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_realloc(s->usable_iova_ranges,
 283                       s->nb_iova_ranges * sizeof(struct IOVARange));
 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     int ret;
 467
 468     trace_qemu_vfio_ram_block_added(s, host, max_size);
 469     ret = qemu_vfio_dma_map(s, host, max_size, false, NULL);
 470     if (ret) {
 471         error_report("qemu_vfio_dma_map(%p, %zu) failed: %s", host, max_size,
 472                      strerror(-ret));
 473     }
 474 }
 475
 476 static void qemu_vfio_ram_block_removed(RAMBlockNotifier *n, void *host,
 477                                         size_t size, size_t max_size)
 478 {
 479     QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
 480     if (host) {
 481         trace_qemu_vfio_ram_block_removed(s, host, max_size);
 482         qemu_vfio_dma_unmap(s, host);
 483     }
 484 }
 485
 486 static void qemu_vfio_open_common(QEMUVFIOState *s)
 487 {
 488     qemu_mutex_init(&s->lock);
 489     s->ram_notifier.ram_block_added = qemu_vfio_ram_block_added;
 490     s->ram_notifier.ram_block_removed = qemu_vfio_ram_block_removed;
 491     s->low_water_mark = QEMU_VFIO_IOVA_MIN;
 492     s->high_water_mark = QEMU_VFIO_IOVA_MAX;
 493     ram_block_notifier_add(&s->ram_notifier);
 494 }
 495
 496 /**
 497  * Open a PCI device, e.g. "0000:00:01.0".
 498  */
 499 QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp)
 500 {
 501     int r;
 502     QEMUVFIOState *s = g_new0(QEMUVFIOState, 1);
 503
 504     /*
 505      * VFIO may pin all memory inside mappings, resulting it in pinning
 506      * all memory inside RAM blocks unconditionally.
 507      */
 508     r = ram_block_discard_disable(true);
 509     if (r) {
 510         error_setg_errno(errp, -r, "Cannot set discarding of RAM broken");
 511         g_free(s);
 512         return NULL;
 513     }
 514
 515     r = qemu_vfio_init_pci(s, device, errp);
 516     if (r) {
 517         ram_block_discard_disable(false);
 518         g_free(s);
 519         return NULL;
 520     }
 521     qemu_vfio_open_common(s);
 522     return s;
 523 }
 524
 525 static void qemu_vfio_dump_mappings(QEMUVFIOState *s)
 526 {
 527     for (int i = 0; i < s->nr_mappings; ++i) {
 528         trace_qemu_vfio_dump_mapping(s->mappings[i].host,
 529                                      s->mappings[i].iova,
 530                                      s->mappings[i].size);
 531     }
 532 }
 533
 534 /**
 535  * Find the mapping entry that contains [host, host + size) and set @index to
 536  * the position. If no entry contains it, @index is the position _after_ which
 537  * to insert the new mapping. IOW, it is the index of the largest element that
 538  * is smaller than @host, or -1 if no entry is.
 539  */
 540 static IOVAMapping *qemu_vfio_find_mapping(QEMUVFIOState *s, void *host,
 541                                            int *index)
 542 {
 543     IOVAMapping *p = s->mappings;
 544     IOVAMapping *q = p ? p + s->nr_mappings - 1 : NULL;
 545     IOVAMapping *mid;
 546     trace_qemu_vfio_find_mapping(s, host);
 547     if (!p) {
 548         *index = -1;
 549         return NULL;
 550     }
 551     while (true) {
 552         mid = p + (q - p) / 2;
 553         if (mid == p) {
 554             break;
 555         }
 556         if (mid->host > host) {
 557             q = mid;
 558         } else if (mid->host < host) {
 559             p = mid;
 560         } else {
 561             break;
 562         }
 563     }
 564     if (mid->host > host) {
 565         mid--;
 566     } else if (mid < &s->mappings[s->nr_mappings - 1]
 567                && (mid + 1)->host <= host) {
 568         mid++;
 569     }
 570     *index = mid - &s->mappings[0];
 571     if (mid >= &s->mappings[0] &&
 572         mid->host <= host && mid->host + mid->size > host) {
 573         assert(mid < &s->mappings[s->nr_mappings]);
 574         return mid;
 575     }
 576     /* At this point *index + 1 is the right position to insert the new
 577      * mapping.*/
 578     return NULL;
 579 }
 580
 581 /**
 582  * Allocate IOVA and create a new mapping record and insert it in @s.
