On Tue, Apr 01, 2025 at 11:18:17AM -0400, Haoqian He wrote:
> Live migration should be terminated if the vhost-user backend crashes
> before the migration completes.
>
> Specifically, since the vhost device will be stopped when VM is stopped
> before the end of the live migration, in current implementation if the
> backend crashes, vhost-user device set_status() won't return failure,
> live migration won't perceive the disconnection between QEMU and the
> backend.
>
> When the VM is migrated to the destination, the inflight IO will be
> resubmitted, and if the IO was completed out of order before, it will
> cause IO error.
>
> To fix this issue:
> 1. Add the return value to set_status() for VirtioDeviceClass.
> a. For the vhost-user device, return failure when the backend crashes.
> b. For other virtio devices, always return 0.
> 2. Return failure if vhost_dev_stop() failed for vhost-user device.
>
> If QEMU loses connection with the vhost-user backend, virtio set_status()
> can return failure to the upper layer, migration_completion() can handle
> the error, terminate the live migration, and restore the VM, so that
> inflight IO can be completed normally.
>
> Signed-off-by: Haoqian He <haoqian...@smartx.com>
> ---
> backends/vhost-user.c | 20 +++++++++----------
> hw/block/vhost-user-blk.c | 27 ++++++++++++++------------
> hw/block/virtio-blk.c | 5 +++--
> hw/char/virtio-serial-bus.c | 3 ++-
> hw/display/vhost-user-gpu.c | 12 +++++++++---
> hw/input/virtio-input.c | 3 ++-
> hw/net/virtio-net.c | 3 ++-
> hw/scsi/vhost-scsi-common.c | 13 +++++++------
> hw/scsi/vhost-scsi.c | 5 +++--
> hw/scsi/vhost-user-scsi.c | 18 ++++++++++-------
> hw/virtio/vdpa-dev.c | 5 +++--
> hw/virtio/vhost-user-base.c | 23 +++++++++++++---------
> hw/virtio/vhost-user-fs.c | 23 +++++++++++++---------
> hw/virtio/vhost-user-scmi.c | 27 +++++++++++++++-----------
> hw/virtio/vhost-user-vsock.c | 15 +++++++++-----
> hw/virtio/vhost-vsock-common.c | 12 ++++++------
> hw/virtio/vhost-vsock.c | 11 ++++++-----
> hw/virtio/virtio-balloon.c | 3 ++-
> hw/virtio/virtio-crypto.c | 3 ++-
> hw/virtio/virtio-iommu.c | 3 ++-
> hw/virtio/virtio-rng.c | 5 +++--
> hw/virtio/virtio.c | 23 +++++++++++++++-------
> include/hw/virtio/vhost-scsi-common.h | 2 +-
> include/hw/virtio/vhost-vsock-common.h | 2 +-
> include/hw/virtio/virtio.h | 2 +-
> include/system/vhost-user-backend.h | 2 +-
> 26 files changed, 161 insertions(+), 109 deletions(-)
>
> diff --git a/backends/vhost-user.c b/backends/vhost-user.c
> index d0e4d71a63..5409e9d4eb 100644
> --- a/backends/vhost-user.c
> +++ b/backends/vhost-user.c
> @@ -97,30 +97,28 @@ err_host_notifiers:
> vhost_dev_disable_notifiers(&b->dev, b->vdev);
> }
>
> -void
> +int
> vhost_user_backend_stop(VhostUserBackend *b)
> {
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
> VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> - int ret = 0;
> + int ret;
>
> if (!b->started) {
> - return;
> + return 0;
> }
>
> - vhost_dev_stop(&b->dev, b->vdev, true);
> + ret = vhost_dev_stop(&b->dev, b->vdev, true);
>
> - if (k->set_guest_notifiers) {
> - ret = k->set_guest_notifiers(qbus->parent,
> - b->dev.nvqs, false);
> - if (ret < 0) {
> - error_report("vhost guest notifier cleanup failed: %d", ret);
> - }
> + if (k->set_guest_notifiers &&
> + k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false)< 0) {
coding style violation.
