qemu/hw/9pfs/virtio-9p-device.c
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   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/qdev-properties.h"
  21#include "hw/virtio/virtio-access.h"
  22#include "qemu/iov.h"
  23#include "qemu/module.h"
  24#include "sysemu/qtest.h"
  25
  26static void virtio_9p_push_and_notify(V9fsPDU *pdu)
  27{
  28    V9fsState *s = pdu->s;
  29    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
  30    VirtQueueElement *elem = v->elems[pdu->idx];
  31
  32    /* push onto queue and notify */
  33    virtqueue_push(v->vq, elem, pdu->size);
  34    g_free(elem);
  35    v->elems[pdu->idx] = NULL;
  36
  37    /* FIXME: we should batch these completions */
  38    virtio_notify(VIRTIO_DEVICE(v), v->vq);
  39}
  40
  41static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
  42{
  43    V9fsVirtioState *v = (V9fsVirtioState *)vdev;
  44    V9fsState *s = &v->state;
  45    V9fsPDU *pdu;
  46    ssize_t len;
  47    VirtQueueElement *elem;
  48
  49    while ((pdu = pdu_alloc(s))) {
  50        P9MsgHeader out;
  51
  52        elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
  53        if (!elem) {
  54            goto out_free_pdu;
  55        }
  56
  57        if (iov_size(elem->in_sg, elem->in_num) < 7) {
  58            virtio_error(vdev,
  59                         "The guest sent a VirtFS request without space for "
  60                         "the reply");
  61            goto out_free_req;
  62        }
  63
  64        len = iov_to_buf(elem->out_sg, elem->out_num, 0, &out, 7);
  65        if (len != 7) {
  66            virtio_error(vdev, "The guest sent a malformed VirtFS request: "
  67                         "header size is %zd, should be 7", len);
  68            goto out_free_req;
  69        }
  70
  71        v->elems[pdu->idx] = elem;
  72
  73        pdu_submit(pdu, &out);
  74    }
  75
  76    return;
  77
  78out_free_req:
  79    virtqueue_detach_element(vq, elem, 0);
  80    g_free(elem);
  81out_free_pdu:
  82    pdu_free(pdu);
  83}
  84
  85static 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
  92static 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
 108static void virtio_9p_reset(VirtIODevice *vdev)
 109{
 110    V9fsVirtioState *v = (V9fsVirtioState *)vdev;
 111
 112    v9fs_reset(&v->state);
 113}
 114
 115static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
 116                                   const char *fmt, va_list ap)
 117{
 118    V9fsState *s = pdu->s;
 119    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 120    VirtQueueElement *elem = v->elems[pdu->idx];
 121    ssize_t ret;
 122
 123    ret = v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
 124    if (ret < 0) {
 125        VirtIODevice *vdev = VIRTIO_DEVICE(v);
 126
 127        virtio_error(vdev, "Failed to encode VirtFS reply type %d",
 128                     pdu->id + 1);
 129    }
 130    return ret;
 131}
 132
 133static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
 134                                     const char *fmt, va_list ap)
 135{
 136    V9fsState *s = pdu->s;
 137    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 138    VirtQueueElement *elem = v->elems[pdu->idx];
 139    ssize_t ret;
 140
 141    ret = v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 142    if (ret < 0) {
 143        VirtIODevice *vdev = VIRTIO_DEVICE(v);
 144
 145        virtio_error(vdev, "Failed to decode VirtFS request type %d", pdu->id);
 146    }
 147    return ret;
 148}
 149
 150static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 151                                        unsigned int *pniov, size_t size)
 152{
 153    V9fsState *s = pdu->s;
 154    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 155    VirtQueueElement *elem = v->elems[pdu->idx];
 156    size_t buf_size = iov_size(elem->in_sg, elem->in_num);
 157
