qemu/hw/virtio/vhost-user-gpio.c

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/*
* Vhost-user GPIO virtio device
*
* Copyright (c) 2022 Viresh Kumar <viresh.kumar@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-gpio.h"
#include "qemu/error-report.h"
#include "standard-headers/linux/virtio_ids.h"
#include "trace.h"
#define REALIZE_CONNECTION_RETRIES 3
/* Features required from VirtIO */
static const int feature_bits[] = {
VIRTIO_F_VERSION_1,
VIRTIO_F_NOTIFY_ON_EMPTY,
VIRTIO_RING_F_INDIRECT_DESC,
VIRTIO_RING_F_EVENT_IDX,
VIRTIO_GPIO_F_IRQ,
VIRTIO_F_RING_RESET,
VHOST_INVALID_FEATURE_BIT
};
static void vu_gpio_get_config(VirtIODevice *vdev, uint8_t *config)
{
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
memcpy(config, &gpio->config, sizeof(gpio->config));
}
static int vu_gpio_config_notifier(struct vhost_dev *dev)
{
VHostUserGPIO *gpio = VHOST_USER_GPIO(dev->vdev);
memcpy(dev->vdev->config, &gpio->config, sizeof(gpio->config));
virtio_notify_config(dev->vdev);
return 0;
}
const VhostDevConfigOps gpio_ops = {
.vhost_dev_config_notifier = vu_gpio_config_notifier,
};
static int vu_gpio_start(VirtIODevice *vdev)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
struct vhost_dev *vhost_dev = &gpio->vhost_dev;
int ret, i;
if (!k->set_guest_notifiers) {
error_report("binding does not support guest notifiers");
return -ENOSYS;
}
ret = vhost_dev_enable_notifiers(vhost_dev, vdev);
if (ret < 0) {
error_report("Error enabling host notifiers: %d", ret);
return ret;
}
ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, true);
if (ret < 0) {
error_report("Error binding guest notifier: %d", ret);
goto err_host_notifiers;
}
/*
* Before we start up we need to ensure we have the final feature
* set needed for the vhost configuration. The backend may also
* apply backend_features when the feature set is sent.
*/
vhost_ack_features(&gpio->vhost_dev, feature_bits, vdev->guest_features);
vhost: enable vrings in vhost_dev_start() for vhost-user devices Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features") properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the vhost-user backend, but we forgot to enable vrings as specified in docs/interop/vhost-user.rst: If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the ring starts directly in the enabled state. If ``VHOST_USER_F_PROTOCOL_FEATURES`` has been negotiated, the ring is initialized in a disabled state and is enabled by ``VHOST_USER_SET_VRING_ENABLE`` with parameter 1. Some vhost-user front-ends already did this by calling vhost_ops.vhost_set_vring_enable() directly: - backends/cryptodev-vhost.c - hw/net/virtio-net.c - hw/virtio/vhost-user-gpio.c But most didn't do that, so we would leave the vrings disabled and some backends would not work. We observed this issue with the rust version of virtiofsd [1], which uses the event loop [2] provided by the vhost-user-backend crate where requests are not processed if vring is not enabled. Let's fix this issue by enabling the vrings in vhost_dev_start() for vhost-user front-ends that don't already do this directly. Same thing also in vhost_dev_stop() where we disable vrings. [1] https://gitlab.com/virtio-fs/virtiofsd [2] https://github.com/rust-vmm/vhost/blob/240fc2966/crates/vhost-user-backend/src/event_loop.rs#L217 Fixes: 02b61f38d3 ("hw/virtio: incorporate backend features in features") Reported-by: German Maglione <gmaglione@redhat.com> Tested-by: German Maglione <gmaglione@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <20221123131630.52020-1-sgarzare@redhat.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-11-30 14:24:36 +03:00
ret = vhost_dev_start(&gpio->vhost_dev, vdev, false);
if (ret < 0) {
error_report("Error starting vhost-user-gpio: %d", ret);
goto err_guest_notifiers;
}
gpio->started_vu = true;
/*
* 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 < gpio->vhost_dev.nvqs; i++) {
vhost_virtqueue_mask(&gpio->vhost_dev, vdev, i, false);
}
/*
* As we must have VHOST_USER_F_PROTOCOL_FEATURES (because
* VHOST_USER_GET_CONFIG requires it) we need to explicitly enable
* the vrings.
