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 /*
  15  * Not so fast! You might want to read the 9p developer docs first:
  16  * https://wiki.qemu.org/Documentation/9p
  17  */
  18
  19 #include "qemu/osdep.h"
  20 #include "hw/virtio/virtio.h"
  21 #include "qemu/sockets.h"
  22 #include "virtio-9p.h"
  23 #include "fsdev/qemu-fsdev.h"
  24 #include "coth.h"
  25 #include "hw/qdev-properties.h"
  26 #include "hw/virtio/virtio-access.h"
  27 #include "qemu/iov.h"
  28 #include "qemu/module.h"
  29 #include "sysemu/qtest.h"
  30
  31 static void virtio_9p_push_and_notify(V9fsPDU *pdu)
  32 {
  33     V9fsState *s = pdu->s;
  34     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
  35     VirtQueueElement *elem = v->elems[pdu->idx];
  36
  37     /* push onto queue and notify */
  38     virtqueue_push(v->vq, elem, pdu->size);
  39     g_free(elem);
  40     v->elems[pdu->idx] = NULL;
  41
  42     /* FIXME: we should batch these completions */
  43     virtio_notify(VIRTIO_DEVICE(v), v->vq);
  44 }
  45
  46 static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
  47 {
  48     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
  49     V9fsState *s = &v->state;
  50     V9fsPDU *pdu;
  51     ssize_t len;
  52     VirtQueueElement *elem;
  53
  54     while ((pdu = pdu_alloc(s))) {
  55         P9MsgHeader out;
  56
  57         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
  58         if (!elem) {
  59             goto out_free_pdu;
  60         }
  61
  62         if (iov_size(elem->in_sg, elem->in_num) < 7) {
  63             virtio_error(vdev,
  64                          "The guest sent a VirtFS request without space for "
  65                          "the reply");
  66             goto out_free_req;
  67         }
  68
  69         len = iov_to_buf(elem->out_sg, elem->out_num, 0, &out, 7);
  70         if (len != 7) {
  71             virtio_error(vdev, "The guest sent a malformed VirtFS request: "
  72                          "header size is %zd, should be 7", len);
  73             goto out_free_req;
  74         }
  75
  76         v->elems[pdu->idx] = elem;
  77
  78         pdu_submit(pdu, &out);
  79     }
  80
  81     return;
  82
  83 out_free_req:
  84     virtqueue_detach_element(vq, elem, 0);
  85     g_free(elem);
  86 out_free_pdu:
  87     pdu_free(pdu);
  88 }
  89
  90 static uint64_t virtio_9p_get_features(VirtIODevice *vdev, uint64_t features,
  91                                        Error **errp)
  92 {
  93     virtio_add_feature(&features, VIRTIO_9P_MOUNT_TAG);
  94     return features;
  95 }
  96
  97 static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
  98 {
  99     int len;
 100     struct virtio_9p_config *cfg;
 101     V9fsVirtioState *v = VIRTIO_9P(vdev);
 102     V9fsState *s = &v->state;
 103
 104     len = strlen(s->tag);
 105     cfg = g_malloc0(sizeof(struct virtio_9p_config) + len);
 106     virtio_stw_p(vdev, &cfg->tag_len, len);
 107     /* We don't copy the terminating null to config space */
 108     memcpy(cfg->tag, s->tag, len);
 109     memcpy(config, cfg, v->config_size);
 110     g_free(cfg);
 111 }
 112
 113 static void virtio_9p_reset(VirtIODevice *vdev)
 114 {
 115     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
 116
 117     v9fs_reset(&v->state);
 118 }
 119
 120 static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
 121                                    const char *fmt, va_list ap)
 122 {
 123     V9fsState *s = pdu->s;
 124     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 125     VirtQueueElement *elem = v->elems[pdu->idx];
 126     ssize_t ret;
 127
 128     ret = v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
 129     if (ret < 0) {
 130         VirtIODevice *vdev = VIRTIO_DEVICE(v);
 131
 132         virtio_error(vdev, "Failed to encode VirtFS reply type %d",
 133                      pdu->id + 1);
 134     }
 135     return ret;
 136 }
 137
 138 static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
 139                                      const char *fmt, va_list ap)
 140 {
 141     V9fsState *s = pdu->s;
 142     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 143     VirtQueueElement *elem = v->elems[pdu->idx];
 144     ssize_t ret;
 145
 146     ret = v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 147     if (ret < 0) {