 158    if (buf_size < size) {
 159        VirtIODevice *vdev = VIRTIO_DEVICE(v);
 160
 161        virtio_error(vdev,
 162                     "VirtFS reply type %d needs %zu bytes, buffer has %zu",
 163                     pdu->id + 1, size, buf_size);
 164    }
 165
 166    *piov = elem->in_sg;
 167    *pniov = elem->in_num;
 168}
 169
 170static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
 171                                         unsigned int *pniov, size_t size)
 172{
 173    V9fsState *s = pdu->s;
 174    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
 175    VirtQueueElement *elem = v->elems[pdu->idx];
 176    size_t buf_size = iov_size(elem->out_sg, elem->out_num);
 177
 178    if (buf_size < size) {
 179        VirtIODevice *vdev = VIRTIO_DEVICE(v);
 180
 181        virtio_error(vdev,
 182                     "VirtFS request type %d needs %zu bytes, buffer has %zu",
 183                     pdu->id, size, buf_size);
 184    }
 185
 186    *piov = elem->out_sg;
 187    *pniov = elem->out_num;
 188}
 189
 190static const V9fsTransport virtio_9p_transport = {
 191    .pdu_vmarshal = virtio_pdu_vmarshal,
 192    .pdu_vunmarshal = virtio_pdu_vunmarshal,
 193    .init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
 194    .init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
 195    .push_and_notify = virtio_9p_push_and_notify,
 196};
 197
 198static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
 199{
 200    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 201    V9fsVirtioState *v = VIRTIO_9P(dev);
 202    V9fsState *s = &v->state;
 203    FsDriverEntry *fse = get_fsdev_fsentry(s->fsconf.fsdev_id);
 204
 205    if (qtest_enabled() && fse) {
 206        fse->export_flags |= V9FS_NO_PERF_WARN;
 207    }
 208
 209    if (v9fs_device_realize_common(s, &virtio_9p_transport, errp)) {
 210        return;
 211    }
 212
 213    v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
 214    virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
 215    v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
 216}
 217
 218static void virtio_9p_device_unrealize(DeviceState *dev)
 219{
 220    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 221    V9fsVirtioState *v = VIRTIO_9P(dev);
 222    V9fsState *s = &v->state;
 223
 224    virtio_delete_queue(v->vq);
 225    virtio_cleanup(vdev);
 226    v9fs_device_unrealize_common(s);
 227}
 228
 229/* virtio-9p device */
 230
 231static const VMStateDescription vmstate_virtio_9p = {
 232    .name = "virtio-9p",
 233    .minimum_version_id = 1,
 234    .version_id = 1,
 235    .fields = (VMStateField[]) {
 236        VMSTATE_VIRTIO_DEVICE,
 237        VMSTATE_END_OF_LIST()
 238    },
 239};
 240
 241static Property virtio_9p_properties[] = {
 242    DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
 243    DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
 244    DEFINE_PROP_END_OF_LIST(),
 245};
 246
 247static void virtio_9p_class_init(ObjectClass *klass, void *data)
 248{
 249    DeviceClass *dc = DEVICE_CLASS(klass);
 250    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 251
 252    device_class_set_props(dc, virtio_9p_properties);
 253    dc->vmsd = &vmstate_virtio_9p;
 254    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 255    vdc->realize = virtio_9p_device_realize;
 256    vdc->unrealize = virtio_9p_device_unrealize;
 257    vdc->get_features = virtio_9p_get_features;
 258    vdc->get_config = virtio_9p_get_config;
 259    vdc->reset = virtio_9p_reset;
 260}
 261
 262static const TypeInfo virtio_device_info = {
 263    .name = TYPE_VIRTIO_9P,
 264    .parent = TYPE_VIRTIO_DEVICE,
 265    .instance_size = sizeof(V9fsVirtioState),
 266    .class_init = virtio_9p_class_init,
 267};
 268
 269static void virtio_9p_register_types(void)
 270{
 271    type_register_static(&virtio_device_info);
 272}
 273
 274type_init(virtio_9p_register_types)
 275