qemu/hw/virtio/vhost-user-scmi.c
Milan Zamazal 63a3520e29 hw/virtio: Add a protection against duplicate vu_scmi_stop calls
The QEMU CI fails in virtio-scmi test occasionally.  As reported by
Thomas Huth, this happens most likely when the system is loaded and it
fails with the following error:

  qemu-system-aarch64: ../../devel/qemu/hw/pci/msix.c:659:
  msix_unset_vector_notifiers: Assertion `dev->msix_vector_use_notifier && dev->msix_vector_release_notifier' failed.
  ../../devel/qemu/tests/qtest/libqtest.c:200: kill_qemu() detected QEMU death from signal 6 (Aborted) (core dumped)

As discovered by Fabiano Rosas, the cause is a duplicate invocation of
msix_unset_vector_notifiers via duplicate vu_scmi_stop calls:

  msix_unset_vector_notifiers
  virtio_pci_set_guest_notifiers
  vu_scmi_stop
  vu_scmi_disconnect
  ...
  qemu_chr_write_buffer

  msix_unset_vector_notifiers
  virtio_pci_set_guest_notifiers
  vu_scmi_stop
  vu_scmi_set_status
  ...
  qemu_cleanup

While vu_scmi_stop calls are protected by vhost_dev_is_started()
check, it's apparently not enough.  vhost-user-blk and vhost-user-gpio
use an extra protection, see f5b22d06fb (vhost: recheck dev state in
the vhost_migration_log routine) for the motivation.  Let's use the
same in vhost-user-scmi, which fixes the failure above.

Fixes: a5dab090e1 ("hw/virtio: Add boilerplate for vhost-user-scmi device")
Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Message-Id: <20230720101037.2161450-1-mzamazal@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
2023-08-03 16:06:49 -04:00

