LCOV - code coverage report
Current view: top level - lib/virtio - virtio.c (source / functions) Hit Total Coverage
Test: ut_cov_unit.info Lines: 0 336 0.0 %
Date: 2024-12-01 18:55:50 Functions: 0 31 0.0 %

          Line data    Source code
       1             : /*   SPDX-License-Identifier: BSD-3-Clause
       2             :  *   Copyright (C) 2010-2016 Intel Corporation. All rights reserved.
       3             :  *   All rights reserved.
       4             :  */
       5             : 
       6             : #include "spdk/stdinc.h"
       7             : 
       8             : #include "spdk/env.h"
       9             : #include "spdk/util.h"
      10             : #include "spdk/barrier.h"
      11             : 
      12             : #include "spdk_internal/virtio.h"
      13             : 
      14             : /* We use SMP memory barrier variants as all virtio_pci devices
      15             :  * are purely virtual. All MMIO is executed on a CPU core, so
      16             :  * there's no need to do full MMIO synchronization.
      17             :  */
      18             : #define virtio_mb()     spdk_smp_mb()
      19             : #define virtio_rmb()    spdk_smp_rmb()
      20             : #define virtio_wmb()    spdk_smp_wmb()
      21             : 
      22             : /* Chain all the descriptors in the ring with an END */
      23             : static inline void
      24           0 : vring_desc_init(struct vring_desc *dp, uint16_t n)
      25             : {
      26             :         uint16_t i;
      27             : 
      28           0 :         for (i = 0; i < n - 1; i++) {
      29           0 :                 dp[i].next = (uint16_t)(i + 1);
      30             :         }
      31           0 :         dp[i].next = VQ_RING_DESC_CHAIN_END;
      32           0 : }
      33             : 
      34             : static void
      35           0 : virtio_init_vring(struct virtqueue *vq)
      36             : {
      37           0 :         int size = vq->vq_nentries;
      38           0 :         struct vring *vr = &vq->vq_ring;
      39           0 :         uint8_t *ring_mem = vq->vq_ring_virt_mem;
      40             : 
      41             :         /*
      42             :          * Reinitialise since virtio port might have been stopped and restarted
      43             :          */
      44           0 :         memset(ring_mem, 0, vq->vq_ring_size);
      45           0 :         vring_init(vr, size, ring_mem, VIRTIO_PCI_VRING_ALIGN);
      46           0 :         vq->vq_used_cons_idx = 0;
      47           0 :         vq->vq_desc_head_idx = 0;
      48           0 :         vq->vq_avail_idx = 0;
      49           0 :         vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
      50           0 :         vq->vq_free_cnt = vq->vq_nentries;
      51           0 :         vq->req_start = VQ_RING_DESC_CHAIN_END;
      52           0 :         vq->req_end = VQ_RING_DESC_CHAIN_END;
      53           0 :         vq->reqs_finished = 0;
      54           0 :         memset(vq->vq_descx, 0, sizeof(struct vq_desc_extra) * vq->vq_nentries);
      55             : 
      56           0 :         vring_desc_init(vr->desc, size);
      57             : 
      58             :         /* Tell the backend not to interrupt us.
