Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

file 941 lines (769 sloc) 25.323 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941
/*
* Virtio Support
*
* Copyright IBM, Corp. 2007
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/

#include <inttypes.h>

#include "trace.h"
#include "qemu-error.h"
#include "virtio.h"
#include "sysemu.h"
#include "qemu-barrier.h"

/* The alignment to use between consumer and producer parts of vring.
* x86 pagesize again. */
#define VIRTIO_PCI_VRING_ALIGN 4096

typedef struct VRingDesc
{
    uint64_t addr;
    uint32_t len;
    uint16_t flags;
    uint16_t next;
} VRingDesc;

typedef struct VRingAvail
{
    uint16_t flags;
    uint16_t idx;
    uint16_t ring[0];
} VRingAvail;

typedef struct VRingUsedElem
{
    uint32_t id;
    uint32_t len;
} VRingUsedElem;

typedef struct VRingUsed
{
    uint16_t flags;
    uint16_t idx;
    VRingUsedElem ring[0];
} VRingUsed;

typedef struct VRing
{
    unsigned int num;
    target_phys_addr_t desc;
    target_phys_addr_t avail;
    target_phys_addr_t used;
} VRing;

struct VirtQueue
{
    VRing vring;
    target_phys_addr_t pa;
    uint16_t last_avail_idx;
    int inuse;
    uint16_t vector;
    void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
    VirtIODevice *vdev;
    EventNotifier guest_notifier;
    EventNotifier host_notifier;
};

/* virt queue functions */
static void virtqueue_init(VirtQueue *vq)
{
    target_phys_addr_t pa = vq->pa;

    vq->vring.desc = pa;
    vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
    vq->vring.used = vring_align(vq->vring.avail +
                                 offsetof(VRingAvail, ring[vq->vring.num]),
                                 VIRTIO_PCI_VRING_ALIGN);
}

static inline uint64_t vring_desc_addr(target_phys_addr_t desc_pa, int i)
{
    target_phys_addr_t pa;
    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr);
    return ldq_phys(pa);
}

static inline uint32_t vring_desc_len(target_phys_addr_t desc_pa, int i)
{
    target_phys_addr_t pa;
    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len);
    return ldl_phys(pa);
}

static inline uint16_t vring_desc_flags(target_phys_addr_t desc_pa, int i)
{
    target_phys_addr_t pa;
    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags);
    return lduw_phys(pa);
}

static inline uint16_t vring_desc_next(target_phys_addr_t desc_pa, int i)
{
    target_phys_addr_t pa;
    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next);
    return lduw_phys(pa);
}

static inline uint16_t vring_avail_flags(VirtQueue *vq)
{
    target_phys_addr_t pa;
    pa = vq->vring.avail + offsetof(VRingAvail, flags);
    return lduw_phys(pa);
}

static inline uint16_t vring_avail_idx(VirtQueue *vq)
{
    target_phys_addr_t pa;
    pa = vq->vring.avail + offsetof(VRingAvail, idx);
    return lduw_phys(pa);
}

static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
{
    target_phys_addr_t pa;
    pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
    return lduw_phys(pa);
}

static inline void vring_used_ring_id(VirtQueue *vq, int i, uint32_t val)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, ring[i].id);
    stl_phys(pa, val);
}

static inline void vring_used_ring_len(VirtQueue *vq, int i, uint32_t val)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, ring[i].len);
    stl_phys(pa, val);
}

static uint16_t vring_used_idx(VirtQueue *vq)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, idx);
    return lduw_phys(pa);
}

static inline void vring_used_idx_increment(VirtQueue *vq, uint16_t val)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, idx);
    stw_phys(pa, vring_used_idx(vq) + val);
}

static inline uint16_t vring_used_flags(VirtQueue *vq)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, flags);
    return lduw_phys(pa);
}

static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, flags);
    stw_phys(pa, lduw_phys(pa) | mask);
}

static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
{
    target_phys_addr_t pa;
    pa = vq->vring.used + offsetof(VRingUsed, flags);
    stw_phys(pa, lduw_phys(pa) & ~mask);
}

void virtio_queue_set_notification(VirtQueue *vq, int enable)
{
    if (enable)
        vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
    else
        vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
}

int virtio_queue_ready(VirtQueue *vq)
{
    return vq->vring.avail != 0;
}

int virtio_queue_empty(VirtQueue *vq)
{
    return vring_avail_idx(vq) == vq->last_avail_idx;
}

void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
                    unsigned int len, unsigned int idx)
{
    unsigned int offset;
    int i;

    trace_virtqueue_fill(vq, elem, len, idx);

    offset = 0;
    for (i = 0; i < elem->in_num; i++) {
        size_t size = MIN(len - offset, elem->in_sg[i].iov_len);

        cpu_physical_memory_unmap(elem->in_sg[i].iov_base,
                                  elem->in_sg[i].iov_len,
                                  1, size);

        offset += elem->in_sg[i].iov_len;
    }

    for (i = 0; i < elem->out_num; i++)
        cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
                                  elem->out_sg[i].iov_len,
                                  0, elem->out_sg[i].iov_len);

    idx = (idx + vring_used_idx(vq)) % vq->vring.num;