*/
g_assert(vhost_dev->vhost_ops &&
vhost_dev->vhost_ops->vhost_set_vring_enable);
ret = vhost_dev->vhost_ops->vhost_set_vring_enable(vhost_dev, true);
if (ret == 0) {
return 0;
}
error_report("Failed to start vrings for vhost-user-gpio: %d", ret);
err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, gpio->vhost_dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&gpio->vhost_dev, vdev);
return ret;
}
static void vu_gpio_stop(VirtIODevice *vdev)
{
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
struct vhost_dev *vhost_dev = &gpio->vhost_dev;
int ret;
if (!gpio->started_vu) {
return;
}
gpio->started_vu = false;
if (!k->set_guest_notifiers) {
return;
}
vhost: enable vrings in vhost_dev_start() for vhost-user devices Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features") properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the vhost-user backend, but we forgot to enable vrings as specified in docs/interop/vhost-user.rst: If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the ring starts directly in the enabled state. If ``VHOST_USER_F_PROTOCOL_FEATURES`` has been negotiated, the ring is initialized in a disabled state and is enabled by ``VHOST_USER_SET_VRING_ENABLE`` with parameter 1. Some vhost-user front-ends already did this by calling vhost_ops.vhost_set_vring_enable() directly: - backends/cryptodev-vhost.c - hw/net/virtio-net.c - hw/virtio/vhost-user-gpio.c But most didn't do that, so we would leave the vrings disabled and some backends would not work. We observed this issue with the rust version of virtiofsd [1], which uses the event loop [2] provided by the vhost-user-backend crate where requests are not processed if vring is not enabled. Let's fix this issue by enabling the vrings in vhost_dev_start() for vhost-user front-ends that don't already do this directly. Same thing also in vhost_dev_stop() where we disable vrings. [1] https://gitlab.com/virtio-fs/virtiofsd [2] https://github.com/rust-vmm/vhost/blob/240fc2966/crates/vhost-user-backend/src/event_loop.rs#L217 Fixes: 02b61f38d3 ("hw/virtio: incorporate backend features in features") Reported-by: German Maglione <gmaglione@redhat.com> Tested-by: German Maglione <gmaglione@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <20221123131630.52020-1-sgarzare@redhat.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-11-30 14:24:36 +03:00
vhost_dev_stop(vhost_dev, vdev, false);
ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
if (ret < 0) {
error_report("vhost guest notifier cleanup failed: %d", ret);
return;
}
vhost_dev_disable_notifiers(vhost_dev, vdev);
}
static void vu_gpio_set_status(VirtIODevice *vdev, uint8_t status)
{
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
bool should_start = virtio_device_should_start(vdev, status);
trace_virtio_gpio_set_status(status);
if (!gpio->connected) {
return;
}
if (vhost_dev_is_started(&gpio->vhost_dev) == should_start) {
return;
}
if (should_start) {
if (vu_gpio_start(vdev)) {
qemu_chr_fe_disconnect(&gpio->chardev);
}
} else {
vu_gpio_stop(vdev);
}
}
static uint64_t vu_gpio_get_features(VirtIODevice *vdev, uint64_t features,
Error **errp)
{
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
return vhost_get_features(&gpio->vhost_dev, feature_bits, features);
}
static void vu_gpio_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 vu_gpio_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
{
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
vhost_virtqueue_mask(&gpio->vhost_dev, vdev, idx, mask);
}
static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserGPIO *gpio)
{
virtio_delete_queue(gpio->command_vq);
virtio_delete_queue(gpio->interrupt_vq);
g_free(gpio->vhost_dev.vqs);
gpio->vhost_dev.vqs = NULL;
virtio_cleanup(vdev);
vhost_user_cleanup(&gpio->vhost_user);
}
static int vu_gpio_connect(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
struct vhost_dev *vhost_dev = &gpio->vhost_dev;
int ret;
if (gpio->connected) {
return 0;
}
gpio->connected = true;
vhost_dev_set_config_notifier(vhost_dev, &gpio_ops);
gpio->vhost_user.supports_config = true;
ret = vhost_dev_init(vhost_dev, &gpio->vhost_user,
VHOST_BACKEND_TYPE_USER, 0, errp);
if (ret < 0) {
