linux/tools/virtio/vringh_test.c
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   1/* Simple test of virtio code, entirely in userpsace. */
   2#define _GNU_SOURCE
   3#include <sched.h>
   4#include <err.h>
   5#include <linux/kernel.h>
   6#include <linux/err.h>
   7#include <linux/virtio.h>
   8#include <linux/vringh.h>
   9#include <linux/virtio_ring.h>
  10#include <linux/virtio_config.h>
  11#include <linux/uaccess.h>
  12#include <sys/types.h>
  13#include <sys/stat.h>
  14#include <sys/mman.h>
  15#include <sys/wait.h>
  16#include <fcntl.h>
  17
  18#define USER_MEM (1024*1024)
  19void *__user_addr_min, *__user_addr_max;
  20void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
  21static u64 user_addr_offset;
  22
  23#define RINGSIZE 256
  24#define ALIGN 4096
  25
  26static bool never_notify_host(struct virtqueue *vq)
  27{
  28        abort();
  29}
  30
  31static void never_callback_guest(struct virtqueue *vq)
  32{
  33        abort();
  34}
  35
  36static bool getrange_iov(struct vringh *vrh, u64 addr, struct vringh_range *r)
  37{
  38        if (addr < (u64)(unsigned long)__user_addr_min - user_addr_offset)
  39                return false;
  40        if (addr >= (u64)(unsigned long)__user_addr_max - user_addr_offset)
  41                return false;
  42
  43        r->start = (u64)(unsigned long)__user_addr_min - user_addr_offset;
  44        r->end_incl = (u64)(unsigned long)__user_addr_max - 1 - user_addr_offset;
  45        r->offset = user_addr_offset;
  46        return true;
  47}
  48
  49/* We return single byte ranges. */
  50static bool getrange_slow(struct vringh *vrh, u64 addr, struct vringh_range *r)
  51{
  52        if (addr < (u64)(unsigned long)__user_addr_min - user_addr_offset)
  53                return false;
  54        if (addr >= (u64)(unsigned long)__user_addr_max - user_addr_offset)
  55                return false;
  56
  57        r->start = addr;
  58        r->end_incl = r->start;
  59        r->offset = user_addr_offset;
  60        return true;
  61}
  62
  63struct guest_virtio_device {
  64        struct virtio_device vdev;
  65        int to_host_fd;
  66        unsigned long notifies;
  67};
  68
  69static bool parallel_notify_host(struct virtqueue *vq)
  70{
  71        int rc;
  72        struct guest_virtio_device *gvdev;
  73
  74        gvdev = container_of(vq->vdev, struct guest_virtio_device, vdev);
  75        rc = write(gvdev->to_host_fd, "", 1);
  76        if (rc < 0)
  77                return false;
  78        gvdev->notifies++;
  79        return true;
  80}
  81
  82static bool no_notify_host(struct virtqueue *vq)
  83{
  84        return true;
  85}
  86
  87#define NUM_XFERS (10000000)
  88
  89/* We aim for two "distant" cpus. */
  90static void find_cpus(unsigned int *first, unsigned int *last)
  91{
  92        unsigned int i;
  93
  94        *first = -1U;
  95        *last = 0;
  96        for (i = 0; i < 4096; i++) {
  97                cpu_set_t set;
  98                CPU_ZERO(&set);
  99                CPU_SET(i, &set);
 100                if (sched_setaffinity(getpid(), sizeof(set), &set) == 0) {
 101                        if (i < *first)
 102                                *first = i;
 103                        if (i > *last)
 104                                *last = i;
 105                }
 106        }
 107}
 108
 109/* Opencoded version for fast mode */
 110static inline int vringh_get_head(struct vringh *vrh, u16 *head)
 111{
 112        u16 avail_idx, i;
 113        int err;
 114
 115        err = get_user(avail_idx, &vrh->vring.avail->idx);
 116        if (err)
 117                return err;
 118
 119        if (vrh->last_avail_idx == avail_idx)
 120                return 0;
 121
 122        /* Only get avail ring entries after they have been exposed by guest. */
 123        virtio_rmb(vrh->weak_barriers);
 124
 125        i = vrh->last_avail_idx & (vrh->vring.num - 1);
 126
 127        err = get_user(*head, &vrh->vring.avail->ring[i]);
 128        if (err)
 129                return err;
 130
 131        vrh->last_avail_idx++;
 132        return 1;
 133}
 134
 135static int parallel_test(u64 features,
 136                         bool (*getrange)(struct vringh *vrh,
 137                                          u64 addr, struct vringh_range *r),
 138                         bool fast_vringh)
 139{
 140        void *host_map, *guest_map;
 141        int fd, mapsize, to_guest[2], to_host[2];
 142        unsigned long xfers = 0, notifies = 0, receives = 0;
 143        unsigned int first_cpu, last_cpu;
 144        cpu_set_t cpu_set;
 145        char buf[128];
 146
