hw/9pfs/virtio-9p-device.c

   1 /*
   2  * Virtio 9p backend
   3  *
   4  * Copyright IBM, Corp. 2010
   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 "hw/virtio/virtio.h"
  16 #include "qemu/sockets.h"
  17 #include "virtio-9p.h"
  18 #include "fsdev/qemu-fsdev.h"
  19 #include "coth.h"
  20 #include "hw/virtio/virtio-access.h"
  21 #include "qemu/iov.h"
  22
  23 static const struct V9fsTransport virtio_9p_transport;
  24
  25 static void virtio_9p_push_and_notify(V9fsPDU *pdu)
  26 {
  27     V9fsState *s = pdu->s;
  28     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
  29     VirtQueueElement *elem = v->elems[pdu->idx];
  30
  31     /* push onto queue and notify */
  32     virtqueue_push(v->vq, elem, pdu->size);
  33     g_free(elem);
  34     v->elems[pdu->idx] = NULL;
  35
  36     /* FIXME: we should batch these completions */
  37     virtio_notify(VIRTIO_DEVICE(v), v->vq);
  38 }
  39
  40 static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
  41 {
  42     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
  43     V9fsState *s = &v->state;
  44     V9fsPDU *pdu;
  45     ssize_t len;
  46     VirtQueueElement *elem;
  47
  48     while ((pdu = pdu_alloc(s))) {
  49         struct {
  50             uint32_t size_le;
  51             uint8_t id;
  52             uint16_t tag_le;
  53         } QEMU_PACKED out;
  54
  55         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
  56         if (!elem) {
  57             goto out_free_pdu;
  58         }
  59
  60         if (elem->in_num == 0) {
  61             virtio_error(vdev,
  62                          "The guest sent a VirtFS request without space for "
  63                          "the reply");
  64             goto out_free_req;
  65         }
  66         QEMU_BUILD_BUG_ON(sizeof(out) != 7);
  67
  68         v->elems[pdu->idx] = elem;
  69         len = iov_to_buf(elem->out_sg, elem->out_num, 0,
  70                          &out, sizeof(out));
  71         if (len != sizeof(out)) {
  72             virtio_error(vdev, "The guest sent a malformed VirtFS request: "
  73                          "header size is %zd, should be 7", len);
  74             goto out_free_req;
  75         }
  76
  77         pdu->size = le32_to_cpu(out.size_le);
  78
  79         pdu->id = out.id;
  80         pdu->tag = le16_to_cpu(out.tag_le);
  81
  82         qemu_co_queue_init(&pdu->complete);
  83         pdu_submit(pdu);
  84     }
  85
  86     return;
  87
  88 out_free_req:
  89     virtqueue_detach_element(vq, elem, 0);
  90     g_free(elem);
  91 out_free_pdu:
  92     pdu_free(pdu);
  93 }
  94
  95 static uint64_t virtio_9p_get_features(VirtIODevice *vdev, uint64_t features,
  96                                        Error **errp)
  97 {
  98     virtio_add_feature(&features, VIRTIO_9P_MOUNT_TAG);
  99     return features;
 100 }
 101
 102 static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
 103 {
 104     int len;
 105     struct virtio_9p_config *cfg;
 106     V9fsVirtioState *v = VIRTIO_9P(vdev);
 107     V9fsState *s = &v->state;
 108
 109     len = strlen(s->tag);
 110     cfg = g_malloc0(sizeof(struct virtio_9p_config) + len);
 111     virtio_stw_p(vdev, &cfg->tag_len, len);
 112     /* We don't copy the terminating null to config space */
 113     memcpy(cfg->tag, s->tag, len);
 114     memcpy(config, cfg, v->config_size);
 115     g_free(cfg);
 116 }
 117
 118 static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
 119 {
 120     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 121     V9fsVirtioState *v = VIRTIO_9P(dev);
 122     V9fsState *s = &v->state;
 123
 124     if (v9fs_device_realize_common(s, errp)) {
 125         goto out;
 126     }
 127
 128     v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
 129     virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
 130     v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
 131     v9fs_register_transport(s, &virtio_9p_transport);
