_region = &dev->regions[i];
 725
 726        DPRINT("Region %d\n", i);
 727        DPRINT("    guest_phys_addr: 0x%016"PRIx64"\n",
 728               msg_region->guest_phys_addr);
 729        DPRINT("    memory_size:     0x%016"PRIx64"\n",
 730               msg_region->memory_size);
 731        DPRINT("    userspace_addr   0x%016"PRIx64"\n",
 732               msg_region->userspace_addr);
 733        DPRINT("    mmap_offset      0x%016"PRIx64"\n",
 734               msg_region->mmap_offset);
 735
 736        dev_region->gpa = msg_region->guest_phys_addr;
 737        dev_region->size = msg_region->memory_size;
 738        dev_region->qva = msg_region->userspace_addr;
 739        dev_region->mmap_offset = msg_region->mmap_offset;
 740
 741        /* We don't use offset argument of mmap() since the
 742         * mapped address has to be page aligned, and we use huge
 743         * pages.  */
 744        mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
 745                         PROT_READ | PROT_WRITE, MAP_SHARED,
 746                         vmsg->fds[i], 0);
 747
 748        if (mmap_addr == MAP_FAILED) {
 749            vu_panic(dev, "region mmap error: %s", strerror(errno));
 750        } else {
 751            dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
 752            DPRINT("    mmap_addr:       0x%016"PRIx64"\n",
 753                   dev_region->mmap_addr);
 754        }
 755
 756        close(vmsg->fds[i]);
 757    }
 758
 759    return false;
 760}
 761
 762static bool
 763vu_set_log_base_exec(VuDev *dev, VhostUserMsg *vmsg)
 764{
 765    int fd;
 766    uint64_t log_mmap_size, log_mmap_offset;
 767    void *rc;
 768
 769    if (vmsg->fd_num != 1 ||
 770        vmsg->size != sizeof(vmsg->payload.log)) {
 771        vu_panic(dev, "Invalid log_base message");
 772        return true;
 773    }
 774
 775    fd = vmsg->fds[0];
 776    log_mmap_offset = vmsg->payload.log.mmap_offset;
 777    log_mmap_size = vmsg->payload.log.mmap_size;
 778    DPRINT("Log mmap_offset: %"PRId64"\n", log_mmap_offset);
 779    DPRINT("Log mmap_size:   %"PRId64"\n", log_mmap_size);
 780
 781    rc = mmap(0, log_mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
 782              log_mmap_offset);
 783    close(fd);
 784    if (rc == MAP_FAILED) {
 785        perror("log mmap error");
 786    }
 787
 788    if (dev->log_table) {
 789        munmap(dev->log_table, dev->log_size);
 790    }
 791    dev->log_table = rc;
 792    dev->log_size = log_mmap_size;
 793
 794    vmsg->size = sizeof(vmsg->payload.u64);
 795    vmsg->fd_num = 0;
 796
 797    return true;
 798}
 799
 800static bool
 801vu_set_log_fd_exec(VuDev *dev, VhostUserMsg *vmsg)
 802{
 803    if (vmsg->fd_num != 1) {
 804        vu_panic(dev, "Invalid log_fd message");
 805        return false;
 806    }
 807
 808    if (dev->log_call_fd != -1) {
 809        close(dev->log_call_fd);
 810    }
 811    dev->log_call_fd = vmsg->fds[0];
 812    DPRINT("Got log_call_fd: %d\n", vmsg->fds[0]);
 813
 814    return false;
 815}
 816
 817static bool
 818vu_set_vring_num_exec(VuDev *dev, VhostUserMsg *vmsg)
 819{
 820    unsigned int index = vmsg->payload.state.index;
 821    unsigned int num = vmsg->payload.state.num;
 822
 823    DPRINT("State.index: %d\n", index);
 824    DPRINT("State.num:   %d\n", num);
 825    dev->vq[index].vring.num = num;
 826
 827    return false;
 828}
 829
 830static bool
 831vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg)
 832{
 833    struct vhost_vring_addr addr = vmsg->payload.addr, *vra = &addr;
 834    unsigned int index = vra->index;
 835    VuVirtq *vq = &dev->vq[index];
 836
 837    DPRINT("vhost_vring_addr:\n");
 838    DPRINT("    index:  %d\n", vra->index);
 839    DPRINT("    flags:  %d\n", vra->flags);
 840    DPRINT("    desc_user_addr:   0x%016" PRIx64 "\n", vra->desc_user_addr);
 841    DPRINT("    used_user_addr:   0x%016" PRIx64 "\n", vra->used_user_addr);
 842    DPRINT("    avail_user_addr:  0x%016" PRIx64 "\n", vra->avail_user_addr);
 843    DPRINT("    log_guest_addr:   0x%016" PRIx64 "\n", vra->log_guest_addr);
 844
 845    vq->vring.flags = vra->flags;
 846    vq->vring.desc = qva_to_va(dev, vra->desc_user_addr);
 847    vq->vring.used = qva_to_va(dev, vra->used_user_addr);
 848    vq->vring.avail = qva_to_va(dev, vra->avail_user_addr);
 849    vq->vring.log_guest_addr = vra->log_guest_addr;
 850
 851    DPRINT("Setting virtq addresses:\n");
 852    DPRINT("    vring_desc  at %p\n", vq->vring.desc);
 853    DPRINT("    vring_used  at %p\n", vq->vring.used);
 854    DPRINT("    vring_avail at %p\n", vq->vring.avail);
 855
 856    if (!(vq->vring.desc && vq->vring.used && vq->vring.avail)) {
 857        vu_panic(dev, "Invalid vring_addr message");
 858        return false;
 859    }
 860
 861    vq->used_idx = vq->vring.used->idx;
 862
 863    if (vq->last_avail_idx != vq->used_idx) {
 864        bool resume = dev->iface->queue_is_processed_in_order &&
 865            dev->iface->queue_is_processed_in_order(dev, index);
 866
 867        DPRINT("Last avail index != used index: %u != %u%s\n",
 868               vq->last_avail_idx, vq->used_idx,
 869               resume ? ", resuming" : "");
 870
 871        if (resume) {
 872            vq->shadow_avail_idx = vq->last_avail_idx = vq->used_idx;
 873        }
 874    }
 875
 876    return false;
 877}
 878
 879static bool
 880vu_set_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
 881{
 882    unsigned int index = vmsg->payload.state.index;
 883    unsigned int num = vmsg->payload.state.num;
 884
 885    DPRINT("State.index: %d\n", index);
 886    DPRINT("State.num:   %d\n", num);
 887    dev->vq[index].shadow_avail_idx = dev->vq[index].last_avail_idx = num;
 888
 889    return false;
 890}
 891
 892static bool
 893vu_get_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
 894{
 895    unsigned int index = vmsg->payload.state.index;
 896
 897    DPRINT("State.index: %d\n", index);
 898    vmsg->payload.state.num = dev->vq[index].last_avail_idx;
 899    vmsg->size = sizeof(vmsg->payload.state);
 900
 901    dev->vq[index].started = false;
 902    if (dev->iface->queue_set_started) {
 903        dev->iface->queue_set_started(dev, index, false);
 904    }
 905