 147        /* Create real file to mmap. */
 148        fd = open("/tmp/vringh_test-file", O_RDWR|O_CREAT|O_TRUNC, 0600);
 149        if (fd < 0)
 150                err(1, "Opening /tmp/vringh_test-file");
 151
 152        /* Extra room at the end for some data, and indirects */
 153        mapsize = vring_size(RINGSIZE, ALIGN)
 154                + RINGSIZE * 2 * sizeof(int)
 155                + RINGSIZE * 6 * sizeof(struct vring_desc);
 156        mapsize = (mapsize + getpagesize() - 1) & ~(getpagesize() - 1);
 157        ftruncate(fd, mapsize);
 158
 159        /* Parent and child use separate addresses, to check our mapping logic! */
 160        host_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
 161        guest_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
 162
 163        pipe(to_guest);
 164        pipe(to_host);
 165
 166        CPU_ZERO(&cpu_set);
 167        find_cpus(&first_cpu, &last_cpu);
 168        printf("Using CPUS %u and %u\n", first_cpu, last_cpu);
 169        fflush(stdout);
 170
 171        if (fork() != 0) {
 172                struct vringh vrh;
 173                int status, err, rlen = 0;
 174                char rbuf[5];
 175
 176                /* We are the host: never access guest addresses! */
 177                munmap(guest_map, mapsize);
 178
 179                __user_addr_min = host_map;
 180                __user_addr_max = __user_addr_min + mapsize;
 181                user_addr_offset = host_map - guest_map;
 182                assert(user_addr_offset);
 183
 184                close(to_guest[0]);
 185                close(to_host[1]);
 186
 187                vring_init(&vrh.vring, RINGSIZE, host_map, ALIGN);
 188                vringh_init_user(&vrh, features, RINGSIZE, true,
 189                                 vrh.vring.desc, vrh.vring.avail, vrh.vring.used);
 190                CPU_SET(first_cpu, &cpu_set);
 191                if (sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set))
 192                        errx(1, "Could not set affinity to cpu %u", first_cpu);
 193
 194                while (xfers < NUM_XFERS) {
 195                        struct iovec host_riov[2], host_wiov[2];
 196                        struct vringh_iov riov, wiov;
 197                        u16 head, written;
 198
 199                        if (fast_vringh) {
 200                                for (;;) {
 201                                        err = vringh_get_head(&vrh, &head);
 202                                        if (err != 0)
 203                                                break;
 204                                        err = vringh_need_notify_user(&vrh);
 205                                        if (err < 0)
 206                                                errx(1, "vringh_need_notify_user: %i",
 207                                                     err);
 208                                        if (err) {
 209                                                write(to_guest[1], "", 1);
 210                                                notifies++;
 211                                        }
 212                                }
 213                                if (err != 1)
 214                                        errx(1, "vringh_get_head");
 215                                written = 0;
 216                                goto complete;
 217                        } else {
 218                                vringh_iov_init(&riov,
 219                                                host_riov,
 220                                                ARRAY_SIZE(host_riov));
 221                                vringh_iov_init(&wiov,
 222                                                host_wiov,
 223                                                ARRAY_SIZE(host_wiov));
 224
 225                                err = vringh_getdesc_user(&vrh, &riov, &wiov,
 226                                                          getrange, &head);
 227                        }
 228                        if (err == 0) {
 229                                err = vringh_need_notify_user(&vrh);
 230                                if (err < 0)
 231                                        errx(1, "vringh_need_notify_user: %i",
 232                                             err);
 233                                if (err) {
 234                                        write(to_guest[1], "", 1);
 235                                        notifies++;
 236                                }
 237
 238                                if (!vringh_notify_enable_user(&vrh))
 239                                        continue;
 240