> + error_report("vhost guest notifier cleanup failed: %d", ret);
> + return -1;
> }
> - assert(ret >= 0);
>
> vhost_dev_disable_notifiers(&b->dev, b->vdev);
> b->started = false;
> + return ret;
> }
>
> static void set_chardev(Object *obj, const char *value, Error **errp)
> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> index ae42327cf8..f355459123 100644
> --- a/hw/block/vhost-user-blk.c
> +++ b/hw/block/vhost-user-blk.c
> @@ -204,7 +204,7 @@ err_host_notifiers:
> return ret;
> }
>
> -static void vhost_user_blk_stop(VirtIODevice *vdev)
> +static int vhost_user_blk_stop(VirtIODevice *vdev)
> {
> VHostUserBlk *s = VHOST_USER_BLK(vdev);
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -212,26 +212,26 @@ static void vhost_user_blk_stop(VirtIODevice *vdev)
> int ret;
>
> if (!s->started_vu) {
> - return;
> + return 0;
> }
> s->started_vu = false;
>
> if (!k->set_guest_notifiers) {
> - return;
> + return 0;
> }
>
> - vhost_dev_stop(&s->dev, vdev, true);
> + ret = vhost_dev_stop(&s->dev, vdev, true);
>
> - ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
> - if (ret < 0) {
> + if (k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false) < 0) {
> error_report("vhost guest notifier cleanup failed: %d", ret);
> - return;
> + return -1;
> }
>
> vhost_dev_disable_notifiers(&s->dev, vdev);
> + return ret;
> }
>
> -static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VHostUserBlk *s = VHOST_USER_BLK(vdev);
> bool should_start = virtio_device_should_start(vdev, status);
> @@ -239,11 +239,11 @@ static void vhost_user_blk_set_status(VirtIODevice
> *vdev, uint8_t status)
> int ret;
>
> if (!s->connected) {
> - return;
> + return -1;
> }
>
> if (vhost_dev_is_started(&s->dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> @@ -253,9 +253,12 @@ static void vhost_user_blk_set_status(VirtIODevice
> *vdev, uint8_t status)
> qemu_chr_fe_disconnect(&s->chardev);
> }
> } else {
> - vhost_user_blk_stop(vdev);
> + ret = vhost_user_blk_stop(vdev);
> + if (ret < 0) {
> + return ret;
> + }
> }
> -
> + return 0;
> }
>
> static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 4a48a16790..4244ee3410 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -1269,7 +1269,7 @@ static uint64_t virtio_blk_get_features(VirtIODevice
> *vdev, uint64_t features,
> return features;
> }
>
> -static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
> +static int virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VirtIOBlock *s = VIRTIO_BLK(vdev);
>
> @@ -1278,7 +1278,7 @@ static void virtio_blk_set_status(VirtIODevice *vdev,
> uint8_t status)
> }
>
> if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> - return;
> + return 0;
> }
>
> /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send
> @@ -1301,6 +1301,7 @@ static void virtio_blk_set_status(VirtIODevice *vdev,
> uint8_t status)
> virtio_vdev_has_feature(vdev,
>
> VIRTIO_BLK_F_WCE));
> }
> + return 0;
> }
>
> static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f)
> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> index b6d2743a9c..22accfd8e4 100644
> --- a/hw/char/virtio-serial-bus.c
> +++ b/hw/char/virtio-serial-bus.c
> @@ -622,7 +622,7 @@ static void guest_reset(VirtIOSerial *vser)
> }
> }
>
> -static void set_status(VirtIODevice *vdev, uint8_t status)
> +static int set_status(VirtIODevice *vdev, uint8_t status)
> {
> VirtIOSerial *vser;
> VirtIOSerialPort *port;
> @@ -650,6 +650,7 @@ static void set_status(VirtIODevice *vdev, uint8_t status)
> vsc->enable_backend(port, vdev->vm_running);
> }
> }
> + return 0;
> }
>
> static void vser_reset(VirtIODevice *vdev)
> diff --git a/hw/display/vhost-user-gpu.c b/hw/display/vhost-user-gpu.c
> index 2aed6243f6..d7d159ecd9 100644
> --- a/hw/display/vhost-user-gpu.c
> +++ b/hw/display/vhost-user-gpu.c
> @@ -513,7 +513,7 @@ vhost_user_gpu_set_config(VirtIODevice *vdev,
> }
> }
>
> -static void
> +static int
> vhost_user_gpu_set_status(VirtIODevice *vdev, uint8_t val)
