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virtio: split into vhost-user-base and vhost-user-device
Lets keep a cleaner split between the base class and the derived vhost-user-device which we can use for generic vhost-user stubs. This includes an update to introduce the vq_size property so the number of entries in a virtq can be defined. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240104210945.1223134-2-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Alex Bennée
Michael S. Tsirkin
parent
df50424b4d
commit
6275989647
6 changed files with 383 additions and 342 deletions
346
hw/virtio/vhost-user-base.c
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346
hw/virtio/vhost-user-base.c
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@ -0,0 +1,346 @@
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/*
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* Base vhost-user-base implementation. This can be used to derive a
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* more fully specified vhost-user backend either generically (see
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* vhost-user-device) or via a specific stub for a device which
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* encapsulates some fixed parameters.
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*
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* Copyright (c) 2023 Linaro Ltd
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* Author: Alex Bennée <alex.bennee@linaro.org>
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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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 "hw/qdev-properties.h"
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#include "hw/virtio/virtio-bus.h"
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#include "hw/virtio/vhost-user-base.h"
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#include "qemu/error-report.h"
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static void vub_start(VirtIODevice *vdev)
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{
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BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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int ret, i;
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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(&vub->vhost_dev, vdev);
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if (ret < 0) {
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error_report("Error enabling host notifiers: %d", -ret);
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return;
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}
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ret = k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, true);
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if (ret < 0) {
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error_report("Error binding guest notifier: %d", -ret);
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goto err_host_notifiers;
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}
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vub->vhost_dev.acked_features = vdev->guest_features;
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ret = vhost_dev_start(&vub->vhost_dev, vdev, true);
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if (ret < 0) {
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error_report("Error starting vhost-user-base: %d", -ret);
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goto err_guest_notifiers;
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}
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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 < vub->vhost_dev.nvqs; i++) {
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vhost_virtqueue_mask(&vub->vhost_dev, vdev, i, false);
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}
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return;
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err_guest_notifiers:
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k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false);
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err_host_notifiers:
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vhost_dev_disable_notifiers(&vub->vhost_dev, vdev);
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}
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static void vub_stop(VirtIODevice *vdev)
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{
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
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int ret;
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if (!k->set_guest_notifiers) {
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return;
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}
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vhost_dev_stop(&vub->vhost_dev, vdev, true);
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ret = k->set_guest_notifiers(qbus->parent, vub->vhost_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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return;
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}
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vhost_dev_disable_notifiers(&vub->vhost_dev, vdev);
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}
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static void vub_set_status(VirtIODevice *vdev, uint8_t status)
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{
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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bool should_start = virtio_device_should_start(vdev, status);
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if (vhost_dev_is_started(&vub->vhost_dev) == should_start) {
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return;
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}
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if (should_start) {
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vub_start(vdev);
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} else {
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vub_stop(vdev);
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}
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}
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/*
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* For an implementation where everything is delegated to the backend
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* we don't do anything other than return the full feature set offered
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* by the daemon (module the reserved feature bit).
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*/
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static uint64_t vub_get_features(VirtIODevice *vdev,
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uint64_t requested_features, Error **errp)
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{
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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/* This should be set when the vhost connection initialises */
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g_assert(vub->vhost_dev.features);
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return vub->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
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}
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/*
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* To handle VirtIO config we need to know the size of the config
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* space. We don't cache the config but re-fetch it from the guest
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* every time in case something has changed.
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*/
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static void vub_get_config(VirtIODevice *vdev, uint8_t *config)
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{
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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Error *local_err = NULL;
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/*
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* There will have been a warning during vhost_dev_init, but lets
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* assert here as nothing will go right now.
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*/
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g_assert(vub->config_size && vub->vhost_user.supports_config == true);
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if (vhost_dev_get_config(&vub->vhost_dev, config,
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vub->config_size, &local_err)) {
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error_report_err(local_err);
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}
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}
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/*
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* When the daemon signals an update to the config we just need to
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* signal the guest as we re-read the config on demand above.
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*/
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static int vub_config_notifier(struct vhost_dev *dev)
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{
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virtio_notify_config(dev->vdev);
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return 0;
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}
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const VhostDevConfigOps vub_config_ops = {
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.vhost_dev_config_notifier = vub_config_notifier,
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};
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static void vub_handle_output(VirtIODevice *vdev, VirtQueue *vq)
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{
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/*
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* Not normally called; it's the daemon that handles the queue;
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* however virtio's cleanup path can call this.