 241                                /* Swallow all notifies at once. */
 242                                if (read(to_host[0], buf, sizeof(buf)) < 1)
 243                                        break;
 244
 245                                vringh_notify_disable_user(&vrh);
 246                                receives++;
 247                                continue;
 248                        }
 249                        if (err != 1)
 250                                errx(1, "vringh_getdesc_user: %i", err);
 251
 252                        /* We simply copy bytes. */
 253                        if (riov.used) {
 254                                rlen = vringh_iov_pull_user(&riov, rbuf,
 255                                                            sizeof(rbuf));
 256                                if (rlen != 4)
 257                                        errx(1, "vringh_iov_pull_user: %i",
 258                                             rlen);
 259                                assert(riov.i == riov.used);
 260                                written = 0;
 261                        } else {
 262                                err = vringh_iov_push_user(&wiov, rbuf, rlen);
 263                                if (err != rlen)
 264                                        errx(1, "vringh_iov_push_user: %i",
 265                                             err);
 266                                assert(wiov.i == wiov.used);
 267                                written = err;
 268                        }
 269                complete:
 270                        xfers++;
 271
 272                        err = vringh_complete_user(&vrh, head, written);
 273                        if (err != 0)
 274                                errx(1, "vringh_complete_user: %i", err);
 275                }
 276
 277                err = vringh_need_notify_user(&vrh);
 278                if (err < 0)
 279                        errx(1, "vringh_need_notify_user: %i", err);
 280                if (err) {
 281                        write(to_guest[1], "", 1);
 282                        notifies++;
 283                }
 284                wait(&status);
 285                if (!WIFEXITED(status))
 286                        errx(1, "Child died with signal %i?", WTERMSIG(status));
 287                if (WEXITSTATUS(status) != 0)
 288                        errx(1, "Child exited %i?", WEXITSTATUS(status));
 289                printf("Host: notified %lu, pinged %lu\n", notifies, receives);
 290                return 0;
 291        } else {
 292                struct guest_virtio_device gvdev;
 293                struct virtqueue *vq;
 294                unsigned int *data;
 295                struct vring_desc *indirects;
 296                unsigned int finished = 0;
 297
 298                /* We pass sg[]s pointing into here, but we need RINGSIZE+1 */
 299                data = guest_map + vring_size(RINGSIZE, ALIGN);
 300                indirects = (void *)data + (RINGSIZE + 1) * 2 * sizeof(int);
 301
 302                /* We are the guest. */
 303                munmap(host_map, mapsize);
 304
 305                close(to_guest[1]);
 306                close(to_host[0]);
 307
 308                gvdev.vdev.features = features;
 309                gvdev.to_host_fd = to_host[1];
 310                gvdev.notifies = 0;
 311
 312                CPU_SET(first_cpu, &cpu_set);
 313                if (sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set))
 314                        err(1, "Could not set affinity to cpu %u", first_cpu);
 315
 316                vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &gvdev.vdev, true,
 317                                         guest_map, fast_vringh ? no_notify_host
 318                                         : parallel_notify_host,
 319                                         never_callback_guest, "guest vq");
 320
 321                /* Don't kfree indirects. */
 322                __kfree_ignore_start = indirects;
 323                __kfree_ignore_end = indirects + RINGSIZE * 6;
 324
 325                while (xfers < NUM_XFERS) {
 326                        struct scatterlist sg[4];
 327                        unsigned int num_sg, len;
 328                        int *dbuf, err;
 329                        bool output = !(xfers % 2);
 330
 331                        /* Consume bufs. */
 332                        while ((dbuf = virtqueue_get_buf(vq, &len)) != NULL) {
 333                                if (len == 4)
 334                                        assert(*dbuf == finished - 1);
 335                                else if (!fast_vringh)