      59             :          * If F_EVENT_IDX is negotiated, we will always set incredibly high
      60             :          * used event idx, so that we will practically never receive an
      61             :          * interrupt. See virtqueue_req_flush()
      62             :          */
      63           0 :         if (vq->vdev->negotiated_features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
      64           0 :                 vring_used_event(&vq->vq_ring) = UINT16_MAX;
      65             :         } else {
      66           0 :                 vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
      67             :         }
      68           0 : }
      69             : 
      70             : static int
      71           0 : virtio_init_queue(struct virtio_dev *dev, uint16_t vtpci_queue_idx)
      72             : {
      73             :         unsigned int vq_size, size;
      74           0 :         struct virtqueue *vq;
      75             :         int rc;
      76             : 
      77           0 :         SPDK_DEBUGLOG(virtio_dev, "setting up queue: %"PRIu16"\n", vtpci_queue_idx);
      78             : 
      79             :         /*
      80             :          * Read the virtqueue size from the Queue Size field
      81             :          * Always power of 2 and if 0 virtqueue does not exist
      82             :          */
      83           0 :         vq_size = virtio_dev_backend_ops(dev)->get_queue_size(dev, vtpci_queue_idx);
      84           0 :         SPDK_DEBUGLOG(virtio_dev, "vq_size: %u\n", vq_size);
      85           0 :         if (vq_size == 0) {
      86           0 :                 SPDK_ERRLOG("virtqueue %"PRIu16" does not exist\n", vtpci_queue_idx);
      87           0 :                 return -EINVAL;
      88             :         }
      89             : 
      90           0 :         if (!spdk_u32_is_pow2(vq_size)) {
      91           0 :                 SPDK_ERRLOG("virtqueue %"PRIu16" size (%u) is not powerof 2\n",
      92             :                             vtpci_queue_idx, vq_size);
      93           0 :                 return -EINVAL;
      94             :         }
      95             : 
      96           0 :         size = sizeof(*vq) + vq_size * sizeof(struct vq_desc_extra);
      97             : 
      98           0 :         if (posix_memalign((void **)&vq, SPDK_CACHE_LINE_SIZE, size)) {
      99           0 :                 SPDK_ERRLOG("can not allocate vq\n");
     100           0 :                 return -ENOMEM;
     101             :         }
     102           0 :         memset(vq, 0, size);
     103           0 :         dev->vqs[vtpci_queue_idx] = vq;
     104             : 
     105           0 :         vq->vdev = dev;
     106           0 :         vq->vq_queue_index = vtpci_queue_idx;
     107           0 :         vq->vq_nentries = vq_size;
     108             : 
     109             :         /*
     110             :          * Reserve a memzone for vring elements
     111             :          */
     112           0 :         size = vring_size(vq_size, VIRTIO_PCI_VRING_ALIGN);
     113           0 :         vq->vq_ring_size = SPDK_ALIGN_CEIL(size, VIRTIO_PCI_VRING_ALIGN);
     114           0 :         SPDK_DEBUGLOG(virtio_dev, "vring_size: %u, rounded_vring_size: %u\n",
     115             :                       size, vq->vq_ring_size);
     116             : 
     117           0 :         vq->owner_thread = NULL;
     118             : 
     119           0 :         rc = virtio_dev_backend_ops(dev)->setup_queue(dev, vq);
     120           0 :         if (rc < 0) {
     121           0 :                 SPDK_ERRLOG("setup_queue failed\n");
     122           0 :                 free(vq);
     123           0 :                 dev->vqs[vtpci_queue_idx] = NULL;
     124           0 :                 return rc;
     125             :         }
     126             : 
     127           0 :         SPDK_DEBUGLOG(virtio_dev, "vq->vq_ring_mem:      0x%" PRIx64 "\n",
     128             :                       vq->vq_ring_mem);
     129           0 :         SPDK_DEBUGLOG(virtio_dev, "vq->vq_ring_virt_mem: 0x%" PRIx64 "\n",
     130             :                       (uint64_t)(uintptr_t)vq->vq_ring_virt_mem);
     131             : 
     132           0 :         virtio_init_vring(vq);
     133           0 :         return 0;
     134             : }
     135             : 
     136             : static void
     137           0 : virtio_free_queues(struct virtio_dev *dev)
     138             : {
     139           0 :         uint16_t nr_vq = dev->max_queues;
     140             :         struct virtqueue *vq;
