util/vfio-helpers.c

   1 /*
   2  * VFIO utility
   3  *
   4  * Copyright 2016 - 2018 Red Hat, Inc.
   5  *
   6  * Authors:
   7  *   Fam Zheng <famz@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include <sys/ioctl.h>
  15 #include <linux/vfio.h>
  16 #include "qapi/error.h"
  17 #include "exec/ramlist.h"
  18 #include "exec/cpu-common.h"
  19 #include "exec/memory.h"
  20 #include "trace.h"
  21 #include "qemu/error-report.h"
  22 #include "standard-headers/linux/pci_regs.h"
  23 #include "qemu/event_notifier.h"
  24 #include "qemu/vfio-helpers.h"
  25 #include "qemu/lockable.h"
  26 #include "trace.h"
  27
  28 #define QEMU_VFIO_DEBUG 0
  29
  30 #define QEMU_VFIO_IOVA_MIN 0x10000ULL
  31 /* XXX: Once VFIO exposes the iova bit width in the IOMMU capability interface,
  32  * we can use a runtime limit; alternatively it's also possible to do platform
  33  * specific detection by reading sysfs entries. Until then, 39 is a safe bet.
  34  **/
  35 #define QEMU_VFIO_IOVA_MAX (1ULL << 39)
  36
  37 typedef struct {
  38     /* Page aligned addr. */
  39     void *host;
  40     size_t size;
  41     uint64_t iova;
  42 } IOVAMapping;
  43
  44 struct IOVARange {
  45     uint64_t start;
  46     uint64_t end;
  47 };
  48
  49 struct QEMUVFIOState {
  50     QemuMutex lock;
  51
  52     /* These fields are protected by BQL */
  53     int container;
  54     int group;
  55     int device;
  56     RAMBlockNotifier ram_notifier;
  57     struct vfio_region_info config_region_info, bar_region_info[6];
  58     struct IOVARange *usable_iova_ranges;
  59     uint8_t nb_iova_ranges;
  60
  61     /* These fields are protected by @lock */
  62     /* VFIO's IO virtual address space is managed by splitting into a few
  63      * sections:
  64      *
  65      * ---------------       <= 0
  66      * |xxxxxxxxxxxxx|
  67      * |-------------|       <= QEMU_VFIO_IOVA_MIN
  68      * |             |
  69      * |    Fixed    |
  70      * |             |
  71      * |-------------|       <= low_water_mark
  72      * |             |
  73      * |    Free     |
  74      * |             |
  75      * |-------------|       <= high_water_mark
  76      * |             |
  77      * |    Temp     |
  78      * |             |
  79      * |-------------|       <= QEMU_VFIO_IOVA_MAX
  80      * |xxxxxxxxxxxxx|
  81      * |xxxxxxxxxxxxx|
  82      * ---------------
  83      *
  84      * - Addresses lower than QEMU_VFIO_IOVA_MIN are reserved as invalid;
  85      *
  86      * - Fixed mappings of HVAs are assigned "low" IOVAs in the range of
  87      *   [QEMU_VFIO_IOVA_MIN, low_water_mark).  Once allocated they will not be
  88      *   reclaimed - low_water_mark never shrinks;
  89      *
  90      * - IOVAs in range [low_water_mark, high_water_mark) are free;
  91      *
  92      * - IOVAs in range [high_water_mark, QEMU_VFIO_IOVA_MAX) are volatile
  93      *   mappings. At each qemu_vfio_dma_reset_temporary() call, the whole area
  94      *   is recycled. The caller should make sure I/O's depending on these
  95      *   mappings are completed before calling.
  96      **/
  97     uint64_t low_water_mark;
  98     uint64_t high_water_mark;
  99     IOVAMapping *mappings;
 100     int nr_mappings;
 101 };
 102
 103 /**
 104  * Find group file by PCI device address as specified @device, and return the
 105  * path. The returned string is owned by caller and should be g_free'ed later.
