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[PATCH 05/12] virtio: add generic vhost-user-device
From: |
Alex Bennée |
Subject: |
[PATCH 05/12] virtio: add generic vhost-user-device |
Date: |
Fri, 14 Apr 2023 17:04:26 +0100 |
In theory we shouldn't need to repeat so much boilerplate to support
vhost-user backends. This provides a generic vhost-user-device for
which the user needs to provide the few bits of information that
aren't currently provided by the vhost-user protocol. This should
provide a baseline implementation from which the other vhost-user stub
can specialise.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
include/hw/virtio/vhost-user-device.h | 32 +++
hw/virtio/vhost-user-device.c | 303 ++++++++++++++++++++++++++
hw/virtio/meson.build | 2 +
3 files changed, 337 insertions(+)
create mode 100644 include/hw/virtio/vhost-user-device.h
create mode 100644 hw/virtio/vhost-user-device.c
diff --git a/include/hw/virtio/vhost-user-device.h
b/include/hw/virtio/vhost-user-device.h
new file mode 100644
index 0000000000..8d77f06721
--- /dev/null
+++ b/include/hw/virtio/vhost-user-device.h
@@ -0,0 +1,32 @@
+/*
+ * Vhost-user generic virtio device
+ *
+ * Copyright (c) 2023 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QEMU_VHOST_USER_DEVICE_H
+#define QEMU_VHOST_USER_DEVICE_H
+
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-user.h"
+
+#define TYPE_VHOST_USER_DEVICE "vhost-user-device"
+OBJECT_DECLARE_SIMPLE_TYPE(VHostUserDevice, VHOST_USER_DEVICE)
+
+struct VHostUserDevice {
+ VirtIODevice parent;
+ /* Properties */
+ CharBackend chardev;
+ uint16_t virtio_id;
+ uint32_t num_vqs;
+ /* State tracking */
+ VhostUserState vhost_user;
+ struct vhost_virtqueue *vhost_vq;
+ struct vhost_dev vhost_dev;
+ GPtrArray *vqs;
+ bool connected;
+};
+
+#endif /* QEMU_VHOST_USER_DEVICE_H */
diff --git a/hw/virtio/vhost-user-device.c b/hw/virtio/vhost-user-device.c
new file mode 100644
index 0000000000..bfbf3b29cb
--- /dev/null
+++ b/hw/virtio/vhost-user-device.c
@@ -0,0 +1,303 @@
+/*
+ * Generic vhost-user stub. This can be used to connect to any
+ * vhost-user backend. All configuration details must be handled by
+ * the vhost-user daemon itself
+ *
+ * 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-device.h"
+#include "qemu/error-report.h"
+
+static void vud_start(VirtIODevice *vdev)
+{
+ BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
+ VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+ int ret, i;
+
+ if (!k->set_guest_notifiers) {
+ error_report("binding does not support guest notifiers");
+ return;
+ }
+
+ ret = vhost_dev_enable_notifiers(&vud->vhost_dev, vdev);
+ if (ret < 0) {
+ error_report("Error enabling host notifiers: %d", -ret);
+ return;
+ }
+
+ ret = k->set_guest_notifiers(qbus->parent, vud->vhost_dev.nvqs, true);
+ if (ret < 0) {
+ error_report("Error binding guest notifier: %d", -ret);
+ goto err_host_notifiers;
+ }
+
+ vud->vhost_dev.acked_features = vdev->guest_features;
+
+ ret = vhost_dev_start(&vud->vhost_dev, vdev, true);
+ if (ret < 0) {
+ error_report("Error starting vhost-user-device: %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 < vud->vhost_dev.nvqs; i++) {
+ vhost_virtqueue_mask(&vud->vhost_dev, vdev, i, false);