 906    if (dev->vq[index].call_fd != -1) {
 907        close(dev->vq[index].call_fd);
 908        dev->vq[index].call_fd = -1;
 909    }
 910    if (dev->vq[index].kick_fd != -1) {
 911        dev->remove_watch(dev, dev->vq[index].kick_fd);
 912        close(dev->vq[index].kick_fd);
 913        dev->vq[index].kick_fd = -1;
 914    }
 915
 916    return true;
 917}
 918
 919static bool
 920vu_check_queue_msg_file(VuDev *dev, VhostUserMsg *vmsg)
 921{
 922    int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
 923
 924    if (index >= dev->max_queues) {
 925        vmsg_close_fds(vmsg);
 926        vu_panic(dev, "Invalid queue index: %u", index);
 927        return false;
 928    }
 929
 930    if (vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK ||
 931        vmsg->fd_num != 1) {
 932        vmsg_close_fds(vmsg);
 933        vu_panic(dev, "Invalid fds in request: %d", vmsg->request);
 934        return false;
 935    }
 936
 937    return true;
 938}
 939
 940static int
 941inflight_desc_compare(const void *a, const void *b)
 942{
 943    VuVirtqInflightDesc *desc0 = (VuVirtqInflightDesc *)a,
 944                        *desc1 = (VuVirtqInflightDesc *)b;
 945
 946    if (desc1->counter > desc0->counter &&
 947        (desc1->counter - desc0->counter) < VIRTQUEUE_MAX_SIZE * 2) {
 948        return 1;
 949    }
 950
 951    return -1;
 952}
 953
 954static int
 955vu_check_queue_inflights(VuDev *dev, VuVirtq *vq)
 956{
 957    int i = 0;
 958
 959    if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
 960        return 0;
 961    }
 962
 963    if (unlikely(!vq->inflight)) {
 964        return -1;
 965    }
 966
 967    if (unlikely(!vq->inflight->version)) {
 968        /* initialize the buffer */
 969        vq->inflight->version = INFLIGHT_VERSION;
 970        return 0;
 971    }
 972
 973    vq->used_idx = vq->vring.used->idx;
 974    vq->resubmit_num = 0;
 975    vq->resubmit_list = NULL;
 976    vq->counter = 0;
 977
 978    if (unlikely(vq->inflight->used_idx != vq->used_idx)) {
 979        vq->inflight->desc[vq->inflight->last_batch_head].inflight = 0;
 980
 981        barrier();
 982
 983        vq->inflight->used_idx = vq->used_idx;
 984    }
 985
 986    for (i = 0; i < vq->inflight->desc_num; i++) {
 987        if (vq->inflight->desc[i].inflight == 1) {
 988            vq->inuse++;
 989        }
 990    }
 991
 992    vq->shadow_avail_idx = vq->last_avail_idx = vq->inuse + vq->used_idx;
 993
 994    if (vq->inuse) {
 995        vq->resubmit_list = calloc(vq->inuse, sizeof(VuVirtqInflightDesc));
 996        if (!vq->resubmit_list) {
 997            return -1;
 998        }
 999
1000        for (i = 0; i < vq->inflight->desc_num; i++) {
1001            if (vq->inflight->desc[i].inflight) {
1002                vq->resubmit_list[vq->resubmit_num].index = i;
1003                vq->resubmit_list[vq->resubmit_num].counter =
1004                                        vq->inflight->desc[i].counter;
1005                vq->resubmit_num++;
1006            }
1007        }
1008
1009        if (vq->resubmit_num > 1) {
1010            qsort(vq->resubmit_list, vq->resubmit_num,
1011                  sizeof(VuVirtqInflightDesc), inflight_desc_compare);
1012        }
1013        vq->counter = vq->resubmit_list[0].counter + 1;
1014    }
1015
1016    /* in case of I/O hang after reconnecting */
1017    if (eventfd_write(vq->kick_fd, 1)) {
1018        return -1;
1019    }
1020
1021    return 0;
1022}
1023
1024static bool
1025vu_set_vring_kick_exec(VuDev *dev, VhostUserMsg *vmsg)
1026{
1027    int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
1028
1029    DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1030
1031    if (!vu_check_queue_msg_file(dev, vmsg)) {
1032        return false;
1033    }
1034
1035    if (dev->vq[index].kick_fd != -1) {
1036        dev->remove_watch(dev, dev->vq[index].kick_fd);
1037        close(dev->vq[index].kick_fd);
1038        dev->vq[index].kick_fd = -1;
1039    }
1040
1041    dev->vq[index].kick_fd = vmsg->fds[0];
1042    DPRINT("Got kick_fd: %d for vq: %d\n", vmsg->fds[0], index);
1043
1044    dev->vq[index].started = true;
1045    if (dev->iface->queue_set_started) {
1046        dev->iface->queue_set_started(dev, index, true);
1047    }
1048
1049    if (dev->vq[index].kick_fd != -1 && dev->vq[index].handler) {
1050        dev->set_watch(dev, dev->vq[index].kick_fd, VU_WATCH_IN,
1051                       vu_kick_cb, (void *)(long)index);
1052
1053        DPRINT("Waiting for kicks on fd: %d for vq: %d\n",
1054               dev->vq[index].kick_fd, index);
1055    }
1056
1057    if (vu_check_queue_inflights(dev, &dev->vq[index])) {
1058        vu_panic(dev, "Failed to check inflights for vq: %d\n", index);
1059    }
1060
1061    return false;
1062}
1063
1064void vu_set_queue_handler(VuDev *dev, VuVirtq *vq,
1065                          vu_queue_handler_cb handler)
1066{
1067    int qidx = vq - dev->vq;
1068
1069    vq->handler = handler;
1070    if (vq->kick_fd >= 0) {
1071        if (handler) {
1072            dev->set_watch(dev, vq->kick_fd, VU_WATCH_IN,
1073                           vu_kick_cb, (void *)(long)qidx);
1074        } else {
1075            dev->remove_watch(dev, vq->kick_fd);
1076        }
1077    }
1078}
1079
1080bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
1081                                int size, int offset)
1082{
1083    int qidx = vq - dev->vq;
1084    int fd_num = 0;
1085    VhostUserMsg vmsg = {
1086        .request = VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG,
1087        .flags = VHOST_USER_VERSION | VHOST_USER_NEED_REPLY_MASK,
1088        .size = sizeof(vmsg.payload.area),
1089        .payload.area = {
1090            .u64 = qidx & VHOST_USER_VRING_IDX_MASK,
1091            .size = size,
1092            .offset = offset,
1093        },
1094    };
1095
1096    if (fd == -1) {
1097        vmsg.payload.area.u64 |= VHOST_USER_VRING_NOFD_MASK;
1098    } else {
1099        vmsg.fds[fd_num++] = fd;
1100    }
1101
1102    vmsg.fd_num = fd_num;
1103
1104    if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD)) {
1105        return false;
1106    }
1107
1108    if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
1109        return false;
1110    }
1111