 106  */
 107 static char *sysfs_find_group_file(const char *device, Error **errp)
 108 {
 109     char *sysfs_link;
 110     char *sysfs_group;
 111     char *p;
 112     char *path = NULL;
 113
 114     sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
 115     sysfs_group = g_malloc0(PATH_MAX);
 116     if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
 117         error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
 118         goto out;
 119     }
 120     p = strrchr(sysfs_group, '/');
 121     if (!p) {
 122         error_setg(errp, "Failed to find iommu group number");
 123         goto out;
 124     }
 125
 126     path = g_strdup_printf("/dev/vfio/%s", p + 1);
 127 out:
 128     g_free(sysfs_link);
 129     g_free(sysfs_group);
 130     return path;
 131 }
 132
 133 static inline void assert_bar_index_valid(QEMUVFIOState *s, int index)
 134 {
 135     assert(index >= 0 && index < ARRAY_SIZE(s->bar_region_info));
 136 }
 137
 138 static int qemu_vfio_pci_init_bar(QEMUVFIOState *s, int index, Error **errp)
 139 {
 140     g_autofree char *barname = NULL;
 141     assert_bar_index_valid(s, index);
 142     s->bar_region_info[index] = (struct vfio_region_info) {
 143         .index = VFIO_PCI_BAR0_REGION_INDEX + index,
 144         .argsz = sizeof(struct vfio_region_info),
 145     };
 146     if (ioctl(s->device, VFIO_DEVICE_GET_REGION_INFO, &s->bar_region_info[index])) {
 147         error_setg_errno(errp, errno, "Failed to get BAR region info");
 148         return -errno;
 149     }
 150     barname = g_strdup_printf("bar[%d]", index);
 151     trace_qemu_vfio_region_info(barname, s->bar_region_info[index].offset,
 152                                 s->bar_region_info[index].size,
 153                                 s->bar_region_info[index].cap_offset);
 154
 155     return 0;
 156 }
 157
 158 /**
 159  * Map a PCI bar area.
 160  */
 161 void *qemu_vfio_pci_map_bar(QEMUVFIOState *s, int index,
 162                             uint64_t offset, uint64_t size, int prot,
 163                             Error **errp)
 164 {
 165     void *p;
 166     assert(QEMU_IS_ALIGNED(offset, qemu_real_host_page_size()));
 167     assert_bar_index_valid(s, index);
 168     p = mmap(NULL, MIN(size, s->bar_region_info[index].size - offset),
 169              prot, MAP_SHARED,
 170              s->device, s->bar_region_info[index].offset + offset);
 171     trace_qemu_vfio_pci_map_bar(index, s->bar_region_info[index].offset ,
 172                                 size, offset, p);
 173     if (p == MAP_FAILED) {
 174         error_setg_errno(errp, errno, "Failed to map BAR region");
 175         p = NULL;
 176     }
 177     return p;
 178 }
 179
 180 /**
 181  * Unmap a PCI bar area.
 182  */
 183 void qemu_vfio_pci_unmap_bar(QEMUVFIOState *s, int index, void *bar,
 184                              uint64_t offset, uint64_t size)
 185 {
 186     if (bar) {
 187         munmap(bar, MIN(size, s->bar_region_info[index].size - offset));
 188     }
 189 }
 190
 191 /**
 192  * Initialize device IRQ with @irq_type and register an event notifier.
