qemu/hw/virtio/virtio.c
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   1/*
   2 * Virtio Support
   3 *
   4 * Copyright IBM, Corp. 2007
   5 *
   6 * Authors:
   7 *  Anthony Liguori   <aliguori@us.ibm.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2.  See
  10 * the COPYING file in the top-level directory.
  11 *
  12 */
  13
  14#include "qemu/osdep.h"
  15#include "qapi/error.h"
  16#include "qemu-common.h"
  17#include "cpu.h"
  18#include "trace.h"
  19#include "exec/address-spaces.h"
  20#include "qemu/error-report.h"
  21#include "hw/virtio/virtio.h"
  22#include "qemu/atomic.h"
  23#include "hw/virtio/virtio-bus.h"
  24#include "hw/virtio/virtio-access.h"
  25#include "sysemu/dma.h"
  26
  27/*
  28 * The alignment to use between consumer and producer parts of vring.
  29 * x86 pagesize again. This is the default, used by transports like PCI
  30 * which don't provide a means for the guest to tell the host the alignment.
  31 */
  32#define VIRTIO_PCI_VRING_ALIGN         4096
  33
  34typedef struct VRingDesc
  35{
  36    uint64_t addr;
  37    uint32_t len;
  38    uint16_t flags;
  39    uint16_t next;
  40} VRingDesc;
  41
  42typedef struct VRingAvail
  43{
  44    uint16_t flags;
  45    uint16_t idx;
  46    uint16_t ring[0];
  47} VRingAvail;
  48
  49typedef struct VRingUsedElem
  50{
  51    uint32_t id;
  52    uint32_t len;
  53} VRingUsedElem;
  54
  55typedef struct VRingUsed
  56{
  57    uint16_t flags;
  58    uint16_t idx;
  59    VRingUsedElem ring[0];
  60} VRingUsed;
  61
  62typedef struct VRingMemoryRegionCaches {
  63    struct rcu_head rcu;
  64    MemoryRegionCache desc;
  65    MemoryRegionCache avail;
  66    MemoryRegionCache used;
  67} VRingMemoryRegionCaches;
  68
  69typedef struct VRing
  70{
  71    unsigned int num;
  72    unsigned int num_default;
  73    unsigned int align;
  74    hwaddr desc;
  75    hwaddr avail;
  76    hwaddr used;
  77    VRingMemoryRegionCaches *caches;
  78} VRing;
  79
  80struct VirtQueue
  81{
  82    VRing vring;
  83
  84    /* Next head to pop */
  85    uint16_t last_avail_idx;
  86
  87    /* Last avail_idx read from VQ. */
  88    uint16_t shadow_avail_idx;
  89
  90    uint16_t used_idx;
  91
  92    /* Last used index value we have signalled on */
  93    uint16_t signalled_used;
  94
  95    /* Last used index value we have signalled on */
  96    bool signalled_used_valid;
  97
  98    /* Notification enabled? */
  99    bool notification;
 100
 101    uint16_t queue_index;
 102
 103    unsigned int inuse;
 104
 105    uint16_t vector;
 106    VirtIOHandleOutput handle_output;
 107    VirtIOHandleAIOOutput handle_aio_output;
 108    VirtIODevice *vdev;
 109    EventNotifier guest_notifier;
 110    EventNotifier host_notifier;
 111    QLIST_ENTRY(VirtQueue) node;
 112};
 113
 114static void virtio_free_region_cache(VRingMemoryRegionCaches *caches)
 115{
 116    if (!caches) {
 117        return;
 118    }
 119
 120    address_space_cache_destroy(&caches->desc);
 121    address_space_cache_destroy(&caches->avail);
 122    address_space_cache_destroy(&caches->used);
 123    g_free(caches);
 124}
 125
 126static void virtio_init_region_cache(VirtIODevice *vdev, int n)
 127{
 128    VirtQueue *vq = &vdev->vq[n];
 129    VRingMemoryRegionCaches *old = vq->vring.caches;
 130    VRingMemoryRegionCaches *new;
 131    hwaddr addr, size;
 132    int event_size;
 133    int64_t len;
 134
 135    event_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
 136
 137    addr = vq->vring.desc;
 138    if (!addr) {
 139        return;
 140    }
 141    new = g_new0(VRingMemoryRegionCaches, 1);
 142    size = virtio_queue_get_desc_size(vdev, n);
 143    len = address_space_cache_init(&new->desc, vdev->dma_as,
 144                                   addr, size, false);
 145    if (len < size) {
 146        virtio_error(vdev, "Cannot map desc");
 147        goto err_desc;
 148    }
 149
 150    size = virtio_queue_get_used_size(vdev, n) + event_size;
 151    len = address_space_cache_init(&new->used, vdev->dma_as,
 152                                   vq->vring.used, size, true);
 153    if (len < size) {
 154        virtio_error(vdev, "Cannot map used");
 155        goto err_used;
 156    }
 157
 158    size = virtio_queue_get_avail_size(vdev, n) + event_size;
 159    len = address_space_cache_init(&new->avail, vdev->dma_as,
 160                                   vq->vring.avail, size, false);
 161    if (len < size) {
 162        virtio_error(vdev, "Cannot map avail");
 163        goto err_avail;
 164    }
 165
 166    atomic_rcu_set(&vq->vring.caches, new);
 167    if (old) {
 168        call_rcu(old, virtio_free_region_cache, rcu);
 169    }
 170    return;
 171
 172err_avail:
 173    address_space_cache_destroy(&new->used);
 174err_used:
 175    address_space_cache_destroy(&new->desc);
 176err_desc:
 177    g_free(new);
 178}
 179
 180/* virt queue functions */
 181void virtio_queue_update_rings(VirtIODevice *vdev, int n)
 182{
 183    VRing *vring = &vdev->vq[n].vring;
 184
 185    if (!vring->desc) {
 186        /* not yet setup -> nothing to do */
 187        return;
 188    }
 189    vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
 190    vring->used = vring_align(vring->avail +
 191                              offsetof(VRingAvail, ring[vring->num]),
 192                              vring->align);
 193    virtio_init_region_cache(vdev, n);
 194}
 195
 196/* Called within rcu_read_lock().  */
 197static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
 198                            MemoryRegionCache *cache, int i)
 199{
 200    address_space_read_cached(cache, i * sizeof(VRingDesc),
 201                              desc, sizeof(VRingDesc));
 202    virtio_tswap64s(vdev, &desc->addr);
 203    virtio_tswap32s(vdev, &desc->len);
 204    virtio_tswap16s(vdev, &desc->flags);
 205    virtio_tswap16s(vdev, &desc->next);
 206}
 207
 208static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq)
 209{
 210    VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
 211    assert(caches != NULL);
 212    return caches;
 213}
 214/* Called within rcu_read_lock().  */
 215static inline uint16_t vring_avail_flags(VirtQueue *vq)
 216{
 217    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 218    hwaddr pa = offsetof(VRingAvail, flags);
 219    return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
 220}
 221
 222/* Called within rcu_read_lock().  */
 223static inline uint16_t vring_avail_idx(VirtQueue *vq)
 224{
 225    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 226    hwaddr pa = offsetof(VRingAvail, idx);
 227    vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
 228    return vq->shadow_avail_idx;
 229}
 230
 231/* Called within rcu_read_lock().  */
 232static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
 233{
 234    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 235    hwaddr pa = offsetof(VRingAvail, ring[i]);
 236    return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
 237}
 238
 239/* Called within rcu_read_lock().  */
 240static inline uint16_t vring_get_used_event(VirtQueue *vq)
 241{
 242    return vring_avail_ring(vq, vq->vring.num);
 243}
 244
 245/* Called within rcu_read_lock().  */
 246static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
 247                                    int i)
 248{
 249    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 250    hwaddr pa = offsetof(VRingUsed, ring[i]);
 251    virtio_tswap32s(vq->vdev, &uelem->id);
 252    virtio_tswap32s(vq->vdev, &uelem->len);
 253    address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
 254    address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
 255}
 256
 257/* Called within rcu_read_lock().  */
 258static uint16_t vring_used_idx(VirtQueue *vq)
 259{
 260    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 261    hwaddr pa = offsetof(VRingUsed, idx);
 262    return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
 263}
 264
 265/* Called within rcu_read_lock().  */
 266static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
 267{
 268    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 269    hwaddr pa = offsetof(VRingUsed, idx);
 270    virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
 271    address_space_cache_invalidate(&caches->used, pa, sizeof(val));
 272    vq->used_idx = val;
 273}
 274
 275/* Called within rcu_read_lock().  */
 276static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
 277{
 278    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 279    VirtIODevice *vdev = vq->vdev;
 280    hwaddr pa = offsetof(VRingUsed, flags);
 281    uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
 282
 283    virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
 284    address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
 285}
 286
 287/* Called within rcu_read_lock().  */
 288static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
 289{
 290    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
 291    VirtIODevice *vdev = vq->vdev;
 292    hwaddr pa = offsetof(VRingUsed, flags);
 293    uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
 294
 295    virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
 296    address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
 297}
 298
 299/* Called within rcu_read_lock().  */
 300static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
 301{
 302    VRingMemoryRegionCaches *caches;
 303    hwaddr pa;
 304    if (!vq->notification) {
 305        return;
 306    }
 307
 308    caches = vring_get_region_caches(vq);
 309    pa = offsetof(VRingUsed, ring[vq->vring.num]);
 310    virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
 311    address_space_cache_invalidate(&caches->used, pa, sizeof(val));
 312}
 313
 314void virtio_queue_set_notification(VirtQueue *vq, int enable)
 315{
 316    vq->notification = enable;
 317
 318    if (!vq->vring.desc) {
 319        return;
 320    }
 321
 322    rcu_read_lock();
 323    if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
 324        vring_set_avail_event(vq, vring_avail_idx(vq));
 325    } else if (enable) {
 326        vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
 327    } else {
 328        vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
 329    }
 330    if (enable) {
 331        /* Expose avail event/used flags before caller checks the avail idx. */
 332        smp_mb();
 333    }
 334    rcu_read_unlock();
 335}
 336
 337int virtio_queue_ready(VirtQueue *vq)
 338{
 339    return vq->vring.avail != 0;
 340}
 341
 342/* Fetch avail_idx from VQ memory only when we really need to know if
 343 * guest has added some buffers.
