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 (elem->in_num == 0) {
  57             virtio_error(vdev,
  58                          "The guest sent a VirtFS request without space for "
  59                          "the reply");
  60             goto out_free_req;
  61         }
  62         QEMU_BUILD_BUG_ON(sizeof(out) != 7);
  63
  64         v->elems[pdu->idx] = elem;
  65         len = iov_to_buf(elem->out_sg, elem->out_num, 0,
  66                          &out, sizeof(out));
  67         if (len != sizeof(out)) {
  68             virtio_error(vdev, "The guest sent a malformed VirtFS request: "
  69                          "header size is %zd, should be 7", len);
  70             goto out_free_req;
  71         }
  72
  73         pdu_submit(pdu, &out);
  74     }
  75
  76     return;
  77
  78 out_free_req:
  79     virtqueue_detach_element(vq, elem, 0);
  80     g_free(elem);
  81 out_free_pdu:
  82     pdu_free(pdu);
  83 }
  84
  85 static uint64_t virtio_9p_get_features(VirtIODevice *vdev, uint64_t features,
  86                                        Error **errp)
  87 {
  88     virtio_add_feature(&features, VIRTIO_9P_MOUNT_TAG);
  89     return features;
  90 }
  91
  92 static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
  93 {
  94     int len;
  95     struct virtio_9p_config *cfg;
  96     V9fsVirtioState *v = VIRTIO_9P(vdev);
  97     V9fsState *s = &v->state;
  98
  99     len = strlen(s->tag);
 100     cfg = g_malloc0(sizeof(struct virtio_9p_config) + len);
 101     virtio_stw_p(vdev, &cfg->tag_len, len);
 102     /* We don't copy the terminating null to config space */
 103     memcpy(cfg->tag, s->tag, len);
 104     memcpy(config, cfg, v->config_size);
 105     g_free(cfg);
 106 }
 107
 108 static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
 109 {
 110     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 111     V9fsVirtioState *v = VIRTIO_9P(dev);
 112     V9fsState *s = &v->state;
 113
 114     if (v9fs_device_realize_common(s, errp)) {
 115         goto out;
 116     }
 117
 118     v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
 119     virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
 120     v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
 121     v9fs_register_transport(s, &virtio_9p_transport);
 122
 123 out:
 124     return;
 125 }
 126
 127 static void virtio_9p_device_unrealize(DeviceState *dev, Error **errp)
 128 {
 129     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 130     V9fsVirtioState *v = VIRTIO_9P(dev);
 131     V9fsState *s = &v->state;
 132
 133     virtio_cleanup(vdev);
 134     v9fs_device_unrealize_common(s, errp);
 135 }
 136
 137 static void virtio_9p_reset(VirtIODevice *vdev)
 138 {
 139     V9fsVirtioState *v = (V9fsVirtioState *)vdev;
 140
 141     v9fs_reset(&v->state);
 142 }
 143
 144 static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
 145                                    const char *fmt, va_list ap)
 146 {
 147     V9fsState *s = pdu->s;
 148     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 149     VirtQueueElement *elem = v->elems[pdu->idx];
 150
 151     return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
 152 }
 153
 154 static ssize_t virtio_pdu_vunmarshal(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_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 162 }
 163
 164 /* The size parameter is used by other transports. Do not drop it. */
 165 static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 166                                         unsigned int *pniov, size_t size)
 167 {
 168     V9fsState *s = pdu->s;
 169     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 170     VirtQueueElement *elem = v->elems[pdu->idx];
 171
 172     *piov = elem->in_sg;
 173     *pniov = elem->in_num;
 174 }
 175
 176 static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 177                                          unsigned int *pniov)
 178 {
 179     V9fsState *s = pdu->s;
 180     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 181     VirtQueueElement *elem = v->elems[pdu->idx];
 182
 183     *piov = elem->out_sg;
 184     *pniov = elem->out_num;
 185 }
 186
 187 static const struct V9fsTransport virtio_9p_transport = {
 188     .pdu_vmarshal = virtio_pdu_vmarshal,
 189     .pdu_vunmarshal = virtio_pdu_vunmarshal,
 190     .init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
 191     .init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
 192     .push_and_notify = virtio_9p_push_and_notify,
 193 };
 194
 195 /* virtio-9p device */
 196
 197 static const VMStateDescription vmstate_virtio_9p = {
 198     .name = "virtio-9p",
 199     .minimum_version_id = 1,
 200     .version_id = 1,
 201     .fields = (VMStateField[]) {
 202         VMSTATE_VIRTIO_DEVICE,
 203         VMSTATE_END_OF_LIST()
 204     },
 205 };
 206
 207 static Property virtio_9p_properties[] = {
 208     DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
 209     DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
 210     DEFINE_PROP_END_OF_LIST(),
 211 };
 212
 213 static void virtio_9p_class_init(ObjectClass *klass, void *data)
 214 {
 215     DeviceClass *dc = DEVICE_CLASS(klass);
 216     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 217
 218     dc->props = virtio_9p_properties;
 219     dc->vmsd = &vmstate_virtio_9p;
 220     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 221     vdc->realize = virtio_9p_device_realize;
 222     vdc->unrealize = virtio_9p_device_unrealize;
 223     vdc->get_features = virtio_9p_get_features;
 224     vdc->get_config = virtio_9p_get_config;
 225     vdc->reset = virtio_9p_reset;
 226 }
 227
 228 static const TypeInfo virtio_device_info = {
 229     .name = TYPE_VIRTIO_9P,
 230     .parent = TYPE_VIRTIO_DEVICE,
 231     .instance_size = sizeof(V9fsVirtioState),
 232     .class_init = virtio_9p_class_init,
 233 };
 234
 235 static void virtio_9p_register_types(void)
 236 {
 237     type_register_static(&virtio_device_info);
 238 }
 239
 240 type_init(virtio_9p_register_types)