 193  */
 194 int qemu_vfio_pci_init_irq(QEMUVFIOState *s, EventNotifier *e,
 195                            int irq_type, Error **errp)
 196 {
 197     int r;
 198     struct vfio_irq_set *irq_set;
 199     size_t irq_set_size;
 200     struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
 201
 202     irq_info.index = irq_type;
 203     if (ioctl(s->device, VFIO_DEVICE_GET_IRQ_INFO, &irq_info)) {
 204         error_setg_errno(errp, errno, "Failed to get device interrupt info");
 205         return -errno;
 206     }
 207     if (!(irq_info.flags & VFIO_IRQ_INFO_EVENTFD)) {
 208         error_setg(errp, "Device interrupt doesn't support eventfd");
 209         return -EINVAL;
 210     }
 211
 212     irq_set_size = sizeof(*irq_set) + sizeof(int);
 213     irq_set = g_malloc0(irq_set_size);
 214
 215     /* Get to a known IRQ state */
 216     *irq_set = (struct vfio_irq_set) {
 217         .argsz = irq_set_size,
 218         .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
 219         .index = irq_info.index,
 220         .start = 0,
 221         .count = 1,
 222     };
 223
 224     *(int *)&irq_set->data = event_notifier_get_fd(e);
 225     r = ioctl(s->device, VFIO_DEVICE_SET_IRQS, irq_set);
 226     g_free(irq_set);
 227     if (r) {
 228         error_setg_errno(errp, errno, "Failed to setup device interrupt");
 229         return -errno;
 230     }
 231     return 0;
 232 }
 233
 234 static int qemu_vfio_pci_read_config(QEMUVFIOState *s, void *buf,
 235                                      int size, int ofs)
 236 {
 237     int ret;
 238
 239     trace_qemu_vfio_pci_read_config(buf, ofs, size,
 240                                     s->config_region_info.offset,
 241                                     s->config_region_info.size);
 242     assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
 243     do {
 244         ret = pread(s->device, buf, size, s->config_region_info.offset + ofs);
 245     } while (ret == -1 && errno == EINTR);
 246     return ret == size ? 0 : -errno;
 247 }
 248
 249 static int qemu_vfio_pci_write_config(QEMUVFIOState *s, void *buf, int size, int ofs)
 250 {
 251     int ret;
 252
 253     trace_qemu_vfio_pci_write_config(buf, ofs, size,
 254                                      s->config_region_info.offset,
 255                                      s->config_region_info.size);
 256     assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
 257     do {
 258         ret = pwrite(s->device, buf, size, s->config_region_info.offset + ofs);
 259     } while (ret == -1 && errno == EINTR);
 260     return ret == size ? 0 : -errno;
 261 }
 262
 263 static void collect_usable_iova_ranges(QEMUVFIOState *s, void *buf)
 264 {
 265     struct vfio_iommu_type1_info *info = (struct vfio_iommu_type1_info *)buf;
 266     struct vfio_info_cap_header *cap = (void *)buf + info->cap_offset;
 267     struct vfio_iommu_type1_info_cap_iova_range *cap_iova_range;
 268     int i;
 269
 270     while (cap->id != VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE) {
 271         if (!cap->next) {
 272             return;
 273         }
 274         cap = (struct vfio_info_cap_header *)(buf + cap->next);
 275     }
 276
 277     cap_iova_range = (struct vfio_iommu_type1_info_cap_iova_range *)cap;
 278
 279     s->nb_iova_ranges = cap_iova_range->nr_iovas;
 280     if (s->nb_iova_ranges > 1) {
 281         s->usable_iova_ranges =
 282             g_renew(struct IOVARange, s->usable_iova_ranges,
 283                     s->nb_iova_ranges);
 284     }
 285
 286     for (i = 0; i < s->nb_iova_ranges; i++) {
 287         s->usable_iova_ranges[i].start = cap_iova_range->iova_ranges[i].start;
 288         s->usable_iova_ranges[i].end = cap_iova_range->iova_ranges[i].end;
 289     }
 290 }
 291
 292 static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device,
 293                               Error **errp)
 294 {
 295     int ret;
 296     int i;
 297     uint16_t pci_cmd;
 298     struct vfio_group_status group_status = { .argsz = sizeof(group_status) };
 299     struct vfio_iommu_type1_info *iommu_info = NULL;
 300     size_t iommu_info_size = sizeof(*iommu_info);
 301     struct vfio_device_info device_info = { .argsz = sizeof(device_info) };
