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         P9MsgHeader out;
  50
  51         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
  52         if (!elem) {
  53             goto out_free_pdu;
  54         }
  55
  56         if (iov_size(elem->in_sg, elem->in_num) < 7) {
  57             virtio_error(vdev,
  58                          "The guest sent a VirtFS request without space for "
  59                          "the reply");
  60             goto out_free_req;
  61         }
  62
  63         len = iov_to_buf(elem->out_sg, elem->out_num, 0, &out, 7);
  64         if (len != 7) {
  65             virtio_error(vdev, "The guest sent a malformed VirtFS request: "
  66                          "header size is %zd, should be 7", len);
  67             goto out_free_req;
  68         }
  69
  70         v->elems[pdu->idx] = elem;
  71
  72         pdu_submit(pdu, &out);
  73     }
  74
  75     return;
  76
  77 out_free_req:
  78     virtqueue_detach_element(vq, elem, 0);
  79     g_free(elem);
  80 out_free_pdu:
  81     pdu_free(pdu);
  82 }
  83
  84 static uint64_t virtio_9p_get_features(VirtIODevice *vdev, uint64_t features,
  85                                        Error **errp)
  86 {
  87     virtio_add_feature(&features, VIRTIO_9P_MOUNT_TAG);
  88     return features;
  89 }
  90
  91 static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
  92 {
  93     int len;
  94     struct virtio_9p_config *cfg;
  95     V9fsVirtioState *v = VIRTIO_9P(vdev);
  96     V9fsState *s = &v->state;
  97
  98     len = strlen(s->tag);
  99     cfg = g_malloc0(sizeof(struct virtio_9p_config) + len);
 100     virtio_stw_p(vdev, &cfg->tag_len, len);
 101     /* We don't copy the terminating null to config space */
 102     memcpy(cfg->tag, s->tag, len);
 103     memcpy(config, cfg, v->config_size);
 104     g_free(cfg);
 105 }
 106
 107 static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
 108 {
 109     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 110     V9fsVirtioState *v = VIRTIO_9P(dev);
 111     V9fsState *s = &v->state;
 112
 113     if (v9fs_device_realize_common(s, errp)) {
 114         goto out;
 115     }
 116
 117     v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
 118     virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
 119     v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
 120     v9fs_register_transport(s, &virtio_9p_transport);
 121
 122 out:
 123     return;
 124 }
 125
 126 static void virtio_9p_device_unrealize(DeviceState *dev, Error **errp)
 127 {
 128     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 129     V9fsVirtioState *v = VIRTIO_9P(dev);
 130     V9fsState *s = &v->state;
 131
 132     virtio_cleanup(vdev);
 133     v9fs_device_unrealize_common(s, errp);
 134 }
 135
 136 static void virtio_9p_reset(VirtIODevice *vdev)
 137 {
 138     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
 139
 140     v9fs_reset(&v->state);
 141 }
 142
 143 static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
 144                                    const char *fmt, va_list ap)
 145 {
 146     V9fsState *s = pdu->s;
 147     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 148     VirtQueueElement *elem = v->elems[pdu->idx];
 149
 150     return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
 151 }
 152
 153 static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
 154                                      const char *fmt, va_list ap)
 155 {
 156     V9fsState *s = pdu->s;
 157     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 158     VirtQueueElement *elem = v->elems[pdu->idx];
 159
 160     return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 161 }
 162
 163 /* The size parameter is used by other transports. Do not drop it. */
 164 static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 165                                         unsigned int *pniov, size_t size)
 166 {
 167     V9fsState *s = pdu->s;
 168     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 169     VirtQueueElement *elem = v->elems[pdu->idx];
 170
 171     *piov = elem->in_sg;
 172     *pniov = elem->in_num;
 173 }
 174
 175 static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 176                                          unsigned int *pniov)
 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->out_sg;
 183     *pniov = elem->out_num;
 184 }
 185
 186 static const struct V9fsTransport virtio_9p_transport = {
 187     .pdu_vmarshal = virtio_pdu_vmarshal,
 188     .pdu_vunmarshal = virtio_pdu_vunmarshal,
 189     .init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
 190     .init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
 191     .push_and_notify = virtio_9p_push_and_notify,
 192 };
 193
 194 /* virtio-9p device */
 195
 196 static const VMStateDescription vmstate_virtio_9p = {
 197     .name = "virtio-9p",
 198     .minimum_version_id = 1,
 199     .version_id = 1,
 200     .fields = (VMStateField[]) {
 201         VMSTATE_VIRTIO_DEVICE,
 202         VMSTATE_END_OF_LIST()
 203     },
 204 };
 205
 206 static Property virtio_9p_properties[] = {
 207     DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
 208     DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
 209     DEFINE_PROP_END_OF_LIST(),
 210 };
 211
 212 static void virtio_9p_class_init(ObjectClass *klass, void *data)
 213 {
 214     DeviceClass *dc = DEVICE_CLASS(klass);
 215     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 216
 217     dc->props = virtio_9p_properties;
 218     dc->vmsd = &vmstate_virtio_9p;
 219     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 220     vdc->realize = virtio_9p_device_realize;
 221     vdc->unrealize = virtio_9p_device_unrealize;
 222     vdc->get_features = virtio_9p_get_features;
 223     vdc->get_config = virtio_9p_get_config;
 224     vdc->reset = virtio_9p_reset;
 225 }
 226
 227 static const TypeInfo virtio_device_info = {
 228     .name = TYPE_VIRTIO_9P,
 229     .parent = TYPE_VIRTIO_DEVICE,
 230     .instance_size = sizeof(V9fsVirtioState),
 231     .class_init = virtio_9p_class_init,
 232 };
 233
 234 static void virtio_9p_register_types(void)
 235 {
 236     type_register_static(&virtio_device_info);
 237 }
 238
 239 type_init(virtio_9p_register_types)