> {
> VhostUserGPU *g = VHOST_USER_GPU(vdev);
> @@ -522,18 +522,24 @@ vhost_user_gpu_set_status(VirtIODevice *vdev, uint8_t
> val)
> if (val & VIRTIO_CONFIG_S_DRIVER_OK && vdev->vm_running) {
> if (!vhost_user_gpu_do_set_socket(g, &err)) {
> error_report_err(err);
> - return;
> + return 0;
> }
> vhost_user_backend_start(g->vhost);
> } else {
> + int ret;
> +
> /* unblock any wait and stop processing */
> if (g->vhost_gpu_fd != -1) {
> vhost_user_gpu_update_blocked(g, true);
> qemu_chr_fe_deinit(&g->vhost_chr, true);
> g->vhost_gpu_fd = -1;
> }
> - vhost_user_backend_stop(g->vhost);
> + ret = vhost_user_backend_stop(g->vhost);
> + if (ret < 0) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> static bool
> diff --git a/hw/input/virtio-input.c b/hw/input/virtio-input.c
> index 1394d99c6b..7ce53b7449 100644
> --- a/hw/input/virtio-input.c
> +++ b/hw/input/virtio-input.c
> @@ -189,7 +189,7 @@ static uint64_t virtio_input_get_features(VirtIODevice
> *vdev, uint64_t f,
> return f;
> }
>
> -static void virtio_input_set_status(VirtIODevice *vdev, uint8_t val)
> +static int virtio_input_set_status(VirtIODevice *vdev, uint8_t val)
> {
> VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
> VirtIOInput *vinput = VIRTIO_INPUT(vdev);
> @@ -202,6 +202,7 @@ static void virtio_input_set_status(VirtIODevice *vdev,
> uint8_t val)
> }
> }
> }
> + return 0;
> }
>
> static void virtio_input_reset(VirtIODevice *vdev)
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index de87cfadff..b7de824baa 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -382,7 +382,7 @@ static void virtio_net_drop_tx_queue_data(VirtIODevice
> *vdev, VirtQueue *vq)
> }
> }
>
> -static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
> +static int virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
> {
> VirtIONet *n = VIRTIO_NET(vdev);
> VirtIONetQueue *q;
> @@ -437,6 +437,7 @@ static void virtio_net_set_status(struct VirtIODevice
> *vdev, uint8_t status)
> }
> }
> }
> + return 0;
> }
>
> static void virtio_net_set_link_status(NetClientState *nc)
> diff --git a/hw/scsi/vhost-scsi-common.c b/hw/scsi/vhost-scsi-common.c
> index 4c8637045d..43525ba46d 100644
> --- a/hw/scsi/vhost-scsi-common.c
> +++ b/hw/scsi/vhost-scsi-common.c
> @@ -101,24 +101,25 @@ err_host_notifiers:
> return ret;
> }
>
> -void vhost_scsi_common_stop(VHostSCSICommon *vsc)
> +int vhost_scsi_common_stop(VHostSCSICommon *vsc)
> {
> VirtIODevice *vdev = VIRTIO_DEVICE(vsc);
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> int ret = 0;
>
> - vhost_dev_stop(&vsc->dev, vdev, true);
> + ret = vhost_dev_stop(&vsc->dev, vdev, true);
>
> if (k->set_guest_notifiers) {
> - ret = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false);
> - if (ret < 0) {
> - error_report("vhost guest notifier cleanup failed: %d", ret);
> + int r = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false);
> + if (r < 0) {
> + error_report("vhost guest notifier cleanup failed: %d", ret);
> + return r;
> }
> }
> - assert(ret >= 0);
>
> vhost_dev_disable_notifiers(&vsc->dev, vdev);
> + return ret;
> }
>
> uint64_t vhost_scsi_common_get_features(VirtIODevice *vdev, uint64_t
> features,
> diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
> index 8039d13fd9..19d5261019 100644
> --- a/hw/scsi/vhost-scsi.c
> +++ b/hw/scsi/vhost-scsi.c
> @@ -114,7 +114,7 @@ static void vhost_scsi_stop(VHostSCSI *s)
> vhost_scsi_common_stop(vsc);
> }
>
> -static void vhost_scsi_set_status(VirtIODevice *vdev, uint8_t val)
> +static int vhost_scsi_set_status(VirtIODevice *vdev, uint8_t val)
> {
> VHostSCSI *s = VHOST_SCSI(vdev);
> VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
> @@ -125,7 +125,7 @@ static void vhost_scsi_set_status(VirtIODevice *vdev,
> uint8_t val)
> }
>
> if (vhost_dev_is_started(&vsc->dev) == start) {
> - return;
> + return 0;
> }
>
> if (start) {
> @@ -139,6 +139,7 @@ static void vhost_scsi_set_status(VirtIODevice *vdev,