 344 * Called within rcu_read_lock().  */
 345static int virtio_queue_empty_rcu(VirtQueue *vq)
 346{
 347    if (unlikely(!vq->vring.avail)) {
 348        return 1;
 349    }
 350
 351    if (vq->shadow_avail_idx != vq->last_avail_idx) {
 352        return 0;
 353    }
 354
 355    return vring_avail_idx(vq) == vq->last_avail_idx;
 356}
 357
 358int virtio_queue_empty(VirtQueue *vq)
 359{
 360    bool empty;
 361
 362    if (unlikely(!vq->vring.avail)) {
 363        return 1;
 364    }
 365
 366    if (vq->shadow_avail_idx != vq->last_avail_idx) {
 367        return 0;
 368    }
 369
 370    rcu_read_lock();
 371    empty = vring_avail_idx(vq) == vq->last_avail_idx;
 372    rcu_read_unlock();
 373    return empty;
 374}
 375
 376static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
 377                               unsigned int len)
 378{
 379    AddressSpace *dma_as = vq->vdev->dma_as;
 380    unsigned int offset;
 381    int i;
 382
 383    offset = 0;
 384    for (i = 0; i < elem->in_num; i++) {
 385        size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
 386
 387        dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
 388                         elem->in_sg[i].iov_len,
 389                         DMA_DIRECTION_FROM_DEVICE, size);
 390
 391        offset += size;
 392    }
 393
 394    for (i = 0; i < elem->out_num; i++)
 395        dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
 396                         elem->out_sg[i].iov_len,
 397                         DMA_DIRECTION_TO_DEVICE,
 398                         elem->out_sg[i].iov_len);
 399}
 400
 401/* virtqueue_detach_element:
 402 * @vq: The #VirtQueue
 403 * @elem: The #VirtQueueElement
 404 * @len: number of bytes written
 405 *
 406 * Detach the element from the virtqueue.  This function is suitable for device
 407 * reset or other situations where a #VirtQueueElement is simply freed and will
 408 * not be pushed or discarded.
 409 */
 410void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
 411                              unsigned int len)
 412{
 413    vq->inuse--;
 414    virtqueue_unmap_sg(vq, elem, len);
 415}
 416
 417/* virtqueue_unpop:
 418 * @vq: The #VirtQueue
 419 * @elem: The #VirtQueueElement
 420 * @len: number of bytes written
 421 *
 422 * Pretend the most recent element wasn't popped from the virtqueue.  The next
 423 * call to virtqueue_pop() will refetch the element.
 424 */
 425void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem,
 426                     unsigned int len)
 427{
 428    vq->last_avail_idx--;
 429    virtqueue_detach_element(vq, elem, len);
 430}
 431
 432/* virtqueue_rewind:
 433 * @vq: The #VirtQueue
 434 * @num: Number of elements to push back
 435 *
 436 * Pretend that elements weren't popped from the virtqueue.  The next
 437 * virtqueue_pop() will refetch the oldest element.
 438 *
 439 * Use virtqueue_unpop() instead if you have a VirtQueueElement.
 440 *
 441 * Returns: true on success, false if @num is greater than the number of in use
 442 * elements.
 443 */
 444bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
 445{
 446    if (num > vq->inuse) {
 447        return false;
 448    }
 449    vq->last_avail_idx -= num;
 450    vq->inuse -= num;
 451    return true;
 452}
 453
 454/* Called within rcu_read_lock().  */
 455void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
 456                    unsigned int len, unsigned int idx)
 457{
 458    VRingUsedElem uelem;
 459
 460    trace_virtqueue_fill(vq, elem, len, idx);
 461
 462    virtqueue_unmap_sg(vq, elem, len);
 463
 464    if (unlikely(vq->vdev->broken)) {
 465        return;
 466    }
 467
 468    if (unlikely(!vq->vring.used)) {
 469        return;
 470    }
 471
 472    idx = (idx + vq->used_idx) % vq->vring.num;
 473
 474    uelem.id = elem->index;
 475    uelem.len = len;
 476    vring_used_write(vq, &uelem, idx);
 477}
 478
 479/* Called within rcu_read_lock().  */
 480void virtqueue_flush(VirtQueue *vq, unsigned int count)
 481{
 482    uint16_t old, new;
 483
 484    if (unlikely(vq->vdev->broken)) {
 485        vq->inuse -= count;
 486        return;
 487    }
 488
 489    if (unlikely(!vq->vring.used)) {
 490        return;
 491    }
 492
 493    /* Make sure buffer is written before we update index. */
 494    smp_wmb();
 495    trace_virtqueue_flush(vq, count);
 496    old = vq->used_idx;
 497    new = old + count;
 498    vring_used_idx_set(vq, new);
 499    vq->inuse -= count;
 500    if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
 501        vq->signalled_used_valid = false;
 502}
 503
 504void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
 505                    unsigned int len)
 506{
 507    rcu_read_lock();
 508    virtqueue_fill(vq, elem, len, 0);
 509    virtqueue_flush(vq, 1);
 510    rcu_read_unlock();
 511}
 512
 513/* Called within rcu_read_lock().  */
 514static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
 515{
 516    uint16_t num_heads = vring_avail_idx(vq) - idx;
 517
 518    /* Check it isn't doing very strange things with descriptor numbers. */
 519    if (num_heads > vq->vring.num) {
 520        virtio_error(vq->vdev, "Guest moved used index from %u to %u",
 521                     idx, vq->shadow_avail_idx);
 522        return -EINVAL;
 523    }
 524    /* On success, callers read a descriptor at vq->last_avail_idx.
 525     * Make sure descriptor read does not bypass avail index read. */
 526    if (num_heads) {
 527        smp_rmb();
 528    }
 529
 530    return num_heads;
 531}
 532
 533/* Called within rcu_read_lock().  */
 534static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
 535                               unsigned int *head)
 536{
 537    /* Grab the next descriptor number they're advertising, and increment
 538     * the index we've seen. */
 539    *head = vring_avail_ring(vq, idx % vq->vring.num);
 540
 541    /* If their number is silly, that's a fatal mistake. */
 542    if (*head >= vq->vring.num) {
 543        virtio_error(vq->vdev, "Guest says index %u is available", *head);
 544        return false;
 545    }
 546
 547    return true;
 548}
 549
 550enum {
 551    VIRTQUEUE_READ_DESC_ERROR = -1,
 552    VIRTQUEUE_READ_DESC_DONE = 0,   /* end of chain */
 553    VIRTQUEUE_READ_DESC_MORE = 1,   /* more buffers in chain */
 554};
 555
 556static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
 557                                    MemoryRegionCache *desc_cache, unsigned int max,
 558                                    unsigned int *next)
 559{
 560    /* If this descriptor says it doesn't chain, we're done. */
 561    if (!(desc->flags & VRING_DESC_F_NEXT)) {
 562        return VIRTQUEUE_READ_DESC_DONE;
 563    }
 564
 565    /* Check they're not leading us off end of descriptors. */
 566    *next = desc->next;
 567    /* Make sure compiler knows to grab that: we don't want it changing! */
 568    smp_wmb();
 569
 570    if (*next >= max) {
 571        virtio_error(vdev, "Desc next is %u", *next);
 572        return VIRTQUEUE_READ_DESC_ERROR;
 573    }
 574
 575    vring_desc_read(vdev, desc, desc_cache, *next);
 576    return VIRTQUEUE_READ_DESC_MORE;
 577}
 578
 579void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
 580                               unsigned int *out_bytes,
 581                               unsigned max_in_bytes, unsigned max_out_bytes)
 582{
 583    VirtIODevice *vdev = vq->vdev;
 584    unsigned int max, idx;
 585    unsigned int total_bufs, in_total, out_total;
 586    VRingMemoryRegionCaches *caches;
 587    MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
 588    int64_t len = 0;
 589    int rc;
 590
 591    if (unlikely(!vq->vring.desc)) {
 592        if (in_bytes) {
 593            *in_bytes = 0;
 594        }
 595        if (out_bytes) {
 596            *out_bytes = 0;
 597        }
 598        return;
 599    }
 600
 601    rcu_read_lock();
 602    idx = vq->last_avail_idx;
 603    total_bufs = in_total = out_total = 0;
 604
 605    max = vq->vring.num;
 606    caches = vring_get_region_caches(vq);
 607    if (caches->desc.len < max * sizeof(VRingDesc)) {
 608        virtio_error(vdev, "Cannot map descriptor ring");
 609        goto err;
 610    }
 611
 612    while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
 613        MemoryRegionCache *desc_cache = &caches->desc;
 614        unsigned int num_bufs;
 615        VRingDesc desc;
 616        unsigned int i;
 617
 618        num_bufs = total_bufs;
 619
 620        if (!virtqueue_get_head(vq, idx++, &i)) {
 621            goto err;
 622        }
 623
 624        vring_desc_read(vdev, &desc, desc_cache, i);
 625
 626        if (desc.flags & VRING_DESC_F_INDIRECT) {
 627            if (desc.len % sizeof(VRingDesc)) {
 628                virtio_error(vdev, "Invalid size for indirect buffer table");
 629                goto err;
 630            }
 631
 632            /* If we've got too many, that implies a descriptor loop. */
 633            if (num_bufs >= max) {
 634                virtio_error(vdev, "Looped descriptor");
 635                goto err;
 636            }
 637
 638            /* loop over the indirect descriptor table */
 639            len = address_space_cache_init(&indirect_desc_cache,
 640                                           vdev->dma_as,
 641                                           desc.addr, desc.len, false);
 642            desc_cache = &indirect_desc_cache;
 643            if (len < desc.len) {
 644                virtio_error(vdev, "Cannot map indirect buffer");
 645                goto err;
 646            }
 647
 648            max = desc.len / sizeof(VRingDesc);
 649            num_bufs = i = 0;
 650            vring_desc_read(vdev, &desc, desc_cache, i);
 651        }
 652
 653        do {
 654            /* If we've got too many, that implies a descriptor loop. */
 655            if (++num_bufs > max) {
 656                virtio_error(vdev, "Looped descriptor");
 657                goto err;
 658            }
 659
 660            if (desc.flags & VRING_DESC_F_WRITE) {
 661                in_total += desc.len;
 662            } else {
 663                out_total += desc.len;
 664            }
 665            if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
 666                goto done;
 667            }
 668
 669            rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, max, &i);
 670        } while (rc == VIRTQUEUE_READ_DESC_MORE);
 671
 672        if (rc == VIRTQUEUE_READ_DESC_ERROR) {
 673            goto err;
 674        }
 675
 676        if (desc_cache == &indirect_desc_cache) {
 677            address_space_cache_destroy(&indirect_desc_cache);
 678            total_bufs++;
 679        } else {
 680            total_bufs = num_bufs;
 681        }
 682    }
 683
 684    if (rc < 0) {
 685        goto err;
 686    }
 687
 688done:
 689    address_space_cache_destroy(&indirect_desc_cache);
 690    if (in_bytes) {
 691        *in_bytes = in_total;
 692    }
 693    if (out_bytes) {
 694        *out_bytes = out_total;
 695    }
 696    rcu_read_unlock();
 697    return;
 698
 699err:
 700    in_total = out_total = 0;
 701    goto done;
 702}
 703
 704int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
 705                          unsigned int out_bytes)
 706{
 707    unsigned int in_total, out_total;
 708
 709    virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
 710    return in_bytes <= in_total && out_bytes <= out_total;
 711}
 712
 713static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg,
 714                               hwaddr *addr, struct iovec *iov,
 715                               unsigned int max_num_sg, bool is_write,
 716                               hwaddr pa, size_t sz)
 717{
 718    bool ok = false;
 719    unsigned num_sg = *p_num_sg;
 720    assert(num_sg <= max_num_sg);
 721
 722    if (!sz) {
 723        virtio_error(vdev, "virtio: zero sized buffers are not allowed");
 724        goto out;
 725    }
 726
 727    while (sz) {
 728        hwaddr len = sz;
 729
 730        if (num_sg == max_num_sg) {
 731            virtio_error(vdev, "virtio: too many write descriptors in "
 732                               "indirect table");
 733            goto out;
 734        }
 735
 736        iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len,
 737                                              is_write ?