    /* Get a pointer to the next entry in the used ring. */
    vring_used_ring_id(vq, idx, elem->index);
    vring_used_ring_len(vq, idx, len);
}

void virtqueue_flush(VirtQueue *vq, unsigned int count)
{
    /* Make sure buffer is written before we update index. */
    smp_wmb();
    trace_virtqueue_flush(vq, count);
    vring_used_idx_increment(vq, count);
    vq->inuse -= count;
}

void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
                    unsigned int len)
{
    virtqueue_fill(vq, elem, len, 0);
    virtqueue_flush(vq, 1);
}

static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
{
    uint16_t num_heads = vring_avail_idx(vq) - idx;

    /* Check it isn't doing very strange things with descriptor numbers. */
    if (num_heads > vq->vring.num) {
        error_report("Guest moved used index from %u to %u",
                     idx, vring_avail_idx(vq));
        exit(1);
    }
    /* On success, callers read a descriptor at vq->last_avail_idx.
* Make sure descriptor read does not bypass avail index read. */
    if (num_heads) {
        smp_rmb();
    }

    return num_heads;
}

static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx)
{
    unsigned int head;

    /* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
    head = vring_avail_ring(vq, idx % vq->vring.num);

    /* If their number is silly, that's a fatal mistake. */
    if (head >= vq->vring.num) {
        error_report("Guest says index %u is available", head);
        exit(1);
    }

    return head;
}

static unsigned virtqueue_next_desc(target_phys_addr_t desc_pa,
                                    unsigned int i, unsigned int max)
{
    unsigned int next;

    /* If this descriptor says it doesn't chain, we're done. */
    if (!(vring_desc_flags(desc_pa, i) & VRING_DESC_F_NEXT))
        return max;

    /* Check they're not leading us off end of descriptors. */
    next = vring_desc_next(desc_pa, i);
    /* Make sure compiler knows to grab that: we don't want it changing! */
    smp_wmb();

    if (next >= max) {
        error_report("Desc next is %u", next);
        exit(1);
    }

    return next;
}

int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int out_bytes)
{
    unsigned int idx;
    int total_bufs, in_total, out_total;

    idx = vq->last_avail_idx;

    total_bufs = in_total = out_total = 0;
    while (virtqueue_num_heads(vq, idx)) {
        unsigned int max, num_bufs, indirect = 0;
        target_phys_addr_t desc_pa;
        int i;

        max = vq->vring.num;
        num_bufs = total_bufs;
        i = virtqueue_get_head(vq, idx++);
        desc_pa = vq->vring.desc;

        if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
            if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
                error_report("Invalid size for indirect buffer table");
                exit(1);
            }

            /* If we've got too many, that implies a descriptor loop. */
            if (num_bufs >= max) {
                error_report("Looped descriptor");
                exit(1);
            }

            /* loop over the indirect descriptor table */
            indirect = 1;
            max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
            num_bufs = i = 0;
            desc_pa = vring_desc_addr(desc_pa, i);
        }

        do {
            /* If we've got too many, that implies a descriptor loop. */
            if (++num_bufs > max) {
                error_report("Looped descriptor");
                exit(1);
            }

            if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
                if (in_bytes > 0 &&
                    (in_total += vring_desc_len(desc_pa, i)) >= in_bytes)
                    return 1;
            } else {
                if (out_bytes > 0 &&
                    (out_total += vring_desc_len(desc_pa, i)) >= out_bytes)
                    return 1;
            }
        } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);

        if (!indirect)
            total_bufs = num_bufs;
        else
            total_bufs++;
    }

    return 0;
}

void virtqueue_map_sg(struct iovec *sg, target_phys_addr_t *addr,
    size_t num_sg, int is_write)
{
    unsigned int i;
    target_phys_addr_t len;

    for (i = 0; i < num_sg; i++) {
        len = sg[i].iov_len;
        sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
        if (sg[i].iov_base == NULL || len != sg[i].iov_len) {
            error_report("virtio: trying to map MMIO memory");
            exit(1);
        }
    }
}

int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
{
    unsigned int i, head, max;
    target_phys_addr_t desc_pa = vq->vring.desc;

    if (!virtqueue_num_heads(vq, vq->last_avail_idx))
        return 0;