     141             :         uint16_t i;
     142             : 
     143           0 :         if (dev->vqs == NULL) {
     144           0 :                 return;
     145             :         }
     146             : 
     147           0 :         for (i = 0; i < nr_vq; i++) {
     148           0 :                 vq = dev->vqs[i];
     149           0 :                 if (!vq) {
     150           0 :                         continue;
     151             :                 }
     152             : 
     153           0 :                 virtio_dev_backend_ops(dev)->del_queue(dev, vq);
     154             : 
     155           0 :                 free(vq);
     156           0 :                 dev->vqs[i] = NULL;
     157             :         }
     158             : 
     159           0 :         free(dev->vqs);
     160           0 :         dev->vqs = NULL;
     161             : }
     162             : 
     163             : static int
     164           0 : virtio_alloc_queues(struct virtio_dev *dev, uint16_t max_queues, uint16_t fixed_vq_num)
     165             : {
     166             :         uint16_t i;
     167             :         int ret;
     168             : 
     169           0 :         if (max_queues == 0) {
     170             :                 /* perfectly fine to have a device with no virtqueues. */
     171           0 :                 return 0;
     172             :         }
     173             : 
     174           0 :         assert(dev->vqs == NULL);
     175           0 :         dev->vqs = calloc(1, sizeof(struct virtqueue *) * max_queues);
     176           0 :         if (!dev->vqs) {
     177           0 :                 SPDK_ERRLOG("failed to allocate %"PRIu16" vqs\n", max_queues);
     178           0 :                 return -ENOMEM;
     179             :         }
     180             : 
     181           0 :         for (i = 0; i < max_queues; i++) {
     182           0 :                 ret = virtio_init_queue(dev, i);
     183           0 :                 if (ret < 0) {
     184           0 :                         virtio_free_queues(dev);
     185           0 :                         return ret;
     186             :                 }
     187             :         }
     188             : 
     189           0 :         dev->max_queues = max_queues;
     190           0 :         dev->fixed_queues_num = fixed_vq_num;
     191           0 :         return 0;
     192             : }
     193             : 
     194             : /**
     195             :  * Negotiate virtio features. For virtio_user this will also set
     196             :  * dev->modern flag if VIRTIO_F_VERSION_1 flag is negotiated.
     197             :  */
     198             : static int
     199           0 : virtio_negotiate_features(struct virtio_dev *dev, uint64_t req_features)
     200             : {
     201           0 :         uint64_t host_features = virtio_dev_backend_ops(dev)->get_features(dev);
     202             :         int rc;
     203             : 
     204           0 :         SPDK_DEBUGLOG(virtio_dev, "guest features = %" PRIx64 "\n", req_features);
     205           0 :         SPDK_DEBUGLOG(virtio_dev, "device features = %" PRIx64 "\n", host_features);
     206             : 
     207           0 :         rc = virtio_dev_backend_ops(dev)->set_features(dev, req_features & host_features);
     208           0 :         if (rc != 0) {
     209           0 :                 SPDK_ERRLOG("failed to negotiate device features.\n");
     210           0 :                 return rc;
     211             :         }
     212             : 
     213           0 :         SPDK_DEBUGLOG(virtio_dev, "negotiated features = %" PRIx64 "\n",
     214             :                       dev->negotiated_features);
     215             : 
     216           0 :         virtio_dev_set_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
     217           0 :         if (!(virtio_dev_get_status(dev) & VIRTIO_CONFIG_S_FEATURES_OK)) {
     218           0 :                 SPDK_ERRLOG("failed to set FEATURES_OK status!\n");
     219             :                 /* either the device failed, or we offered some features that
     220             :                  * depend on other, not offered features.
     221             :                  */
     222           0 :                 return -EINVAL;
     223             :         }
     224             : 
     225           0 :         return 0;
     226             : }
     227             : 
     228             : int
     229           0 : virtio_dev_construct(struct virtio_dev *vdev, const char *name,
     230             :                      const struct virtio_dev_ops *ops, void *ctx)