 738                                              DMA_DIRECTION_FROM_DEVICE :
 739                                              DMA_DIRECTION_TO_DEVICE);
 740        if (!iov[num_sg].iov_base) {
 741            virtio_error(vdev, "virtio: bogus descriptor or out of resources");
 742            goto out;
 743        }
 744
 745        iov[num_sg].iov_len = len;
 746        addr[num_sg] = pa;
 747
 748        sz -= len;
 749        pa += len;
 750        num_sg++;
 751    }
 752    ok = true;
 753
 754out:
 755    *p_num_sg = num_sg;
 756    return ok;
 757}
 758
 759/* Only used by error code paths before we have a VirtQueueElement (therefore
 760 * virtqueue_unmap_sg() can't be used).  Assumes buffers weren't written to
 761 * yet.
 762 */
 763static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
 764                                    struct iovec *iov)
 765{
 766    unsigned int i;
 767
 768    for (i = 0; i < out_num + in_num; i++) {
 769        int is_write = i >= out_num;
 770
 771        cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0);
 772        iov++;
 773    }
 774}
 775
 776static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
 777                                hwaddr *addr, unsigned int *num_sg,
 778                                int is_write)
 779{
 780    unsigned int i;
 781    hwaddr len;
 782
 783    for (i = 0; i < *num_sg; i++) {
 784        len = sg[i].iov_len;
 785        sg[i].iov_base = dma_memory_map(vdev->dma_as,
 786                                        addr[i], &len, is_write ?
 787                                        DMA_DIRECTION_FROM_DEVICE :
 788                                        DMA_DIRECTION_TO_DEVICE);
 789        if (!sg[i].iov_base) {
 790            error_report("virtio: error trying to map MMIO memory");
 791            exit(1);
 792        }
 793        if (len != sg[i].iov_len) {
 794            error_report("virtio: unexpected memory split");
 795            exit(1);
 796        }
 797    }
 798}
 799
 800void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
 801{
 802    virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num, 1);
 803    virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num, 0);
 804}
 805
 806static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
 807{
 808    VirtQueueElement *elem;
 809    size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
 810    size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
 811    size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
 812    size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0]));
 813    size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
 814    size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
 815
 816    assert(sz >= sizeof(VirtQueueElement));
 817    elem = g_malloc(out_sg_end);
 818    trace_virtqueue_alloc_element(elem, sz, in_num, out_num);
 819    elem->out_num = out_num;
 820    elem->in_num = in_num;
 821    elem->in_addr = (void *)elem + in_addr_ofs;
 822    elem->out_addr = (void *)elem + out_addr_ofs;
 823    elem->in_sg = (void *)elem + in_sg_ofs;
 824    elem->out_sg = (void *)elem + out_sg_ofs;
 825    return elem;
 826}
 827
 828void *virtqueue_pop(VirtQueue *vq, size_t sz)
 829{
 830    unsigned int i, head, max;
 831    VRingMemoryRegionCaches *caches;
 832    MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
 833    MemoryRegionCache *desc_cache;
 834    int64_t len;
 835    VirtIODevice *vdev = vq->vdev;
 836    VirtQueueElement *elem = NULL;
 837    unsigned out_num, in_num;
 838    hwaddr addr[VIRTQUEUE_MAX_SIZE];
 839    struct iovec iov[VIRTQUEUE_MAX_SIZE];
 840    VRingDesc desc;
 841    int rc;
 842
 843    if (unlikely(vdev->broken)) {
 844        return NULL;
 845    }
 846    rcu_read_lock();
 847    if (virtio_queue_empty_rcu(vq)) {
 848        goto done;
 849    }
 850    /* Needed after virtio_queue_empty(), see comment in
 851     * virtqueue_num_heads(). */
 852    smp_rmb();
 853
 854    /* When we start there are none of either input nor output. */
 855    out_num = in_num = 0;
 856
 857    max = vq->vring.num;
 858
 859    if (vq->inuse >= vq->vring.num) {
 860        virtio_error(vdev, "Virtqueue size exceeded");
 861        goto done;
 862    }
 863
 864    if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
 865        goto done;
 866    }
 867
 868    if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
 869        vring_set_avail_event(vq, vq->last_avail_idx);
 870    }
 871
 872    i = head;
 873
 874    caches = vring_get_region_caches(vq);
 875    if (caches->desc.len < max * sizeof(VRingDesc)) {
 876        virtio_error(vdev, "Cannot map descriptor ring");
 877        goto done;
 878    }
 879
 880    desc_cache = &caches->desc;
 881    vring_desc_read(vdev, &desc, desc_cache, i);
 882    if (desc.flags & VRING_DESC_F_INDIRECT) {
 883        if (desc.len % sizeof(VRingDesc)) {
 884            virtio_error(vdev, "Invalid size for indirect buffer table");
 885            goto done;
 886        }
 887
 888        /* loop over the indirect descriptor table */
 889        len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
 890                                       desc.addr, desc.len, false);
 891        desc_cache = &indirect_desc_cache;
 892        if (len < desc.len) {
 893            virtio_error(vdev, "Cannot map indirect buffer");
 894            goto done;
 895        }
 896
 897        max = desc.len / sizeof(VRingDesc);
 898        i = 0;
 899        vring_desc_read(vdev, &desc, desc_cache, i);
 900    }
 901
 902    /* Collect all the descriptors */
 903    do {
 904        bool map_ok;
 905
 906        if (desc.flags & VRING_DESC_F_WRITE) {
 907            map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
 908                                        iov + out_num,
 909                                        VIRTQUEUE_MAX_SIZE - out_num, true,
 910                                        desc.addr, desc.len);
 911        } else {
 912            if (in_num) {
 913                virtio_error(vdev, "Incorrect order for descriptors");
 914                goto err_undo_map;
 915            }
 916            map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
 917                                        VIRTQUEUE_MAX_SIZE, false,
 918                                        desc.addr, desc.len);
 919        }
 920        if (!map_ok) {
 921            goto err_undo_map;
 922        }
 923
 924        /* If we've got too many, that implies a descriptor loop. */
 925        if ((in_num + out_num) > max) {
 926            virtio_error(vdev, "Looped descriptor");
 927            goto err_undo_map;
 928        }
 929
 930        rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, max, &i);
 931    } while (rc == VIRTQUEUE_READ_DESC_MORE);
 932
 933    if (rc == VIRTQUEUE_READ_DESC_ERROR) {
 934        goto err_undo_map;
 935    }
 936
 937    /* Now copy what we have collected and mapped */
 938    elem = virtqueue_alloc_element(sz, out_num, in_num);
 939    elem->index = head;
 940    for (i = 0; i < out_num; i++) {
 941        elem->out_addr[i] = addr[i];
 942        elem->out_sg[i] = iov[i];
 943    }
 944    for (i = 0; i < in_num; i++) {
 945        elem->in_addr[i] = addr[out_num + i];
 946        elem->in_sg[i] = iov[out_num + i];
 947    }
 948
 949    vq->inuse++;
 950
 951    trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
 952done:
 953    address_space_cache_destroy(&indirect_desc_cache);
 954    rcu_read_unlock();
 955
 956    return elem;
 957
 958err_undo_map:
 959    virtqueue_undo_map_desc(out_num, in_num, iov);
 960    goto done;
 961}
 962
 963/* virtqueue_drop_all:
 964 * @vq: The #VirtQueue
 965 * Drops all queued buffers and indicates them to the guest
 966 * as if they are done. Useful when buffers can not be
 967 * processed but must be returned to the guest.