return ret;
}
/* restore vhost state */
if (virtio_device_started(vdev, vdev->status)) {
vu_gpio_start(vdev);
}
return 0;
}
static void vu_gpio_event(void *opaque, QEMUChrEvent event);
static void vu_gpio_disconnect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
if (!gpio->connected) {
return;
}
gpio->connected = false;
vu_gpio_stop(vdev);
vhost_dev_cleanup(&gpio->vhost_dev);
/* Re-instate the event handler for new connections */
qemu_chr_fe_set_handlers(&gpio->chardev,
NULL, NULL, vu_gpio_event,
NULL, dev, NULL, true);
}
static void vu_gpio_event(void *opaque, QEMUChrEvent event)
{
DeviceState *dev = opaque;
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
Error *local_err = NULL;
switch (event) {
case CHR_EVENT_OPENED:
if (vu_gpio_connect(dev, &local_err) < 0) {
qemu_chr_fe_disconnect(&gpio->chardev);
return;
}
break;
case CHR_EVENT_CLOSED:
/* defer close until later to avoid circular close */
vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev,
vu_gpio_disconnect);
break;
case CHR_EVENT_BREAK:
case CHR_EVENT_MUX_IN:
case CHR_EVENT_MUX_OUT:
/* Ignore */
break;
}
}
static int vu_gpio_realize_connect(VHostUserGPIO *gpio, Error **errp)
{
VirtIODevice *vdev = &gpio->parent_obj;
DeviceState *dev = &vdev->parent_obj;
struct vhost_dev *vhost_dev = &gpio->vhost_dev;
int ret;
ret = qemu_chr_fe_wait_connected(&gpio->chardev, errp);
if (ret < 0) {
return ret;
}
/*
* vu_gpio_connect() may have already connected (via the event
* callback) in which case it will just report success.
*/
ret = vu_gpio_connect(dev, errp);
if (ret < 0) {
qemu_chr_fe_disconnect(&gpio->chardev);
return ret;
}
g_assert(gpio->connected);
ret = vhost_dev_get_config(vhost_dev, (uint8_t *)&gpio->config,
sizeof(gpio->config), errp);
if (ret < 0) {
error_report("vhost-user-gpio: get config failed");
qemu_chr_fe_disconnect(&gpio->chardev);
vhost_dev_cleanup(vhost_dev);
return ret;
}
return 0;
}
static void vu_gpio_device_realize(DeviceState *dev, Error **errp)
{
ERRP_GUARD();
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
int retries, ret;
if (!gpio->chardev.chr) {
error_setg(errp, "vhost-user-gpio: chardev is mandatory");
return;
}
if (!vhost_user_init(&gpio->vhost_user, &gpio->chardev, errp)) {
return;
}
virtio_init(vdev, VIRTIO_ID_GPIO, sizeof(gpio->config));
gpio->vhost_dev.nvqs = 2;
gpio->command_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
gpio->interrupt_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
gpio->vhost_dev.vqs = g_new0(struct vhost_virtqueue, gpio->vhost_dev.nvqs);
gpio->connected = false;
qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, vu_gpio_event, NULL,
dev, NULL, true);
retries = REALIZE_CONNECTION_RETRIES;
g_assert(!*errp);
do {
if (*errp) {
error_prepend(errp, "Reconnecting after error: ");
error_report_err(*errp);
*errp = NULL;
}
ret = vu_gpio_realize_connect(gpio, errp);
} while (ret < 0 && retries--);
if (ret < 0) {
do_vhost_user_cleanup(vdev, gpio);
}
return;
}
static void vu_gpio_device_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
vu_gpio_set_status(vdev, 0);
qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, NULL, NULL, NULL, NULL,
false);
vhost_dev_cleanup(&gpio->vhost_dev);
do_vhost_user_cleanup(vdev, gpio);
}
static const VMStateDescription vu_gpio_vmstate = {
.name = "vhost-user-gpio",
.unmigratable = 1,
};
static Property vu_gpio_properties[] = {
DEFINE_PROP_CHR("chardev", VHostUserGPIO, chardev),
DEFINE_PROP_END_OF_LIST(),
};
static void vu_gpio_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
device_class_set_props(dc, vu_gpio_properties);
dc->vmsd = &vu_gpio_vmstate;
set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
vdc->realize = vu_gpio_device_realize;
vdc->unrealize = vu_gpio_device_unrealize;
vdc->get_features = vu_gpio_get_features;
vdc->get_config = vu_gpio_get_config;
vdc->set_status = vu_gpio_set_status;
vdc->guest_notifier_mask = vu_gpio_guest_notifier_mask;
}
static const TypeInfo vu_gpio_info = {
.name = TYPE_VHOST_USER_GPIO,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VHostUserGPIO),
.class_init = vu_gpio_class_init,
};
static void vu_gpio_register_types(void)
{
type_register_static(&vu_gpio_info);
}
type_init(vu_gpio_register_types)