 148         VirtIODevice *vdev = VIRTIO_DEVICE(v);
 149
 150         virtio_error(vdev, "Failed to decode VirtFS request type %d", pdu->id);
 151     }
 152     return ret;
 153 }
 154
 155 static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 156                                         unsigned int *pniov, size_t size)
 157 {
 158     V9fsState *s = pdu->s;
 159     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 160     VirtQueueElement *elem = v->elems[pdu->idx];
 161     size_t buf_size = iov_size(elem->in_sg, elem->in_num);
 162
 163     if (buf_size < size) {
 164         VirtIODevice *vdev = VIRTIO_DEVICE(v);
 165
 166         virtio_error(vdev,
 167                      "VirtFS reply type %d needs %zu bytes, buffer has %zu",
 168                      pdu->id + 1, size, buf_size);
 169     }
 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, 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     size_t buf_size = iov_size(elem->out_sg, elem->out_num);
 182
 183     if (buf_size < size) {
 184         VirtIODevice *vdev = VIRTIO_DEVICE(v);
 185
 186         virtio_error(vdev,
 187                      "VirtFS request type %d needs %zu bytes, buffer has %zu",
 188                      pdu->id, size, buf_size);
 189     }
 190
 191     *piov = elem->out_sg;
 192     *pniov = elem->out_num;
 193 }
 194
 195 static const V9fsTransport virtio_9p_transport = {
 196     .pdu_vmarshal = virtio_pdu_vmarshal,
 197     .pdu_vunmarshal = virtio_pdu_vunmarshal,
 198     .init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
 199     .init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
 200     .push_and_notify = virtio_9p_push_and_notify,
 201 };
 202
 203 static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
 204 {
 205     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 206     V9fsVirtioState *v = VIRTIO_9P(dev);
 207     V9fsState *s = &v->state;
 208     FsDriverEntry *fse = get_fsdev_fsentry(s->fsconf.fsdev_id);
 209
 210     if (qtest_enabled() && fse) {
 211         fse->export_flags |= V9FS_NO_PERF_WARN;
 212     }
 213
 214     if (v9fs_device_realize_common(s, &virtio_9p_transport, errp)) {
 215         return;
 216     }
 217
 218     v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
 219     virtio_init(vdev, VIRTIO_ID_9P, v->config_size);
 220     v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
 221 }
 222
 223 static void virtio_9p_device_unrealize(DeviceState *dev)
 224 {
 225     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 226     V9fsVirtioState *v = VIRTIO_9P(dev);
 227     V9fsState *s = &v->state;
 228
 229     virtio_delete_queue(v->vq);
 230     virtio_cleanup(vdev);
 231     v9fs_device_unrealize_common(s);
 232 }
 233
 234 /* virtio-9p device */
 235
 236 static const VMStateDescription vmstate_virtio_9p = {
 237     .name = "virtio-9p",
 238     .minimum_version_id = 1,
 239     .version_id = 1,
 240     .fields = (VMStateField[]) {
 241         VMSTATE_VIRTIO_DEVICE,
 242         VMSTATE_END_OF_LIST()
 243     },
 244 };
 245
 246 static Property virtio_9p_properties[] = {
 247     DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
 248     DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
 249     DEFINE_PROP_END_OF_LIST(),
 250 };
 251
 252 static void virtio_9p_class_init(ObjectClass *klass, void *data)
 253 {
 254     DeviceClass *dc = DEVICE_CLASS(klass);
 255     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 256
 257     device_class_set_props(dc, virtio_9p_properties);
 258     dc->vmsd = &vmstate_virtio_9p;
 259     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 260     vdc->realize = virtio_9p_device_realize;
 261     vdc->unrealize = virtio_9p_device_unrealize;
 262     vdc->get_features = virtio_9p_get_features;
 263     vdc->get_config = virtio_9p_get_config;
 264     vdc->reset = virtio_9p_reset;
 265 }
 266
 267 static const TypeInfo virtio_device_info = {
 268     .name = TYPE_VIRTIO_9P,
 269     .parent = TYPE_VIRTIO_DEVICE,
 270     .instance_size = sizeof(V9fsVirtioState),
 271     .class_init = virtio_9p_class_init,
 272 };
 273
 274 static void virtio_9p_register_types(void)
 275 {
 276     type_register_static(&virtio_device_info);
 277 }
 278
 279 type_init(virtio_9p_register_types)