 968 */
 969unsigned int virtqueue_drop_all(VirtQueue *vq)
 970{
 971    unsigned int dropped = 0;
 972    VirtQueueElement elem = {};
 973    VirtIODevice *vdev = vq->vdev;
 974    bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
 975
 976    if (unlikely(vdev->broken)) {
 977        return 0;
 978    }
 979
 980    while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) {
 981        /* works similar to virtqueue_pop but does not map buffers
 982        * and does not allocate any memory */
 983        smp_rmb();
 984        if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) {
 985            break;
 986        }
 987        vq->inuse++;
 988        vq->last_avail_idx++;
 989        if (fEventIdx) {
 990            vring_set_avail_event(vq, vq->last_avail_idx);
 991        }
 992        /* immediately push the element, nothing to unmap
 993         * as both in_num and out_num are set to 0 */
 994        virtqueue_push(vq, &elem, 0);
 995        dropped++;
 996    }
 997
 998    return dropped;
 999}
1000
1001/* Reading and writing a structure directly to QEMUFile is *awful*, but
1002 * it is what QEMU has always done by mistake.  We can change it sooner
1003 * or later by bumping the version number of the affected vm states.
1004 * In the meanwhile, since the in-memory layout of VirtQueueElement
1005 * has changed, we need to marshal to and from the layout that was
1006 * used before the change.
1007 */
1008typedef struct VirtQueueElementOld {
1009    unsigned int index;
1010    unsigned int out_num;
1011    unsigned int in_num;
1012    hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
1013    hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
1014    struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
1015    struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
1016} VirtQueueElementOld;
1017
1018void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz)
1019{
1020    VirtQueueElement *elem;
1021    VirtQueueElementOld data;
1022    int i;
1023
1024    qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1025
1026    /* TODO: teach all callers that this can fail, and return failure instead
1027     * of asserting here.
1028     * When we do, we might be able to re-enable NDEBUG below.
1029     */
1030#ifdef NDEBUG
1031#error building with NDEBUG is not supported
1032#endif
1033    assert(ARRAY_SIZE(data.in_addr) >= data.in_num);
1034    assert(ARRAY_SIZE(data.out_addr) >= data.out_num);
1035
1036    elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
1037    elem->index = data.index;
1038
1039    for (i = 0; i < elem->in_num; i++) {
1040        elem->in_addr[i] = data.in_addr[i];
1041    }
1042
1043    for (i = 0; i < elem->out_num; i++) {
1044        elem->out_addr[i] = data.out_addr[i];
1045    }
1046
1047    for (i = 0; i < elem->in_num; i++) {
1048        /* Base is overwritten by virtqueue_map.  */
1049        elem->in_sg[i].iov_base = 0;
1050        elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
1051    }
1052
1053    for (i = 0; i < elem->out_num; i++) {
1054        /* Base is overwritten by virtqueue_map.  */
1055        elem->out_sg[i].iov_base = 0;
1056        elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
1057    }
1058
1059    virtqueue_map(vdev, elem);
1060    return elem;
1061}
1062
1063void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem)
1064{
1065    VirtQueueElementOld data;
1066    int i;
1067
1068    memset(&data, 0, sizeof(data));
1069    data.index = elem->index;
1070    data.in_num = elem->in_num;
1071    data.out_num = elem->out_num;
1072
1073    for (i = 0; i < elem->in_num; i++) {
1074        data.in_addr[i] = elem->in_addr[i];
1075    }
1076
1077    for (i = 0; i < elem->out_num; i++) {
1078        data.out_addr[i] = elem->out_addr[i];
1079    }
1080
1081    for (i = 0; i < elem->in_num; i++) {
1082        /* Base is overwritten by virtqueue_map when loading.  Do not
1083         * save it, as it would leak the QEMU address space layout.  */
1084        data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
1085    }
1086
1087    for (i = 0; i < elem->out_num; i++) {
1088        /* Do not save iov_base as above.  */
1089        data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
1090    }
1091    qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1092}
1093
1094/* virtio device */
1095static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
1096{
1097    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1098    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1099
1100    if (unlikely(vdev->broken)) {
1101        return;
1102    }
1103
1104    if (k->notify) {
1105        k->notify(qbus->parent, vector);
1106    }
1107}
1108
1109void virtio_update_irq(VirtIODevice *vdev)
1110{
1111    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
1112}
1113
1114static int virtio_validate_features(VirtIODevice *vdev)
1115{
1116    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1117
1118    if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) &&
1119        !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
1120        return -EFAULT;
1121    }
1122
1123    if (k->validate_features) {
1124        return k->validate_features(vdev);
1125    } else {
1126        return 0;
1127    }
1128}
1129
1130int virtio_set_status(VirtIODevice *vdev, uint8_t val)
1131{
1132    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1133    trace_virtio_set_status(vdev, val);
1134
1135    if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1136        if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
1137            val & VIRTIO_CONFIG_S_FEATURES_OK) {
1138            int ret = virtio_validate_features(vdev);
1139
1140            if (ret) {
1141                return ret;
1142            }
1143        }
1144    }
1145    if (k->set_status) {
1146        k->set_status(vdev, val);
1147    }
1148    vdev->status = val;
1149    return 0;
1150}
1151
1152bool target_words_bigendian(void);
1153static enum virtio_device_endian virtio_default_endian(void)
1154{
1155    if (target_words_bigendian()) {
1156        return VIRTIO_DEVICE_ENDIAN_BIG;
1157    } else {
1158        return VIRTIO_DEVICE_ENDIAN_LITTLE;
1159    }
1160}
1161
1162static enum virtio_device_endian virtio_current_cpu_endian(void)
1163{
1164    CPUClass *cc = CPU_GET_CLASS(current_cpu);
1165
1166    if (cc->virtio_is_big_endian(current_cpu)) {
1167        return VIRTIO_DEVICE_ENDIAN_BIG;
1168    } else {
1169        return VIRTIO_DEVICE_ENDIAN_LITTLE;
1170    }
1171}
1172
1173static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq)
1174{
1175    VRingMemoryRegionCaches *caches;
1176
1177    caches = atomic_read(&vq->vring.caches);
1178    atomic_rcu_set(&vq->vring.caches, NULL);
1179    if (caches) {
1180        call_rcu(caches, virtio_free_region_cache, rcu);
1181    }
1182}
1183
1184void virtio_reset(void *opaque)
1185{
1186    VirtIODevice *vdev = opaque;
1187    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1188    int i;
1189
1190    virtio_set_status(vdev, 0);
1191    if (current_cpu) {
1192        /* Guest initiated reset */
1193        vdev->device_endian = virtio_current_cpu_endian();
1194    } else {
1195        /* System reset */
1196        vdev->device_endian = virtio_default_endian();
1197    }
1198
1199    if (k->reset) {
1200        k->reset(vdev);
1201    }
1202
1203    vdev->broken = false;
1204    vdev->guest_features = 0;
1205    vdev->queue_sel = 0;
1206    vdev->status = 0;
1207    atomic_set(&vdev->isr, 0);
1208    vdev->config_vector = VIRTIO_NO_VECTOR;
1209    virtio_notify_vector(vdev, vdev->config_vector);
1210
1211    for(i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1212        vdev->vq[i].vring.desc = 0;
1213        vdev->vq[i].vring.avail = 0;
1214        vdev->vq[i].vring.used = 0;
1215        vdev->vq[i].last_avail_idx = 0;
1216        vdev->vq[i].shadow_avail_idx = 0;
1217        vdev->vq[i].used_idx = 0;
1218        virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
1219        vdev->vq[i].signalled_used = 0;
1220        vdev->vq[i].signalled_used_valid = false;
1221        vdev->vq[i].notification = true;
1222        vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
1223        vdev->vq[i].inuse = 0;
1224        virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
1225    }
1226}
1227
1228uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
1229{
1230    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1231    uint8_t val;
1232
1233    if (addr + sizeof(val) > vdev->config_len) {
1234        return (uint32_t)-1;
1235    }
1236
1237    k->get_config(vdev, vdev->config);
1238
1239    val = ldub_p(vdev->config + addr);
1240    return val;
1241}
1242
1243uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
1244{
1245    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1246    uint16_t val;
1247
1248    if (addr + sizeof(val) > vdev->config_len) {
1249        return (uint32_t)-1;
1250    }
1251
1252    k->get_config(vdev, vdev->config);
1253
1254    val = lduw_p(vdev->config + addr);
1255    return val;
1256}
1257
1258uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
1259{
1260    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1261    uint32_t val;
1262
1263    if (addr + sizeof(val) > vdev->config_len) {
1264        return (uint32_t)-1;
1265    }
1266
1267    k->get_config(vdev, vdev->config);
1268
1269    val = ldl_p(vdev->config + addr);
1270    return val;
1271}
1272
1273void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1274{
1275    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1276    uint8_t val = data;
1277
1278    if (addr + sizeof(val) > vdev->config_len) {
1279        return;
1280    }
1281
1282    stb_p(vdev->config + addr, val);
1283
1284    if (k->set_config) {
1285        k->set_config(vdev, vdev->config);
1286    }
1287}
1288
1289void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1290{
1291    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1292    uint16_t val = data;
1293
1294    if (addr + sizeof(val) > vdev->config_len) {
1295        return;
1296    }
1297
1298    stw_p(vdev->config + addr, val);
1299
1300    if (k->set_config) {
1301        k->set_config(vdev, vdev->config);
1302    }
1303}
1304
1305void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1306{
1307    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1308    uint32_t val = data;
1309
