blob: a83167191ee69cf0bd9dd50b86251debdd38b9c3 [file] [log] [blame]
/*
* Base vhost-user-base implementation. This can be used to derive a
* more fully specified vhost-user backend either generically (see
* vhost-user-device) or via a specific stub for a device which
* encapsulates some fixed parameters.
*
* Copyright (c) 2023 Linaro Ltd
* Author: Alex Bennée <alex.bennee@linaro.org>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/vhost-user-base.h"
#include "qemu/error-report.h"
static void vub_start(VirtIODevice *vdev)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VHostUserBase *vub = VHOST_USER_BASE(vdev);
int ret, i;
if (!k->set_guest_notifiers) {
error_report("binding does not support guest notifiers");
return;
}
ret = vhost_dev_enable_notifiers(&vub->vhost_dev, vdev);
if (ret < 0) {
error_report("Error enabling host notifiers: %d", -ret);
return;
}
ret = k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, true);
if (ret < 0) {
error_report("Error binding guest notifier: %d", -ret);
goto err_host_notifiers;
}
vub->vhost_dev.acked_features = vdev->guest_features;
ret = vhost_dev_start(&vub->vhost_dev, vdev, true);
if (ret < 0) {
error_report("Error starting vhost-user-base: %d", -ret);
goto err_guest_notifiers;
}
/*
* guest_notifier_mask/pending not used yet, so just unmask
* everything here. virtio-pci will do the right thing by
* enabling/disabling irqfd.
*/
for (i = 0; i < vub->vhost_dev.nvqs; i++) {
vhost_virtqueue_mask(&vub->vhost_dev, vdev, i, false);
}
return;
err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&vub->vhost_dev, vdev);
}
static void vub_stop(VirtIODevice *vdev)
{
VHostUserBase *vub = VHOST_USER_BASE(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int ret;
if (!k->set_guest_notifiers) {
return;
}
vhost_dev_stop(&vub->vhost_dev, vdev, true);
ret = k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false);
if (ret < 0) {
error_report("vhost guest notifier cleanup failed: %d", ret);
return;
}
vhost_dev_disable_notifiers(&vub->vhost_dev, vdev);
}
static void vub_set_status(VirtIODevice *vdev, uint8_t status)
{
VHostUserBase *vub = VHOST_USER_BASE(vdev);
bool should_start = virtio_device_should_start(vdev, status);
if (vhost_dev_is_started(&vub->vhost_dev) == should_start) {
return;
}
if (should_start) {
vub_start(vdev);
} else {
vub_stop(vdev);
}
}
/*
* For an implementation where everything is delegated to the backend
* we don't do anything other than return the full feature set offered
* by the daemon (module the reserved feature bit).
*/
static uint64_t vub_get_features(VirtIODevice *vdev,
uint64_t requested_features, Error **errp)
{
VHostUserBase *vub = VHOST_USER_BASE(vdev);
/* This should be set when the vhost connection initialises */
g_assert(vub->vhost_dev.features);
return vub->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
}
/*
* To handle VirtIO config we need to know the size of the config
* space. We don't cache the config but re-fetch it from the guest
* every time in case something has changed.
*/
static void vub_get_config(VirtIODevice *vdev, uint8_t *config)
{
VHostUserBase *vub = VHOST_USER_BASE(vdev);
Error *local_err = NULL;
/*
* There will have been a warning during vhost_dev_init, but lets
* assert here as nothing will go right now.
*/
g_assert(vub->config_size && vub->vhost_user.supports_config == true);
if (vhost_dev_get_config(&vub->vhost_dev, config,
vub->config_size, &local_err)) {
error_report_err(local_err);
}
}
static void vub_set_config(VirtIODevice *vdev, const uint8_t *config_data)
{
VHostUserBase *vub = VHOST_USER_BASE(vdev);
int ret;
g_assert(vub->config_size && vub->vhost_user.supports_config == true);
ret = vhost_dev_set_config(&vub->vhost_dev, config_data,
0, vub->config_size,
VHOST_SET_CONFIG_TYPE_FRONTEND);
if (ret) {
error_report("vhost guest set device config space failed: %d", ret);
return;
}
}
/*
* When the daemon signals an update to the config we just need to
* signal the guest as we re-read the config on demand above.
*/
static int vub_config_notifier(struct vhost_dev *dev)
{
virtio_notify_config(dev->vdev);
return 0;
}
const VhostDevConfigOps vub_config_ops = {
.vhost_dev_config_notifier = vub_config_notifier,
};
static void vub_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
/*
* Not normally called; it's the daemon that handles the queue;
* however virtio's cleanup path can call this.