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*/
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}
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static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserBase *vub)
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{
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vhost_user_cleanup(&vub->vhost_user);
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for (int i = 0; i < vub->num_vqs; i++) {
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VirtQueue *vq = g_ptr_array_index(vub->vqs, i);
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virtio_delete_queue(vq);
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}
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virtio_cleanup(vdev);
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}
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static int vub_connect(DeviceState *dev)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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struct vhost_dev *vhost_dev = &vub->vhost_dev;
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if (vub->connected) {
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return 0;
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}
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vub->connected = true;
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/*
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* If we support VHOST_USER_GET_CONFIG we must enable the notifier
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* so we can ping the guest when it updates.
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*/
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if (vub->vhost_user.supports_config) {
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vhost_dev_set_config_notifier(vhost_dev, &vub_config_ops);
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}
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/* restore vhost state */
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if (virtio_device_started(vdev, vdev->status)) {
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vub_start(vdev);
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}
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return 0;
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}
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static void vub_disconnect(DeviceState *dev)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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if (!vub->connected) {
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return;
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}
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vub->connected = false;
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if (vhost_dev_is_started(&vub->vhost_dev)) {
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vub_stop(vdev);
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}
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}
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static void vub_event(void *opaque, QEMUChrEvent event)
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{
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DeviceState *dev = opaque;
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserBase *vub = VHOST_USER_BASE(vdev);
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switch (event) {
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case CHR_EVENT_OPENED:
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if (vub_connect(dev) < 0) {
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qemu_chr_fe_disconnect(&vub->chardev);
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return;
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}
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break;
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case CHR_EVENT_CLOSED:
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vub_disconnect(dev);
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break;
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case CHR_EVENT_BREAK:
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case CHR_EVENT_MUX_IN:
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case CHR_EVENT_MUX_OUT:
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/* Ignore */
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break;
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}
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}
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static void vub_device_realize(DeviceState *dev, Error **errp)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserBase *vub = VHOST_USER_BASE(dev);
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int ret;
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if (!vub->chardev.chr) {
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error_setg(errp, "vhost-user-base: missing chardev");
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return;
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}
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if (!vub->virtio_id) {
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error_setg(errp, "vhost-user-base: need to define device id");
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return;
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}
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if (!vub->num_vqs) {
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vub->num_vqs = 1; /* reasonable default? */
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}
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if (!vub->vq_size) {
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vub->vq_size = 64;
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}
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/*
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* We can't handle config requests unless we know the size of the
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* config region, specialisations of the vhost-user-base will be
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* able to set this.
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*/
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if (vub->config_size) {
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vub->vhost_user.supports_config = true;
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}
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if (!vhost_user_init(&vub->vhost_user, &vub->chardev, errp)) {
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return;
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}
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virtio_init(vdev, vub->virtio_id, vub->config_size);
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/*
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* Disable guest notifiers, by default all notifications will be via the
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* asynchronous vhost-user socket.
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*/
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vdev->use_guest_notifier_mask = false;
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/* Allocate queues */
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vub->vqs = g_ptr_array_sized_new(vub->num_vqs);
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for (int i = 0; i < vub->num_vqs; i++) {
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g_ptr_array_add(vub->vqs,
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virtio_add_queue(vdev, vub->vq_size,
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vub_handle_output));
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}
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vub->vhost_dev.nvqs = vub->num_vqs;
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vub->vhost_dev.vqs = g_new0(struct vhost_virtqueue, vub->vhost_dev.nvqs);
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/* connect to backend */
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ret = vhost_dev_init(&vub->vhost_dev, &vub->vhost_user,
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VHOST_BACKEND_TYPE_USER, 0, errp);
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if (ret < 0) {
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do_vhost_user_cleanup(vdev, vub);
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}
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qemu_chr_fe_set_handlers(&vub->chardev, NULL, NULL, vub_event, NULL,
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dev, NULL, true);
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}
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static void vub_device_unrealize(DeviceState *dev)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserBase *vub = VHOST_USER_BASE(dev);
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struct vhost_virtqueue *vhost_vqs = vub->vhost_dev.vqs;
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/* This will stop vhost backend if appropriate. */
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vub_set_status(vdev, 0);
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vhost_dev_cleanup(&vub->vhost_dev);
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g_free(vhost_vqs);
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do_vhost_user_cleanup(vdev, vub);
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}
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static void vub_class_init(ObjectClass *klass, void *data)
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{
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VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
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vdc->realize = vub_device_realize;
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vdc->unrealize = vub_device_unrealize;
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vdc->get_features = vub_get_features;
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vdc->get_config = vub_get_config;
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vdc->set_status = vub_set_status;
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}
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static const TypeInfo vub_types[] = {
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{
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.name = TYPE_VHOST_USER_BASE,
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.parent = TYPE_VIRTIO_DEVICE,
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.instance_size = sizeof(VHostUserBase),
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.class_init = vub_class_init,
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.class_size = sizeof(VHostUserBaseClass),
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.abstract = true
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}
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};
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DEFINE_TYPES(vub_types)
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