314 lines
8.3 KiB
C

/*
* Vhost-user SCMI virtio device
*
* SPDX-FileCopyrightText: Red Hat, Inc.
* SPDX-License-Identifier: GPL-2.0-or-later
*
* Implementation based on other vhost-user devices in QEMU.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/vhost-user-scmi.h"
#include "standard-headers/linux/virtio_ids.h"
#include "standard-headers/linux/virtio_scmi.h"
#include "trace.h"
/*
* In this version, we don't support VIRTIO_SCMI_F_SHARED_MEMORY.
* Note that VIRTIO_SCMI_F_SHARED_MEMORY is currently not supported in
* Linux VirtIO SCMI guest driver.
*/
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_F_RING_RESET,
VIRTIO_SCMI_F_P2A_CHANNELS,
VHOST_INVALID_FEATURE_BIT
};
static int vu_scmi_start(VirtIODevice *vdev)
{
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
struct vhost_dev *vhost_dev = &scmi->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;
}
vhost_ack_features(&scmi->vhost_dev, feature_bits, vdev->guest_features);
ret = vhost_dev_start(&scmi->vhost_dev, vdev, true);
if (ret < 0) {
error_report("Error starting vhost-user-scmi: %d", ret);
goto err_guest_notifiers;
}
scmi->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 < scmi->vhost_dev.nvqs; i++) {
vhost_virtqueue_mask(&scmi->vhost_dev, vdev, i, false);
}
return 0;
err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(vhost_dev, vdev);
return ret;
}
static void vu_scmi_stop(VirtIODevice *vdev)
{
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
struct vhost_dev *vhost_dev = &scmi->vhost_dev;
int ret;
/* vhost_dev_is_started() check in the callers is not fully reliable. */
if (!scmi->started_vu) {
return;
}
scmi->started_vu = false;
if (!k->set_guest_notifiers) {
return;
}
vhost_dev_stop(vhost_dev, vdev, true);
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_scmi_set_status(VirtIODevice *vdev, uint8_t status)
{
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
bool should_start = virtio_device_should_start(vdev, status);
if (!scmi->connected) {
return;
}
if (vhost_dev_is_started(&scmi->vhost_dev) == should_start) {
return;
}
if (should_start) {
vu_scmi_start(vdev);
} else {
vu_scmi_stop(vdev);
}
}
static uint64_t vu_scmi_get_features(VirtIODevice *vdev, uint64_t features,
Error **errp)
{
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
return vhost_get_features(&scmi->vhost_dev, feature_bits, features);
}
static void vu_scmi_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_scmi_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
{
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
if (idx == VIRTIO_CONFIG_IRQ_IDX) {
return;
}
vhost_virtqueue_mask(&scmi->vhost_dev, vdev, idx, mask);
}
static bool vu_scmi_guest_notifier_pending(VirtIODevice *vdev, int idx)
{
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
return vhost_virtqueue_pending(&scmi->vhost_dev, idx);
}
static void vu_scmi_connect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
if (scmi->connected) {
return;
}
scmi->connected = true;
/* restore vhost state */
if (virtio_device_started(vdev, vdev->status)) {
vu_scmi_start(vdev);
}
}
static void vu_scmi_disconnect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
if (!scmi->connected) {
return;
}
scmi->connected = false;
if (vhost_dev_is_started(&scmi->vhost_dev)) {
vu_scmi_stop(vdev);
}
}
static void vu_scmi_event(void *opaque, QEMUChrEvent event)
{
DeviceState *dev = opaque;
switch (event) {
case CHR_EVENT_OPENED:
vu_scmi_connect(dev);
break;
case CHR_EVENT_CLOSED:
vu_scmi_disconnect(dev);
break;
case CHR_EVENT_BREAK:
case CHR_EVENT_MUX_IN:
case CHR_EVENT_MUX_OUT:
/* Ignore */
break;
}
}
static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserSCMI *scmi)
{
virtio_delete_queue(scmi->cmd_vq);
virtio_delete_queue(scmi->event_vq);
g_free(scmi->vhost_dev.vqs);
virtio_cleanup(vdev);
vhost_user_cleanup(&scmi->vhost_user);
}
static void vu_scmi_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserSCMI *scmi = VHOST_USER_SCMI(dev);
int ret;
if (!scmi->chardev.chr) {
error_setg(errp, "vhost-user-scmi: chardev is mandatory");
return;
}
vdev->host_features |= (1ULL << VIRTIO_SCMI_F_P2A_CHANNELS);
if (!vhost_user_init(&scmi->vhost_user, &scmi->chardev, errp)) {
return;
}
virtio_init(vdev, VIRTIO_ID_SCMI, 0);
scmi->cmd_vq = virtio_add_queue(vdev, 256, vu_scmi_handle_output);
scmi->event_vq = virtio_add_queue(vdev, 256, vu_scmi_handle_output);
scmi->vhost_dev.nvqs = 2;
scmi->vhost_dev.vqs = g_new0(struct vhost_virtqueue, scmi->vhost_dev.nvqs);
ret = vhost_dev_init(&scmi->vhost_dev, &scmi->vhost_user,
VHOST_BACKEND_TYPE_USER, 0, errp);
if (ret < 0) {
error_setg_errno(errp, -ret,
"vhost-user-scmi: vhost_dev_init() failed");
do_vhost_user_cleanup(vdev, scmi);
return;
}
qemu_chr_fe_set_handlers(&scmi->chardev, NULL, NULL, vu_scmi_event, NULL,
dev, NULL, true);
return;
}
static void vu_scmi_device_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserSCMI *scmi = VHOST_USER_SCMI(dev);
vu_scmi_set_status(vdev, 0);
vhost_dev_cleanup(&scmi->vhost_dev);
do_vhost_user_cleanup(vdev, scmi);
}
static const VMStateDescription vu_scmi_vmstate = {
.name = "vhost-user-scmi",
.unmigratable = 1,
};
static Property vu_scmi_properties[] = {
DEFINE_PROP_CHR("chardev", VHostUserSCMI, chardev),
DEFINE_PROP_END_OF_LIST(),
};
static void vu_scmi_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
device_class_set_props(dc, vu_scmi_properties);
dc->vmsd = &vu_scmi_vmstate;
set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
vdc->realize = vu_scmi_device_realize;
vdc->unrealize = vu_scmi_device_unrealize;
vdc->get_features = vu_scmi_get_features;
vdc->set_status = vu_scmi_set_status;
vdc->guest_notifier_mask = vu_scmi_guest_notifier_mask;
vdc->guest_notifier_pending = vu_scmi_guest_notifier_pending;
}
static const TypeInfo vu_scmi_info = {
.name = TYPE_VHOST_USER_SCMI,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VHostUserSCMI),
.class_init = vu_scmi_class_init,
};
static void vu_scmi_register_types(void)
{
type_register_static(&vu_scmi_info);
}
type_init(vu_scmi_register_types)