*/
}
static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserBase *vub)
{
vhost_user_cleanup(&vub->vhost_user);
for (int i = 0; i < vub->num_vqs; i++) {
VirtQueue *vq = g_ptr_array_index(vub->vqs, i);
virtio_delete_queue(vq);
}
virtio_cleanup(vdev);
}
static int vub_connect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBase *vub = VHOST_USER_BASE(vdev);
struct vhost_dev *vhost_dev = &vub->vhost_dev;
if (vub->connected) {
return 0;
}
vub->connected = true;
/*
* If we support VHOST_USER_GET_CONFIG we must enable the notifier
* so we can ping the guest when it updates.
*/
if (vub->vhost_user.supports_config) {
vhost_dev_set_config_notifier(vhost_dev, &vub_config_ops);
}
/* restore vhost state */
if (virtio_device_started(vdev, vdev->status)) {
vub_start(vdev);
}
return 0;
}
static void vub_event(void *opaque, QEMUChrEvent event);
static void vub_disconnect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBase *vub = VHOST_USER_BASE(vdev);
if (!vub->connected) {
return;
}
vub->connected = false;
vub_stop(vdev);
vhost_dev_cleanup(&vub->vhost_dev);
/* Re-instate the event handler for new connections */
qemu_chr_fe_set_handlers(&vub->chardev,
NULL, NULL, vub_event,
NULL, dev, NULL, true);
}
static void vub_event(void *opaque, QEMUChrEvent event)
{
DeviceState *dev = opaque;
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBase *vub = VHOST_USER_BASE(vdev);
switch (event) {
case CHR_EVENT_OPENED:
if (vub_connect(dev) < 0) {
qemu_chr_fe_disconnect(&vub->chardev);
return;
}
break;
case CHR_EVENT_CLOSED:
/* defer close until later to avoid circular close */
vhost_user_async_close(dev, &vub->chardev, &vub->vhost_dev,
vub_disconnect, vub_event);
break;
case CHR_EVENT_BREAK:
case CHR_EVENT_MUX_IN:
case CHR_EVENT_MUX_OUT:
/* Ignore */
break;
}
}
static void vub_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBase *vub = VHOST_USER_BASE(dev);
int ret;
if (!vub->chardev.chr) {
error_setg(errp, "vhost-user-base: missing chardev");
return;
}
if (!vub->virtio_id) {
error_setg(errp, "vhost-user-base: need to define device id");
return;
}
if (!vub->num_vqs) {
vub->num_vqs = 1; /* reasonable default? */
}
if (!vub->vq_size) {
vub->vq_size = 64;
}
/*
* We can't handle config requests unless we know the size of the
* config region, specialisations of the vhost-user-base will be
* able to set this.
*/
if (vub->config_size) {
vub->vhost_user.supports_config = true;
}
if (!vhost_user_init(&vub->vhost_user, &vub->chardev, errp)) {
return;
}
virtio_init(vdev, vub->virtio_id, vub->config_size);
/*
* Disable guest notifiers, by default all notifications will be via the
* asynchronous vhost-user socket.
*/
vdev->use_guest_notifier_mask = false;
/* Allocate queues */
vub->vqs = g_ptr_array_sized_new(vub->num_vqs);
for (int i = 0; i < vub->num_vqs; i++) {
g_ptr_array_add(vub->vqs,
virtio_add_queue(vdev, vub->vq_size,
vub_handle_output));
}
vub->vhost_dev.nvqs = vub->num_vqs;
vub->vhost_dev.vqs = g_new0(struct vhost_virtqueue, vub->vhost_dev.nvqs);
/* connect to backend */
ret = vhost_dev_init(&vub->vhost_dev, &vub->vhost_user,
VHOST_BACKEND_TYPE_USER, 0, errp);
if (ret < 0) {
do_vhost_user_cleanup(vdev, vub);
}
qemu_chr_fe_set_handlers(&vub->chardev, NULL, NULL, vub_event, NULL,
dev, NULL, true);
}
static void vub_device_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBase *vub = VHOST_USER_BASE(dev);
struct vhost_virtqueue *vhost_vqs = vub->vhost_dev.vqs;
/* This will stop vhost backend if appropriate. */
vub_set_status(vdev, 0);
vhost_dev_cleanup(&vub->vhost_dev);
g_free(vhost_vqs);
do_vhost_user_cleanup(vdev, vub);
}
static void vub_class_init(ObjectClass *klass, void *data)
{
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
vdc->realize = vub_device_realize;
vdc->unrealize = vub_device_unrealize;
vdc->get_features = vub_get_features;
vdc->get_config = vub_get_config;
vdc->set_config = vub_set_config;
vdc->set_status = vub_set_status;
}
static const TypeInfo vub_types[] = {
{
.name = TYPE_VHOST_USER_BASE,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VHostUserBase),
.class_init = vub_class_init,
.class_size = sizeof(VHostUserBaseClass),
.abstract = true
}
};
DEFINE_TYPES(vub_types)