> uint8_t val)
> } else {
> vhost_scsi_stop(s);
> }
> + return 0;
> }
>
> static void vhost_dummy_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
> index adb41b9816..aba9fb82d2 100644
> --- a/hw/scsi/vhost-user-scsi.c
> +++ b/hw/scsi/vhost-user-scsi.c
> @@ -52,19 +52,19 @@ static int vhost_user_scsi_start(VHostUserSCSI *s, Error
> **errp)
> return ret;
> }
>
> -static void vhost_user_scsi_stop(VHostUserSCSI *s)
> +static int vhost_user_scsi_stop(VHostUserSCSI *s)
> {
> VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
>
> if (!s->started_vu) {
> - return;
> + return 0;
> }
> s->started_vu = false;
>
> - vhost_scsi_common_stop(vsc);
> + return vhost_scsi_common_stop(vsc);
> }
>
> -static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VHostUserSCSI *s = (VHostUserSCSI *)vdev;
> DeviceState *dev = DEVICE(vdev);
> @@ -75,11 +75,11 @@ static void vhost_user_scsi_set_status(VirtIODevice
> *vdev, uint8_t status)
> int ret;
>
> if (!s->connected) {
> - return;
> + return -1;
> }
>
> if (vhost_dev_is_started(&vsc->dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> @@ -91,8 +91,12 @@ static void vhost_user_scsi_set_status(VirtIODevice *vdev,
> uint8_t status)
> qemu_chr_fe_disconnect(&vs->conf.chardev);
> }
> } else {
> - vhost_user_scsi_stop(s);
> + ret = vhost_user_scsi_stop(s);
> + if (ret) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> static void vhost_user_scsi_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c
> index a7e73b1c99..d80d46baed 100644
> --- a/hw/virtio/vdpa-dev.c
> +++ b/hw/virtio/vdpa-dev.c
> @@ -312,7 +312,7 @@ static void vhost_vdpa_device_stop(VirtIODevice *vdev)
> vhost_dev_disable_notifiers(&s->dev, vdev);
> }
>
> -static void vhost_vdpa_device_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vhost_vdpa_device_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> bool should_start = virtio_device_started(vdev, status);
> @@ -324,7 +324,7 @@ static void vhost_vdpa_device_set_status(VirtIODevice
> *vdev, uint8_t status)
> }
>
> if (s->started == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> @@ -335,6 +335,7 @@ static void vhost_vdpa_device_set_status(VirtIODevice
> *vdev, uint8_t status)
> } else {
> vhost_vdpa_device_stop(vdev);
> }
> + return 0;
> }
>
> static const Property vhost_vdpa_device_properties[] = {
> diff --git a/hw/virtio/vhost-user-base.c b/hw/virtio/vhost-user-base.c
> index 2bc3423326..37718653bd 100644
> --- a/hw/virtio/vhost-user-base.c
> +++ b/hw/virtio/vhost-user-base.c
> @@ -66,7 +66,7 @@ err_host_notifiers:
> vhost_dev_disable_notifiers(&vub->vhost_dev, vdev);
> }
>
> -static void vub_stop(VirtIODevice *vdev)
> +static int vub_stop(VirtIODevice *vdev)
> {
> VHostUserBase *vub = VHOST_USER_BASE(vdev);
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -74,34 +74,39 @@ static void vub_stop(VirtIODevice *vdev)
> int ret;
>
> if (!k->set_guest_notifiers) {
> - return;
> + return 0;
> }
>
> - vhost_dev_stop(&vub->vhost_dev, vdev, true);
> + ret = vhost_dev_stop(&vub->vhost_dev, vdev, true);
>
> - ret = k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false);
> - if (ret < 0) {
> + if (k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false) <
> 0) {
> error_report("vhost guest notifier cleanup failed: %d", ret);
> - return;
> + return -1;
> }
>
> vhost_dev_disable_notifiers(&vub->vhost_dev, vdev);
> + return ret;
> }
>
> -static void vub_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vub_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VHostUserBase *vub = VHOST_USER_BASE(vdev);
> bool should_start = virtio_device_should_start(vdev, status);
>
> if (vhost_dev_is_started(&vub->vhost_dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> vub_start(vdev);
> } else {
> - vub_stop(vdev);
> + int ret;
> + ret = vub_stop(vdev);
> + if (ret < 0) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> /*
> diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
> index 3f00d79ed0..266c179671 100644
> --- a/hw/virtio/vhost-user-fs.c
> +++ b/hw/virtio/vhost-user-fs.c
> @@ -100,7 +100,7 @@ err_host_notifiers:
> vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
> }
>
> -static void vuf_stop(VirtIODevice *vdev)
> +static int vuf_stop(VirtIODevice *vdev)
> {
> VHostUserFS *fs = VHOST_USER_FS(vdev);
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -108,34 +108,39 @@ static void vuf_stop(VirtIODevice *vdev)
> int ret;
>
> if (!k->set_guest_notifiers) {
> - return;
> + return 0;
> }
>
> - vhost_dev_stop(&fs->vhost_dev, vdev, true);
> + ret = vhost_dev_stop(&fs->vhost_dev, vdev, true);
>
> - ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
> - if (ret < 0) {
> + if (k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false) < 0)
> {
> error_report("vhost guest notifier cleanup failed: %d", ret);
> - return;
> + return -1;
> }
>
> vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
> + return ret;
> }
>
> -static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vuf_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VHostUserFS *fs = VHOST_USER_FS(vdev);
> bool should_start = virtio_device_should_start(vdev, status);
>
> if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> vuf_start(vdev);
> } else {
> - vuf_stop(vdev);
> + int ret;
> + ret = vuf_stop(vdev);
> + if (ret < 0) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> static uint64_t vuf_get_features(VirtIODevice *vdev,
> diff --git a/hw/virtio/vhost-user-scmi.c b/hw/virtio/vhost-user-scmi.c
> index 410a936ca7..a9778f1f4b 100644
> --- a/hw/virtio/vhost-user-scmi.c
> +++ b/hw/virtio/vhost-user-scmi.c
> @@ -83,7 +83,7 @@ err_host_notifiers:
> return ret;
> }
>
> -static void vu_scmi_stop(VirtIODevice *vdev)
> +static int vu_scmi_stop(VirtIODevice *vdev)
> {
> VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -93,41 +93,46 @@ static void vu_scmi_stop(VirtIODevice *vdev)
>
> /* vhost_dev_is_started() check in the callers is not fully reliable. */
> if (!scmi->started_vu) {
> - return;
> + return 0;
> }
> scmi->started_vu = false;
>
> if (!k->set_guest_notifiers) {
> - return;
> + return 0;
> }
>
> - vhost_dev_stop(vhost_dev, vdev, true);
> + ret = vhost_dev_stop(vhost_dev, vdev, true);
>
> - ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
> - if (ret < 0) {
> + if (k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false) < 0) {
> error_report("vhost guest notifier cleanup failed: %d", ret);
> - return;
> + return -1;
> }
> vhost_dev_disable_notifiers(vhost_dev, vdev);
> + return ret;
> }
>
> -static void vu_scmi_set_status(VirtIODevice *vdev, uint8_t status)
> +static int 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;
> + return -1;
> }
> if (vhost_dev_is_started(&scmi->vhost_dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> vu_scmi_start(vdev);
> } else {
> - vu_scmi_stop(vdev);
> + int ret;
> + ret = vu_scmi_stop(vdev);
> + if (ret < 0) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> static uint64_t vu_scmi_get_features(VirtIODevice *vdev, uint64_t features,
> diff --git a/hw/virtio/vhost-user-vsock.c b/hw/virtio/vhost-user-vsock.c
> index 293273080b..7a4aec7bf4 100644
> --- a/hw/virtio/vhost-user-vsock.c
> +++ b/hw/virtio/vhost-user-vsock.c
> @@ -54,23 +54,28 @@ const VhostDevConfigOps vsock_ops = {
> .vhost_dev_config_notifier = vuv_handle_config_change,
> };
>
> -static void vuv_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vuv_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
> bool should_start = virtio_device_should_start(vdev, status);
> + int ret;
>
> if (vhost_dev_is_started(&vvc->vhost_dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> - int ret = vhost_vsock_common_start(vdev);
> + ret = vhost_vsock_common_start(vdev);
> if (ret < 0) {
> - return;
> + return ret;
> }
> } else {
> - vhost_vsock_common_stop(vdev);