1112    return vu_process_message_reply(dev, &vmsg);
1113}
1114
1115static bool
1116vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg)
1117{
1118    int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
1119
1120    DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1121
1122    if (!vu_check_queue_msg_file(dev, vmsg)) {
1123        return false;
1124    }
1125
1126    if (dev->vq[index].call_fd != -1) {
1127        close(dev->vq[index].call_fd);
1128        dev->vq[index].call_fd = -1;
1129    }
1130
1131    dev->vq[index].call_fd = vmsg->fds[0];
1132
1133    /* in case of I/O hang after reconnecting */
1134    if (eventfd_write(vmsg->fds[0], 1)) {
1135        return -1;
1136    }
1137
1138    DPRINT("Got call_fd: %d for vq: %d\n", vmsg->fds[0], index);
1139
1140    return false;
1141}
1142
1143static bool
1144vu_set_vring_err_exec(VuDev *dev, VhostUserMsg *vmsg)
1145{
1146    int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
1147
1148    DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1149
1150    if (!vu_check_queue_msg_file(dev, vmsg)) {
1151        return false;
1152    }
1153
1154    if (dev->vq[index].err_fd != -1) {
1155        close(dev->vq[index].err_fd);
1156        dev->vq[index].err_fd = -1;
1157    }
1158
1159    dev->vq[index].err_fd = vmsg->fds[0];
1160
1161    return false;
1162}
1163
1164static bool
1165vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
1166{
1167    uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_MQ |
1168                        1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |
1169                        1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ |
1170                        1ULL << VHOST_USER_PROTOCOL_F_HOST_NOTIFIER |
1171                        1ULL << VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD;
1172
1173    if (have_userfault()) {
1174        features |= 1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT;
1175    }
1176
1177    if (dev->iface->get_config && dev->iface->set_config) {
1178        features |= 1ULL << VHOST_USER_PROTOCOL_F_CONFIG;
1179    }
1180
1181    if (dev->iface->get_protocol_features) {
1182        features |= dev->iface->get_protocol_features(dev);
1183    }
1184
1185    vmsg_set_reply_u64(vmsg, features);
1186    return true;
1187}
1188
1189static bool
1190vu_set_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
1191{
1192    uint64_t features = vmsg->payload.u64;
1193
1194    DPRINT("u64: 0x%016"PRIx64"\n", features);
1195
1196    dev->protocol_features = vmsg->payload.u64;
1197
1198    if (dev->iface->set_protocol_features) {
1199        dev->iface->set_protocol_features(dev, features);
1200    }
1201
1202    return false;
1203}
1204
1205static bool
1206vu_get_queue_num_exec(VuDev *dev, VhostUserMsg *vmsg)
1207{
1208    vmsg_set_reply_u64(vmsg, dev->max_queues);
1209    return true;
1210}
1211
1212static bool
1213vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg)
1214{
1215    unsigned int index = vmsg->payload.state.index;
1216    unsigned int enable = vmsg->payload.state.num;
1217
1218    DPRINT("State.index: %d\n", index);
1219    DPRINT("State.enable:   %d\n", enable);
1220
1221    if (index >= dev->max_queues) {
1222        vu_panic(dev, "Invalid vring_enable index: %u", index);
1223        return false;
1224    }
1225
1226    dev->vq[index].enable = enable;
1227    return false;
1228}
1229
1230static bool
1231vu_set_slave_req_fd(VuDev *dev, VhostUserMsg *vmsg)
1232{
1233    if (vmsg->fd_num != 1) {
1234        vu_panic(dev, "Invalid slave_req_fd message (%d fd's)", vmsg->fd_num);
1235        return false;
1236    }
1237
1238    if (dev->slave_fd != -1) {
1239        close(dev->slave_fd);
1240    }
1241    dev->slave_fd = vmsg->fds[0];
1242    DPRINT("Got slave_fd: %d\n", vmsg->fds[0]);
1243
1244    return false;
1245}
1246
1247static bool
1248vu_get_config(VuDev *dev, VhostUserMsg *vmsg)
1249{
1250    int ret = -1;
1251
1252    if (dev->iface->get_config) {
1253        ret = dev->iface->get_config(dev, vmsg->payload.config.region,
1254                                     vmsg->payload.config.size);
1255    }
1256
1257    if (ret) {
1258        /* resize to zero to indicate an error to master */
1259        vmsg->size = 0;
1260    }
1261
1262    return true;
1263}
1264
1265static bool
1266vu_set_config(VuDev *dev, VhostUserMsg *vmsg)
1267{
1268    int ret = -1;
1269
1270    if (dev->iface->set_config) {
1271        ret = dev->iface->set_config(dev, vmsg->payload.config.region,
1272                                     vmsg->payload.config.offset,
1273                                     vmsg->payload.config.size,
1274                                     vmsg->payload.config.flags);
1275        if (ret) {
1276            vu_panic(dev, "Set virtio configuration space failed");
1277        }
1278    }
1279
1280    return false;
1281}
1282
1283static bool
1284vu_set_postcopy_advise(VuDev *dev, VhostUserMsg *vmsg)
1285{
1286    dev->postcopy_ufd = -1;
1287#ifdef UFFDIO_API
1288    struct uffdio_api api_struct;
1289
1290    dev->postcopy_ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
1291    vmsg->size = 0;
1292#endif
1293
1294    if (dev->postcopy_ufd == -1) {
1295        vu_panic(dev, "Userfaultfd not available: %s", strerror(errno));
1296        goto out;
1297    }
1298
1299#ifdef UFFDIO_API
1300    api_struct.api = UFFD_API;
1301    api_struct.features = 0;
1302    if (ioctl(dev->postcopy_ufd, UFFDIO_API, &api_struct)) {
1303        vu_panic(dev, "Failed UFFDIO_API: %s", strerror(errno));
1304        close(dev->postcopy_ufd);
1305        dev->postcopy_ufd = -1;
1306        goto out;
1307    }
1308    /* TODO: Stash feature flags somewhere */
1309#endif
1310
1311out:
1312    /* Return a ufd to the QEMU */
1313    vmsg->fd_num = 1;
1314    vmsg->fds[0] = dev->postcopy_ufd;
1315    return true; /* = send a reply */
1316}
1317
1318static bool
1319vu_set_postcopy_listen(VuDev *dev, VhostUserMsg *vmsg)
1320{
1321    if (dev->nregions) {
1322        vu_panic(dev, "Regions already registered at postcopy-listen");
1323        vmsg_set_reply_u64(vmsg, -1);
1324        return true;
1325    }
1326    dev->postcopy_listening = true;
1327
1328    vmsg_set_reply_u64(vmsg, 0);
1329    return true;
1330}
1331
1332static bool