 302     char *group_file = NULL;
 303
 304     s->usable_iova_ranges = NULL;
 305
 306     /* Create a new container */
 307     s->container = open("/dev/vfio/vfio", O_RDWR);
 308
 309     if (s->container == -1) {
 310         error_setg_errno(errp, errno, "Failed to open /dev/vfio/vfio");
 311         return -errno;
 312     }
 313     if (ioctl(s->container, VFIO_GET_API_VERSION) != VFIO_API_VERSION) {
 314         error_setg(errp, "Invalid VFIO version");
 315         ret = -EINVAL;
 316         goto fail_container;
 317     }
 318
 319     if (!ioctl(s->container, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
 320         error_setg_errno(errp, errno, "VFIO IOMMU Type1 is not supported");
 321         ret = -EINVAL;
 322         goto fail_container;
 323     }
 324
 325     /* Open the group */
 326     group_file = sysfs_find_group_file(device, errp);
 327     if (!group_file) {
 328         ret = -EINVAL;
 329         goto fail_container;
 330     }
 331
 332     s->group = open(group_file, O_RDWR);
 333     if (s->group == -1) {
 334         error_setg_errno(errp, errno, "Failed to open VFIO group file: %s",
 335                          group_file);
 336         g_free(group_file);
 337         ret = -errno;
 338         goto fail_container;
 339     }
 340     g_free(group_file);
 341
 342     /* Test the group is viable and available */
 343     if (ioctl(s->group, VFIO_GROUP_GET_STATUS, &group_status)) {
 344         error_setg_errno(errp, errno, "Failed to get VFIO group status");
 345         ret = -errno;
 346         goto fail;
 347     }
 348
 349     if (!(group_status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
 350         error_setg(errp, "VFIO group is not viable");
 351         ret = -EINVAL;
 352         goto fail;
 353     }
 354
 355     /* Add the group to the container */
 356     if (ioctl(s->group, VFIO_GROUP_SET_CONTAINER, &s->container)) {
 357         error_setg_errno(errp, errno, "Failed to add group to VFIO container");
 358         ret = -errno;
 359         goto fail;
 360     }
 361
 362     /* Enable the IOMMU model we want */
 363     if (ioctl(s->container, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU)) {
 364         error_setg_errno(errp, errno, "Failed to set VFIO IOMMU type");
 365         ret = -errno;
 366         goto fail;
 367     }
 368
 369     iommu_info = g_malloc0(iommu_info_size);
 370     iommu_info->argsz = iommu_info_size;
 371
 372     /* Get additional IOMMU info */
 373     if (ioctl(s->container, VFIO_IOMMU_GET_INFO, iommu_info)) {
 374         error_setg_errno(errp, errno, "Failed to get IOMMU info");
 375         ret = -errno;
 376         goto fail;
 377     }
 378
 379     /*
 380      * if the kernel does not report usable IOVA regions, choose
 381      * the legacy [QEMU_VFIO_IOVA_MIN, QEMU_VFIO_IOVA_MAX -1] region
 382      */
 383     s->nb_iova_ranges = 1;
 384     s->usable_iova_ranges = g_new0(struct IOVARange, 1);
 385     s->usable_iova_ranges[0].start = QEMU_VFIO_IOVA_MIN;
 386     s->usable_iova_ranges[0].end = QEMU_VFIO_IOVA_MAX - 1;
 387
 388     if (iommu_info->argsz > iommu_info_size) {
 389         iommu_info_size = iommu_info->argsz;
 390         iommu_info = g_realloc(iommu_info, iommu_info_size);
 391         if (ioctl(s->container, VFIO_IOMMU_GET_INFO, iommu_info)) {
 392             ret = -errno;
 393             goto fail;
 394         }
 395         collect_usable_iova_ranges(s, iommu_info);
 396     }
 397
 398     s->device = ioctl(s->group, VFIO_GROUP_GET_DEVICE_FD, device);
 399
 400     if (s->device < 0) {
 401         error_setg_errno(errp, errno, "Failed to get device fd");
 402         ret = -errno;
 403         goto fail;
 404     }
 405
 406     /* Test and setup the device */
 407     if (ioctl(s->device, VFIO_DEVICE_GET_INFO, &device_info)) {
 408         error_setg_errno(errp, errno, "Failed to get device info");
 409         ret = -errno;
 410         goto fail;
 411     }
 412
 413     if (device_info.num_regions < VFIO_PCI_CONFIG_REGION_INDEX) {
 414         error_setg(errp, "Invalid device regions");
 415         ret = -EINVAL;
 416         goto fail;
 417     }
 418
 419     s->config_region_info = (struct vfio_region_info) {
 420         .index = VFIO_PCI_CONFIG_REGION_INDEX,