> + ret = vhost_vsock_common_stop(vdev);
> + if (ret < 0) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> static uint64_t vuv_get_features(VirtIODevice *vdev,
> diff --git a/hw/virtio/vhost-vsock-common.c b/hw/virtio/vhost-vsock-common.c
> index 9ac587d20c..bbfbbdb317 100644
> --- a/hw/virtio/vhost-vsock-common.c
> +++ b/hw/virtio/vhost-vsock-common.c
> @@ -95,7 +95,7 @@ err_host_notifiers:
> return ret;
> }
>
> -void vhost_vsock_common_stop(VirtIODevice *vdev)
> +int vhost_vsock_common_stop(VirtIODevice *vdev)
> {
> VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
> BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -103,18 +103,18 @@ void vhost_vsock_common_stop(VirtIODevice *vdev)
> int ret;
>
> if (!k->set_guest_notifiers) {
> - return;
> + return 0;
> }
>
> - vhost_dev_stop(&vvc->vhost_dev, vdev, true);
> + ret = vhost_dev_stop(&vvc->vhost_dev, vdev, true);
>
> - ret = k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false);
> - if (ret < 0) {
> + if (k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false) <
> 0) {
> error_report("vhost guest notifier cleanup failed: %d", ret);
> - return;
> + return -1;
> }
>
> vhost_dev_disable_notifiers(&vvc->vhost_dev, vdev);
> + return ret;
> }
>
>
> diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
> index 940b30fa27..62b36b28f5 100644
> --- a/hw/virtio/vhost-vsock.c
> +++ b/hw/virtio/vhost-vsock.c
> @@ -67,37 +67,38 @@ static int vhost_vsock_set_running(VirtIODevice *vdev,
> int start)
> }
>
>
> -static void vhost_vsock_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vhost_vsock_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
> bool should_start = virtio_device_should_start(vdev, status);
> int ret;
>
> if (vhost_dev_is_started(&vvc->vhost_dev) == should_start) {
> - return;
> + return 0;
> }
>
> if (should_start) {
> ret = vhost_vsock_common_start(vdev);
> if (ret < 0) {
> - return;
> + return 0;
> }
>
> ret = vhost_vsock_set_running(vdev, 1);
> if (ret < 0) {
> vhost_vsock_common_stop(vdev);
> error_report("Error starting vhost vsock: %d", -ret);
> - return;
> + return 0;
> }
> } else {
> ret = vhost_vsock_set_running(vdev, 0);
> if (ret < 0) {
> error_report("vhost vsock set running failed: %d", ret);
> - return;
> + return 0;
> }
>
> vhost_vsock_common_stop(vdev);
> }
> + return 0;
> }
>
> static uint64_t vhost_vsock_get_features(VirtIODevice *vdev,
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 2eb5a14fa2..e719c078aa 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -958,7 +958,7 @@ static void virtio_balloon_device_reset(VirtIODevice
> *vdev)
> s->poison_val = 0;
> }
>
> -static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status)
> +static int virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
>
> @@ -988,6 +988,7 @@ static void virtio_balloon_set_status(VirtIODevice *vdev,
> uint8_t status)
> qemu_mutex_unlock(&s->free_page_lock);
> }
> }
> + return 0;
> }
>
> static ResettableState *virtio_balloon_get_reset_state(Object *obj)
> diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c
> index a1b3c90618..626279dc5b 100644
> --- a/hw/virtio/virtio-crypto.c
> +++ b/hw/virtio/virtio-crypto.c
> @@ -1197,11 +1197,12 @@ static void virtio_crypto_vhost_status(VirtIOCrypto
> *c, uint8_t status)
> }
> }
>
> -static void virtio_crypto_set_status(VirtIODevice *vdev, uint8_t status)
> +static int virtio_crypto_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VirtIOCrypto *vcrypto = VIRTIO_CRYPTO(vdev);
>
> virtio_crypto_vhost_status(vcrypto, status);
> + return 0;
> }
>
> static void virtio_crypto_guest_notifier_mask(VirtIODevice *vdev, int idx,
> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> index b6e7e01ef7..63ec12014f 100644
> --- a/hw/virtio/virtio-iommu.c
> +++ b/hw/virtio/virtio-iommu.c
> @@ -1522,9 +1522,10 @@ static void virtio_iommu_device_reset_exit(Object
> *obj, ResetType type)
> NULL, NULL, virtio_iommu_put_endpoint);
> }
>