+ }
+
+ return;
+
+err_guest_notifiers:
+ k->set_guest_notifiers(qbus->parent, vud->vhost_dev.nvqs, false);
+err_host_notifiers:
+ vhost_dev_disable_notifiers(&vud->vhost_dev, vdev);
+}
+
+static void vud_stop(VirtIODevice *vdev)
+{
+ VHostUserDevice *vud = VHOST_USER_DEVICE(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(&vud->vhost_dev, vdev, true);
+
+ ret = k->set_guest_notifiers(qbus->parent, vud->vhost_dev.nvqs, false);
+ if (ret < 0) {
+ error_report("vhost guest notifier cleanup failed: %d", ret);
+ return;
+ }
+
+ vhost_dev_disable_notifiers(&vud->vhost_dev, vdev);
+}
+
+static void vud_set_status(VirtIODevice *vdev, uint8_t status)
+{
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+ bool should_start = virtio_device_should_start(vdev, status);
+
+ if (vhost_dev_is_started(&vud->vhost_dev) == should_start) {
+ return;
+ }
+
+ if (should_start) {
+ vud_start(vdev);
+ } else {
+ vud_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 vud_get_features(VirtIODevice *vdev,
+ uint64_t requested_features, Error **errp)
+{
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+ /* This should be set when the vhost connection initialises */
+ g_assert(vud->vhost_dev.features);
+ return vud->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
+}
+
+static void vud_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, VHostUserDevice *vud)
+{
+ vhost_user_cleanup(&vud->vhost_user);
+
+ for (int i = 0; i < vud->num_vqs; i++) {
+ VirtQueue *vq = g_ptr_array_index(vud->vqs, i);
+ virtio_delete_queue(vq);
+ }
+
+ virtio_cleanup(vdev);
+}
+
+static int vud_connect(DeviceState *dev)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+
+ if (vud->connected) {
+ return 0;
+ }
+ vud->connected = true;
+
+ /* restore vhost state */
+ if (virtio_device_started(vdev, vdev->status)) {
+ vud_start(vdev);
+ }
+
+ return 0;
+}
+
+static void vud_disconnect(DeviceState *dev)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+
+ if (!vud->connected) {
+ return;
+ }
+ vud->connected = false;
+
+ if (vhost_dev_is_started(&vud->vhost_dev)) {
+ vud_stop(vdev);
+ }
+}
+
+static void vud_event(void *opaque, QEMUChrEvent event)
+{
+ DeviceState *dev = opaque;
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+
+ switch (event) {
+ case CHR_EVENT_OPENED:
+ if (vud_connect(dev) < 0) {
+ qemu_chr_fe_disconnect(&vud->chardev);
+ return;
+ }
+ break;
+ case CHR_EVENT_CLOSED:
+ vud_disconnect(dev);
+ break;
+ case CHR_EVENT_BREAK:
+ case CHR_EVENT_MUX_IN:
+ case CHR_EVENT_MUX_OUT:
+ /* Ignore */
+ break;
+ }
+}
+
+static void vud_device_realize(DeviceState *dev, Error **errp)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserDevice *vud = VHOST_USER_DEVICE(dev);
+ int ret;
+
+ if (!vud->chardev.chr) {
+ error_setg(errp, "vhost-user-device: missing chardev");
+ return;
+ }
+
+ if (!vud->virtio_id) {
+ error_setg(errp, "vhost-user-device: need to define device id");
+ return;
+ }
+
+ if (!vud->num_vqs) {
+ vud->num_vqs = 1; /* reasonable default? */
+ }
+
+ if (!vhost_user_init(&vud->vhost_user, &vud->chardev, errp)) {
+ return;
+ }
+
+ virtio_init(vdev, vud->virtio_id, 0);
+
+ /*
+ * Disable guest notifiers, by default all notifications will be via the
+ * asynchronous vhost-user socket.