     231             : {
     232             :         int rc;
     233             : 
     234           0 :         vdev->name = strdup(name);
     235           0 :         if (vdev->name == NULL) {
     236           0 :                 return -ENOMEM;
     237             :         }
     238             : 
     239           0 :         rc = pthread_mutex_init(&vdev->mutex, NULL);
     240           0 :         if (rc != 0) {
     241           0 :                 free(vdev->name);
     242           0 :                 return -rc;
     243             :         }
     244             : 
     245           0 :         vdev->backend_ops = ops;
     246           0 :         vdev->ctx = ctx;
     247             : 
     248           0 :         return 0;
     249             : }
     250             : 
     251             : int
     252           0 : virtio_dev_reset(struct virtio_dev *dev, uint64_t req_features)
     253             : {
     254           0 :         req_features |= (1ULL << VIRTIO_F_VERSION_1);
     255             : 
     256           0 :         virtio_dev_stop(dev);
     257             : 
     258           0 :         virtio_dev_set_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
     259           0 :         if (!(virtio_dev_get_status(dev) & VIRTIO_CONFIG_S_ACKNOWLEDGE)) {
     260           0 :                 SPDK_ERRLOG("Failed to set VIRTIO_CONFIG_S_ACKNOWLEDGE status.\n");
     261           0 :                 return -EIO;
     262             :         }
     263             : 
     264           0 :         virtio_dev_set_status(dev, VIRTIO_CONFIG_S_DRIVER);
     265           0 :         if (!(virtio_dev_get_status(dev) & VIRTIO_CONFIG_S_DRIVER)) {
     266           0 :                 SPDK_ERRLOG("Failed to set VIRTIO_CONFIG_S_DRIVER status.\n");
     267           0 :                 return -EIO;
     268             :         }
     269             : 
     270           0 :         return virtio_negotiate_features(dev, req_features);
     271             : }
     272             : 
     273             : int
     274           0 : virtio_dev_start(struct virtio_dev *vdev, uint16_t max_queues, uint16_t fixed_queue_num)
     275             : {
     276             :         int ret;
     277             : 
     278           0 :         ret = virtio_alloc_queues(vdev, max_queues, fixed_queue_num);
     279           0 :         if (ret < 0) {
     280           0 :                 return ret;
     281             :         }
     282             : 
     283           0 :         virtio_dev_set_status(vdev, VIRTIO_CONFIG_S_DRIVER_OK);
     284           0 :         if (!(virtio_dev_get_status(vdev) & VIRTIO_CONFIG_S_DRIVER_OK)) {
     285           0 :                 SPDK_ERRLOG("Failed to set VIRTIO_CONFIG_S_DRIVER_OK status.\n");
     286           0 :                 return -1;
     287             :         }
     288             : 
     289           0 :         return 0;
     290             : }
     291             : 
     292             : void
     293           0 : virtio_dev_destruct(struct virtio_dev *dev)
     294             : {
     295           0 :         virtio_dev_backend_ops(dev)->destruct_dev(dev);
     296           0 :         pthread_mutex_destroy(&dev->mutex);
     297           0 :         free(dev->name);
     298           0 : }
     299             : 
     300             : static void
     301           0 : vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx)
     302             : {
     303             :         struct vring_desc *dp, *dp_tail;
     304             :         struct vq_desc_extra *dxp;
     305           0 :         uint16_t desc_idx_last = desc_idx;
     306             : 
     307           0 :         dp  = &vq->vq_ring.desc[desc_idx];
     308           0 :         dxp = &vq->vq_descx[desc_idx];
     309           0 :         vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt + dxp->ndescs);
     310           0 :         if ((dp->flags & VRING_DESC_F_INDIRECT) == 0) {
     311           0 :                 while (dp->flags & VRING_DESC_F_NEXT) {
     312           0 :                         desc_idx_last = dp->next;
     313           0 :                         dp = &vq->vq_ring.desc[dp->next];
     314             :                 }
     315             :         }
     316           0 :         dxp->ndescs = 0;
     317             : 
     318             :         /*
     319             :          * We must append the existing free chain, if any, to the end of
     320             :          * newly freed chain. If the virtqueue was completely used, then
     321             :          * head would be VQ_RING_DESC_CHAIN_END (ASSERTed above).