 583  */
 584 static IOVAMapping *qemu_vfio_add_mapping(QEMUVFIOState *s,
 585                                           void *host, size_t size,
 586                                           int index, uint64_t iova)
 587 {
 588     int shift;
 589     IOVAMapping m = {.host = host, .size = size, .iova = iova};
 590     IOVAMapping *insert;
 591
 592     assert(QEMU_IS_ALIGNED(size, qemu_real_host_page_size));
 593     assert(QEMU_IS_ALIGNED(s->low_water_mark, qemu_real_host_page_size));
 594     assert(QEMU_IS_ALIGNED(s->high_water_mark, qemu_real_host_page_size));
 595     trace_qemu_vfio_new_mapping(s, host, size, index, iova);
 596
 597     assert(index >= 0);
 598     s->nr_mappings++;
 599     s->mappings = g_renew(IOVAMapping, s->mappings, s->nr_mappings);
 600     insert = &s->mappings[index];
 601     shift = s->nr_mappings - index - 1;
 602     if (shift) {
 603         memmove(insert + 1, insert, shift * sizeof(s->mappings[0]));
 604     }
 605     *insert = m;
 606     return insert;
 607 }
 608
 609 /* Do the DMA mapping with VFIO. */
 610 static int qemu_vfio_do_mapping(QEMUVFIOState *s, void *host, size_t size,
 611                                 uint64_t iova)
 612 {
 613     struct vfio_iommu_type1_dma_map dma_map = {
 614         .argsz = sizeof(dma_map),
 615         .flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
 616         .iova = iova,
 617         .vaddr = (uintptr_t)host,
 618         .size = size,
 619     };
 620     trace_qemu_vfio_do_mapping(s, host, iova, size);
 621
 622     if (ioctl(s->container, VFIO_IOMMU_MAP_DMA, &dma_map)) {
 623         error_report("VFIO_MAP_DMA failed: %s", strerror(errno));
 624         return -errno;
 625     }
 626     return 0;
 627 }
 628
 629 /**
 630  * Undo the DMA mapping from @s with VFIO, and remove from mapping list.
 631  */
 632 static void qemu_vfio_undo_mapping(QEMUVFIOState *s, IOVAMapping *mapping,
 633                                    Error **errp)
 634 {
 635     int index;
 636     struct vfio_iommu_type1_dma_unmap unmap = {
 637         .argsz = sizeof(unmap),
 638         .flags = 0,
 639         .iova = mapping->iova,
 640         .size = mapping->size,
 641     };
 642
 643     index = mapping - s->mappings;
 644     assert(mapping->size > 0);
 645     assert(QEMU_IS_ALIGNED(mapping->size, qemu_real_host_page_size));
 646     assert(index >= 0 && index < s->nr_mappings);
 647     if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
 648         error_setg_errno(errp, errno, "VFIO_UNMAP_DMA failed");
 649     }
 650     memmove(mapping, &s->mappings[index + 1],
 651             sizeof(s->mappings[0]) * (s->nr_mappings - index - 1));
 652     s->nr_mappings--;
 653     s->mappings = g_renew(IOVAMapping, s->mappings, s->nr_mappings);
 654 }
 655
 656 /* Check if the mapping list is (ascending) ordered. */
 657 static bool qemu_vfio_verify_mappings(QEMUVFIOState *s)
 658 {
 659     int i;
 660     if (QEMU_VFIO_DEBUG) {
 661         for (i = 0; i < s->nr_mappings - 1; ++i) {
 662             if (!(s->mappings[i].host < s->mappings[i + 1].host)) {
 663                 fprintf(stderr, "item %d not sorted!\n", i);
 664                 qemu_vfio_dump_mappings(s);
 665                 return false;
 666             }
 667             if (!(s->mappings[i].host + s->mappings[i].size <=
 668                   s->mappings[i + 1].host)) {
 669                 fprintf(stderr, "item %d overlap with next!\n", i);
 670                 qemu_vfio_dump_mappings(s);
 671                 return false;
 672             }
 673         }
 674     }
 675     return true;
 676 }
 677
 678 static int
 679 qemu_vfio_find_fixed_iova(QEMUVFIOState *s, size_t size, uint64_t *iova)
 680 {
 681     int i;
 682
 683     for (i = 0; i < s->nb_iova_ranges; i++) {
 684         if (s->usable_iova_ranges[i].end < s->low_water_mark) {
 685             continue;
 686         }
 687         s->low_water_mark =
 688             MAX(s->low_water_mark, s->usable_iova_ranges[i].start);
 689
 690         if (s->usable_iova_ranges[i].end - s->low_water_mark + 1 >= size ||
 691             s->usable_iova_ranges[i].end - s->low_water_mark + 1 == 0) {
 692             *iova = s->low_water_mark;
 693             s->low_water_mark += size;
 694             return 0;
 695         }
 696     }
 697     return -ENOMEM;
 698 }
 699
 700 static int
 701 qemu_vfio_find_temp_iova(QEMUVFIOState *s, size_t size, uint64_t *iova)
 702 {
 703     int i;
 704
 705     for (i = s->nb_iova_ranges - 1; i >= 0; i--) {
 706         if (s->usable_iova_ranges[i].start > s->high_water_mark) {
 707             continue;
 708         }
 709         s->high_water_mark =
 710             MIN(s->high_water_mark, s->usable_iova_ranges[i].end + 1);
 711
 712         if (s->high_water_mark - s->usable_iova_ranges[i].start + 1 >= size ||
 713             s->high_water_mark - s->usable_iova_ranges[i].start + 1 == 0) {
 714             *iova = s->high_water_mark - size;
 715             s->high_water_mark = *iova;
 716             return 0;
 717         }
 718     }
 719     return -ENOMEM;
 720 }
 721
 722 /* Map [host, host + size) area into a contiguous IOVA address space, and store
 723  * the result in @iova if not NULL. The caller need to make sure the area is
 724  * aligned to page size, and mustn't overlap with existing mapping areas (split
 725  * mapping status within this area is not allowed).