 421         .argsz = sizeof(struct vfio_region_info),
 422     };
 423     if (ioctl(s->device, VFIO_DEVICE_GET_REGION_INFO, &s->config_region_info)) {
 424         error_setg_errno(errp, errno, "Failed to get config region info");
 425         ret = -errno;
 426         goto fail;
 427     }
 428     trace_qemu_vfio_region_info("config", s->config_region_info.offset,
 429                                 s->config_region_info.size,
 430                                 s->config_region_info.cap_offset);
 431
 432     for (i = 0; i < ARRAY_SIZE(s->bar_region_info); i++) {
 433         ret = qemu_vfio_pci_init_bar(s, i, errp);
 434         if (ret) {
 435             goto fail;
 436         }
 437     }
 438
 439     /* Enable bus master */
 440     ret = qemu_vfio_pci_read_config(s, &pci_cmd, sizeof(pci_cmd), PCI_COMMAND);
 441     if (ret) {
 442         goto fail;
 443     }
 444     pci_cmd |= PCI_COMMAND_MASTER;
 445     ret = qemu_vfio_pci_write_config(s, &pci_cmd, sizeof(pci_cmd), PCI_COMMAND);
 446     if (ret) {
 447         goto fail;
 448     }
 449     g_free(iommu_info);
 450     return 0;
 451 fail:
 452     g_free(s->usable_iova_ranges);
 453     s->usable_iova_ranges = NULL;
 454     s->nb_iova_ranges = 0;
 455     g_free(iommu_info);
 456     close(s->group);
 457 fail_container:
 458     close(s->container);
 459     return ret;
 460 }
 461
 462 static void qemu_vfio_ram_block_added(RAMBlockNotifier *n, void *host,
 463                                       size_t size, size_t max_size)
 464 {
 465     QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
 466     Error *local_err = NULL;
 467     int ret;
 468
 469     trace_qemu_vfio_ram_block_added(s, host, max_size);
 470     ret = qemu_vfio_dma_map(s, host, max_size, false, NULL, &local_err);
 471     if (ret) {
 472         error_reportf_err(local_err,
 473                           "qemu_vfio_dma_map(%p, %zu) failed: ",
 474                           host, max_size);
 475     }
 476 }
 477
 478 static void qemu_vfio_ram_block_removed(RAMBlockNotifier *n, void *host,
 479                                         size_t size, size_t max_size)
 480 {
 481     QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
 482     if (host) {
 483         trace_qemu_vfio_ram_block_removed(s, host, max_size);
 484         qemu_vfio_dma_unmap(s, host);
 485     }
 486 }
 487
 488 static void qemu_vfio_open_common(QEMUVFIOState *s)
 489 {
 490     qemu_mutex_init(&s->lock);
 491     s->ram_notifier.ram_block_added = qemu_vfio_ram_block_added;
 492     s->ram_notifier.ram_block_removed = qemu_vfio_ram_block_removed;
 493     s->low_water_mark = QEMU_VFIO_IOVA_MIN;
 494     s->high_water_mark = QEMU_VFIO_IOVA_MAX;
 495     ram_block_notifier_add(&s->ram_notifier);
 496 }
 497
 498 /**
 499  * Open a PCI device, e.g. "0000:00:01.0".
 500  */
 501 QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp)
 502 {
 503     int r;
 504     QEMUVFIOState *s = g_new0(QEMUVFIOState, 1);
 505
 506     /*
 507      * VFIO may pin all memory inside mappings, resulting it in pinning
 508      * all memory inside RAM blocks unconditionally.
 509      */
 510     r = ram_block_discard_disable(true);
 511     if (r) {
 512         error_setg_errno(errp, -r, "Cannot set discarding of RAM broken");
 513         g_free(s);
 514         return NULL;
 515     }
 516
 517     r = qemu_vfio_init_pci(s, device, errp);
 518     if (r) {
 519         ram_block_discard_disable(false);
 520         g_free(s);
 521         return NULL;
 522     }
 523     qemu_vfio_open_common(s);
 524     return s;
 525 }
 526
 527 static void qemu_vfio_dump_mappings(QEMUVFIOState *s)
 528 {
 529     for (int i = 0; i < s->nr_mappings; ++i) {
 530         trace_qemu_vfio_dump_mapping(s->mappings[i].host,
 531                                      s->mappings[i].iova,
 532                                      s->mappings[i].size);
 533     }
 534 }
 535
 536 /**
 537  * Find the mapping entry that contains [host, host + size) and set @index to
 538  * the position. If no entry contains it, @index is the position _after_ which
 539  * to insert the new mapping. IOW, it is the index of the largest element that
 540  * is smaller than @host, or -1 if no entry is.