     322             :          */
     323           0 :         if (vq->vq_desc_tail_idx == VQ_RING_DESC_CHAIN_END) {
     324           0 :                 vq->vq_desc_head_idx = desc_idx;
     325             :         } else {
     326           0 :                 dp_tail = &vq->vq_ring.desc[vq->vq_desc_tail_idx];
     327           0 :                 dp_tail->next = desc_idx;
     328             :         }
     329             : 
     330           0 :         vq->vq_desc_tail_idx = desc_idx_last;
     331           0 :         dp->next = VQ_RING_DESC_CHAIN_END;
     332           0 : }
     333             : 
     334             : static uint16_t
     335           0 : virtqueue_dequeue_burst_rx(struct virtqueue *vq, void **rx_pkts,
     336             :                            uint32_t *len, uint16_t num)
     337             : {
     338             :         struct vring_used_elem *uep;
     339             :         void *cookie;
     340             :         uint16_t used_idx, desc_idx;
     341             :         uint16_t i;
     342             : 
     343             :         /*  Caller does the check */
     344           0 :         for (i = 0; i < num ; i++) {
     345           0 :                 used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
     346           0 :                 uep = &vq->vq_ring.used->ring[used_idx];
     347           0 :                 desc_idx = (uint16_t) uep->id;
     348           0 :                 len[i] = uep->len;
     349           0 :                 cookie = vq->vq_descx[desc_idx].cookie;
     350             : 
     351           0 :                 if (spdk_unlikely(cookie == NULL)) {
     352           0 :                         SPDK_WARNLOG("vring descriptor with no mbuf cookie at %"PRIu16"\n",
     353             :                                      vq->vq_used_cons_idx);
     354           0 :                         break;
     355             :                 }
     356             : 
     357           0 :                 __builtin_prefetch(cookie);
     358             : 
     359           0 :                 rx_pkts[i]  = cookie;
     360           0 :                 vq->vq_used_cons_idx++;
     361           0 :                 vq_ring_free_chain(vq, desc_idx);
     362           0 :                 vq->vq_descx[desc_idx].cookie = NULL;
     363             :         }
     364             : 
     365           0 :         return i;
     366             : }
     367             : 
     368             : static void
     369           0 : finish_req(struct virtqueue *vq)
     370             : {
     371             :         struct vring_desc *desc;
     372             :         uint16_t avail_idx;
     373             : 
     374           0 :         desc = &vq->vq_ring.desc[vq->req_end];
     375           0 :         desc->flags &= ~VRING_DESC_F_NEXT;
     376             : 
     377             :         /*
     378             :          * Place the head of the descriptor chain into the next slot and make
     379             :          * it usable to the host. The chain is made available now rather than
     380             :          * deferring to virtqueue_req_flush() in the hopes that if the host is
     381             :          * currently running on another CPU, we can keep it processing the new
     382             :          * descriptor.
     383             :          */
     384           0 :         avail_idx = (uint16_t)(vq->vq_avail_idx & (vq->vq_nentries - 1));
     385           0 :         vq->vq_ring.avail->ring[avail_idx] = vq->req_start;
     386           0 :         vq->vq_avail_idx++;
     387           0 :         vq->req_end = VQ_RING_DESC_CHAIN_END;
     388           0 :         virtio_wmb();
     389           0 :         vq->vq_ring.avail->idx = vq->vq_avail_idx;
     390           0 :         vq->reqs_finished++;
     391           0 : }
     392             : 
     393             : int
     394           0 : virtqueue_req_start(struct virtqueue *vq, void *cookie, int iovcnt)
     395             : {
     396             :         struct vq_desc_extra *dxp;
     397             : 
     398             :         /* Reserve enough entries to handle iov split */
     399           0 :         if (2 * iovcnt > vq->vq_free_cnt) {
     400           0 :                 return iovcnt > vq->vq_nentries ? -EINVAL : -ENOMEM;
     401             :         }
     402             : 
     403           0 :         if (vq->req_end != VQ_RING_DESC_CHAIN_END) {
     404           0 :                 finish_req(vq);
     405             :         }
     406             : 
     407           0 :         vq->req_start = vq->vq_desc_head_idx;
     408           0 :         dxp = &vq->vq_descx[vq->req_start];
     409           0 :         dxp->cookie = cookie;
     410           0 :         dxp->ndescs = 0;
     411             : 
     412           0 :         return 0;
     413             : }
     414             : 
     415             : void
     416           0 : virtqueue_req_flush(struct virtqueue *vq)
     417             : {
     418             :         uint16_t reqs_finished;
     419             : 
     420           0 :         if (vq->req_end == VQ_RING_DESC_CHAIN_END) {
     421             :                 /* no non-empty requests have been started */
     422           0 :                 return;
     423             :         }
     424             : 
     425           0 :         finish_req(vq);
     426           0 :         virtio_mb();
     427             : 
     428           0 :         reqs_finished = vq->reqs_finished;
     429           0 :         vq->reqs_finished = 0;
     430             : 
     431           0 :         if (vq->vdev->negotiated_features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
     432             :                 /* Set used event idx to a value the device will never reach.
     433             :                  * This effectively disables interrupts.