    /* When we start there are none of either input nor output. */
    elem->out_num = elem->in_num = 0;

    max = vq->vring.num;

    i = head = virtqueue_get_head(vq, vq->last_avail_idx++);

    if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
        if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
            error_report("Invalid size for indirect buffer table");
            exit(1);
        }

        /* loop over the indirect descriptor table */
        max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
        desc_pa = vring_desc_addr(desc_pa, i);
        i = 0;
    }

    /* Collect all the descriptors */
    do {
        struct iovec *sg;

        if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
            elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i);
            sg = &elem->in_sg[elem->in_num++];
        } else {
            elem->out_addr[elem->out_num] = vring_desc_addr(desc_pa, i);
            sg = &elem->out_sg[elem->out_num++];
        }

        sg->iov_len = vring_desc_len(desc_pa, i);

        /* If we've got too many, that implies a descriptor loop. */
        if ((elem->in_num + elem->out_num) > max) {
            error_report("Looped descriptor");
            exit(1);
        }
    } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);

    /* Now map what we have collected */
    virtqueue_map_sg(elem->in_sg, elem->in_addr, elem->in_num, 1);
    virtqueue_map_sg(elem->out_sg, elem->out_addr, elem->out_num, 0);

    elem->index = head;

    vq->inuse++;

    trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
    return elem->in_num + elem->out_num;
}

/* virtio device */
static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
{
    if (vdev->binding->notify) {
        vdev->binding->notify(vdev->binding_opaque, vector);
    }
}

void virtio_update_irq(VirtIODevice *vdev)
{
    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
}

void virtio_reset(void *opaque)
{
    VirtIODevice *vdev = opaque;
    int i;

    virtio_set_status(vdev, 0);

    if (vdev->reset)
        vdev->reset(vdev);

    vdev->guest_features = 0;
    vdev->queue_sel = 0;
    vdev->status = 0;
    vdev->isr = 0;
    vdev->config_vector = VIRTIO_NO_VECTOR;
    virtio_notify_vector(vdev, vdev->config_vector);

    for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
        vdev->vq[i].vring.desc = 0;
        vdev->vq[i].vring.avail = 0;
        vdev->vq[i].vring.used = 0;
        vdev->vq[i].last_avail_idx = 0;
        vdev->vq[i].pa = 0;
        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
    }
}

uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
{
    uint8_t val;

    vdev->get_config(vdev, vdev->config);

    if (addr > (vdev->config_len - sizeof(val)))
        return (uint32_t)-1;

    memcpy(&val, vdev->config + addr, sizeof(val));
    return val;
}

uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
{
    uint16_t val;

    vdev->get_config(vdev, vdev->config);

    if (addr > (vdev->config_len - sizeof(val)))
        return (uint32_t)-1;

    memcpy(&val, vdev->config + addr, sizeof(val));
    return val;
}

uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
{
    uint32_t val;

    vdev->get_config(vdev, vdev->config);

    if (addr > (vdev->config_len - sizeof(val)))
        return (uint32_t)-1;

    memcpy(&val, vdev->config + addr, sizeof(val));
    return val;
}

void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
{
    uint8_t val = data;

    if (addr > (vdev->config_len - sizeof(val)))
        return;

    memcpy(vdev->config + addr, &val, sizeof(val));

    if (vdev->set_config)
        vdev->set_config(vdev, vdev->config);
}

void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
{
    uint16_t val = data;

    if (addr > (vdev->config_len - sizeof(val)))
        return;

    memcpy(vdev->config + addr, &val, sizeof(val));

    if (vdev->set_config)
        vdev->set_config(vdev, vdev->config);
}

void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
{
    uint32_t val = data;

    if (addr > (vdev->config_len - sizeof(val)))
        return;

    memcpy(vdev->config + addr, &val, sizeof(val));

    if (vdev->set_config)
        vdev->set_config(vdev, vdev->config);
}

void virtio_queue_set_addr(VirtIODevice *vdev, int n, target_phys_addr_t addr)
{
    vdev->vq[n].pa = addr;
    virtqueue_init(&vdev->vq[n]);
}

target_phys_addr_t virtio_queue_get_addr(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].pa;
}

int virtio_queue_get_num(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.num;
}

void virtio_queue_notify_vq(VirtQueue *vq)
{
    if (vq->vring.desc) {
        VirtIODevice *vdev = vq->vdev;
        trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
        vq->handle_output(vdev, vq);
    }
}

void virtio_queue_notify(VirtIODevice *vdev, int n)
{
    if (n < VIRTIO_PCI_QUEUE_MAX) {
        virtio_queue_notify_vq(&vdev->vq[n]);
    }
}

uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
{
    return n < VIRTIO_PCI_QUEUE_MAX ? vdev->vq[n].vector :
        VIRTIO_NO_VECTOR;
}

void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
{
    if (n < VIRTIO_PCI_QUEUE_MAX)
        vdev->vq[n].vector = vector;
}

VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
                            void (*handle_output)(VirtIODevice *, VirtQueue *))
{
    int i;

    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
        if (vdev->vq[i].vring.num == 0)
            break;
    }

    if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
        abort();

    vdev->vq[i].vring.num = queue_size;
    vdev->vq[i].handle_output = handle_output;

    return &vdev->vq[i];
}

void virtio_irq(VirtQueue *vq)
{
    trace_virtio_irq(vq);
    vq->vdev->isr |= 0x01;
    virtio_notify_vector(vq->vdev, vq->vector);
}

int virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
{
    /* We need to expose used array entries before checking used event. */
    smp_mb();
    /* Always notify when queue is empty (when feature acknowledge) */
    if ((vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT) &&
        (!(vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) ||
         (vq->inuse || vring_avail_idx(vq) != vq->last_avail_idx)))
        return 0;

    trace_virtio_notify(vdev, vq);
    vdev->isr |= 0x01;
    virtio_notify_vector(vdev, vq->vector);
    return 1;
}

void virtio_notify_config(VirtIODevice *vdev)
{
    if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
        return;

    vdev->isr |= 0x03;
    virtio_notify_vector(vdev, vdev->config_vector);
}

void virtio_save(VirtIODevice *vdev, QEMUFile *f)
{
    int i;

    if (vdev->binding->save_config)
        vdev->binding->save_config(vdev->binding_opaque, f);

    qemu_put_8s(f, &vdev->status);
    qemu_put_8s(f, &vdev->isr);
    qemu_put_be16s(f, &vdev->queue_sel);
    qemu_put_be32s(f, &vdev->guest_features);
    qemu_put_be32(f, vdev->config_len);
    qemu_put_buffer(f, vdev->config, vdev->config_len);

    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
        if (vdev->vq[i].vring.num == 0)
            break;
    }

    qemu_put_be32(f, i);

    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
        if (vdev->vq[i].vring.num == 0)
            break;

        qemu_put_be32(f, vdev->vq[i].vring.num);
        qemu_put_be64(f, vdev->vq[i].pa);
        qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
        if (vdev->binding->save_queue)
            vdev->binding->save_queue(vdev->binding_opaque, i, f);
    }
}

int virtio_load(VirtIODevice *vdev, QEMUFile *f)
{
    int num, i, ret;
    uint32_t features;
    uint32_t supported_features =
        vdev->binding->get_features(vdev->binding_opaque);

    if (vdev->binding->load_config) {
        ret = vdev->binding->load_config(vdev->binding_opaque, f);
        if (ret)
            return ret;
    }

    qemu_get_8s(f, &vdev->status);
    qemu_get_8s(f, &vdev->isr);
    qemu_get_be16s(f, &vdev->queue_sel);
    qemu_get_be32s(f, &features);
    if (features & ~supported_features) {
        error_report("Features 0x%x unsupported. Allowed features: 0x%x",
                     features, supported_features);
        return -1;
    }
    if (vdev->set_features)
        vdev->set_features(vdev, features);
    vdev->guest_features = features;
    vdev->config_len = qemu_get_be32(f);
    qemu_get_buffer(f, vdev->config, vdev->config_len);

    num = qemu_get_be32(f);

    for (i = 0; i < num; i++) {
        vdev->vq[i].vring.num = qemu_get_be32(f);
        vdev->vq[i].pa = qemu_get_be64(f);
        qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);

        if (vdev->vq[i].pa) {
            uint16_t nheads;
            virtqueue_init(&vdev->vq[i]);
            nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
            /* Check it isn't doing very strange things with descriptor numbers. */
            if (nheads > vdev->vq[i].vring.num) {
                error_report("VQ %d size 0x%x Guest index 0x%x "
                             "inconsistent with Host index 0x%x: delta 0x%x\n",
                             i, vdev->vq[i].vring.num,
                             vring_avail_idx(&vdev->vq[i]),
                             vdev->vq[i].last_avail_idx, nheads);
                return -1;
            }
        } else if (vdev->vq[i].last_avail_idx) {
            error_report("VQ %d address 0x0 "
                         "inconsistent with Host index 0x%x\n",
                         i, vdev->vq[i].last_avail_idx);
                return -1;
}
        if (vdev->binding->load_queue) {
            ret = vdev->binding->load_queue(vdev->binding_opaque, i, f);
            if (ret)
                return ret;
        }
    }

