backends/vhost-user.c

   1 /*
   2  * QEMU vhost-user backend
   3  *
   4  * Copyright (C) 2018 Red Hat Inc
   5  *
   6  * Authors:
   7  *  Marc-André Lureau <marcandre.lureau@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13
  14 #include "qemu/osdep.h"
  15 #include "qapi/error.h"
  16 #include "qemu/error-report.h"
  17 #include "qom/object_interfaces.h"
  18 #include "sysemu/vhost-user-backend.h"
  19 #include "sysemu/kvm.h"
  20 #include "io/channel-command.h"
  21 #include "hw/virtio/virtio-bus.h"
  22
  23 int
  24 vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
  25                             unsigned nvqs, Error **errp)
  26 {
  27     int ret;
  28
  29     assert(!b->vdev && vdev);
  30
  31     if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
  32         return -1;
  33     }
  34
  35     b->vdev = vdev;
  36     b->dev.nvqs = nvqs;
  37     b->dev.vqs = g_new0(struct vhost_virtqueue, nvqs);
  38
  39     ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
  40                          errp);
  41     if (ret < 0) {
  42         return -1;
  43     }
  44
  45     return 0;
  46 }
  47
  48 void
  49 vhost_user_backend_start(VhostUserBackend *b)
  50 {
  51     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
  52     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  53     int ret, i ;
  54
  55     if (b->started) {
  56         return;
  57     }
  58
  59     if (!k->set_guest_notifiers) {
  60         error_report("binding does not support guest notifiers");
  61         return;
  62     }
  63
  64     ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
  65     if (ret < 0) {
  66         return;
  67     }
  68
  69     ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
  70     if (ret < 0) {
  71         error_report("Error binding guest notifier");
  72         goto err_host_notifiers;
  73     }
  74
  75     b->dev.acked_features = b->vdev->guest_features;
  76     ret = vhost_dev_start(&b->dev, b->vdev, true);
  77     if (ret < 0) {
  78         error_report("Error start vhost dev");
  79         goto err_guest_notifiers;
  80     }
  81
  82     /* guest_notifier_mask/pending not used yet, so just unmask
  83      * everything here.  virtio-pci will do the right thing by
  84      * enabling/disabling irqfd.
  85      */
  86     for (i = 0; i < b->dev.nvqs; i++) {
  87         vhost_virtqueue_mask(&b->dev, b->vdev,
  88                              b->dev.vq_index + i, false);
  89     }
  90
  91     b->started = true;
  92     return;
  93
  94 err_guest_notifiers:
  95     k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
  96 err_host_notifiers:
  97     vhost_dev_disable_notifiers(&b->dev, b->vdev);
  98 }
  99
 100 void
 101 vhost_user_backend_stop(VhostUserBackend *b)
 102 {
 103     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
 104     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 105     int ret = 0;
 106
 107     if (!b->started) {
 108         return;
 109     }
 110
 111     vhost_dev_stop(&b->dev, b->vdev, true);
 112
 113     if (k->set_guest_notifiers) {
 114         ret = k->set_guest_notifiers(qbus->parent,
 115                                      b->dev.nvqs, false);
 116         if (ret < 0) {
 117             error_report("vhost guest notifier cleanup failed: %d", ret);
 118         }
 119     }
 120     assert(ret >= 0);
 121
 122     vhost_dev_disable_notifiers(&b->dev, b->vdev);
 123     b->started = false;
 124 }
 125
 126 static void set_chardev(Object *obj, const char *value, Error **errp)
 127 {
 128     VhostUserBackend *b = VHOST_USER_BACKEND(obj);
 129     Chardev *chr;
 130
 131     if (b->completed) {
 132         error_setg(errp, "Property 'chardev' can no longer be set");
 133         return;
 134     }
 135
 136     g_free(b->chr_name);
 137     b->chr_name = g_strdup(value);
 138
 139     chr = qemu_chr_find(b->chr_name);
 140     if (chr == NULL) {
 141         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
 142                   "Chardev '%s' not found", b->chr_name);
 143         return;
 144     }
 145
 146     if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
 147         return;
 148     }
 149
 150     b->completed = true;
 151     /* could call vhost_dev_init() so early message can be exchanged */
 152 }
 153
 154 static char *get_chardev(Object *obj, Error **errp)
 155 {
 156     VhostUserBackend *b = VHOST_USER_BACKEND(obj);
 157     Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
 158
 159     if (chr && chr->label) {
 160         return g_strdup(chr->label);
 161     }
 162
 163     return NULL;
 164 }
 165
 166 static void vhost_user_backend_class_init(ObjectClass *oc, void *data)
 167 {
 168     object_class_property_add_str(oc, "chardev", get_chardev, set_chardev);
 169 }
 170
 171 static void vhost_user_backend_finalize(Object *obj)
 172 {
 173     VhostUserBackend *b = VHOST_USER_BACKEND(obj);
 174
 175     g_free(b->dev.vqs);
 176     g_free(b->chr_name);
 177
 178     vhost_user_cleanup(&b->vhost_user);
 179     qemu_chr_fe_deinit(&b->chr, true);
 180 }
 181
 182 static const TypeInfo vhost_user_backend_info = {
 183     .name = TYPE_VHOST_USER_BACKEND,
 184     .parent = TYPE_OBJECT,
 185     .instance_size = sizeof(VhostUserBackend),
 186     .class_init = vhost_user_backend_class_init,
 187     .instance_finalize = vhost_user_backend_finalize,
 188 };
 189
 190 static void register_types(void)
 191 {
 192     type_register_static(&vhost_user_backend_info);
 193 }
 194
 195 type_init(register_types);