     434             :                  */
     435           0 :                 vring_used_event(&vq->vq_ring) = vq->vq_used_cons_idx - vq->vq_nentries - 1;
     436             : 
     437           0 :                 if (!vring_need_event(vring_avail_event(&vq->vq_ring),
     438           0 :                                       vq->vq_avail_idx,
     439           0 :                                       vq->vq_avail_idx - reqs_finished)) {
     440           0 :                         return;
     441             :                 }
     442           0 :         } else if (vq->vq_ring.used->flags & VRING_USED_F_NO_NOTIFY) {
     443           0 :                 return;
     444             :         }
     445             : 
     446           0 :         virtio_dev_backend_ops(vq->vdev)->notify_queue(vq->vdev, vq);
     447           0 :         SPDK_DEBUGLOG(virtio_dev, "Notified backend after xmit\n");
     448             : }
     449             : 
     450             : void
     451           0 : virtqueue_req_abort(struct virtqueue *vq)
     452             : {
     453             :         struct vring_desc *desc;
     454             : 
     455           0 :         if (vq->req_start == VQ_RING_DESC_CHAIN_END) {
     456             :                 /* no requests have been started */
     457           0 :                 return;
     458             :         }
     459             : 
     460           0 :         desc = &vq->vq_ring.desc[vq->req_end];
     461           0 :         desc->flags &= ~VRING_DESC_F_NEXT;
     462             : 
     463           0 :         vq_ring_free_chain(vq, vq->req_start);
     464           0 :         vq->req_start = VQ_RING_DESC_CHAIN_END;
     465             : }
     466             : 
     467             : void
     468           0 : virtqueue_req_add_iovs(struct virtqueue *vq, struct iovec *iovs, uint16_t iovcnt,
     469             :                        enum spdk_virtio_desc_type desc_type)
     470             : {
     471             :         struct vring_desc *desc;
     472             :         struct vq_desc_extra *dxp;
     473             :         uint16_t i, prev_head, new_head;
     474           0 :         uint64_t processed_length, iovec_length, current_length;
     475             :         void *current_base;
     476           0 :         uint16_t used_desc_count = 0;
     477             : 
     478           0 :         assert(vq->req_start != VQ_RING_DESC_CHAIN_END);
     479           0 :         assert(iovcnt <= vq->vq_free_cnt);
     480             : 
     481             :         /* TODO use indirect descriptors if iovcnt is high enough
     482             :          * or the caller specifies SPDK_VIRTIO_DESC_F_INDIRECT
     483             :          */
     484             : 
     485           0 :         prev_head = vq->req_end;
     486           0 :         new_head = vq->vq_desc_head_idx;
     487           0 :         for (i = 0; i < iovcnt; ++i) {
     488           0 :                 processed_length = 0;
     489           0 :                 iovec_length = iovs[i].iov_len;
     490           0 :                 current_base = iovs[i].iov_base;
     491             : 
     492           0 :                 while (processed_length < iovec_length) {
     493           0 :                         desc = &vq->vq_ring.desc[new_head];
     494           0 :                         current_length = iovec_length - processed_length;
     495             : 
     496           0 :                         if (!vq->vdev->is_hw) {
     497           0 :                                 desc->addr  = (uintptr_t)current_base;
     498             :                         } else {
     499           0 :                                 desc->addr = spdk_vtophys(current_base, &current_length);
     500             :                         }
     501             : 
     502           0 :                         desc->len = current_length;
     503             :                         /* always set NEXT flag. unset it on the last descriptor
     504             :                          * in the request-ending function.