 336                                        assert(*dbuf == finished);
 337                                finished++;
 338                        }
 339
 340                        /* Produce a buffer. */
 341                        dbuf = data + (xfers % (RINGSIZE + 1));
 342
 343                        if (output)
 344                                *dbuf = xfers;
 345                        else
 346                                *dbuf = -1;
 347
 348                        switch ((xfers / sizeof(*dbuf)) % 4) {
 349                        case 0:
 350                                /* Nasty three-element sg list. */
 351                                sg_init_table(sg, num_sg = 3);
 352                                sg_set_buf(&sg[0], (void *)dbuf, 1);
 353                                sg_set_buf(&sg[1], (void *)dbuf + 1, 2);
 354                                sg_set_buf(&sg[2], (void *)dbuf + 3, 1);
 355                                break;
 356                        case 1:
 357                                sg_init_table(sg, num_sg = 2);
 358                                sg_set_buf(&sg[0], (void *)dbuf, 1);
 359                                sg_set_buf(&sg[1], (void *)dbuf + 1, 3);
 360                                break;
 361                        case 2:
 362                                sg_init_table(sg, num_sg = 1);
 363                                sg_set_buf(&sg[0], (void *)dbuf, 4);
 364                                break;
 365                        case 3:
 366                                sg_init_table(sg, num_sg = 4);
 367                                sg_set_buf(&sg[0], (void *)dbuf, 1);
 368                                sg_set_buf(&sg[1], (void *)dbuf + 1, 1);
 369                                sg_set_buf(&sg[2], (void *)dbuf + 2, 1);
 370                                sg_set_buf(&sg[3], (void *)dbuf + 3, 1);
 371                                break;
 372                        }
 373
 374                        /* May allocate an indirect, so force it to allocate
 375                         * user addr */
 376                        __kmalloc_fake = indirects + (xfers % RINGSIZE) * 4;
 377                        if (output)
 378                                err = virtqueue_add_outbuf(vq, sg, num_sg, dbuf,
 379                                                           GFP_KERNEL);
 380                        else
 381                                err = virtqueue_add_inbuf(vq, sg, num_sg,
 382                                                          dbuf, GFP_KERNEL);
 383
 384                        if (err == -ENOSPC) {
 385                                if (!virtqueue_enable_cb_delayed(vq))
 386                                        continue;
 387                                /* Swallow all notifies at once. */
 388                                if (read(to_guest[0], buf, sizeof(buf)) < 1)
 389                                        break;
 390                                
 391                                receives++;
 392                                virtqueue_disable_cb(vq);
 393                                continue;
 394                        }
 395
 396                        if (err)
 397                                errx(1, "virtqueue_add_in/outbuf: %i", err);
 398
 399                        xfers++;
 400                        virtqueue_kick(vq);
 401                }
 402
 403                /* Any extra? */
 404                while (finished != xfers) {
 405                        int *dbuf;
 406                        unsigned int len;
 407
 408                        /* Consume bufs. */
 409                        dbuf = virtqueue_get_buf(vq, &len);
 410                        if (dbuf) {
 411                                if (len == 4)
 412                                        assert(*dbuf == finished - 1);
 413                                else
 414                                        assert(len == 0);
 415                                finished++;
 416                                continue;
 417                        }
 418
 419                        if (!virtqueue_enable_cb_delayed(vq))
 420                                continue;
 421                        if (read(to_guest[0], buf, sizeof(buf)) < 1)
 422                                break;
 423                                
 424                        receives++;
 425                        virtqueue_disable_cb(vq);
 426                }
 427
 428                printf("Guest: notified %lu, pinged %lu\n",
 429                       gvdev.notifies, receives);
 430                vring_del_virtqueue(vq);
 431                return 0;
