qemu/hw/9pfs/virtio-9p-device.c
Christian Schoenebeck 6f56908427 9pfs: add link to 9p developer docs
To lower the entry level for new developers, add a link to the 9p
developer docs (i.e. qemu wiki) to MAINTAINERS and to the beginning of
9p source files, that is to: https://wiki.qemu.org/Documentation/9p

Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Acked-by: Greg Kurz <groug@kaod.org>
Message-Id: <E1leeDf-0008GZ-9q@lizzy.crudebyte.com>
2021-07-05 13:03:16 +02:00

280 lines
7.8 KiB
C

/*
* Virtio 9p backend
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
/*
* Not so fast! You might want to read the 9p developer docs first:
* https://wiki.qemu.org/Documentation/9p
*/
#include "qemu/osdep.h"
#include "hw/virtio/virtio.h"
#include "qemu/sockets.h"
#include "virtio-9p.h"
#include "fsdev/qemu-fsdev.h"
#include "coth.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/virtio-access.h"
#include "qemu/iov.h"
#include "qemu/module.h"
#include "sysemu/qtest.h"
static void virtio_9p_push_and_notify(V9fsPDU *pdu)
{
V9fsState *s = pdu->s;
V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
VirtQueueElement *elem = v->elems[pdu->idx];
/* push onto queue and notify */
virtqueue_push(v->vq, elem, pdu->size);
g_free(elem);
v->elems[pdu->idx] = NULL;
/* FIXME: we should batch these completions */
virtio_notify(VIRTIO_DEVICE(v), v->vq);
}
static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
{
V9fsVirtioState *v = (V9fsVirtioState *)vdev;
V9fsState *s = &v->state;
V9fsPDU *pdu;
ssize_t len;
VirtQueueElement *elem;
while ((pdu = pdu_alloc(s))) {
P9MsgHeader out;
elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
if (!elem) {
goto out_free_pdu;
}
if (iov_size(elem->in_sg, elem->in_num) < 7) {
virtio_error(vdev,
"The guest sent a VirtFS request without space for "
"the reply");
goto out_free_req;
}
len = iov_to_buf(elem->out_sg, elem->out_num, 0, &out, 7);
if (len != 7) {
virtio_error(vdev, "The guest sent a malformed VirtFS request: "
"header size is %zd, should be 7", len);
goto out_free_req;
}
v->elems[pdu->idx] = elem;
pdu_submit(pdu, &out);
}
return;
out_free_req:
virtqueue_detach_element(vq, elem, 0);
g_free(elem);
out_free_pdu:
pdu_free(pdu);
}
static uint64_t virtio_9p_get_features(VirtIODevice *vdev, uint64_t features,
Error **errp)
{
virtio_add_feature(&features, VIRTIO_9P_MOUNT_TAG);
return features;
}
static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
{
int len;
struct virtio_9p_config *cfg;
V9fsVirtioState *v = VIRTIO_9P(vdev);
V9fsState *s = &v->state;
len = strlen(s->tag);
cfg = g_malloc0(sizeof(struct virtio_9p_config) + len);
virtio_stw_p(vdev, &cfg->tag_len, len);
/* We don't copy the terminating null to config space */
memcpy(cfg->tag, s->tag, len);
memcpy(config, cfg, v->config_size);
g_free(cfg);
}
static void virtio_9p_reset(VirtIODevice *vdev)
{
V9fsVirtioState *v = (V9fsVirtioState *)vdev;
v9fs_reset(&v->state);
}
static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
const char *fmt, va_list ap)
{
V9fsState *s = pdu->s;
V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
VirtQueueElement *elem = v->elems[pdu->idx];
ssize_t ret;
ret = v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
if (ret < 0) {
VirtIODevice *vdev = VIRTIO_DEVICE(v);
virtio_error(vdev, "Failed to encode VirtFS reply type %d",
pdu->id + 1);
}
return ret;
}
static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
const char *fmt, va_list ap)
{
V9fsState *s = pdu->s;
V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
VirtQueueElement *elem = v->elems[pdu->idx];
ssize_t ret;
ret = v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
if (ret < 0) {
VirtIODevice *vdev = VIRTIO_DEVICE(v);
virtio_error(vdev, "Failed to decode VirtFS request type %d", pdu->id);
}
return ret;
}
static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
unsigned int *pniov, size_t size)
{
V9fsState *s = pdu->s;
V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
VirtQueueElement *elem = v->elems[pdu->idx];
size_t buf_size = iov_size(elem->in_sg, elem->in_num);
if (buf_size < size) {
VirtIODevice *vdev = VIRTIO_DEVICE(v);
virtio_error(vdev,
"VirtFS reply type %d needs %zu bytes, buffer has %zu",
pdu->id + 1, size, buf_size);
}
*piov = elem->in_sg;
*pniov = elem->in_num;
}
static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
unsigned int *pniov, size_t size)
{
V9fsState *s = pdu->s;
V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
VirtQueueElement *elem = v->elems[pdu->idx];
size_t buf_size = iov_size(elem->out_sg, elem->out_num);
if (buf_size < size) {
VirtIODevice *vdev = VIRTIO_DEVICE(v);
virtio_error(vdev,
"VirtFS request type %d needs %zu bytes, buffer has %zu",
pdu->id, size, buf_size);
}
*piov = elem->out_sg;
*pniov = elem->out_num;
}
static const V9fsTransport virtio_9p_transport = {
.pdu_vmarshal = virtio_pdu_vmarshal,
.pdu_vunmarshal = virtio_pdu_vunmarshal,
.init_in_iov_from_pdu = virtio_init_in_iov_from_pdu,
.init_out_iov_from_pdu = virtio_init_out_iov_from_pdu,
.push_and_notify = virtio_9p_push_and_notify,
};
static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
V9fsVirtioState *v = VIRTIO_9P(dev);
V9fsState *s = &v->state;
FsDriverEntry *fse = get_fsdev_fsentry(s->fsconf.fsdev_id);
if (qtest_enabled() && fse) {
fse->export_flags |= V9FS_NO_PERF_WARN;
}
if (v9fs_device_realize_common(s, &virtio_9p_transport, errp)) {
return;
}
v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
}
static void virtio_9p_device_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
V9fsVirtioState *v = VIRTIO_9P(dev);
V9fsState *s = &v->state;
virtio_delete_queue(v->vq);
virtio_cleanup(vdev);
v9fs_device_unrealize_common(s);
}
/* virtio-9p device */
static const VMStateDescription vmstate_virtio_9p = {
.name = "virtio-9p",
.minimum_version_id = 1,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
};
static Property virtio_9p_properties[] = {
DEFINE_PROP_STRING("mount_tag", V9fsVirtioState, state.fsconf.tag),
DEFINE_PROP_STRING("fsdev", V9fsVirtioState, state.fsconf.fsdev_id),
DEFINE_PROP_END_OF_LIST(),
};
static void virtio_9p_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
device_class_set_props(dc, virtio_9p_properties);
dc->vmsd = &vmstate_virtio_9p;
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
vdc->realize = virtio_9p_device_realize;
vdc->unrealize = virtio_9p_device_unrealize;
vdc->get_features = virtio_9p_get_features;
vdc->get_config = virtio_9p_get_config;
vdc->reset = virtio_9p_reset;
}
static const TypeInfo virtio_device_info = {
.name = TYPE_VIRTIO_9P,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(V9fsVirtioState),
.class_init = virtio_9p_class_init,
};
static void virtio_9p_register_types(void)
{
type_register_static(&virtio_device_info);
}
type_init(virtio_9p_register_types)