 541  */
 542 static IOVAMapping *qemu_vfio_find_mapping(QEMUVFIOState *s, void *host,
 543                                            int *index)
 544 {
 545     IOVAMapping *p = s->mappings;
 546     IOVAMapping *q = p ? p + s->nr_mappings - 1 : NULL;
 547     IOVAMapping *mid;
 548     trace_qemu_vfio_find_mapping(s, host);
 549     if (!p) {
 550         *index = -1;
 551         return NULL;
 552     }
 553     while (true) {
 554         mid = p + (q - p) / 2;
 555         if (mid == p) {
 556             break;
 557         }
 558         if (mid->host > host) {
 559             q = mid;
 560         } else if (mid->host < host) {
 561             p = mid;
 562         } else {
 563             break;
 564         }
 565     }
 566     if (mid->host > host) {
 567         mid--;
 568     } else if (mid < &s->mappings[s->nr_mappings - 1]
 569                && (mid + 1)->host <= host) {
 570         mid++;
 571     }
 572     *index = mid - &s->mappings[0];
 573     if (mid >= &s->mappings[0] &&
 574         mid->host <= host && mid->host + mid->size > host) {
 575         assert(mid < &s->mappings[s->nr_mappings]);
 576         return mid;
 577     }
 578     /* At this point *index + 1 is the right position to insert the new
 579      * mapping.*/
 580     return NULL;
 581 }
 582
 583 /**
 584  * Allocate IOVA and create a new mapping record and insert it in @s.
 585  */
 586 static IOVAMapping *qemu_vfio_add_mapping(QEMUVFIOState *s,
 587                                           void *host, size_t size,
 588                                           int index, uint64_t iova)
 589 {
 590     int shift;
 591     IOVAMapping m = {.host = host, .size = size, .iova = iova};
 592     IOVAMapping *insert;
 593
 594     assert(QEMU_IS_ALIGNED(size, qemu_real_host_page_size()));
 595     assert(QEMU_IS_ALIGNED(s->low_water_mark, qemu_real_host_page_size()));
 596     assert(QEMU_IS_ALIGNED(s->high_water_mark, qemu_real_host_page_size()));
 597     trace_qemu_vfio_new_mapping(s, host, size, index, iova);
 598
 599     assert(index >= 0);
 600     s->nr_mappings++;
 601     s->mappings = g_renew(IOVAMapping, s->mappings, s->nr_mappings);
 602     insert = &s->mappings[index];
 603     shift = s->nr_mappings - index - 1;
 604     if (shift) {
 605         memmove(insert + 1, insert, shift * sizeof(s->mappings[0]));
 606     }
 607     *insert = m;
 608     return insert;
 609 }
 610
 611 /* Do the DMA mapping with VFIO. */
 612 static int qemu_vfio_do_mapping(QEMUVFIOState *s, void *host, size_t size,
 613                                 uint64_t iova, Error **errp)
 614 {
 615     struct vfio_iommu_type1_dma_map dma_map = {
 616         .argsz = sizeof(dma_map),
 617         .flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
 618         .iova = iova,
 619         .vaddr = (uintptr_t)host,
 620         .size = size,
 621     };
 622     trace_qemu_vfio_do_mapping(s, host, iova, size);
 623
 624     if (ioctl(s->container, VFIO_IOMMU_MAP_DMA, &dma_map)) {
 625         error_setg_errno(errp, errno, "VFIO_MAP_DMA failed");
 626         return -errno;
 627     }
 628     return 0;
 629 }
 630
 631 /**
 632  * Undo the DMA mapping from @s with VFIO, and remove from mapping list.
