hw/virtio/vhost-shadow-virtqueue.h

   1 /*
   2  * vhost shadow virtqueue
   3  *
   4  * SPDX-FileCopyrightText: Red Hat, Inc. 2021
   5  * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-or-later
   8  */
   9
  10 #ifndef VHOST_SHADOW_VIRTQUEUE_H
  11 #define VHOST_SHADOW_VIRTQUEUE_H
  12
  13 #include "qemu/event_notifier.h"
  14 #include "hw/virtio/virtio.h"
  15 #include "standard-headers/linux/vhost_types.h"
  16 #include "hw/virtio/vhost-iova-tree.h"
  17
  18 /* Shadow virtqueue to relay notifications */
  19 typedef struct VhostShadowVirtqueue {
  20     /* Shadow vring */
  21     struct vring vring;
  22
  23     /* Shadow kick notifier, sent to vhost */
  24     EventNotifier hdev_kick;
  25     /* Shadow call notifier, sent to vhost */
  26     EventNotifier hdev_call;
  27
  28     /*
  29      * Borrowed virtqueue's guest to host notifier. To borrow it in this event
  30      * notifier allows to recover the VhostShadowVirtqueue from the event loop
  31      * easily. If we use the VirtQueue's one, we don't have an easy way to
  32      * retrieve VhostShadowVirtqueue.
  33      *
  34      * So shadow virtqueue must not clean it, or we would lose VirtQueue one.
  35      */
  36     EventNotifier svq_kick;
  37
  38     /* Guest's call notifier, where the SVQ calls guest. */
  39     EventNotifier svq_call;
  40
  41     /* Virtio queue shadowing */
  42     VirtQueue *vq;
  43
  44     /* Virtio device */
  45     VirtIODevice *vdev;
  46
  47     /* IOVA mapping */
  48     VhostIOVATree *iova_tree;
  49
  50     /* Map for use the guest's descriptors */
  51     VirtQueueElement **ring_id_maps;
  52
  53     /* Next VirtQueue element that guest made available */
  54     VirtQueueElement *next_guest_avail_elem;
  55
  56     /* Next head to expose to the device */
  57     uint16_t shadow_avail_idx;
  58
  59     /* Next free descriptor */
  60     uint16_t free_head;
  61
  62     /* Last seen used idx */
  63     uint16_t shadow_used_idx;
  64
  65     /* Next head to consume from the device */
  66     uint16_t last_used_idx;
  67 } VhostShadowVirtqueue;
  68
  69 bool vhost_svq_valid_features(uint64_t features, Error **errp);
  70
  71 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
  72 void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
  73 void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
  74                               struct vhost_vring_addr *addr);
  75 size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
  76 size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
  77
  78 void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
  79                      VirtQueue *vq);
  80 void vhost_svq_stop(VhostShadowVirtqueue *svq);
  81
  82 VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree);
  83
  84 void vhost_svq_free(gpointer vq);
  85 G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
  86
  87 #endif