 432        }
 433}
 434
 435int main(int argc, char *argv[])
 436{
 437        struct virtio_device vdev;
 438        struct virtqueue *vq;
 439        struct vringh vrh;
 440        struct scatterlist guest_sg[RINGSIZE], *sgs[2];
 441        struct iovec host_riov[2], host_wiov[2];
 442        struct vringh_iov riov, wiov;
 443        struct vring_used_elem used[RINGSIZE];
 444        char buf[28];
 445        u16 head;
 446        int err;
 447        unsigned i;
 448        void *ret;
 449        bool (*getrange)(struct vringh *vrh, u64 addr, struct vringh_range *r);
 450        bool fast_vringh = false, parallel = false;
 451
 452        getrange = getrange_iov;
 453        vdev.features = 0;
 454
 455        while (argv[1]) {
 456                if (strcmp(argv[1], "--indirect") == 0)
 457                        __virtio_set_bit(&vdev, VIRTIO_RING_F_INDIRECT_DESC);
 458                else if (strcmp(argv[1], "--eventidx") == 0)
 459                        __virtio_set_bit(&vdev, VIRTIO_RING_F_EVENT_IDX);
 460                else if (strcmp(argv[1], "--virtio-1") == 0)
 461                        __virtio_set_bit(&vdev, VIRTIO_F_VERSION_1);
 462                else if (strcmp(argv[1], "--slow-range") == 0)
 463                        getrange = getrange_slow;
 464                else if (strcmp(argv[1], "--fast-vringh") == 0)
 465                        fast_vringh = true;
 466                else if (strcmp(argv[1], "--parallel") == 0)
 467                        parallel = true;
 468                else
 469                        errx(1, "Unknown arg %s", argv[1]);
 470                argv++;
 471        }
 472
 473        if (parallel)
 474                return parallel_test(vdev.features, getrange, fast_vringh);
 475
 476        if (posix_memalign(&__user_addr_min, PAGE_SIZE, USER_MEM) != 0)
 477                abort();
 478        __user_addr_max = __user_addr_min + USER_MEM;
 479        memset(__user_addr_min, 0, vring_size(RINGSIZE, ALIGN));
 480
 481        /* Set up guest side. */
 482        vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &vdev, true,
 483                                 __user_addr_min,
 484                                 never_notify_host, never_callback_guest,
 485                                 "guest vq");
 486
 487        /* Set up host side. */
 488        vring_init(&vrh.vring, RINGSIZE, __user_addr_min, ALIGN);
 489        vringh_init_user(&vrh, vdev.features, RINGSIZE, true,
 490                         vrh.vring.desc, vrh.vring.avail, vrh.vring.used);
 491
 492        /* No descriptor to get yet... */
 493        err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
 494        if (err != 0)
 495                errx(1, "vringh_getdesc_user: %i", err);
 496
 497        /* Guest puts in a descriptor. */
 498        memcpy(__user_addr_max - 1, "a", 1);
 499        sg_init_table(guest_sg, 1);
 500        sg_set_buf(&guest_sg[0], __user_addr_max - 1, 1);
 501        sg_init_table(guest_sg+1, 1);
 502        sg_set_buf(&guest_sg[1], __user_addr_max - 3, 2);
 503        sgs[0] = &guest_sg[0];
 504        sgs[1] = &guest_sg[1];
 505
 506        /* May allocate an indirect, so force it to allocate user addr */
 507        __kmalloc_fake = __user_addr_min + vring_size(RINGSIZE, ALIGN);
 508        err = virtqueue_add_sgs(vq, sgs, 1, 1, &err, GFP_KERNEL);
 509        if (err)
 510                errx(1, "virtqueue_add_sgs: %i", err);
 511        __kmalloc_fake = NULL;
 512
 513        /* Host retreives it. */
 514        vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
 515        vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
 516
 517        err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
 518        if (err != 1)
 519                errx(1, "vringh_getdesc_user: %i", err);
 520
 521        assert(riov.used == 1);
 522        assert(riov.iov[0].iov_base == __user_addr_max - 1);
 523        assert(riov.iov[0].iov_len == 1);
 524        if (getrange != getrange_slow) {
 525                assert(wiov.used == 1);
 526                assert(wiov.iov[0].iov_base == __user_addr_max - 3);
 527                assert(wiov.iov[0].iov_len == 2);
 528        } else {
 529                assert(wiov.used == 2);
 530                assert(wiov.iov[0].iov_base == __user_addr_max - 3);
 531                assert(wiov.iov[0].iov_len == 1);
 532                assert(wiov.iov[1].iov_base == __user_addr_max - 2);
 533                assert(wiov.iov[1].iov_len == 1);
 534        }
 535
 536        err = vringh_iov_pull_user(&riov, buf, 5);
 537        if (err != 1)
 538                errx(1, "vringh_iov_pull_user: %i", err);