 633  */
 634 static void qemu_vfio_undo_mapping(QEMUVFIOState *s, IOVAMapping *mapping,
 635                                    Error **errp)
 636 {
 637     int index;
 638     struct vfio_iommu_type1_dma_unmap unmap = {
 639         .argsz = sizeof(unmap),
 640         .flags = 0,
 641         .iova = mapping->iova,
 642         .size = mapping->size,
 643     };
 644
 645     index = mapping - s->mappings;
 646     assert(mapping->size > 0);
 647     assert(QEMU_IS_ALIGNED(mapping->size, qemu_real_host_page_size()));
 648     assert(index >= 0 && index < s->nr_mappings);
 649     if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
 650         error_setg_errno(errp, errno, "VFIO_UNMAP_DMA failed");
 651     }
 652     memmove(mapping, &s->mappings[index + 1],
 653             sizeof(s->mappings[0]) * (s->nr_mappings - index - 1));
 654     s->nr_mappings--;
 655     s->mappings = g_renew(IOVAMapping, s->mappings, s->nr_mappings);
 656 }
 657
 658 /* Check if the mapping list is (ascending) ordered. */
 659 static bool qemu_vfio_verify_mappings(QEMUVFIOState *s)
 660 {
 661     int i;
 662     if (QEMU_VFIO_DEBUG) {
 663         for (i = 0; i < s->nr_mappings - 1; ++i) {
 664             if (!(s->mappings[i].host < s->mappings[i + 1].host)) {
 665                 error_report("item %d not sorted!", i);
 666                 qemu_vfio_dump_mappings(s);
 667                 return false;
 668             }
 669             if (!(s->mappings[i].host + s->mappings[i].size <=
 670                   s->mappings[i + 1].host)) {
 671                 error_report("item %d overlap with next!", i);
 672                 qemu_vfio_dump_mappings(s);
 673                 return false;
 674             }
 675         }
 676     }
 677     return true;
 678 }
 679
 680 static bool qemu_vfio_find_fixed_iova(QEMUVFIOState *s, size_t size,
 681                                       uint64_t *iova, Error **errp)
 682 {
 683     int i;
 684
 685     for (i = 0; i < s->nb_iova_ranges; i++) {
 686         if (s->usable_iova_ranges[i].end < s->low_water_mark) {
 687             continue;
 688         }
 689         s->low_water_mark =
 690             MAX(s->low_water_mark, s->usable_iova_ranges[i].start);
 691
 692         if (s->usable_iova_ranges[i].end - s->low_water_mark + 1 >= size ||
 693             s->usable_iova_ranges[i].end - s->low_water_mark + 1 == 0) {
 694             *iova = s->low_water_mark;
 695             s->low_water_mark += size;
 696             return true;
 697         }
 698     }
 699     error_setg(errp, "fixed iova range not found");
 700
 701     return false;
 702 }
 703
 704 static bool qemu_vfio_find_temp_iova(QEMUVFIOState *s, size_t size,
 705                                      uint64_t *iova, Error **errp)
 706 {
 707     int i;
 708
 709     for (i = s->nb_iova_ranges - 1; i >= 0; i--) {
 710         if (s->usable_iova_ranges[i].start > s->high_water_mark) {
 711             continue;
 712         }
 713         s->high_water_mark =
 714             MIN(s->high_water_mark, s->usable_iova_ranges[i].end + 1);
 715
 716         if (s->high_water_mark - s->usable_iova_ranges[i].start + 1 >= size ||
 717             s->high_water_mark - s->usable_iova_ranges[i].start + 1 == 0) {
 718             *iova = s->high_water_mark - size;
 719             s->high_water_mark = *iova;
 720             return true;
 721         }
 722     }
 723     error_setg(errp, "temporary iova range not found");
 724
 725     return false;
 726 }
 727
 728 /**
 729  * qemu_vfio_water_mark_reached:
 730  *
 731  * Returns %true if high watermark has been reached, %false otherwise.
 732  */
 733 static bool qemu_vfio_water_mark_reached(QEMUVFIOState *s, size_t size,
 734                                          Error **errp)
 735 {
 736     if (s->high_water_mark - s->low_water_mark + 1 < size) {
 737         error_setg(errp, "iova exhausted (water mark reached)");
 738         return true;
 739     }
 740     return false;
 741 }
 742
 743 /* Map [host, host + size) area into a contiguous IOVA address space, and store
 744  * the result in @iova if not NULL. The caller need to make sure the area is
 745  * aligned to page size, and mustn't overlap with existing mapping areas (split
 746  * mapping status within this area is not allowed).