     505             :                          */
     506           0 :                         desc->flags = desc_type | VRING_DESC_F_NEXT;
     507             : 
     508           0 :                         prev_head = new_head;
     509           0 :                         new_head = desc->next;
     510           0 :                         used_desc_count++;
     511             : 
     512           0 :                         processed_length += current_length;
     513           0 :                         current_base += current_length;
     514             :                 }
     515             :         }
     516             : 
     517           0 :         dxp = &vq->vq_descx[vq->req_start];
     518           0 :         dxp->ndescs += used_desc_count;
     519             : 
     520           0 :         vq->req_end = prev_head;
     521           0 :         vq->vq_desc_head_idx = new_head;
     522           0 :         vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - used_desc_count);
     523           0 :         if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END) {
     524           0 :                 assert(vq->vq_free_cnt == 0);
     525           0 :                 vq->vq_desc_tail_idx = VQ_RING_DESC_CHAIN_END;
     526             :         }
     527           0 : }
     528             : 
     529             : #define DESC_PER_CACHELINE (SPDK_CACHE_LINE_SIZE / sizeof(struct vring_desc))
     530             : uint16_t
     531           0 : virtio_recv_pkts(struct virtqueue *vq, void **io, uint32_t *len, uint16_t nb_pkts)
     532             : {
     533             :         uint16_t nb_used, num;
     534             : 
     535           0 :         nb_used = vq->vq_ring.used->idx - vq->vq_used_cons_idx;
     536           0 :         virtio_rmb();
     537             : 
     538           0 :         num = (uint16_t)(spdk_likely(nb_used <= nb_pkts) ? nb_used : nb_pkts);
     539           0 :         if (spdk_likely(num > DESC_PER_CACHELINE)) {
     540           0 :                 num = num - ((vq->vq_used_cons_idx + num) % DESC_PER_CACHELINE);
     541             :         }
     542             : 
     543           0 :         return virtqueue_dequeue_burst_rx(vq, io, len, num);
     544             : }
     545             : 
     546             : int
     547           0 : virtio_dev_acquire_queue(struct virtio_dev *vdev, uint16_t index)
     548             : {
     549           0 :         struct virtqueue *vq = NULL;
     550             : 
     551           0 :         if (index >= vdev->max_queues) {
     552           0 :                 SPDK_ERRLOG("requested vq index %"PRIu16" exceeds max queue count %"PRIu16".\n",
     553             :                             index, vdev->max_queues);
     554           0 :                 return -1;
     555             :         }
     556             : 
     557           0 :         pthread_mutex_lock(&vdev->mutex);
     558           0 :         vq = vdev->vqs[index];
     559           0 :         if (vq == NULL || vq->owner_thread != NULL) {
     560           0 :                 pthread_mutex_unlock(&vdev->mutex);
     561           0 :                 return -1;
     562             :         }
     563             : 
     564           0 :         vq->owner_thread = spdk_get_thread();
     565           0 :         pthread_mutex_unlock(&vdev->mutex);
     566           0 :         return 0;
     567             : }
     568             : 
     569             : int32_t
     570           0 : virtio_dev_find_and_acquire_queue(struct virtio_dev *vdev, uint16_t start_index)
     571             : {
     572           0 :         struct virtqueue *vq = NULL;
     573             :         uint16_t i;
     574             : 
     575           0 :         pthread_mutex_lock(&vdev->mutex);
     576           0 :         for (i = start_index; i < vdev->max_queues; ++i) {
     577           0 :                 vq = vdev->vqs[i];
     578           0 :                 if (vq != NULL && vq->owner_thread == NULL) {
     579           0 :                         break;
     580             :                 }
     581             :         }
     582             : 
     583           0 :         if (vq == NULL || i == vdev->max_queues) {
     584           0 :                 SPDK_ERRLOG("no more unused virtio queues with idx >= %"PRIu16".\n", start_index);
     585           0 :                 pthread_mutex_unlock(&vdev->mutex);
     586           0 :                 return -1;
     587             :         }
     588             : 
     589           0 :         vq->owner_thread = spdk_get_thread();
     590           0 :         pthread_mutex_unlock(&vdev->mutex);
     591           0 :         return i;
     592             : }
     593             : 
     594             : struct spdk_thread *
     595           0 : virtio_dev_queue_get_thread(struct virtio_dev *vdev, uint16_t index)
     596             : {
     597           0 :         struct spdk_thread *thread = NULL;
     598             : 
     599           0 :         if (index >= vdev->max_queues) {
     600           0 :                 SPDK_ERRLOG("given vq index %"PRIu16" exceeds max queue count %"PRIu16"\n",