1333vu_set_postcopy_end(VuDev *dev, VhostUserMsg *vmsg)
1334{
1335    DPRINT("%s: Entry\n", __func__);
1336    dev->postcopy_listening = false;
1337    if (dev->postcopy_ufd > 0) {
1338        close(dev->postcopy_ufd);
1339        dev->postcopy_ufd = -1;
1340        DPRINT("%s: Done close\n", __func__);
1341    }
1342
1343    vmsg_set_reply_u64(vmsg, 0);
1344    DPRINT("%s: exit\n", __func__);
1345    return true;
1346}
1347
1348static inline uint64_t
1349vu_inflight_queue_size(uint16_t queue_size)
1350{
1351    return ALIGN_UP(sizeof(VuDescStateSplit) * queue_size +
1352           sizeof(uint16_t), INFLIGHT_ALIGNMENT);
1353}
1354
1355static bool
1356vu_get_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
1357{
1358    int fd;
1359    void *addr;
1360    uint64_t mmap_size;
1361    uint16_t num_queues, queue_size;
1362
1363    if (vmsg->size != sizeof(vmsg->payload.inflight)) {
1364        vu_panic(dev, "Invalid get_inflight_fd message:%d", vmsg->size);
1365        vmsg->payload.inflight.mmap_size = 0;
1366        return true;
1367    }
1368
1369    num_queues = vmsg->payload.inflight.num_queues;
1370    queue_size = vmsg->payload.inflight.queue_size;
1371
1372    DPRINT("set_inflight_fd num_queues: %"PRId16"\n", num_queues);
1373    DPRINT("set_inflight_fd queue_size: %"PRId16"\n", queue_size);
1374
1375    mmap_size = vu_inflight_queue_size(queue_size) * num_queues;
1376
1377    addr = qemu_memfd_alloc("vhost-inflight", mmap_size,
1378                            F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
1379                            &fd, NULL);
1380
1381    if (!addr) {
1382        vu_panic(dev, "Failed to alloc vhost inflight area");
1383        vmsg->payload.inflight.mmap_size = 0;
1384        return true;
1385    }
1386
1387    memset(addr, 0, mmap_size);
1388
1389    dev->inflight_info.addr = addr;
1390    dev->inflight_info.size = vmsg->payload.inflight.mmap_size = mmap_size;
1391    dev->inflight_info.fd = vmsg->fds[0] = fd;
1392    vmsg->fd_num = 1;
1393    vmsg->payload.inflight.mmap_offset = 0;
1394
1395    DPRINT("send inflight mmap_size: %"PRId64"\n",
1396           vmsg->payload.inflight.mmap_size);
1397    DPRINT("send inflight mmap offset: %"PRId64"\n",
1398           vmsg->payload.inflight.mmap_offset);
1399
1400    return true;
1401}
1402
1403static bool
1404vu_set_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
1405{
1406    int fd, i;
1407    uint64_t mmap_size, mmap_offset;
1408    uint16_t num_queues, queue_size;
1409    void *rc;
1410
1411    if (vmsg->fd_num != 1 ||
1412        vmsg->size != sizeof(vmsg->payload.inflight)) {
1413        vu_panic(dev, "Invalid set_inflight_fd message size:%d fds:%d",
1414                 vmsg->size, vmsg->fd_num);
1415        return false;
1416    }
1417
1418    fd = vmsg->fds[0];
1419    mmap_size = vmsg->payload.inflight.mmap_size;
1420    mmap_offset = vmsg->payload.inflight.mmap_offset;
1421    num_queues = vmsg->payload.inflight.num_queues;
1422    queue_size = vmsg->payload.inflight.queue_size;
1423
1424    DPRINT("set_inflight_fd mmap_size: %"PRId64"\n", mmap_size);
1425    DPRINT("set_inflight_fd mmap_offset: %"PRId64"\n", mmap_offset);
1426    DPRINT("set_inflight_fd num_queues: %"PRId16"\n", num_queues);
1427    DPRINT("set_inflight_fd queue_size: %"PRId16"\n", queue_size);
1428
1429    rc = mmap(0, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED,
1430              fd, mmap_offset);
1431
1432    if (rc == MAP_FAILED) {
1433        vu_panic(dev, "set_inflight_fd mmap error: %s", strerror(errno));
1434        return false;
1435    }
1436
1437    if (dev->inflight_info.fd) {
1438        close(dev->inflight_info.fd);
1439    }
1440
1441    if (dev->inflight_info.addr) {
1442        munmap(dev->inflight_info.addr, dev->inflight_info.size);
1443    }
1444
1445    dev->inflight_info.fd = fd;
1446    dev->inflight_info.addr = rc;
1447    dev->inflight_info.size = mmap_size;
1448
1449    for (i = 0; i < num_queues; i++) {
1450        dev->vq[i].inflight = (VuVirtqInflight *)rc;
1451        dev->vq[i].inflight->desc_num = queue_size;
1452        rc = (void *)((char *)rc + vu_inflight_queue_size(queue_size));
1453    }
1454
1455    return false;
1456}
1457
1458static bool
1459vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
1460{
1461    int do_reply = 0;
1462
1463    /* Print out generic part of the request. */
1464    DPRINT("================ Vhost user message ================\n");
1465    DPRINT("Request: %s (%d)\n", vu_request_to_string(vmsg->request),
1466           vmsg->request);
1467    DPRINT("Flags:   0x%x\n", vmsg->flags);
1468    DPRINT("Size:    %d\n", vmsg->size);
1469
1470    if (vmsg->fd_num) {
1471        int i;
1472        DPRINT("Fds:");
1473        for (i = 0; i < vmsg->fd_num; i++) {
1474            DPRINT(" %d", vmsg->fds[i]);
1475        }
1476        DPRINT("\n");
1477    }
1478
1479    if (dev->iface->process_msg &&
1480        dev->iface->process_msg(dev, vmsg, &do_reply)) {
1481        return do_reply;
1482    }
1483
1484    switch (vmsg->request) {
1485    case VHOST_USER_GET_FEATURES:
1486        return vu_get_features_exec(dev, vmsg);
1487    case VHOST_USER_SET_FEATURES:
1488        return vu_set_features_exec(dev, vmsg);
1489    case VHOST_USER_GET_PROTOCOL_FEATURES:
1490        return vu_get_protocol_features_exec(dev, vmsg);
1491    case VHOST_USER_SET_PROTOCOL_FEATURES:
1492        return vu_set_protocol_features_exec(dev, vmsg);
1493    case VHOST_USER_SET_OWNER:
1494        return vu_set_owner_exec(dev, vmsg);
1495    case VHOST_USER_RESET_OWNER:
1496        return vu_reset_device_exec(dev, vmsg);
1497    case VHOST_USER_SET_MEM_TABLE:
1498        return vu_set_mem_table_exec(dev, vmsg);
1499    case VHOST_USER_SET_LOG_BASE:
1500        return vu_set_log_base_exec(dev, vmsg);
1501    case VHOST_USER_SET_LOG_FD:
1502        return vu_set_log_fd_exec(dev, vmsg);
1503    case VHOST_USER_SET_VRING_NUM:
1504        return vu_set_vring_num_exec(dev, vmsg);
1505    case VHOST_USER_SET_VRING_ADDR:
1506        return vu_set_vring_addr_exec(dev, vmsg);
1507    case VHOST_USER_SET_VRING_BASE:
1508        return vu_set_vring_base_exec(dev, vmsg);
1509    case VHOST_USER_GET_VRING_BASE:
1510        return vu_get_vring_base_exec(dev, vmsg);