 726  */
 727 int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
 728                       bool temporary, uint64_t *iova)
 729 {
 730     int ret = 0;
 731     int index;
 732     IOVAMapping *mapping;
 733     uint64_t iova0;
 734
 735     assert(QEMU_PTR_IS_ALIGNED(host, qemu_real_host_page_size));
 736     assert(QEMU_IS_ALIGNED(size, qemu_real_host_page_size));
 737     trace_qemu_vfio_dma_map(s, host, size, temporary, iova);
 738     qemu_mutex_lock(&s->lock);
 739     mapping = qemu_vfio_find_mapping(s, host, &index);
 740     if (mapping) {
 741         iova0 = mapping->iova + ((uint8_t *)host - (uint8_t *)mapping->host);
 742     } else {
 743         if (s->high_water_mark - s->low_water_mark + 1 < size) {
 744             ret = -ENOMEM;
 745             goto out;
 746         }
 747         if (!temporary) {
 748             if (qemu_vfio_find_fixed_iova(s, size, &iova0)) {
 749                 ret = -ENOMEM;
 750                 goto out;
 751             }
 752
 753             mapping = qemu_vfio_add_mapping(s, host, size, index + 1, iova0);
 754             if (!mapping) {
 755                 ret = -ENOMEM;
 756                 goto out;
 757             }
 758             assert(qemu_vfio_verify_mappings(s));
 759             ret = qemu_vfio_do_mapping(s, host, size, iova0);
 760             if (ret) {
 761                 qemu_vfio_undo_mapping(s, mapping, NULL);
 762                 goto out;
 763             }
 764             qemu_vfio_dump_mappings(s);
 765         } else {
 766             if (qemu_vfio_find_temp_iova(s, size, &iova0)) {
 767                 ret = -ENOMEM;
 768                 goto out;
 769             }
 770             ret = qemu_vfio_do_mapping(s, host, size, iova0);
 771             if (ret) {
 772                 goto out;
 773             }
 774         }
 775     }
 776     trace_qemu_vfio_dma_mapped(s, host, iova0, size);
 777     if (iova) {
 778         *iova = iova0;
 779     }
 780 out:
 781     qemu_mutex_unlock(&s->lock);
 782     return ret;
 783 }
 784
 785 /* Reset the high watermark and free all "temporary" mappings. */
 786 int qemu_vfio_dma_reset_temporary(QEMUVFIOState *s)
 787 {
 788     struct vfio_iommu_type1_dma_unmap unmap = {
 789         .argsz = sizeof(unmap),
 790         .flags = 0,
 791         .iova = s->high_water_mark,
 792         .size = QEMU_VFIO_IOVA_MAX - s->high_water_mark,
 793     };
 794     trace_qemu_vfio_dma_reset_temporary(s);
 795     QEMU_LOCK_GUARD(&s->lock);
 796     if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
 797         error_report("VFIO_UNMAP_DMA failed: %s", strerror(errno));
 798         return -errno;
 799     }
 800     s->high_water_mark = QEMU_VFIO_IOVA_MAX;
 801     return 0;
 802 }
 803
 804 /* Unmapping the whole area that was previously mapped with
 805  * qemu_vfio_dma_map(). */
 806 void qemu_vfio_dma_unmap(QEMUVFIOState *s, void *host)
 807 {
 808     int index = 0;
 809     IOVAMapping *m;
 810
 811     if (!host) {
 812         return;
 813     }
 814
 815     trace_qemu_vfio_dma_unmap(s, host);
 816     qemu_mutex_lock(&s->lock);
 817     m = qemu_vfio_find_mapping(s, host, &index);
 818     if (!m) {
 819         goto out;
 820     }
 821     qemu_vfio_undo_mapping(s, m, NULL);
 822 out:
 823     qemu_mutex_unlock(&s->lock);
 824 }
 825
 826 static void qemu_vfio_reset(QEMUVFIOState *s)
 827 {
 828     ioctl(s->device, VFIO_DEVICE_RESET);
 829 }
 830
 831 /* Close and free the VFIO resources. */
 832 void qemu_vfio_close(QEMUVFIOState *s)
 833 {
 834     int i;
 835
 836     if (!s) {
 837         return;
 838     }
 839     for (i = 0; i < s->nr_mappings; ++i) {
 840         qemu_vfio_undo_mapping(s, &s->mappings[i], NULL);
 841     }
 842     ram_block_notifier_remove(&s->ram_notifier);
 843     g_free(s->usable_iova_ranges);
 844     s->nb_iova_ranges = 0;
 845     qemu_vfio_reset(s);
 846     close(s->device);
 847     close(s->group);
 848     close(s->container);
 849     ram_block_discard_disable(false);
 850 }