 539        assert(buf[0] == 'a');
 540        assert(riov.i == 1);
 541        assert(vringh_iov_pull_user(&riov, buf, 5) == 0);
 542
 543        memcpy(buf, "bcdef", 5);
 544        err = vringh_iov_push_user(&wiov, buf, 5);
 545        if (err != 2)
 546                errx(1, "vringh_iov_push_user: %i", err);
 547        assert(memcmp(__user_addr_max - 3, "bc", 2) == 0);
 548        assert(wiov.i == wiov.used);
 549        assert(vringh_iov_push_user(&wiov, buf, 5) == 0);
 550
 551        /* Host is done. */
 552        err = vringh_complete_user(&vrh, head, err);
 553        if (err != 0)
 554                errx(1, "vringh_complete_user: %i", err);
 555
 556        /* Guest should see used token now. */
 557        __kfree_ignore_start = __user_addr_min + vring_size(RINGSIZE, ALIGN);
 558        __kfree_ignore_end = __kfree_ignore_start + 1;
 559        ret = virtqueue_get_buf(vq, &i);
 560        if (ret != &err)
 561                errx(1, "virtqueue_get_buf: %p", ret);
 562        assert(i == 2);
 563
 564        /* Guest puts in a huge descriptor. */
 565        sg_init_table(guest_sg, RINGSIZE);
 566        for (i = 0; i < RINGSIZE; i++) {
 567                sg_set_buf(&guest_sg[i],
 568                           __user_addr_max - USER_MEM/4, USER_MEM/4);
 569        }
 570
 571        /* Fill contents with recognisable garbage. */
 572        for (i = 0; i < USER_MEM/4; i++)
 573                ((char *)__user_addr_max - USER_MEM/4)[i] = i;
 574
 575        /* This will allocate an indirect, so force it to allocate user addr */
 576        __kmalloc_fake = __user_addr_min + vring_size(RINGSIZE, ALIGN);
 577        err = virtqueue_add_outbuf(vq, guest_sg, RINGSIZE, &err, GFP_KERNEL);
 578        if (err)
 579                errx(1, "virtqueue_add_outbuf (large): %i", err);
 580        __kmalloc_fake = NULL;
 581
 582        /* Host picks it up (allocates new iov). */
 583        vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
 584        vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
 585
 586        err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
 587        if (err != 1)
 588                errx(1, "vringh_getdesc_user: %i", err);
 589
 590        assert(riov.max_num & VRINGH_IOV_ALLOCATED);
 591        assert(riov.iov != host_riov);
 592        if (getrange != getrange_slow)
 593                assert(riov.used == RINGSIZE);
 594        else
 595                assert(riov.used == RINGSIZE * USER_MEM/4);
 596
 597        assert(!(wiov.max_num & VRINGH_IOV_ALLOCATED));
 598        assert(wiov.used == 0);
 599
 600        /* Pull data back out (in odd chunks), should be as expected. */
 601        for (i = 0; i < RINGSIZE * USER_MEM/4; i += 3) {
 602                err = vringh_iov_pull_user(&riov, buf, 3);
 603                if (err != 3 && i + err != RINGSIZE * USER_MEM/4)
 604                        errx(1, "vringh_iov_pull_user large: %i", err);
 605                assert(buf[0] == (char)i);
 606                assert(err < 2 || buf[1] == (char)(i + 1));
 607                assert(err < 3 || buf[2] == (char)(i + 2));
 608        }
 609        assert(riov.i == riov.used);
 610        vringh_iov_cleanup(&riov);
 611        vringh_iov_cleanup(&wiov);
 612
 613        /* Complete using multi interface, just because we can. */
 614        used[0].id = head;
 615        used[0].len = 0;
 616        err = vringh_complete_multi_user(&vrh, used, 1);
 617        if (err)
 618                errx(1, "vringh_complete_multi_user(1): %i", err);
 619
 620        /* Free up those descriptors. */
 621        ret = virtqueue_get_buf(vq, &i);
 622        if (ret != &err)
 623                errx(1, "virtqueue_get_buf: %p", ret);
 624
 625        /* Add lots of descriptors. */
 626        sg_init_table(guest_sg, 1);
 627        sg_set_buf(&guest_sg[0], __user_addr_max - 1, 1);
 628        for (i = 0; i < RINGSIZE; i++) {
 629                err = virtqueue_add_outbuf(vq, guest_sg, 1, &err, GFP_KERNEL);
 630                if (err)
 631                        errx(1, "virtqueue_add_outbuf (multiple): %i", err);
 632        }
 633
 634        /* Now get many, and consume them all at once. */
 635        vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
 636        vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
 637
 638        for (i = 0; i < RINGSIZE; i++) {
 639                err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
 640                if (err != 1)
 641                        errx(1, "vringh_getdesc_user: %i", err);
 642                used[i].id = head;
 643                used[i].len = 0;
 644        }
 645        /* Make sure it wraps around ring, to test! */