     601             :                             index, vdev->max_queues);
     602           0 :                 abort(); /* This is not recoverable */
     603             :         }
     604             : 
     605           0 :         pthread_mutex_lock(&vdev->mutex);
     606           0 :         thread = vdev->vqs[index]->owner_thread;
     607           0 :         pthread_mutex_unlock(&vdev->mutex);
     608             : 
     609           0 :         return thread;
     610             : }
     611             : 
     612             : bool
     613           0 : virtio_dev_queue_is_acquired(struct virtio_dev *vdev, uint16_t index)
     614             : {
     615           0 :         return virtio_dev_queue_get_thread(vdev, index) != NULL;
     616             : }
     617             : 
     618             : void
     619           0 : virtio_dev_release_queue(struct virtio_dev *vdev, uint16_t index)
     620             : {
     621           0 :         struct virtqueue *vq = NULL;
     622             : 
     623           0 :         if (index >= vdev->max_queues) {
     624           0 :                 SPDK_ERRLOG("given vq index %"PRIu16" exceeds max queue count %"PRIu16".\n",
     625             :                             index, vdev->max_queues);
     626           0 :                 return;
     627             :         }
     628             : 
     629           0 :         pthread_mutex_lock(&vdev->mutex);
     630           0 :         vq = vdev->vqs[index];
     631           0 :         if (vq == NULL) {
     632           0 :                 SPDK_ERRLOG("virtqueue at index %"PRIu16" is not initialized.\n", index);
     633           0 :                 pthread_mutex_unlock(&vdev->mutex);
     634           0 :                 return;
     635             :         }
     636             : 
     637           0 :         assert(vq->owner_thread == spdk_get_thread());
     638           0 :         vq->owner_thread = NULL;
     639           0 :         pthread_mutex_unlock(&vdev->mutex);
     640             : }
     641             : 
     642             : int
     643           0 : virtio_dev_read_dev_config(struct virtio_dev *dev, size_t offset,
     644             :                            void *dst, int length)
     645             : {
     646           0 :         return virtio_dev_backend_ops(dev)->read_dev_cfg(dev, offset, dst, length);
     647             : }
     648             : 
     649             : int
     650           0 : virtio_dev_write_dev_config(struct virtio_dev *dev, size_t offset,
     651             :                             const void *src, int length)
     652             : {
     653           0 :         return virtio_dev_backend_ops(dev)->write_dev_cfg(dev, offset, src, length);
     654             : }
     655             : 
     656             : void
     657           0 : virtio_dev_stop(struct virtio_dev *dev)
     658             : {
     659           0 :         virtio_dev_backend_ops(dev)->set_status(dev, VIRTIO_CONFIG_S_RESET);
     660             :         /* flush status write */
     661           0 :         virtio_dev_backend_ops(dev)->get_status(dev);
     662           0 :         virtio_free_queues(dev);
     663           0 : }
     664             : 
     665             : void
     666           0 : virtio_dev_set_status(struct virtio_dev *dev, uint8_t status)
     667             : {
     668           0 :         if (status != VIRTIO_CONFIG_S_RESET) {
     669           0 :                 status |= virtio_dev_backend_ops(dev)->get_status(dev);
     670             :         }
     671             : 
     672           0 :         virtio_dev_backend_ops(dev)->set_status(dev, status);
     673           0 : }
     674             : 
     675             : uint8_t
     676           0 : virtio_dev_get_status(struct virtio_dev *dev)
     677             : {
     678           0 :         return virtio_dev_backend_ops(dev)->get_status(dev);
     679             : }
     680             : 
     681             : const struct virtio_dev_ops *
     682           0 : virtio_dev_backend_ops(struct virtio_dev *dev)
     683             : {
     684           0 :         return dev->backend_ops;
     685             : }
     686             : 
     687             : void
     688           0 : virtio_dev_dump_json_info(struct virtio_dev *hw, struct spdk_json_write_ctx *w)
     689             : {
     690           0 :         spdk_json_write_named_object_begin(w, "virtio");
     691             : 
     692           0 :         spdk_json_write_named_uint32(w, "vq_count", hw->max_queues);
     693             : 
     694           0 :         spdk_json_write_named_uint32(w, "vq_size",
     695           0 :                                      virtio_dev_backend_ops(hw)->get_queue_size(hw, 0));
     696             : 
     697           0 :         virtio_dev_backend_ops(hw)->dump_json_info(hw, w);
     698             : 
     699           0 :         spdk_json_write_object_end(w);
     700           0 : }
     701             : 
     702           0 : SPDK_LOG_REGISTER_COMPONENT(virtio_dev)

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