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 static bool
  24 ioeventfd_enabled(void)
  25 {
  26     return kvm_enabled() && kvm_eventfds_enabled();
  27 }
  28
  29 int
  30 vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
  31                             unsigned nvqs, Error **errp)
  32 {
  33     int ret;
  34
  35     assert(!b->vdev && vdev);
  36
  37     if (!ioeventfd_enabled()) {
  38         error_setg(errp, "vhost initialization failed: requires kvm");
  39         return -1;
  40     }
  41
  42     if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
  43         return -1;
  44     }
  45
  46     b->vdev = vdev;
  47     b->dev.nvqs = nvqs;
  48     b->dev.vqs = g_new0(struct vhost_virtqueue, nvqs);
  49
  50     ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
  51                          errp);
  52     if (ret < 0) {
  53         return -1;
  54     }
  55
  56     return 0;
  57 }
  58
  59 void
  60 vhost_user_backend_start(VhostUserBackend *b)
  61 {
  62     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
  63     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  64     int ret, i ;
  65
  66     if (b->started) {
  67         return;
  68     }
  69
  70     if (!k->set_guest_notifiers) {
  71         error_report("binding does not support guest notifiers");
  72         return;
  73     }
  74
  75     ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
  76     if (ret < 0) {
  77         return;
  78     }
  79
  80     ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
  81     if (ret < 0) {
  82         error_report("Error binding guest notifier");
  83         goto err_host_notifiers;
  84     }
  85
  86     b->dev.acked_features = b->vdev->guest_features;
  87     ret = vhost_dev_start(&b->dev, b->vdev, true);
  88     if (ret < 0) {
  89         error_report("Error start vhost dev");
  90         goto err_guest_notifiers;
  91     }
  92
  93     /* guest_notifier_mask/pending not used yet, so just unmask
  94      * everything here.  virtio-pci will do the right thing by
  95      * enabling/disabling irqfd.
  96      */
  97     for (i = 0; i < b->dev.nvqs; i++) {
  98         vhost_virtqueue_mask(&b->dev, b->vdev,
  99                              b->dev.vq_index + i, false);
 100     }
 101
 102     b->started = true;
 103     return;
 104
 105 err_guest_notifiers:
 106     k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
 107 err_host_notifiers:
 108     vhost_dev_disable_notifiers(&b->dev, b->vdev);
 109 }
 110
 111 void
 112 vhost_user_backend_stop(VhostUserBackend *b)
 113 {
 114     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
 115     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 116     int ret = 0;
 117
 118     if (!b->started) {
 119         return;
 120     }
 121
 122     vhost_dev_stop(&b->dev, b->vdev, true);
 123
 124     if (k->set_guest_notifiers) {
 125         ret = k->set_guest_notifiers(qbus->parent,
 126                                      b->dev.nvqs, false);
 127         if (ret < 0) {
 128             error_report("vhost guest notifier cleanup failed: %d", ret);
 129         }
 130     }
 131     assert(ret >= 0);
 132
 133     vhost_dev_disable_notifiers(&b->dev, b->vdev);
 134     b->started = false;
 135 }
 136
 137 static void set_chardev(Object *obj, const char *value, Error **errp)
 138 {
 139     VhostUserBackend *b = VHOST_USER_BACKEND(obj);
 140     Chardev *chr;
 141
 142     if (b->completed) {
 143         error_setg(errp, "Property 'chardev' can no longer be set");
 144         return;
 145     }
 146
 147     g_free(b->chr_name);
 148     b->chr_name = g_strdup(value);
 149
 150     chr = qemu_chr_find(b->chr_name);
 151     if (chr == NULL) {
 152         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
 153                   "Chardev '%s' not found", b->chr_name);
 154         return;
 155     }
 156
 157     if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
 158         return;
 159     }
 160
 161     b->completed = true;
 162     /* could call vhost_dev_init() so early message can be exchanged */
 163 }
 164
 165 static char *get_chardev(Object *obj, Error **errp)
 166 {
 167     VhostUserBackend *b = VHOST_USER_BACKEND(obj);
 168     Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
 169
 170     if (chr && chr->label) {
 171         return g_strdup(chr->label);
 172     }
 173
 174     return NULL;
 175 }
 176
 177 static void vhost_user_backend_class_init(ObjectClass *oc, void *data)
 178 {
 179     object_class_property_add_str(oc, "chardev", get_chardev, set_chardev);
 180 }
 181
 182 static void vhost_user_backend_finalize(Object *obj)
 183 {
 184     VhostUserBackend *b = VHOST_USER_BACKEND(obj);
 185
 186     g_free(b->dev.vqs);
 187     g_free(b->chr_name);
 188
 189     vhost_user_cleanup(&b->vhost_user);
 190     qemu_chr_fe_deinit(&b->chr, true);
 191 }
 192
 193 static const TypeInfo vhost_user_backend_info = {
 194     .name = TYPE_VHOST_USER_BACKEND,
 195     .parent = TYPE_OBJECT,
 196     .instance_size = sizeof(VhostUserBackend),
 197     .class_init = vhost_user_backend_class_init,
 198     .instance_finalize = vhost_user_backend_finalize,
 199 };
 200
 201 static void register_types(void)
 202 {
 203     type_register_static(&vhost_user_backend_info);
 204 }
 205
 206 type_init(register_types);