qemu-e2k/hw/9pfs/virtio-9p-device.c

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/*
* 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.
*
*/
#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/virtio/virtio-access.h"
#include "qemu/iov.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);
}
virtio-9p: add reset handler Virtio devices should implement the VirtIODevice->reset() function to perform necessary cleanup actions and to bring the device to a quiescent state. In the case of the virtio-9p device, this means: - emptying the list of active PDUs (i.e. draining all in-flight I/O) - freeing all fids (i.e. close open file descriptors and free memory) That's what this patch does. The reset handler first waits for all active PDUs to complete. Since completion happens in the QEMU global aio context, we just have to loop around aio_poll() until the active list is empty. The freeing part involves some actions to be performed on the backend, like closing file descriptors or flushing extended attributes to the underlying filesystem. The virtfs_reset() function already does the job: it calls free_fid() for all open fids not involved in an ongoing I/O operation. We are sure this is the case since we have drained the PDU active list. The current code implements all backend accesses with coroutines, but we want to stay synchronous on the reset path. We can either change the current code to be able to run when not in coroutine context, or create a coroutine context and wait for virtfs_reset() to complete. This patch goes for the latter because it results in simpler code. Note that we also need to create a dummy PDU because it is also an API to pass the FsContext pointer to all backend callbacks. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-17 14:13:58 +02:00
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;
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, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
V9fsVirtioState *v = VIRTIO_9P(dev);
V9fsState *s = &v->state;
virtio_cleanup(vdev);
v9fs_device_unrealize_common(s, errp);
}
/* 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);
dc->props = 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;
virtio-9p: add reset handler Virtio devices should implement the VirtIODevice->reset() function to perform necessary cleanup actions and to bring the device to a quiescent state. In the case of the virtio-9p device, this means: - emptying the list of active PDUs (i.e. draining all in-flight I/O) - freeing all fids (i.e. close open file descriptors and free memory) That's what this patch does. The reset handler first waits for all active PDUs to complete. Since completion happens in the QEMU global aio context, we just have to loop around aio_poll() until the active list is empty. The freeing part involves some actions to be performed on the backend, like closing file descriptors or flushing extended attributes to the underlying filesystem. The virtfs_reset() function already does the job: it calls free_fid() for all open fids not involved in an ongoing I/O operation. We are sure this is the case since we have drained the PDU active list. The current code implements all backend accesses with coroutines, but we want to stay synchronous on the reset path. We can either change the current code to be able to run when not in coroutine context, or create a coroutine context and wait for virtfs_reset() to complete. This patch goes for the latter because it results in simpler code. Note that we also need to create a dummy PDU because it is also an API to pass the FsContext pointer to all backend callbacks. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-17 14:13:58 +02:00
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)