 646        assert(vrh.vring.used->idx % RINGSIZE != 0);
 647        err = vringh_complete_multi_user(&vrh, used, RINGSIZE);
 648        if (err)
 649                errx(1, "vringh_complete_multi_user: %i", err);
 650
 651        /* Free those buffers. */
 652        for (i = 0; i < RINGSIZE; i++) {
 653                unsigned len;
 654                assert(virtqueue_get_buf(vq, &len) != NULL);
 655        }
 656
 657        /* Test weird (but legal!) indirect. */
 658        if (__virtio_test_bit(&vdev, VIRTIO_RING_F_INDIRECT_DESC)) {
 659                char *data = __user_addr_max - USER_MEM/4;
 660                struct vring_desc *d = __user_addr_max - USER_MEM/2;
 661                struct vring vring;
 662
 663                /* Force creation of direct, which we modify. */
 664                __virtio_clear_bit(&vdev, VIRTIO_RING_F_INDIRECT_DESC);
 665                vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &vdev, true,
 666                                         __user_addr_min,
 667                                         never_notify_host,
 668                                         never_callback_guest,
 669                                         "guest vq");
 670
 671                sg_init_table(guest_sg, 4);
 672                sg_set_buf(&guest_sg[0], d, sizeof(*d)*2);
 673                sg_set_buf(&guest_sg[1], d + 2, sizeof(*d)*1);
 674                sg_set_buf(&guest_sg[2], data + 6, 4);
 675                sg_set_buf(&guest_sg[3], d + 3, sizeof(*d)*3);
 676
 677                err = virtqueue_add_outbuf(vq, guest_sg, 4, &err, GFP_KERNEL);
 678                if (err)
 679                        errx(1, "virtqueue_add_outbuf (indirect): %i", err);
 680
 681                vring_init(&vring, RINGSIZE, __user_addr_min, ALIGN);
 682
 683                /* They're used in order, but double-check... */
 684                assert(vring.desc[0].addr == (unsigned long)d);
 685                assert(vring.desc[1].addr == (unsigned long)(d+2));
 686                assert(vring.desc[2].addr == (unsigned long)data + 6);
 687                assert(vring.desc[3].addr == (unsigned long)(d+3));
 688                vring.desc[0].flags |= VRING_DESC_F_INDIRECT;
 689                vring.desc[1].flags |= VRING_DESC_F_INDIRECT;
 690                vring.desc[3].flags |= VRING_DESC_F_INDIRECT;
 691
 692                /* First indirect */
 693                d[0].addr = (unsigned long)data;
 694                d[0].len = 1;
 695                d[0].flags = VRING_DESC_F_NEXT;
 696                d[0].next = 1;
 697                d[1].addr = (unsigned long)data + 1;
 698                d[1].len = 2;
 699                d[1].flags = 0;
 700
 701                /* Second indirect */
 702                d[2].addr = (unsigned long)data + 3;
 703                d[2].len = 3;
 704                d[2].flags = 0;
 705
 706                /* Third indirect */
 707                d[3].addr = (unsigned long)data + 10;
 708                d[3].len = 5;
 709                d[3].flags = VRING_DESC_F_NEXT;
 710                d[3].next = 1;
 711                d[4].addr = (unsigned long)data + 15;
 712                d[4].len = 6;
 713                d[4].flags = VRING_DESC_F_NEXT;
 714                d[4].next = 2;
 715                d[5].addr = (unsigned long)data + 21;
 716                d[5].len = 7;
 717                d[5].flags = 0;
 718
 719                /* Host picks it up (allocates new iov). */
 720                vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
 721                vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
 722
 723                err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
 724                if (err != 1)
 725                        errx(1, "vringh_getdesc_user: %i", err);
 726
 727                if (head != 0)
 728                        errx(1, "vringh_getdesc_user: head %i not 0", head);
 729
 730                assert(riov.max_num & VRINGH_IOV_ALLOCATED);
 731                if (getrange != getrange_slow)
 732                        assert(riov.used == 7);
 733                else
 734                        assert(riov.used == 28);
 735                err = vringh_iov_pull_user(&riov, buf, 29);
 736                assert(err == 28);
 737
 738                /* Data should be linear. */
 739                for (i = 0; i < err; i++)
 740                        assert(buf[i] == i);
 741                vringh_iov_cleanup(&riov);
 742        }
 743
 744        /* Don't leak memory... */
 745        vring_del_virtqueue(vq);
 746        free(__user_addr_min);
 747
 748        return 0;
 749}
 750