1310    if (addr + sizeof(val) > vdev->config_len) {
1311        return;
1312    }
1313
1314    stl_p(vdev->config + addr, val);
1315
1316    if (k->set_config) {
1317        k->set_config(vdev, vdev->config);
1318    }
1319}
1320
1321uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
1322{
1323    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1324    uint8_t val;
1325
1326    if (addr + sizeof(val) > vdev->config_len) {
1327        return (uint32_t)-1;
1328    }
1329
1330    k->get_config(vdev, vdev->config);
1331
1332    val = ldub_p(vdev->config + addr);
1333    return val;
1334}
1335
1336uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
1337{
1338    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1339    uint16_t val;
1340
1341    if (addr + sizeof(val) > vdev->config_len) {
1342        return (uint32_t)-1;
1343    }
1344
1345    k->get_config(vdev, vdev->config);
1346
1347    val = lduw_le_p(vdev->config + addr);
1348    return val;
1349}
1350
1351uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
1352{
1353    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1354    uint32_t val;
1355
1356    if (addr + sizeof(val) > vdev->config_len) {
1357        return (uint32_t)-1;
1358    }
1359
1360    k->get_config(vdev, vdev->config);
1361
1362    val = ldl_le_p(vdev->config + addr);
1363    return val;
1364}
1365
1366void virtio_config_modern_writeb(VirtIODevice *vdev,
1367                                 uint32_t addr, uint32_t data)
1368{
1369    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1370    uint8_t val = data;
1371
1372    if (addr + sizeof(val) > vdev->config_len) {
1373        return;
1374    }
1375
1376    stb_p(vdev->config + addr, val);
1377
1378    if (k->set_config) {
1379        k->set_config(vdev, vdev->config);
1380    }
1381}
1382
1383void virtio_config_modern_writew(VirtIODevice *vdev,
1384                                 uint32_t addr, uint32_t data)
1385{
1386    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1387    uint16_t val = data;
1388
1389    if (addr + sizeof(val) > vdev->config_len) {
1390        return;
1391    }
1392
1393    stw_le_p(vdev->config + addr, val);
1394
1395    if (k->set_config) {
1396        k->set_config(vdev, vdev->config);
1397    }
1398}
1399
1400void virtio_config_modern_writel(VirtIODevice *vdev,
1401                                 uint32_t addr, uint32_t data)
1402{
1403    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1404    uint32_t val = data;
1405
1406    if (addr + sizeof(val) > vdev->config_len) {
1407        return;
1408    }
1409
1410    stl_le_p(vdev->config + addr, val);
1411
1412    if (k->set_config) {
1413        k->set_config(vdev, vdev->config);
1414    }
1415}
1416
1417void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
1418{
1419    vdev->vq[n].vring.desc = addr;
1420    virtio_queue_update_rings(vdev, n);
1421}
1422
1423hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
1424{
1425    return vdev->vq[n].vring.desc;
1426}
1427
1428void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
1429                            hwaddr avail, hwaddr used)
1430{
1431    vdev->vq[n].vring.desc = desc;
1432    vdev->vq[n].vring.avail = avail;
1433    vdev->vq[n].vring.used = used;
1434    virtio_init_region_cache(vdev, n);
1435}
1436
1437void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
1438{
1439    /* Don't allow guest to flip queue between existent and
1440     * nonexistent states, or to set it to an invalid size.
1441     */
1442    if (!!num != !!vdev->vq[n].vring.num ||
1443        num > VIRTQUEUE_MAX_SIZE ||
1444        num < 0) {
1445        return;
1446    }
1447    vdev->vq[n].vring.num = num;
1448}
1449
1450VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
1451{
1452    return QLIST_FIRST(&vdev->vector_queues[vector]);
1453}
1454
1455VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
1456{
1457    return QLIST_NEXT(vq, node);
1458}
1459
1460int virtio_queue_get_num(VirtIODevice *vdev, int n)
1461{
1462    return vdev->vq[n].vring.num;
1463}
1464
1465int virtio_queue_get_max_num(VirtIODevice *vdev, int n)
1466{
1467    return vdev->vq[n].vring.num_default;
1468}
1469
1470int virtio_get_num_queues(VirtIODevice *vdev)
1471{
1472    int i;
1473
1474    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1475        if (!virtio_queue_get_num(vdev, i)) {
1476            break;
1477        }
1478    }
1479
1480    return i;
1481}
1482
1483void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
1484{
1485    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1486    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1487
1488    /* virtio-1 compliant devices cannot change the alignment */
1489    if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1490        error_report("tried to modify queue alignment for virtio-1 device");
1491        return;
1492    }
1493    /* Check that the transport told us it was going to do this
1494     * (so a buggy transport will immediately assert rather than
1495     * silently failing to migrate this state)
1496     */
1497    assert(k->has_variable_vring_alignment);
1498
1499    vdev->vq[n].vring.align = align;
1500    virtio_queue_update_rings(vdev, n);
1501}
1502
1503static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
1504{
1505    if (vq->vring.desc && vq->handle_aio_output) {
1506        VirtIODevice *vdev = vq->vdev;
1507
1508        trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1509        return vq->handle_aio_output(vdev, vq);
1510    }
1511
1512    return false;
1513}
1514
1515static void virtio_queue_notify_vq(VirtQueue *vq)
1516{
1517    if (vq->vring.desc && vq->handle_output) {
1518        VirtIODevice *vdev = vq->vdev;
1519
1520        if (unlikely(vdev->broken)) {
1521            return;
1522        }
1523
1524        trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1525        vq->handle_output(vdev, vq);
1526    }
1527}
1528
1529void virtio_queue_notify(VirtIODevice *vdev, int n)
1530{
1531    VirtQueue *vq = &vdev->vq[n];
1532
1533    if (unlikely(!vq->vring.desc || vdev->broken)) {
1534        return;
1535    }
1536
1537    trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1538    if (vq->handle_aio_output) {
1539        event_notifier_set(&vq->host_notifier);
1540    } else if (vq->handle_output) {
1541        vq->handle_output(vdev, vq);
1542    }
1543}
1544
1545uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
1546{
1547    return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector :
1548        VIRTIO_NO_VECTOR;
1549}
1550
1551void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
1552{
1553    VirtQueue *vq = &vdev->vq[n];
1554
1555    if (n < VIRTIO_QUEUE_MAX) {
1556        if (vdev->vector_queues &&
1557            vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
1558            QLIST_REMOVE(vq, node);
1559        }
1560        vdev->vq[n].vector = vector;
1561        if (vdev->vector_queues &&
1562            vector != VIRTIO_NO_VECTOR) {
1563            QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
1564        }
1565    }
1566}
1567
1568VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
1569                            VirtIOHandleOutput handle_output)
1570{
1571    int i;
1572
1573    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1574        if (vdev->vq[i].vring.num == 0)
1575            break;
1576    }
1577
1578    if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
1579        abort();
1580
1581    vdev->vq[i].vring.num = queue_size;
1582    vdev->vq[i].vring.num_default = queue_size;
1583    vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
1584    vdev->vq[i].handle_output = handle_output;
1585    vdev->vq[i].handle_aio_output = NULL;
1586
1587    return &vdev->vq[i];
1588}
1589
1590void virtio_del_queue(VirtIODevice *vdev, int n)
1591{
1592    if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
1593        abort();
1594    }
1595
1596    vdev->vq[n].vring.num = 0;
1597    vdev->vq[n].vring.num_default = 0;
1598}
1599
1600static void virtio_set_isr(VirtIODevice *vdev, int value)
1601{
1602    uint8_t old = atomic_read(&vdev->isr);
1603
1604    /* Do not write ISR if it does not change, so that its cacheline remains
1605     * shared in the common case where the guest does not read it.
1606     */
1607    if ((old & value) != value) {
1608        atomic_or(&vdev->isr, value);
1609    }
1610}
1611
1612/* Called within rcu_read_lock().  */
1613static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
1614{
1615    uint16_t old, new;
1616    bool v;
1617    /* We need to expose used array entries before checking used event. */
1618    smp_mb();
1619    /* Always notify when queue is empty (when feature acknowledge) */
1620    if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
1621        !vq->inuse && virtio_queue_empty(vq)) {
1622        return true;
1623    }
1624
1625    if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
1626        return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
1627    }
1628
1629    v = vq->signalled_used_valid;
1630    vq->signalled_used_valid = true;
1631    old = vq->signalled_used;
1632    new = vq->signalled_used = vq->used_idx;
1633    return !v || vring_need_event(vring_get_used_event(vq), new, old);
1634}
1635
1636void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
1637{
1638    bool should_notify;
1639    rcu_read_lock();
1640    should_notify = virtio_should_notify(vdev, vq);
1641    rcu_read_unlock();
1642
1643    if (!should_notify) {
1644        return;
1645    }
1646
1647    trace_virtio_notify_irqfd(vdev, vq);
1648
1649    /*
1650     * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but
1651     * windows drivers included in virtio-win 1.8.0 (circa 2015) are
1652     * incorrectly polling this bit during crashdump and hibernation
1653     * in MSI mode, causing a hang if this bit is never updated.
1654     * Recent releases of Windows do not really shut down, but rather
1655     * log out and hibernate to make the next startup faster.  Hence,
1656     * this manifested as a more serious hang during shutdown with
1657     *
1658     * Next driver release from 2016 fixed this problem, so working around it
1659     * is not a must, but it's easy to do so let's do it here.
1660     *
1661     * Note: it's safe to update ISR from any thread as it was switched
1662     * to an atomic operation.