1511    case VHOST_USER_SET_VRING_KICK:
1512        return vu_set_vring_kick_exec(dev, vmsg);
1513    case VHOST_USER_SET_VRING_CALL:
1514        return vu_set_vring_call_exec(dev, vmsg);
1515    case VHOST_USER_SET_VRING_ERR:
1516        return vu_set_vring_err_exec(dev, vmsg);
1517    case VHOST_USER_GET_QUEUE_NUM:
1518        return vu_get_queue_num_exec(dev, vmsg);
1519    case VHOST_USER_SET_VRING_ENABLE:
1520        return vu_set_vring_enable_exec(dev, vmsg);
1521    case VHOST_USER_SET_SLAVE_REQ_FD:
1522        return vu_set_slave_req_fd(dev, vmsg);
1523    case VHOST_USER_GET_CONFIG:
1524        return vu_get_config(dev, vmsg);
1525    case VHOST_USER_SET_CONFIG:
1526        return vu_set_config(dev, vmsg);
1527    case VHOST_USER_NONE:
1528        /* if you need processing before exit, override iface->process_msg */
1529        exit(0);
1530    case VHOST_USER_POSTCOPY_ADVISE:
1531        return vu_set_postcopy_advise(dev, vmsg);
1532    case VHOST_USER_POSTCOPY_LISTEN:
1533        return vu_set_postcopy_listen(dev, vmsg);
1534    case VHOST_USER_POSTCOPY_END:
1535        return vu_set_postcopy_end(dev, vmsg);
1536    case VHOST_USER_GET_INFLIGHT_FD:
1537        return vu_get_inflight_fd(dev, vmsg);
1538    case VHOST_USER_SET_INFLIGHT_FD:
1539        return vu_set_inflight_fd(dev, vmsg);
1540    default:
1541        vmsg_close_fds(vmsg);
1542        vu_panic(dev, "Unhandled request: %d", vmsg->request);
1543    }
1544
1545    return false;
1546}
1547
1548bool
1549vu_dispatch(VuDev *dev)
1550{
1551    VhostUserMsg vmsg = { 0, };
1552    int reply_requested;
1553    bool success = false;
1554
1555    if (!vu_message_read(dev, dev->sock, &vmsg)) {
1556        goto end;
1557    }
1558
1559    reply_requested = vu_process_message(dev, &vmsg);
1560    if (!reply_requested) {
1561        success = true;
1562        goto end;
1563    }
1564
1565    if (!vu_send_reply(dev, dev->sock, &vmsg)) {
1566        goto end;
1567    }
1568
1569    success = true;
1570
1571end:
1572    free(vmsg.data);
1573    return success;
1574}
1575
1576void
1577vu_deinit(VuDev *dev)
1578{
1579    int i;
1580
1581    for (i = 0; i < dev->nregions; i++) {
1582        VuDevRegion *r = &dev->regions[i];
1583        void *m = (void *) (uintptr_t) r->mmap_addr;
1584        if (m != MAP_FAILED) {
1585            munmap(m, r->size + r->mmap_offset);
1586        }
1587    }
1588    dev->nregions = 0;
1589
1590    for (i = 0; i < dev->max_queues; i++) {
1591        VuVirtq *vq = &dev->vq[i];
1592
1593        if (vq->call_fd != -1) {
1594            close(vq->call_fd);
1595            vq->call_fd = -1;
1596        }
1597
1598        if (vq->kick_fd != -1) {
1599            close(vq->kick_fd);
1600            vq->kick_fd = -1;
1601        }
1602
1603        if (vq->err_fd != -1) {
1604            close(vq->err_fd);
1605            vq->err_fd = -1;
1606        }
1607
1608        if (vq->resubmit_list) {
1609            free(vq->resubmit_list);
1610            vq->resubmit_list = NULL;
1611        }
1612
1613        vq->inflight = NULL;
1614    }
1615
1616    if (dev->inflight_info.addr) {
1617        munmap(dev->inflight_info.addr, dev->inflight_info.size);
1618        dev->inflight_info.addr = NULL;
1619    }
1620
1621    if (dev->inflight_info.fd > 0) {
1622        close(dev->inflight_info.fd);
1623        dev->inflight_info.fd = -1;
1624    }
1625
1626    vu_close_log(dev);
1627    if (dev->slave_fd != -1) {
1628        close(dev->slave_fd);
1629        dev->slave_fd = -1;
1630    }
1631
1632    if (dev->sock != -1) {
1633        close(dev->sock);
1634    }
1635
1636    free(dev->vq);
1637    dev->vq = NULL;
1638}
1639
1640bool
1641vu_init(VuDev *dev,
1642        uint16_t max_queues,
1643        int socket,
1644        vu_panic_cb panic,
1645        vu_set_watch_cb set_watch,
1646        vu_remove_watch_cb remove_watch,
1647        const VuDevIface *iface)
1648{
1649    uint16_t i;
1650
1651    assert(max_queues > 0);
1652    assert(socket >= 0);
1653    assert(set_watch);
1654    assert(remove_watch);
1655    assert(iface);
1656    assert(panic);
1657
1658    memset(dev, 0, sizeof(*dev));
1659
1660    dev->sock = socket;
1661    dev->panic = panic;
1662    dev->set_watch = set_watch;
1663    dev->remove_watch = remove_watch;
1664    dev->iface = iface;
1665    dev->log_call_fd = -1;
1666    dev->slave_fd = -1;
1667    dev->max_queues = max_queues;
1668
1669    dev->vq = malloc(max_queues * sizeof(dev->vq[0]));
1670    if (!dev->vq) {
1671        DPRINT("%s: failed to malloc virtqueues\n", __func__);
1672        return false;
1673    }
1674
1675    for (i = 0; i < max_queues; i++) {
1676        dev->vq[i] = (VuVirtq) {
1677            .call_fd = -1, .kick_fd = -1, .err_fd = -1,
1678            .notification = true,
1679        };
1680    }
1681
1682    return true;
1683}
1684
1685VuVirtq *
1686vu_get_queue(VuDev *dev, int qidx)
1687{
1688    assert(qidx < dev->max_queues);
1689    return &dev->vq[qidx];
1690}
1691
1692bool
1693vu_queue_enabled(VuDev *dev, VuVirtq *vq)
1694{
1695    return vq->enable;
1696}
1697
1698bool
1699vu_queue_started(const VuDev *dev, const VuVirtq *vq)
1700{
1701    return vq->started;
1702}
1703
1704static inline uint16_t
1705vring_avail_flags(VuVirtq *vq)
1706{
1707    return vq->vring.avail->flags;
1708}
1709
1710static inline uint16_t
1711vring_avail_idx(VuVirtq *vq)
1712{
1713    vq->shadow_avail_idx = vq->vring.avail->idx;
1714
1715    return vq->shadow_avail_idx;
1716}
1717
1718static inline uint16_t
1719vring_avail_ring(VuVirtq *vq, int i)
1720{
1721    return vq->vring.avail->ring[i];
1722}
1723
1724static inline uint16_t
1725vring_get_used_event(VuVirtq *vq)
1726{
1727    return vring_avail_ring(vq, vq->vring.num);
1728}
1729
1730static int
1731virtqueue_num_heads(VuDev *dev, VuVirtq *vq, unsigned int idx)
1732{
1733    uint16_t num_heads = vring_avail_idx(vq) - idx;
1734
1735    /* Check it isn't doing very strange things with descriptor numbers. */
1736    if (num_heads > vq->vring.num) {
1737        vu_panic(dev, "Guest moved used index from %u to %u",
1738                 idx, vq->shadow_avail_idx);
1739        return -1;
1740    }
1741    if (num_heads) {
1742        /* On success, callers read a descriptor at vq->last_avail_idx.