+ */
+ vdev->use_guest_notifier_mask = false;
+
+ /* Allocate queues */
+ vud->vqs = g_ptr_array_sized_new(vud->num_vqs);
+ for (int i = 0; i < vud->num_vqs; i++) {
+ g_ptr_array_add(vud->vqs,
+ virtio_add_queue(vdev, 4, vud_handle_output));
+ }
+
+ vud->vhost_dev.nvqs = vud->num_vqs;
+ vud->vhost_dev.vqs = g_new0(struct vhost_virtqueue, vud->vhost_dev.nvqs);
+
+ /* connect to backend */
+ fprintf(stderr, "%s: doing vhost_dev_init()\n", __func__);
+ ret = vhost_dev_init(&vud->vhost_dev, &vud->vhost_user,
+ VHOST_BACKEND_TYPE_USER, 0, errp);
+
+ if (ret < 0) {
+ do_vhost_user_cleanup(vdev, vud);
+ }
+
+ qemu_chr_fe_set_handlers(&vud->chardev, NULL, NULL, vud_event, NULL,
+ dev, NULL, true);
+}
+
+static void vud_device_unrealize(DeviceState *dev)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserDevice *vud = VHOST_USER_DEVICE(dev);
+ struct vhost_virtqueue *vhost_vqs = vud->vhost_dev.vqs;
+
+ /* This will stop vhost backend if appropriate. */
+ vud_set_status(vdev, 0);
+ vhost_dev_cleanup(&vud->vhost_dev);
+ g_free(vhost_vqs);
+ do_vhost_user_cleanup(vdev, vud);
+}
+
+static const VMStateDescription vud_vmstate = {
+ .name = "vhost-user-device",
+ .unmigratable = 1,
+};
+
+static Property vud_properties[] = {
+ DEFINE_PROP_CHR("chardev", VHostUserDevice, chardev),
+ DEFINE_PROP_UINT16("virtio-id", VHostUserDevice, virtio_id, 0),
+ DEFINE_PROP_UINT32("num_vqs", VHostUserDevice, num_vqs, 1),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vud_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+ VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+ device_class_set_props(dc, vud_properties);
+ dc->vmsd = &vud_vmstate;
+ set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+ vdc->realize = vud_device_realize;
+ vdc->unrealize = vud_device_unrealize;
+ vdc->get_features = vud_get_features;
+ vdc->set_status = vud_set_status;
+}
+
+static const TypeInfo vud_info = {
+ .name = TYPE_VHOST_USER_DEVICE,
+ .parent = TYPE_VIRTIO_DEVICE,
+ .instance_size = sizeof(VHostUserDevice),
+ .class_init = vud_class_init,
+};
+
+static void vud_register_types(void)
+{
+ type_register_static(&vud_info);
+}
+
+type_init(vud_register_types)
diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index bdec78bfc6..43e5fa3f7d 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -10,7 +10,9 @@ specific_virtio_ss.add(files('virtio-config-io.c',
'virtio-qmp.c'))
if have_vhost
specific_virtio_ss.add(files('vhost.c', 'vhost-backend.c',
'vhost-iova-tree.c'))
if have_vhost_user
+ # fixme - this really should be generic
specific_virtio_ss.add(files('vhost-user.c'))
+ softmmu_virtio_ss.add(files('vhost-user-device.c'))
endif
if have_vhost_vdpa
specific_virtio_ss.add(files('vhost-vdpa.c', 'vhost-shadow-virtqueue.c'))
--
2.39.2
- [PATCH 00/12] virtio: add vhost-user-generic and reduce copy and paste, Alex Bennée, 2023/04/14
- [PATCH 03/12] include/hw/virtio: add kerneldoc for virtio_init, Alex Bennée, 2023/04/14
- [PATCH 02/12] include/hw/virtio: document virtio_notify_config, Alex Bennée, 2023/04/14
- [PATCH 06/12] virtio: add PCI stub for vhost-user-device, Alex Bennée, 2023/04/14
- [PATCH 01/12] hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments, Alex Bennée, 2023/04/14
- [PATCH 12/12] docs/system: add a basic enumeration of vhost-user devices, Alex Bennée, 2023/04/14
- [PATCH 11/12] hw/virtio: derive vhost-user-gpio from vhost-user-device (!BROKEN), Alex Bennée, 2023/04/14
- [PATCH 05/12] virtio: add generic vhost-user-device,
Alex Bennée <=
- [PATCH 09/12] hw/virtio: derive vhost-user-rng from vhost-user-device, Alex Bennée, 2023/04/14
- [PATCH 04/12] include/hw/virtio: document some more usage of notifiers, Alex Bennée, 2023/04/14
- [PATCH 10/12] hw/virtio: add config support to vhost-user-device, Alex Bennée, 2023/04/14
- [PATCH 08/12] qom: allow for properties to become "fixed", Alex Bennée, 2023/04/14
- [PATCH 07/12] include: attempt to document device_class_set_props, Alex Bennée, 2023/04/14
- Re: [PATCH 00/12] virtio: add vhost-user-generic and reduce copy and paste, Viresh Kumar, 2023/04/17