1663     */
1664    virtio_set_isr(vq->vdev, 0x1);
1665    event_notifier_set(&vq->guest_notifier);
1666}
1667
1668static void virtio_irq(VirtQueue *vq)
1669{
1670    virtio_set_isr(vq->vdev, 0x1);
1671    virtio_notify_vector(vq->vdev, vq->vector);
1672}
1673
1674void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
1675{
1676    bool should_notify;
1677    rcu_read_lock();
1678    should_notify = virtio_should_notify(vdev, vq);
1679    rcu_read_unlock();
1680
1681    if (!should_notify) {
1682        return;
1683    }
1684
1685    trace_virtio_notify(vdev, vq);
1686    virtio_irq(vq);
1687}
1688
1689void virtio_notify_config(VirtIODevice *vdev)
1690{
1691    if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
1692        return;
1693
1694    virtio_set_isr(vdev, 0x3);
1695    vdev->generation++;
1696    virtio_notify_vector(vdev, vdev->config_vector);
1697}
1698
1699static bool virtio_device_endian_needed(void *opaque)
1700{
1701    VirtIODevice *vdev = opaque;
1702
1703    assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
1704    if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1705        return vdev->device_endian != virtio_default_endian();
1706    }
1707    /* Devices conforming to VIRTIO 1.0 or later are always LE. */
1708    return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
1709}
1710
1711static bool virtio_64bit_features_needed(void *opaque)
1712{
1713    VirtIODevice *vdev = opaque;
1714
1715    return (vdev->host_features >> 32) != 0;
1716}
1717
1718static bool virtio_virtqueue_needed(void *opaque)
1719{
1720    VirtIODevice *vdev = opaque;
1721
1722    return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
1723}
1724
1725static bool virtio_ringsize_needed(void *opaque)
1726{
1727    VirtIODevice *vdev = opaque;
1728    int i;
1729
1730    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1731        if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) {
1732            return true;
1733        }
1734    }
1735    return false;
1736}
1737
1738static bool virtio_extra_state_needed(void *opaque)
1739{
1740    VirtIODevice *vdev = opaque;
1741    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1742    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1743
1744    return k->has_extra_state &&
1745        k->has_extra_state(qbus->parent);
1746}
1747
1748static bool virtio_broken_needed(void *opaque)
1749{
1750    VirtIODevice *vdev = opaque;
1751
1752    return vdev->broken;
1753}
1754
1755static const VMStateDescription vmstate_virtqueue = {
1756    .name = "virtqueue_state",
1757    .version_id = 1,
1758    .minimum_version_id = 1,
1759    .fields = (VMStateField[]) {
1760        VMSTATE_UINT64(vring.avail, struct VirtQueue),
1761        VMSTATE_UINT64(vring.used, struct VirtQueue),
1762        VMSTATE_END_OF_LIST()
1763    }
1764};
1765
1766static const VMStateDescription vmstate_virtio_virtqueues = {
1767    .name = "virtio/virtqueues",
1768    .version_id = 1,
1769    .minimum_version_id = 1,
1770    .needed = &virtio_virtqueue_needed,
1771    .fields = (VMStateField[]) {
1772        VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
1773                      VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue),
1774        VMSTATE_END_OF_LIST()
1775    }
1776};
1777
1778static const VMStateDescription vmstate_ringsize = {
1779    .name = "ringsize_state",
1780    .version_id = 1,
1781    .minimum_version_id = 1,
1782    .fields = (VMStateField[]) {
1783        VMSTATE_UINT32(vring.num_default, struct VirtQueue),
1784        VMSTATE_END_OF_LIST()
1785    }
1786};
1787
1788static const VMStateDescription vmstate_virtio_ringsize = {
1789    .name = "virtio/ringsize",
1790    .version_id = 1,
1791    .minimum_version_id = 1,
1792    .needed = &virtio_ringsize_needed,
1793    .fields = (VMStateField[]) {
1794        VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
1795                      VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue),
1796        VMSTATE_END_OF_LIST()
1797    }
1798};
1799
1800static int get_extra_state(QEMUFile *f, void *pv, size_t size,
1801                           VMStateField *field)
1802{
1803    VirtIODevice *vdev = pv;
1804    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1805    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1806
1807    if (!k->load_extra_state) {
1808        return -1;
1809    } else {
1810        return k->load_extra_state(qbus->parent, f);
1811    }
1812}
1813
1814static int put_extra_state(QEMUFile *f, void *pv, size_t size,
1815                           VMStateField *field, QJSON *vmdesc)
1816{
1817    VirtIODevice *vdev = pv;
1818    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1819    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1820
1821    k->save_extra_state(qbus->parent, f);
1822    return 0;
1823}
1824
1825static const VMStateInfo vmstate_info_extra_state = {
1826    .name = "virtqueue_extra_state",
1827    .get = get_extra_state,
1828    .put = put_extra_state,
1829};
1830
1831static const VMStateDescription vmstate_virtio_extra_state = {
1832    .name = "virtio/extra_state",
1833    .version_id = 1,
1834    .minimum_version_id = 1,
1835    .needed = &virtio_extra_state_needed,
1836    .fields = (VMStateField[]) {
1837        {
1838            .name         = "extra_state",
1839            .version_id   = 0,
1840            .field_exists = NULL,
1841            .size         = 0,
1842            .info         = &vmstate_info_extra_state,
1843            .flags        = VMS_SINGLE,
1844            .offset       = 0,
1845        },
1846        VMSTATE_END_OF_LIST()
1847    }
1848};
1849
1850static const VMStateDescription vmstate_virtio_device_endian = {
1851    .name = "virtio/device_endian",
1852    .version_id = 1,
1853    .minimum_version_id = 1,
1854    .needed = &virtio_device_endian_needed,
1855    .fields = (VMStateField[]) {
1856        VMSTATE_UINT8(device_endian, VirtIODevice),
1857        VMSTATE_END_OF_LIST()
1858    }
1859};
1860
1861static const VMStateDescription vmstate_virtio_64bit_features = {
1862    .name = "virtio/64bit_features",
1863    .version_id = 1,
1864    .minimum_version_id = 1,
1865    .needed = &virtio_64bit_features_needed,
1866    .fields = (VMStateField[]) {
1867        VMSTATE_UINT64(guest_features, VirtIODevice),
1868        VMSTATE_END_OF_LIST()
1869    }
1870};
1871
1872static const VMStateDescription vmstate_virtio_broken = {
1873    .name = "virtio/broken",
1874    .version_id = 1,
1875    .minimum_version_id = 1,
1876    .needed = &virtio_broken_needed,
1877    .fields = (VMStateField[]) {
1878        VMSTATE_BOOL(broken, VirtIODevice),
1879        VMSTATE_END_OF_LIST()
1880    }
1881};
1882
1883static const VMStateDescription vmstate_virtio = {
1884    .name = "virtio",
1885    .version_id = 1,
1886    .minimum_version_id = 1,
1887    .minimum_version_id_old = 1,
1888    .fields = (VMStateField[]) {
1889        VMSTATE_END_OF_LIST()
1890    },
1891    .subsections = (const VMStateDescription*[]) {
1892        &vmstate_virtio_device_endian,
1893        &vmstate_virtio_64bit_features,
1894        &vmstate_virtio_virtqueues,
1895        &vmstate_virtio_ringsize,
1896        &vmstate_virtio_broken,
1897        &vmstate_virtio_extra_state,
1898        NULL
1899    }
1900};
1901
1902void virtio_save(VirtIODevice *vdev, QEMUFile *f)
1903{
1904    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1905    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1906    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
1907    uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
1908    int i;
1909
1910    if (k->save_config) {
1911        k->save_config(qbus->parent, f);
1912    }
1913
1914    qemu_put_8s(f, &vdev->status);
1915    qemu_put_8s(f, &vdev->isr);
1916    qemu_put_be16s(f, &vdev->queue_sel);
1917    qemu_put_be32s(f, &guest_features_lo);
1918    qemu_put_be32(f, vdev->config_len);
1919    qemu_put_buffer(f, vdev->config, vdev->config_len);
1920
1921    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1922        if (vdev->vq[i].vring.num == 0)
1923            break;
1924    }
1925
1926    qemu_put_be32(f, i);
1927
1928    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1929        if (vdev->vq[i].vring.num == 0)
1930            break;
1931
1932        qemu_put_be32(f, vdev->vq[i].vring.num);
1933        if (k->has_variable_vring_alignment) {
1934            qemu_put_be32(f, vdev->vq[i].vring.align);
1935        }
1936        /*
1937         * Save desc now, the rest of the ring addresses are saved in
1938         * subsections for VIRTIO-1 devices.
1939         */
1940        qemu_put_be64(f, vdev->vq[i].vring.desc);
1941        qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
1942        if (k->save_queue) {
1943            k->save_queue(qbus->parent, i, f);
1944        }
1945    }
1946
1947    if (vdc->save != NULL) {
1948        vdc->save(vdev, f);
1949    }
1950
1951    if (vdc->vmsd) {
1952        vmstate_save_state(f, vdc->vmsd, vdev, NULL);
1953    }
1954
1955    /* Subsections */
1956    vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
1957}
1958
1959/* A wrapper for use as a VMState .put function */
1960static int virtio_device_put(QEMUFile *f, void *opaque, size_t size,
1961                              VMStateField *field, QJSON *vmdesc)
1962{
1963    virtio_save(VIRTIO_DEVICE(opaque), f);
1964
1965    return 0;
1966}
1967
1968/* A wrapper for use as a VMState .get function */
1969static int virtio_device_get(QEMUFile *f, void *opaque, size_t size,
1970                             VMStateField *field)
1971{
1972    VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
1973    DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev));
1974
1975    return virtio_load(vdev, f, dc->vmsd->version_id);
1976}
1977
1978const VMStateInfo  virtio_vmstate_info = {
1979    .name = "virtio",
1980    .get = virtio_device_get,
1981    .put = virtio_device_put,
1982};
1983
1984static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
1985{
1986    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1987    bool bad = (val & ~(vdev->host_features)) != 0;
1988
1989    val &= vdev->host_features;
1990    if (k->set_features) {
1991        k->set_features(vdev, val);
1992    }
1993    vdev->guest_features = val;
1994    return bad ? -1 : 0;
1995}
1996
1997int virtio_set_features(VirtIODevice *vdev, uint64_t val)
1998{
1999   /*
2000     * The driver must not attempt to set features after feature negotiation
2001     * has finished.
