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