1743         * Make sure descriptor read does not bypass avail index read. */
1744        smp_rmb();
1745    }
1746
1747    return num_heads;
1748}
1749
1750static bool
1751virtqueue_get_head(VuDev *dev, VuVirtq *vq,
1752                   unsigned int idx, unsigned int *head)
1753{
1754    /* Grab the next descriptor number they're advertising, and increment
1755     * the index we've seen. */
1756    *head = vring_avail_ring(vq, idx % vq->vring.num);
1757
1758    /* If their number is silly, that's a fatal mistake. */
1759    if (*head >= vq->vring.num) {
1760        vu_panic(dev, "Guest says index %u is available", head);
1761        return false;
1762    }
1763
1764    return true;
1765}
1766
1767static int
1768virtqueue_read_indirect_desc(VuDev *dev, struct vring_desc *desc,
1769                             uint64_t addr, size_t len)
1770{
1771    struct vring_desc *ori_desc;
1772    uint64_t read_len;
1773
1774    if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc))) {
1775        return -1;
1776    }
1777
1778    if (len == 0) {
1779        return -1;
1780    }
1781
1782    while (len) {
1783        read_len = len;
1784        ori_desc = vu_gpa_to_va(dev, &read_len, addr);
1785        if (!ori_desc) {
1786            return -1;
1787        }
1788
1789        memcpy(desc, ori_desc, read_len);
1790        len -= read_len;
1791        addr += read_len;
1792        desc += read_len;
1793    }
1794
1795    return 0;
1796}
1797
1798enum {
1799    VIRTQUEUE_READ_DESC_ERROR = -1,
1800    VIRTQUEUE_READ_DESC_DONE = 0,   /* end of chain */
1801    VIRTQUEUE_READ_DESC_MORE = 1,   /* more buffers in chain */
1802};
1803
1804static int
1805virtqueue_read_next_desc(VuDev *dev, struct vring_desc *desc,
1806                         int i, unsigned int max, unsigned int *next)
1807{
1808    /* If this descriptor says it doesn't chain, we're done. */
1809    if (!(desc[i].flags & VRING_DESC_F_NEXT)) {
1810        return VIRTQUEUE_READ_DESC_DONE;
1811    }
1812
1813    /* Check they're not leading us off end of descriptors. */
1814    *next = desc[i].next;
1815    /* Make sure compiler knows to grab that: we don't want it changing! */
1816    smp_wmb();
1817
1818    if (*next >= max) {
1819        vu_panic(dev, "Desc next is %u", next);
1820        return VIRTQUEUE_READ_DESC_ERROR;
1821    }
1822
1823    return VIRTQUEUE_READ_DESC_MORE;
1824}
1825
1826void
1827vu_queue_get_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int *in_bytes,
1828                         unsigned int *out_bytes,
1829                         unsigned max_in_bytes, unsigned max_out_bytes)
1830{
1831    unsigned int idx;
1832    unsigned int total_bufs, in_total, out_total;
1833    int rc;
1834
1835    idx = vq->last_avail_idx;
1836
1837    total_bufs = in_total = out_total = 0;
1838    if (unlikely(dev->broken) ||
1839        unlikely(!vq->vring.avail)) {
1840        goto done;
1841    }
1842
1843    while ((rc = virtqueue_num_heads(dev, vq, idx)) > 0) {
1844        unsigned int max, desc_len, num_bufs, indirect = 0;
1845        uint64_t desc_addr, read_len;
1846        struct vring_desc *desc;
1847        struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
1848        unsigned int i;
1849
1850        max = vq->vring.num;
1851        num_bufs = total_bufs;
1852        if (!virtqueue_get_head(dev, vq, idx++, &i)) {
1853            goto err;
1854        }
1855        desc = vq->vring.desc;
1856
1857        if (desc[i].flags & VRING_DESC_F_INDIRECT) {
1858            if (desc[i].len % sizeof(struct vring_desc)) {
1859                vu_panic(dev, "Invalid size for indirect buffer table");
1860                goto err;
1861            }
1862
1863            /* If we've got too many, that implies a descriptor loop. */
1864            if (num_bufs >= max) {
1865                vu_panic(dev, "Looped descriptor");
1866                goto err;
1867            }
1868
1869            /* loop over the indirect descriptor table */
1870            indirect = 1;
1871            desc_addr = desc[i].addr;
1872            desc_len = desc[i].len;
1873            max = desc_len / sizeof(struct vring_desc);
1874            read_len = desc_len;
1875            desc = vu_gpa_to_va(dev, &read_len, desc_addr);
1876            if (unlikely(desc && read_len != desc_len)) {
1877                /* Failed to use zero copy */
1878                desc = NULL;
1879                if (!virtqueue_read_indirect_desc(dev, desc_buf,
1880                                                  desc_addr,
1881                                                  desc_len)) {
1882                    desc = desc_buf;
1883                }
1884            }
1885            if (!desc) {
1886                vu_panic(dev, "Invalid indirect buffer table");
1887                goto err;
1888            }
1889            num_bufs = i = 0;
1890        }
1891
1892        do {
1893            /* If we've got too many, that implies a descriptor loop. */
1894            if (++num_bufs > max) {
1895                vu_panic(dev, "Looped descriptor");
1896                goto err;
1897            }
1898
1899            if (desc[i].flags & VRING_DESC_F_WRITE) {
1900                in_total += desc[i].len;
1901            } else {
1902                out_total += desc[i].len;
1903            }
1904            if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1905                goto done;
1906            }
1907            rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
1908        } while (rc == VIRTQUEUE_READ_DESC_MORE);
1909
1910        if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1911            goto err;
1912        }
1913
1914        if (!indirect) {
1915            total_bufs = num_bufs;
1916        } else {
1917            total_bufs++;
1918        }
1919    }
1920    if (rc < 0) {
1921        goto err;
1922    }
1923done:
1924    if (in_bytes) {
1925        *in_bytes = in_total;
1926    }
1927    if (out_bytes) {
1928        *out_bytes = out_total;
1929    }
1930    return;
1931
1932err:
1933    in_total = out_total = 0;
1934    goto done;
1935}
1936
1937bool
1938vu_queue_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int in_bytes,
1939                     unsigned int out_bytes)
1940{
1941    unsigned int in_total, out_total;
1942
1943    vu_queue_get_avail_bytes(dev, vq, &in_total, &out_total,
1944                             in_bytes, out_bytes);
1945
1946    return in_bytes <= in_total && out_bytes <= out_total;
1947}
1948
1949/* Fetch avail_idx from VQ memory only when we really need to know if
1950 * guest has added some buffers. */
1951bool
1952vu_queue_empty(VuDev *dev, VuVirtq *vq)
1953{
1954    if (unlikely(dev->broken) ||
1955        unlikely(!vq->vring.avail)) {
1956        return true;
1957    }
1958
1959    if (vq->shadow_avail_idx != vq->last_avail_idx) {
1960        return false;
1961    }
1962
1963    return vring_avail_idx(vq) == vq->last_avail_idx;
1964}
1965
1966static bool
1967vring_notify(VuDev *dev, VuVirtq *vq)
1968{
1969    uint16_t old, new;
1970    bool v;
1971
1972    /* We need to expose used array entries before checking used event. */
1973    smp_mb();
1974
1975    /* Always notify when queue is empty (when feature acknowledge) */
1976    if (vu_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
1977        !vq->inuse && vu_queue_empty(dev, vq)) {
1978        return true;
1979    }
1980
1981    if (!vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
1982        return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
1983    }
1984
1985    v = vq->signalled_used_valid;
1986    vq->signalled_used_valid = true;
1987    old = vq->signalled_used;
1988    new = vq->signalled_used = vq->used_idx;
1989    return !v || vring_need_event(vring_get_used_event(vq), new, old);
1990}
1991
1992void
1993vu_queue_notify(VuDev *dev, VuVirtq *vq)
1994{
1995    if (unlikely(dev->broken) ||
1996        unlikely(!vq->vring.avail)) {
1997        return;
1998    }
1999
2000    if (!vring_notify(dev, vq)) {
2001        DPRINT("skipped notify...\n");
2002        return;
2003    }
2004
2005    if (eventfd_write(vq->call_fd, 1) < 0) {