2002     */
2003    if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
2004        return -EINVAL;
2005    }
2006    return virtio_set_features_nocheck(vdev, val);
2007}
2008
2009int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
2010{
2011    int i, ret;
2012    int32_t config_len;
2013    uint32_t num;
2014    uint32_t features;
2015    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2016    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2017    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
2018
2019    /*
2020     * We poison the endianness to ensure it does not get used before
2021     * subsections have been loaded.
2022     */
2023    vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
2024
2025    if (k->load_config) {
2026        ret = k->load_config(qbus->parent, f);
2027        if (ret)
2028            return ret;
2029    }
2030
2031    qemu_get_8s(f, &vdev->status);
2032    qemu_get_8s(f, &vdev->isr);
2033    qemu_get_be16s(f, &vdev->queue_sel);
2034    if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
2035        return -1;
2036    }
2037    qemu_get_be32s(f, &features);
2038
2039    /*
2040     * Temporarily set guest_features low bits - needed by
2041     * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
2042     * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ.
2043     *
2044     * Note: devices should always test host features in future - don't create
2045     * new dependencies like this.
2046     */
2047    vdev->guest_features = features;
2048
2049    config_len = qemu_get_be32(f);
2050
2051    /*
2052     * There are cases where the incoming config can be bigger or smaller
2053     * than what we have; so load what we have space for, and skip
2054     * any excess that's in the stream.
2055     */
2056    qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
2057
2058    while (config_len > vdev->config_len) {
2059        qemu_get_byte(f);
2060        config_len--;
2061    }
2062
2063    num = qemu_get_be32(f);
2064
2065    if (num > VIRTIO_QUEUE_MAX) {
2066        error_report("Invalid number of virtqueues: 0x%x", num);
2067        return -1;
2068    }
2069
2070    for (i = 0; i < num; i++) {
2071        vdev->vq[i].vring.num = qemu_get_be32(f);
2072        if (k->has_variable_vring_alignment) {
2073            vdev->vq[i].vring.align = qemu_get_be32(f);
2074        }
2075        vdev->vq[i].vring.desc = qemu_get_be64(f);
2076        qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
2077        vdev->vq[i].signalled_used_valid = false;
2078        vdev->vq[i].notification = true;
2079
2080        if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
2081            error_report("VQ %d address 0x0 "
2082                         "inconsistent with Host index 0x%x",
2083                         i, vdev->vq[i].last_avail_idx);
2084            return -1;
2085        }
2086        if (k->load_queue) {
2087            ret = k->load_queue(qbus->parent, i, f);
2088            if (ret)
2089                return ret;
2090        }
2091    }
2092
2093    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
2094
2095    if (vdc->load != NULL) {
2096        ret = vdc->load(vdev, f, version_id);
2097        if (ret) {
2098            return ret;
2099        }
2100    }
2101
2102    if (vdc->vmsd) {
2103        ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
2104        if (ret) {
2105            return ret;
2106        }
2107    }
2108
2109    /* Subsections */
2110    ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
2111    if (ret) {
2112        return ret;
2113    }
2114
2115    if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
2116        vdev->device_endian = virtio_default_endian();
2117    }
2118
2119    if (virtio_64bit_features_needed(vdev)) {
2120        /*
2121         * Subsection load filled vdev->guest_features.  Run them
2122         * through virtio_set_features to sanity-check them against
2123         * host_features.
2124         */
2125        uint64_t features64 = vdev->guest_features;
2126        if (virtio_set_features_nocheck(vdev, features64) < 0) {
2127            error_report("Features 0x%" PRIx64 " unsupported. "
2128                         "Allowed features: 0x%" PRIx64,
2129                         features64, vdev->host_features);
2130            return -1;
2131        }
2132    } else {
2133        if (virtio_set_features_nocheck(vdev, features) < 0) {
2134            error_report("Features 0x%x unsupported. "
2135                         "Allowed features: 0x%" PRIx64,
2136                         features, vdev->host_features);
2137            return -1;
2138        }
2139    }
2140
2141    rcu_read_lock();
2142    for (i = 0; i < num; i++) {
2143        if (vdev->vq[i].vring.desc) {
2144            uint16_t nheads;
2145
2146            /*
2147             * VIRTIO-1 devices migrate desc, used, and avail ring addresses so
2148             * only the region cache needs to be set up.  Legacy devices need
2149             * to calculate used and avail ring addresses based on the desc
2150             * address.
2151             */
2152            if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2153                virtio_init_region_cache(vdev, i);
2154            } else {
2155                virtio_queue_update_rings(vdev, i);
2156            }
2157
2158            nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
2159            /* Check it isn't doing strange things with descriptor numbers. */
2160            if (nheads > vdev->vq[i].vring.num) {
2161                error_report("VQ %d size 0x%x Guest index 0x%x "
2162                             "inconsistent with Host index 0x%x: delta 0x%x",
2163                             i, vdev->vq[i].vring.num,
2164                             vring_avail_idx(&vdev->vq[i]),
2165                             vdev->vq[i].last_avail_idx, nheads);
2166                return -1;
2167            }
2168            vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]);
2169            vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]);
2170
2171            /*
2172             * Some devices migrate VirtQueueElements that have been popped
2173             * from the avail ring but not yet returned to the used ring.
2174             * Since max ring size < UINT16_MAX it's safe to use modulo
2175             * UINT16_MAX + 1 subtraction.
2176             */
2177            vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
2178                                vdev->vq[i].used_idx);
2179            if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
2180                error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
2181                             "used_idx 0x%x",
2182                             i, vdev->vq[i].vring.num,
2183                             vdev->vq[i].last_avail_idx,
2184                             vdev->vq[i].used_idx);
2185                return -1;
2186            }
2187        }
2188    }
2189    rcu_read_unlock();
2190
2191    return 0;
2192}
2193
2194void virtio_cleanup(VirtIODevice *vdev)
2195{
2196    qemu_del_vm_change_state_handler(vdev->vmstate);
2197}
2198
2199static void virtio_vmstate_change(void *opaque, int running, RunState state)
2200{
2201    VirtIODevice *vdev = opaque;
2202    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2203    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2204    bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
2205    vdev->vm_running = running;
2206
2207    if (backend_run) {
2208        virtio_set_status(vdev, vdev->status);
2209    }
2210
2211    if (k->vmstate_change) {
2212        k->vmstate_change(qbus->parent, backend_run);
2213    }
2214
2215    if (!backend_run) {
2216        virtio_set_status(vdev, vdev->status);
2217    }
2218}
2219
2220void virtio_instance_init_common(Object *proxy_obj, void *data,
2221                                 size_t vdev_size, const char *vdev_name)
2222{
2223    DeviceState *vdev = data;
2224
2225    object_initialize(vdev, vdev_size, vdev_name);
2226    object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL);
2227    object_unref(OBJECT(vdev));
2228    qdev_alias_all_properties(vdev, proxy_obj);
2229}
2230
2231void virtio_init(VirtIODevice *vdev, const char *name,
2232                 uint16_t device_id, size_t config_size)
2233{
2234    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2235    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2236    int i;
2237    int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
2238
2239    if (nvectors) {
2240        vdev->vector_queues =
2241            g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
2242    }
2243
2244    vdev->device_id = device_id;
2245    vdev->status = 0;
2246    atomic_set(&vdev->isr, 0);
2247    vdev->queue_sel = 0;
2248    vdev->config_vector = VIRTIO_NO_VECTOR;
2249    vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_QUEUE_MAX);
2250    vdev->vm_running = runstate_is_running();
2251    vdev->broken = false;
2252    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2253        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
2254        vdev->vq[i].vdev = vdev;
2255        vdev->vq[i].queue_index = i;
2256    }
2257
2258    vdev->name = name;
2259    vdev->config_len = config_size;
2260    if (vdev->config_len) {
2261        vdev->config = g_malloc0(config_size);
2262    } else {
2263        vdev->config = NULL;
2264    }
2265    vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
2266                                                     vdev);
2267    vdev->device_endian = virtio_default_endian();
2268    vdev->use_guest_notifier_mask = true;
2269}
2270
2271hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
2272{
2273    return vdev->vq[n].vring.desc;
2274}
2275
2276hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
2277{
2278    return vdev->vq[n].vring.avail;
2279}
2280
2281hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
2282{
2283    return vdev->vq[n].vring.used;
2284}
2285
2286hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
2287{
2288    return sizeof(VRingDesc) * vdev->vq[n].vring.num;
2289}
2290
2291hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
2292{
2293    return offsetof(VRingAvail, ring) +
2294        sizeof(uint16_t) * vdev->vq[n].vring.num;
2295}
2296
2297hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
2298{
2299    return offsetof(VRingUsed, ring) +
2300        sizeof(VRingUsedElem) * vdev->vq[n].vring.num;
2301}
2302
2303uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
2304{
2305    return vdev->vq[n].last_avail_idx;
2306}
2307
2308void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
2309{
2310    vdev->vq[n].last_avail_idx = idx;
2311    vdev->vq[n].shadow_avail_idx = idx;
2312}
2313
2314void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
2315{
2316    rcu_read_lock();
2317    if (vdev->vq[n].vring.desc) {
2318        vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
2319    }
2320    rcu_read_unlock();
2321}
2322
2323void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
2324{
2325    vdev->vq[n].signalled_used_valid = false;
2326}
2327