 747  */
 748 int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
 749                       bool temporary, uint64_t *iova, Error **errp)
 750 {
 751     int index;
 752     IOVAMapping *mapping;
 753     uint64_t iova0;
 754
 755     assert(QEMU_PTR_IS_ALIGNED(host, qemu_real_host_page_size()));
 756     assert(QEMU_IS_ALIGNED(size, qemu_real_host_page_size()));
 757     trace_qemu_vfio_dma_map(s, host, size, temporary, iova);
 758     QEMU_LOCK_GUARD(&s->lock);
 759     mapping = qemu_vfio_find_mapping(s, host, &index);
 760     if (mapping) {
 761         iova0 = mapping->iova + ((uint8_t *)host - (uint8_t *)mapping->host);
 762     } else {
 763         int ret;
 764
 765         if (qemu_vfio_water_mark_reached(s, size, errp)) {
 766             return -ENOMEM;
 767         }
 768         if (!temporary) {
 769             if (!qemu_vfio_find_fixed_iova(s, size, &iova0, errp)) {
 770                 return -ENOMEM;
 771             }
 772
 773             mapping = qemu_vfio_add_mapping(s, host, size, index + 1, iova0);
 774             assert(qemu_vfio_verify_mappings(s));
 775             ret = qemu_vfio_do_mapping(s, host, size, iova0, errp);
 776             if (ret < 0) {
 777                 qemu_vfio_undo_mapping(s, mapping, NULL);
 778                 return ret;
 779             }
 780             qemu_vfio_dump_mappings(s);
 781         } else {
 782             if (!qemu_vfio_find_temp_iova(s, size, &iova0, errp)) {
 783                 return -ENOMEM;
 784             }
 785             ret = qemu_vfio_do_mapping(s, host, size, iova0, errp);
 786             if (ret < 0) {
 787                 return ret;
 788             }
 789         }
 790     }
 791     trace_qemu_vfio_dma_mapped(s, host, iova0, size);
 792     if (iova) {
 793         *iova = iova0;
 794     }
 795     return 0;
 796 }
 797
 798 /* Reset the high watermark and free all "temporary" mappings. */
 799 int qemu_vfio_dma_reset_temporary(QEMUVFIOState *s)
 800 {
 801     struct vfio_iommu_type1_dma_unmap unmap = {
 802         .argsz = sizeof(unmap),
 803         .flags = 0,
 804         .iova = s->high_water_mark,
 805         .size = QEMU_VFIO_IOVA_MAX - s->high_water_mark,
 806     };
 807     trace_qemu_vfio_dma_reset_temporary(s);
 808     QEMU_LOCK_GUARD(&s->lock);
 809     if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
 810         error_report("VFIO_UNMAP_DMA failed: %s", strerror(errno));
 811         return -errno;
 812     }
 813     s->high_water_mark = QEMU_VFIO_IOVA_MAX;
 814     return 0;
 815 }
 816
 817 /* Unmapping the whole area that was previously mapped with
 818  * qemu_vfio_dma_map(). */
 819 void qemu_vfio_dma_unmap(QEMUVFIOState *s, void *host)
 820 {
 821     int index = 0;
 822     IOVAMapping *m;
 823
 824     if (!host) {
 825         return;
 826     }
 827
 828     trace_qemu_vfio_dma_unmap(s, host);
 829     QEMU_LOCK_GUARD(&s->lock);
 830     m = qemu_vfio_find_mapping(s, host, &index);
 831     if (!m) {
 832         return;
 833     }
 834     qemu_vfio_undo_mapping(s, m, NULL);
 835 }
 836
 837 static void qemu_vfio_reset(QEMUVFIOState *s)
 838 {
 839     ioctl(s->device, VFIO_DEVICE_RESET);
 840 }
 841
 842 /* Close and free the VFIO resources. */
 843 void qemu_vfio_close(QEMUVFIOState *s)
 844 {
 845     int i;
 846
 847     if (!s) {
 848         return;
 849     }
 850     for (i = 0; i < s->nr_mappings; ++i) {
 851         qemu_vfio_undo_mapping(s, &s->mappings[i], NULL);
 852     }
 853     ram_block_notifier_remove(&s->ram_notifier);
 854     g_free(s->usable_iova_ranges);
 855     s->nb_iova_ranges = 0;
 856     qemu_vfio_reset(s);
 857     close(s->device);
 858     close(s->group);
 859     close(s->container);
 860     ram_block_discard_disable(false);
 861 }