2006        vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
2007    }
2008}
2009
2010static inline void
2011vring_used_flags_set_bit(VuVirtq *vq, int mask)
2012{
2013    uint16_t *flags;
2014
2015    flags = (uint16_t *)((char*)vq->vring.used +
2016                         offsetof(struct vring_used, flags));
2017    *flags |= mask;
2018}
2019
2020static inline void
2021vring_used_flags_unset_bit(VuVirtq *vq, int mask)
2022{
2023    uint16_t *flags;
2024
2025    flags = (uint16_t *)((char*)vq->vring.used +
2026                         offsetof(struct vring_used, flags));
2027    *flags &= ~mask;
2028}
2029
2030static inline void
2031vring_set_avail_event(VuVirtq *vq, uint16_t val)
2032{
2033    if (!vq->notification) {
2034        return;
2035    }
2036
2037    *((uint16_t *) &vq->vring.used->ring[vq->vring.num]) = val;
2038}
2039
2040void
2041vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int enable)
2042{
2043    vq->notification = enable;
2044    if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
2045        vring_set_avail_event(vq, vring_avail_idx(vq));
2046    } else if (enable) {
2047        vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
2048    } else {
2049        vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
2050    }
2051    if (enable) {
2052        /* Expose avail event/used flags before caller checks the avail idx. */
2053        smp_mb();
2054    }
2055}
2056
2057static void
2058virtqueue_map_desc(VuDev *dev,
2059                   unsigned int *p_num_sg, struct iovec *iov,
2060                   unsigned int max_num_sg, bool is_write,
2061                   uint64_t pa, size_t sz)
2062{
2063    unsigned num_sg = *p_num_sg;
2064
2065    assert(num_sg <= max_num_sg);
2066
2067    if (!sz) {
2068        vu_panic(dev, "virtio: zero sized buffers are not allowed");
2069        return;
2070    }
2071
2072    while (sz) {
2073        uint64_t len = sz;
2074
2075        if (num_sg == max_num_sg) {
2076            vu_panic(dev, "virtio: too many descriptors in indirect table");
2077            return;
2078        }
2079
2080        iov[num_sg].iov_base = vu_gpa_to_va(dev, &len, pa);
2081        if (iov[num_sg].iov_base == NULL) {
2082            vu_panic(dev, "virtio: invalid address for buffers");
2083            return;
2084        }
2085        iov[num_sg].iov_len = len;
2086        num_sg++;
2087        sz -= len;
2088        pa += len;
2089    }
2090
2091    *p_num_sg = num_sg;
2092}
2093
2094static void *
2095virtqueue_alloc_element(size_t sz,
2096                                     unsigned out_num, unsigned in_num)
2097{
2098    VuVirtqElement *elem;
2099    size_t in_sg_ofs = ALIGN_UP(sz, __alignof__(elem->in_sg[0]));
2100    size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
2101    size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
2102
2103    assert(sz >= sizeof(VuVirtqElement));
2104    elem = malloc(out_sg_end);
2105    elem->out_num = out_num;
2106    elem->in_num = in_num;
2107    elem->in_sg = (void *)elem + in_sg_ofs;
2108    elem->out_sg = (void *)elem + out_sg_ofs;
2109    return elem;
2110}
2111
2112static void *
2113vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int idx, size_t sz)
2114{
2115    struct vring_desc *desc = vq->vring.desc;
2116    uint64_t desc_addr, read_len;
2117    unsigned int desc_len;
2118    unsigned int max = vq->vring.num;
2119    unsigned int i = idx;
2120    VuVirtqElement *elem;
2121    unsigned int out_num = 0, in_num = 0;
2122    struct iovec iov[VIRTQUEUE_MAX_SIZE];
2123    struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
2124    int rc;
2125
2126    if (desc[i].flags & VRING_DESC_F_INDIRECT) {
2127        if (desc[i].len % sizeof(struct vring_desc)) {
2128            vu_panic(dev, "Invalid size for indirect buffer table");
2129        }
2130
2131        /* loop over the indirect descriptor table */
2132        desc_addr = desc[i].addr;
2133        desc_len = desc[i].len;
2134        max = desc_len / sizeof(struct vring_desc);
2135        read_len = desc_len;
2136        desc = vu_gpa_to_va(dev, &read_len, desc_addr);
2137        if (unlikely(desc && read_len != desc_len)) {
2138            /* Failed to use zero copy */
2139            desc = NULL;
2140            if (!virtqueue_read_indirect_desc(dev, desc_buf,
2141                                              desc_addr,
2142                                              desc_len)) {
2143                desc = desc_buf;
2144            }
2145        }
2146        if (!desc) {
2147            vu_panic(dev, "Invalid indirect buffer table");
2148            return NULL;
2149        }
2150        i = 0;
2151    }
2152
2153    /* Collect all the descriptors */
2154    do {
2155        if (desc[i].flags & VRING_DESC_F_WRITE) {
2156            virtqueue_map_desc(dev, &in_num, iov + out_num,
2157                               VIRTQUEUE_MAX_SIZE - out_num, true,
2158                               desc[i].addr, desc[i].len);
2159        } else {
2160            if (in_num) {
2161                vu_panic(dev, "Incorrect order for descriptors");
2162                return NULL;
2163            }
2164            virtqueue_map_desc(dev, &out_num, iov,
2165                               VIRTQUEUE_MAX_SIZE, false,
2166                               desc[i].addr, desc[i].len);
2167        }
2168
2169        /* If we've got too many, that implies a descriptor loop. */
2170        if ((in_num + out_num) > max) {
2171            vu_panic(dev, "Looped descriptor");
2172        }
2173        rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
2174    } while (rc == VIRTQUEUE_READ_DESC_MORE);
2175
2176    if (rc == VIRTQUEUE_READ_DESC_ERROR) {
2177        vu_panic(dev, "read descriptor error");
2178        return NULL;
2179    }
2180
2181    /* Now copy what we have collected and mapped */
2182    elem = virtqueue_alloc_element(sz, out_num, in_num);
2183    elem->index = idx;
2184    for (i = 0; i < out_num; i++) {
2185        elem->out_sg[i] = iov[i];
2186    }
2187    for (i = 0; i < in_num; i++) {
2188        elem->in_sg[i] = iov[out_num + i];
2189    }
2190
2191    return elem;
2192}
2193
2194static int
2195vu_queue_inflight_get(VuDev *dev, VuVirtq *vq, int desc_idx)
2196{
2197    if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
2198        return 0;
2199    }
2200
2201    if (unlikely(!vq->inflight)) {
2202        return -1;
2203    }
2204
2205    vq->inflight->desc[desc_idx].counter = vq->counter++;
2206    vq->inflight->desc[desc_idx].inflight = 1;
2207
2208    return 0;
2209}
2210
2211static int
2212vu_queue_inflight_pre_put(VuDev *dev, VuVirtq *vq, int desc_idx)
2213{
2214    if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
2215        return 0;
2216    }
2217
2218    if (unlikely(!vq->inflight)) {
2219        return -1;
2220    }
2221
2222    vq->inflight->last_batch_head = desc_idx;
2223
2224    return 0;
2225}
2226
2227static int
2228vu_queue_inflight_post_put(VuDev *dev, VuVirtq *vq, int desc_idx)
2229{
2230    if (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
2231        return 0;
2232    }
2233
2234    if (unlikely(!vq->inflight)) {
2235        return -1;
2236    }
2237
2238    barrier();
2239
2240    vq->inflight->desc[desc_idx].inflight = 0;
2241
2242    barrier();
2243
2244    vq->inflight->used_idx = vq->used_idx;
2245
2246    return 0;
2247}
2248
2249void *
2250vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
2251{
2252    int i;
2253    unsigned int head;
2254    VuVirtqElement *elem;
2255
2256    if (unlikely(dev->broken) ||
2257        unlikely(!vq->vring.avail)) {
2258        return NULL;
2259    }
2260
2261    if (unlikely(vq->resubmit_list && vq->resubmit_num > 0)) {
2262        i = (--vq->resubmit_num);
2263        elem = vu_queue_map_desc(dev, vq, vq->resubmit_list[i].index, sz);
2264
2265        if (!vq->resubmit_num) {
2266            free(vq->resubmit_list);
2267            vq->resubmit_list = NULL;
2268        }
2269
2270        return elem;
2271    }
2272
2273    if (vu_queue_empty(dev, vq)) {
2274        return NULL;
2275    }
2276    /*
2277     * Needed after virtio_queue_empty(), see comment in
2278     * virtqueue_num_heads().