2328VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
2329{
2330    return vdev->vq + n;
2331}
2332
2333uint16_t virtio_get_queue_index(VirtQueue *vq)
2334{
2335    return vq->queue_index;
2336}
2337
2338static void virtio_queue_guest_notifier_read(EventNotifier *n)
2339{
2340    VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
2341    if (event_notifier_test_and_clear(n)) {
2342        virtio_irq(vq);
2343    }
2344}
2345
2346void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
2347                                                bool with_irqfd)
2348{
2349    if (assign && !with_irqfd) {
2350        event_notifier_set_handler(&vq->guest_notifier,
2351                                   virtio_queue_guest_notifier_read);
2352    } else {
2353        event_notifier_set_handler(&vq->guest_notifier, NULL);
2354    }
2355    if (!assign) {
2356        /* Test and clear notifier before closing it,
2357         * in case poll callback didn't have time to run. */
2358        virtio_queue_guest_notifier_read(&vq->guest_notifier);
2359    }
2360}
2361
2362EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
2363{
2364    return &vq->guest_notifier;
2365}
2366
2367static void virtio_queue_host_notifier_aio_read(EventNotifier *n)
2368{
2369    VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2370    if (event_notifier_test_and_clear(n)) {
2371        virtio_queue_notify_aio_vq(vq);
2372    }
2373}
2374
2375static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n)
2376{
2377    VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2378
2379    virtio_queue_set_notification(vq, 0);
2380}
2381
2382static bool virtio_queue_host_notifier_aio_poll(void *opaque)
2383{
2384    EventNotifier *n = opaque;
2385    VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2386    bool progress;
2387
2388    if (!vq->vring.desc || virtio_queue_empty(vq)) {
2389        return false;
2390    }
2391
2392    progress = virtio_queue_notify_aio_vq(vq);
2393
2394    /* In case the handler function re-enabled notifications */
2395    virtio_queue_set_notification(vq, 0);
2396    return progress;
2397}
2398
2399static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
2400{
2401    VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2402
2403    /* Caller polls once more after this to catch requests that race with us */
2404    virtio_queue_set_notification(vq, 1);
2405}
2406
2407void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx,
2408                                                VirtIOHandleAIOOutput handle_output)
2409{
2410    if (handle_output) {
2411        vq->handle_aio_output = handle_output;
2412        aio_set_event_notifier(ctx, &vq->host_notifier, true,
2413                               virtio_queue_host_notifier_aio_read,
2414                               virtio_queue_host_notifier_aio_poll);
2415        aio_set_event_notifier_poll(ctx, &vq->host_notifier,
2416                                    virtio_queue_host_notifier_aio_poll_begin,
2417                                    virtio_queue_host_notifier_aio_poll_end);
2418    } else {
2419        aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL);
2420        /* Test and clear notifier before after disabling event,
2421         * in case poll callback didn't have time to run. */
2422        virtio_queue_host_notifier_aio_read(&vq->host_notifier);
2423        vq->handle_aio_output = NULL;
2424    }
2425}
2426
2427void virtio_queue_host_notifier_read(EventNotifier *n)
2428{
2429    VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2430    if (event_notifier_test_and_clear(n)) {
2431        virtio_queue_notify_vq(vq);
2432    }
2433}
2434
2435EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
2436{
2437    return &vq->host_notifier;
2438}
2439
2440void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
2441{
2442    g_free(vdev->bus_name);
2443    vdev->bus_name = g_strdup(bus_name);
2444}
2445
2446void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...)
2447{
2448    va_list ap;
2449
2450    va_start(ap, fmt);
2451    error_vreport(fmt, ap);
2452    va_end(ap);
2453
2454    if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2455        virtio_set_status(vdev, vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET);
2456        virtio_notify_config(vdev);
2457    }
2458
2459    vdev->broken = true;
2460}
2461
2462static void virtio_memory_listener_commit(MemoryListener *listener)
2463{
2464    VirtIODevice *vdev = container_of(listener, VirtIODevice, listener);
2465    int i;
2466
2467    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2468        if (vdev->vq[i].vring.num == 0) {
2469            break;
2470        }
2471        virtio_init_region_cache(vdev, i);
2472    }
2473}
2474
2475static void virtio_device_realize(DeviceState *dev, Error **errp)
2476{
2477    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
2478    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
2479    Error *err = NULL;
2480
2481    /* Devices should either use vmsd or the load/save methods */
2482    assert(!vdc->vmsd || !vdc->load);
2483
2484    if (vdc->realize != NULL) {
2485        vdc->realize(dev, &err);
2486        if (err != NULL) {
2487            error_propagate(errp, err);
2488            return;
2489        }
2490    }
2491
2492    virtio_bus_device_plugged(vdev, &err);
2493    if (err != NULL) {
2494        error_propagate(errp, err);
2495        return;
2496    }
2497
2498    vdev->listener.commit = virtio_memory_listener_commit;
2499    memory_listener_register(&vdev->listener, vdev->dma_as);
2500}
2501
2502static void virtio_device_unrealize(DeviceState *dev, Error **errp)
2503{
2504    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
2505    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
2506    Error *err = NULL;
2507
2508    virtio_bus_device_unplugged(vdev);
2509
2510    if (vdc->unrealize != NULL) {
2511        vdc->unrealize(dev, &err);
2512        if (err != NULL) {
2513            error_propagate(errp, err);
2514            return;
2515        }
2516    }
2517
2518    g_free(vdev->bus_name);
2519    vdev->bus_name = NULL;
2520}
2521
2522static void virtio_device_free_virtqueues(VirtIODevice *vdev)
2523{
2524    int i;
2525    if (!vdev->vq) {
2526        return;
2527    }
2528
2529    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2530        if (vdev->vq[i].vring.num == 0) {
2531            break;
2532        }
2533        virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
2534    }
2535    g_free(vdev->vq);
2536}
2537
2538static void virtio_device_instance_finalize(Object *obj)
2539{
2540    VirtIODevice *vdev = VIRTIO_DEVICE(obj);
2541
2542    memory_listener_unregister(&vdev->listener);
2543    virtio_device_free_virtqueues(vdev);
2544
2545    g_free(vdev->config);
2546    g_free(vdev->vector_queues);
2547}
2548
2549static Property virtio_properties[] = {
2550    DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
2551    DEFINE_PROP_END_OF_LIST(),
2552};
2553
2554static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
2555{
2556    VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
2557    int n, r, err;
2558
2559    for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2560        VirtQueue *vq = &vdev->vq[n];
2561        if (!virtio_queue_get_num(vdev, n)) {
2562            continue;
2563        }
2564        r = virtio_bus_set_host_notifier(qbus, n, true);
2565        if (r < 0) {
2566            err = r;
2567            goto assign_error;
2568        }
2569        event_notifier_set_handler(&vq->host_notifier,
2570                                   virtio_queue_host_notifier_read);
2571    }
2572
2573    for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2574        /* Kick right away to begin processing requests already in vring */
2575        VirtQueue *vq = &vdev->vq[n];
2576        if (!vq->vring.num) {
2577            continue;
2578        }
2579        event_notifier_set(&vq->host_notifier);
2580    }
2581    return 0;
2582
2583assign_error:
2584    while (--n >= 0) {
2585        VirtQueue *vq = &vdev->vq[n];
2586        if (!virtio_queue_get_num(vdev, n)) {
2587            continue;
2588        }
2589
2590        event_notifier_set_handler(&vq->host_notifier, NULL);
2591        r = virtio_bus_set_host_notifier(qbus, n, false);
2592        assert(r >= 0);
2593    }
2594    return err;
2595}
2596
2597int virtio_device_start_ioeventfd(VirtIODevice *vdev)
2598{
2599    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2600    VirtioBusState *vbus = VIRTIO_BUS(qbus);
2601
2602    return virtio_bus_start_ioeventfd(vbus);
2603}
2604
2605static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
2606{
2607    VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
2608    int n, r;
2609
2610    for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2611        VirtQueue *vq = &vdev->vq[n];
2612
2613        if (!virtio_queue_get_num(vdev, n)) {
2614            continue;
2615        }
2616        event_notifier_set_handler(&vq->host_notifier, NULL);
2617        r = virtio_bus_set_host_notifier(qbus, n, false);
2618        assert(r >= 0);
2619    }
2620}
2621
2622void virtio_device_stop_ioeventfd(VirtIODevice *vdev)
2623{
2624    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2625    VirtioBusState *vbus = VIRTIO_BUS(qbus);
2626
2627    virtio_bus_stop_ioeventfd(vbus);
2628}
2629
2630int virtio_device_grab_ioeventfd(VirtIODevice *vdev)
2631{
2632    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2633    VirtioBusState *vbus = VIRTIO_BUS(qbus);
2634
2635    return virtio_bus_grab_ioeventfd(vbus);
2636}
2637
2638void virtio_device_release_ioeventfd(VirtIODevice *vdev)
2639{
2640    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2641    VirtioBusState *vbus = VIRTIO_BUS(qbus);
2642
2643    virtio_bus_release_ioeventfd(vbus);
2644}
2645
2646static void virtio_device_class_init(ObjectClass *klass, void *data)
2647{
2648    /* Set the default value here. */
2649    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
2650    DeviceClass *dc = DEVICE_CLASS(klass);
2651
2652    dc->realize = virtio_device_realize;
2653    dc->unrealize = virtio_device_unrealize;
2654    dc->bus_type = TYPE_VIRTIO_BUS;
2655    dc->props = virtio_properties;
2656    vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl;
2657    vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
2658
2659    vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
2660}
2661
2662bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
2663{
2664    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2665    VirtioBusState *vbus = VIRTIO_BUS(qbus);
2666
2667    return virtio_bus_ioeventfd_enabled(vbus);
2668}
2669
2670static const TypeInfo virtio_device_info = {
2671    .name = TYPE_VIRTIO_DEVICE,
2672    .parent = TYPE_DEVICE,
2673    .instance_size = sizeof(VirtIODevice),
2674    .class_init = virtio_device_class_init,
2675    .instance_finalize = virtio_device_instance_finalize,
2676    .abstract = true,
2677    .class_size = sizeof(VirtioDeviceClass),
2678};
2679
2680static void virtio_register_types(void)
2681{
2682    type_register_static(&virtio_device_info);
2683}
2684
2685type_init(virtio_register_types)
2686