qemu/backends/vhost-user.c
Kevin Wolf a6945f2287 vhost: Add Error parameter to vhost_dev_init()
This allows callers to return better error messages instead of making
one up while the real error ends up on stderr. Most callers can
immediately make use of this because they already have an Error
parameter themselves. The others just keep printing the error with
error_report_err().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-2-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-06-30 13:15:44 +02:00

208 lines
4.9 KiB
C

/*
* QEMU vhost-user backend
*
* Copyright (C) 2018 Red Hat Inc
*
* Authors:
* Marc-André Lureau <marcandre.lureau@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "qemu/error-report.h"
#include "qom/object_interfaces.h"
#include "sysemu/vhost-user-backend.h"
#include "sysemu/kvm.h"
#include "io/channel-command.h"
#include "hw/virtio/virtio-bus.h"
static bool
ioeventfd_enabled(void)
{
return kvm_enabled() && kvm_eventfds_enabled();
}
int
vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
unsigned nvqs, Error **errp)
{
int ret;
assert(!b->vdev && vdev);
if (!ioeventfd_enabled()) {
error_setg(errp, "vhost initialization failed: requires kvm");
return -1;
}
if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
return -1;
}
b->vdev = vdev;
b->dev.nvqs = nvqs;
b->dev.vqs = g_new0(struct vhost_virtqueue, nvqs);
ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0,
errp);
if (ret < 0) {
return -1;
}
return 0;
}
void
vhost_user_backend_start(VhostUserBackend *b)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int ret, i ;
if (b->started) {
return;
}
if (!k->set_guest_notifiers) {
error_report("binding does not support guest notifiers");
return;
}
ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
if (ret < 0) {
return;
}
ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
if (ret < 0) {
error_report("Error binding guest notifier");
goto err_host_notifiers;
}
b->dev.acked_features = b->vdev->guest_features;
ret = vhost_dev_start(&b->dev, b->vdev);
if (ret < 0) {
error_report("Error start vhost dev");
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 < b->dev.nvqs; i++) {
vhost_virtqueue_mask(&b->dev, b->vdev,
b->dev.vq_index + i, false);
}
b->started = true;
return;
err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&b->dev, b->vdev);
}
void
vhost_user_backend_stop(VhostUserBackend *b)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int ret = 0;
if (!b->started) {
return;
}
vhost_dev_stop(&b->dev, b->vdev);
if (k->set_guest_notifiers) {
ret = k->set_guest_notifiers(qbus->parent,
b->dev.nvqs, false);
if (ret < 0) {
error_report("vhost guest notifier cleanup failed: %d", ret);
}
}
assert(ret >= 0);
vhost_dev_disable_notifiers(&b->dev, b->vdev);
b->started = false;
}
static void set_chardev(Object *obj, const char *value, Error **errp)
{
VhostUserBackend *b = VHOST_USER_BACKEND(obj);
Chardev *chr;
if (b->completed) {
error_setg(errp, QERR_PERMISSION_DENIED);
return;
}
g_free(b->chr_name);
b->chr_name = g_strdup(value);
chr = qemu_chr_find(b->chr_name);
if (chr == NULL) {
error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
"Chardev '%s' not found", b->chr_name);
return;
}
if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
return;
}
b->completed = true;
/* could call vhost_dev_init() so early message can be exchanged */
}
static char *get_chardev(Object *obj, Error **errp)
{
VhostUserBackend *b = VHOST_USER_BACKEND(obj);
Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
if (chr && chr->label) {
return g_strdup(chr->label);
}
return NULL;
}
static void vhost_user_backend_class_init(ObjectClass *oc, void *data)
{
object_class_property_add_str(oc, "chardev", get_chardev, set_chardev);
}
static void vhost_user_backend_finalize(Object *obj)
{
VhostUserBackend *b = VHOST_USER_BACKEND(obj);
g_free(b->dev.vqs);
g_free(b->chr_name);
vhost_user_cleanup(&b->vhost_user);
qemu_chr_fe_deinit(&b->chr, true);
}
static const TypeInfo vhost_user_backend_info = {
.name = TYPE_VHOST_USER_BACKEND,
.parent = TYPE_OBJECT,
.instance_size = sizeof(VhostUserBackend),
.class_init = vhost_user_backend_class_init,
.instance_finalize = vhost_user_backend_finalize,
};
static void register_types(void)
{
type_register_static(&vhost_user_backend_info);
}
type_init(register_types);