 132
 133 out:
 134     return;
 135 }
 136
 137 static void virtio_9p_device_unrealize(DeviceState *dev, Error **errp)
 138 {
 139     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 140     V9fsVirtioState *v = VIRTIO_9P(dev);
 141     V9fsState *s = &v->state;
 142
 143     virtio_cleanup(vdev);
 144     v9fs_device_unrealize_common(s, errp);
 145 }
 146
 147 static void virtio_9p_reset(VirtIODevice *vdev)
 148 {
 149     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
 150
 151     v9fs_reset(&v->state);
 152 }
 153
 154 static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
 155                                    const char *fmt, va_list ap)
 156 {
 157     V9fsState *s = pdu->s;
 158     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 159     VirtQueueElement *elem = v->elems[pdu->idx];
 160
 161     return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
 162 }
 163
 164 static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
 165                                      const char *fmt, va_list ap)
 166 {
 167     V9fsState *s = pdu->s;
 168     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 169     VirtQueueElement *elem = v->elems[pdu->idx];
 170
 171     return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 172 }
 173
 174 /* The size parameter is used by other transports. Do not drop it. */
 175 static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 176                                         unsigned int *pniov, size_t size)
 177 {
 178     V9fsState *s = pdu->s;
 179     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 180     VirtQueueElement *elem = v->elems[pdu->idx];
 181
 182     *piov = elem->in_sg;
 183     *pniov = elem->in_num;
 184 }
 185
 186 static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 187                                          unsigned int *pniov)
 188 {
 189     V9fsState *s = pdu->s;
 190     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 191     VirtQueueElement *elem = v->elems[pdu->idx];
 192
 193     *piov = elem->out_sg;
 194     *pniov = elem->out_num;
 195 }
 196
 197 static const struct V9fsTransport virtio_9p_transport = {
 198     .pdu_vmarshal = virtio_pdu_vmarshal,
 199     .pdu_vunmarshal = virtio_pdu_vunmarshal,
 200     .init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
 201     .init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
 202     .push_and_notify = virtio_9p_push_and_notify,
 203 };
 204
 205 /* virtio-9p device */
 206
 207 static const VMStateDescription vmstate_virtio_9p = {
 208     .name = "virtio-9p",
 209     .minimum_version_id = 1,
 210     .version_id = 1,
 211     .fields = (VMStateField[]) {
 212         VMSTATE_VIRTIO_DEVICE,
 213         VMSTATE_END_OF_LIST()
 214     },
 215 };
 216
 217 static Property virtio_9p_properties[] = {
 218     DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
 219     DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
 220     DEFINE_PROP_END_OF_LIST(),
 221 };
 222
 223 static void virtio_9p_class_init(ObjectClass *klass, void *data)
 224 {
 225     DeviceClass *dc = DEVICE_CLASS(klass);
 226     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 227
 228     dc->props = virtio_9p_properties;
 229     dc->vmsd = &vmstate_virtio_9p;
 230     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 231     vdc->realize = virtio_9p_device_realize;
 232     vdc->unrealize = virtio_9p_device_unrealize;
 233     vdc->get_features = virtio_9p_get_features;
 234     vdc->get_config = virtio_9p_get_config;
 235     vdc->reset = virtio_9p_reset;
 236 }
 237
 238 static const TypeInfo virtio_device_info = {
 239     .name = TYPE_VIRTIO_9P,
 240     .parent = TYPE_VIRTIO_DEVICE,
 241     .instance_size = sizeof(V9fsVirtioState),
 242     .class_init = virtio_9p_class_init,
 243 };
 244
 245 static void virtio_9p_register_types(void)
 246 {
 247     type_register_static(&virtio_device_info);
 248 }
 249
 250 type_init(virtio_9p_register_types)