2279     */
2280    smp_rmb();
2281
2282    if (vq->inuse >= vq->vring.num) {
2283        vu_panic(dev, "Virtqueue size exceeded");
2284        return NULL;
2285    }
2286
2287    if (!virtqueue_get_head(dev, vq, vq->last_avail_idx++, &head)) {
2288        return NULL;
2289    }
2290
2291    if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
2292        vring_set_avail_event(vq, vq->last_avail_idx);
2293    }
2294
2295    elem = vu_queue_map_desc(dev, vq, head, sz);
2296
2297    if (!elem) {
2298        return NULL;
2299    }
2300
2301    vq->inuse++;
2302
2303    vu_queue_inflight_get(dev, vq, head);
2304
2305    return elem;
2306}
2307
2308static void
2309vu_queue_detach_element(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem,
2310                        size_t len)
2311{
2312    vq->inuse--;
2313    /* unmap, when DMA support is added */
2314}
2315
2316void
2317vu_queue_unpop(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem,
2318               size_t len)
2319{
2320    vq->last_avail_idx--;
2321    vu_queue_detach_element(dev, vq, elem, len);
2322}
2323
2324bool
2325vu_queue_rewind(VuDev *dev, VuVirtq *vq, unsigned int num)
2326{
2327    if (num > vq->inuse) {
2328        return false;
2329    }
2330    vq->last_avail_idx -= num;
2331    vq->inuse -= num;
2332    return true;
2333}
2334
2335static inline
2336void vring_used_write(VuDev *dev, VuVirtq *vq,
2337                      struct vring_used_elem *uelem, int i)
2338{
2339    struct vring_used *used = vq->vring.used;
2340
2341    used->ring[i] = *uelem;
2342    vu_log_write(dev, vq->vring.log_guest_addr +
2343                 offsetof(struct vring_used, ring[i]),
2344                 sizeof(used->ring[i]));
2345}
2346
2347
2348static void
2349vu_log_queue_fill(VuDev *dev, VuVirtq *vq,
2350                  const VuVirtqElement *elem,
2351                  unsigned int len)
2352{
2353    struct vring_desc *desc = vq->vring.desc;
2354    unsigned int i, max, min, desc_len;
2355    uint64_t desc_addr, read_len;
2356    struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
2357    unsigned num_bufs = 0;
2358
2359    max = vq->vring.num;
2360    i = elem->index;
2361
2362    if (desc[i].flags & VRING_DESC_F_INDIRECT) {
2363        if (desc[i].len % sizeof(struct vring_desc)) {
2364            vu_panic(dev, "Invalid size for indirect buffer table");
2365        }
2366
2367        /* loop over the indirect descriptor table */
2368        desc_addr = desc[i].addr;
2369        desc_len = desc[i].len;
2370        max = desc_len / sizeof(struct vring_desc);
2371        read_len = desc_len;
2372        desc = vu_gpa_to_va(dev, &read_len, desc_addr);
2373        if (unlikely(desc && read_len != desc_len)) {
2374            /* Failed to use zero copy */
2375            desc = NULL;
2376            if (!virtqueue_read_indirect_desc(dev, desc_buf,
2377                                              desc_addr,
2378                                              desc_len)) {
2379                desc = desc_buf;
2380            }
2381        }
2382        if (!desc) {
2383            vu_panic(dev, "Invalid indirect buffer table");
2384            return;
2385        }
2386        i = 0;
2387    }
2388
2389    do {
2390        if (++num_bufs > max) {
2391            vu_panic(dev, "Looped descriptor");
2392            return;
2393        }
2394
2395        if (desc[i].flags & VRING_DESC_F_WRITE) {
2396            min = MIN(desc[i].len, len);
2397            vu_log_write(dev, desc[i].addr, min);
2398            len -= min;
2399        }
2400
2401    } while (len > 0 &&
2402             (virtqueue_read_next_desc(dev, desc, i, max, &i)
2403              == VIRTQUEUE_READ_DESC_MORE));
2404}
2405
2406void
2407vu_queue_fill(VuDev *dev, VuVirtq *vq,
2408              const VuVirtqElement *elem,
2409              unsigned int len, unsigned int idx)
2410{
2411    struct vring_used_elem uelem;
2412
2413    if (unlikely(dev->broken) ||
2414        unlikely(!vq->vring.avail)) {
2415        return;
2416    }
2417
2418    vu_log_queue_fill(dev, vq, elem, len);
2419
2420    idx = (idx + vq->used_idx) % vq->vring.num;
2421
2422    uelem.id = elem->index;
2423    uelem.len = len;
2424    vring_used_write(dev, vq, &uelem, idx);
2425}
2426
2427static inline
2428void vring_used_idx_set(VuDev *dev, VuVirtq *vq, uint16_t val)
2429{
2430    vq->vring.used->idx = val;
2431    vu_log_write(dev,
2432                 vq->vring.log_guest_addr + offsetof(struct vring_used, idx),
2433                 sizeof(vq->vring.used->idx));
2434
2435    vq->used_idx = val;
2436}
2437
2438void
2439vu_queue_flush(VuDev *dev, VuVirtq *vq, unsigned int count)
2440{
2441    uint16_t old, new;
2442
2443    if (unlikely(dev->broken) ||
2444        unlikely(!vq->vring.avail)) {
2445        return;
2446    }
2447
2448    /* Make sure buffer is written before we update index. */
2449    smp_wmb();
2450
2451    old = vq->used_idx;
2452    new = old + count;
2453    vring_used_idx_set(dev, vq, new);
2454    vq->inuse -= count;
2455    if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) {
2456        vq->signalled_used_valid = false;
2457    }
2458}
2459
2460void
2461vu_queue_push(VuDev *dev, VuVirtq *vq,
2462              const VuVirtqElement *elem, unsigned int len)
2463{
2464    vu_queue_fill(dev, vq, elem, len, 0);
2465    vu_queue_inflight_pre_put(dev, vq, elem->index);
2466    vu_queue_flush(dev, vq, 1);
2467    vu_queue_inflight_post_put(dev, vq, elem->index);
2468}
2469