    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
    return 0;
}

void virtio_cleanup(VirtIODevice *vdev)
{
    qemu_del_vm_change_state_handler(vdev->vmstate);
    if (vdev->config)
        qemu_free(vdev->config);
    qemu_free(vdev->vq);
}

static void virtio_vmstate_change(void *opaque, int running, int reason)
{
    VirtIODevice *vdev = opaque;
    bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
    vdev->vm_running = running;

    if (backend_run) {
        virtio_set_status(vdev, vdev->status);
    }

    if (vdev->binding->vmstate_change) {
        vdev->binding->vmstate_change(vdev->binding_opaque, backend_run);
    }

    if (!backend_run) {
        virtio_set_status(vdev, vdev->status);
    }
}

VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
                                 size_t config_size, size_t struct_size)
{
    VirtIODevice *vdev;
    int i;

    vdev = qemu_mallocz(struct_size);

    vdev->device_id = device_id;
    vdev->status = 0;
    vdev->isr = 0;
    vdev->queue_sel = 0;
    vdev->config_vector = VIRTIO_NO_VECTOR;
    vdev->vq = qemu_mallocz(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX);
    for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
        vdev->vq[i].vdev = vdev;
    }

    vdev->name = name;
    vdev->config_len = config_size;
    if (vdev->config_len)
        vdev->config = qemu_mallocz(config_size);
    else
        vdev->config = NULL;

    vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change, vdev);

    return vdev;
}

void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding,
                        void *opaque)
{
    vdev->binding = binding;
    vdev->binding_opaque = opaque;
}

target_phys_addr_t virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.desc;
}

target_phys_addr_t virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.avail;
}

target_phys_addr_t virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.used;
}

target_phys_addr_t virtio_queue_get_ring_addr(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.desc;
}

target_phys_addr_t virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
{
    return sizeof(VRingDesc) * vdev->vq[n].vring.num;
}

target_phys_addr_t virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
{
    return offsetof(VRingAvail, ring) +
        sizeof(uint64_t) * vdev->vq[n].vring.num;
}

target_phys_addr_t virtio_queue_get_used_size(VirtIODevice *vdev, int n)
{
    return offsetof(VRingUsed, ring) +
        sizeof(VRingUsedElem) * vdev->vq[n].vring.num;
}

target_phys_addr_t virtio_queue_get_ring_size(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.used - vdev->vq[n].vring.desc +
virtio_queue_get_used_size(vdev, n);
}

uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].last_avail_idx;
}

void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
{
    vdev->vq[n].last_avail_idx = idx;
}

VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
{
    return vdev->vq + n;
}

EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
{
    return &vq->guest_notifier;
}
EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
{
    return &vq->host_notifier;
}

int virtqueue_handled(VirtQueue *vq)
{
smp_mb();
return (vq->last_avail_idx == vring_used_idx(vq) ||
vq->last_avail_idx != vring_avail_idx(vq));
}

/*
* We need to go through and check if we have hit the 'stalled' condition.
* Due to the way that the virtio driver is implemented in the Linux kernel, it
* will potentially kick the guest to process data, disable the queue, but not
* enable interrupts before the host is done processing packets. When this
* happens all network traffic from the guest ends up getting corked up because
* the guest disabled the queue and is waiting for an interrupt from the host to
* go and enable it again. In fact, when in this state a little bit of libproc
* magic gets us going again rather reliably.
*
* Eventually the guest will go through and unmask interrupts saying that it
* wants an injection. If we reach a point in time where the last seen available
* index is equal to the available index ring and is equal to the used index
* ring, then we'll go ahead and install the interupt.
*/
int virtqueue_stalled(VirtQueue *vq)
{
smp_mb();

if (vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT)
return (0);

if (vring_used_flags(vq) & VRING_USED_F_NO_NOTIFY)
return (0);

if (vq->inuse)
return (0);

/* We could have also lost the interrupt the other way */
if (vq->last_avail_idx != vring_avail_idx(vq))
return (2);

if (vq->last_avail_idx != vring_used_idx(vq))
return (0);

/*
* Interrupts are enabled and we're at a point in time where we would
* have stalled. Let's go ahead and inject the interrupt.
*/
trace_virtio_notify(vq->vdev, vq);
vq->vdev->isr |= 0x01;
virtio_notify_vector(vq->vdev, vq->vector);
return (1);
}
Something went wrong with that request. Please try again.