qemu/backends/vhost-user.c
Alex Bennée e1a0e635c9 backends/vhost-user: remove the ioeventfd check
While ioeventfds are needed for good performance with KVM guests it
should not be a gating requirement. We can run vhost-user backends using
simulated ioeventfds or inband signalling.

With this change I can run:

  $QEMU $OPTS \
    -display gtk,gl=on \
    -device vhost-user-gpu-pci,chardev=vhgpu \
    -chardev socket,id=vhgpu,path=vhgpu.sock

with:

  ./contrib/vhost-user-gpu/vhost-user-gpu \
    -s vhgpu.sock \
    -v

and at least see things start-up - although the display gets rotated by
180 degrees. Once lightdm takes over we never make it to the login
prompt and just get a blank screen.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20221202132231.1048669-1-alex.bennee@linaro.org>

Message-Id: <20230130124728.175610-1-alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-03-02 03:10:47 -05:00

196 lines
4.6 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 "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"
int
vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
unsigned nvqs, Error **errp)
{
int ret;
assert(!b->vdev && vdev);
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, true);
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, true);
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, "Property 'chardev' can no longer be set");
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);