> -static void virtio_iommu_set_status(VirtIODevice *vdev, uint8_t status)
> +static int virtio_iommu_set_status(VirtIODevice *vdev, uint8_t status)
> {
> trace_virtio_iommu_device_status(status);
> + return 0;
> }
>
> static void virtio_iommu_instance_init(Object *obj)
> diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
> index a515fc5cd9..4748d039f9 100644
> --- a/hw/virtio/virtio-rng.c
> +++ b/hw/virtio/virtio-rng.c
> @@ -159,17 +159,18 @@ static void check_rate_limit(void *opaque)
> vrng->activate_timer = true;
> }
>
> -static void virtio_rng_set_status(VirtIODevice *vdev, uint8_t status)
> +static int virtio_rng_set_status(VirtIODevice *vdev, uint8_t status)
> {
> VirtIORNG *vrng = VIRTIO_RNG(vdev);
>
> if (!vdev->vm_running) {
> - return;
> + return 0;
> }
> vdev->status = status;
>
> /* Something changed, try to process buffers */
> virtio_rng_process(vrng);
> + return 0;
> }
>
> static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 202a052053..8d292b45c5 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -2221,12 +2221,12 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val)
> {
> VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> trace_virtio_set_status(vdev, val);
> + int ret = 0;
>
> if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
> if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
> val & VIRTIO_CONFIG_S_FEATURES_OK) {
> - int ret = virtio_validate_features(vdev);
> -
> + ret = virtio_validate_features(vdev);
> if (ret) {
> return ret;
> }
> @@ -2239,11 +2239,15 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val)
> }
>
> if (k->set_status) {
> - k->set_status(vdev, val);
> + ret = k->set_status(vdev, val);
> + if (ret) {
> + qemu_log("set %s status to %d failed, old status: %d\n",
> + vdev->name, val, vdev->status);
> + }
> }
> vdev->status = val;
>
> - return 0;
> + return ret;
> }
>
> static enum virtio_device_endian virtio_default_endian(void)
> @@ -3419,7 +3423,7 @@ void virtio_cleanup(VirtIODevice *vdev)
> qemu_del_vm_change_state_handler(vdev->vmstate);
> }
>
> -static void virtio_vmstate_change(void *opaque, bool running, RunState state)
> +static int virtio_vmstate_change(void *opaque, bool running, RunState state)
> {
> VirtIODevice *vdev = opaque;
> BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
> @@ -3436,8 +3440,13 @@ static void virtio_vmstate_change(void *opaque, bool
> running, RunState state)
> }
>
> if (!backend_run) {
> - virtio_set_status(vdev, vdev->status);
> + // the return value was used for stopping VM during migration
this style of comment violates the qemu coding style
besides, no idea what it means.
> + int ret = virtio_set_status(vdev, vdev->status);
> + if (ret) {
> + return ret;
> + }
> }
> + return 0;
> }
>
> void virtio_instance_init_common(Object *proxy_obj, void *data,
> @@ -3489,7 +3498,7 @@ void virtio_init(VirtIODevice *vdev, uint16_t
> device_id, size_t config_size)
> vdev->config = NULL;
> }
> vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev),
> - virtio_vmstate_change, NULL, vdev);
> + NULL, virtio_vmstate_change, vdev);
> vdev->device_endian = virtio_default_endian();
> vdev->use_guest_notifier_mask = true;
> }
> diff --git a/include/hw/virtio/vhost-scsi-common.h
> b/include/hw/virtio/vhost-scsi-common.h
> index c5d2c09455..d54d9c916f 100644
> --- a/include/hw/virtio/vhost-scsi-common.h
> +++ b/include/hw/virtio/vhost-scsi-common.h
> @@ -40,7 +40,7 @@ struct VHostSCSICommon {
> };
>
> int vhost_scsi_common_start(VHostSCSICommon *vsc, Error **errp);
> -void vhost_scsi_common_stop(VHostSCSICommon *vsc);
> +int vhost_scsi_common_stop(VHostSCSICommon *vsc);
> char *vhost_scsi_common_get_fw_dev_path(FWPathProvider *p, BusState *bus,
> DeviceState *dev);
> void vhost_scsi_common_set_config(VirtIODevice *vdev, const uint8_t *config);
> diff --git a/include/hw/virtio/vhost-vsock-common.h
> b/include/hw/virtio/vhost-vsock-common.h
> index 75a74e8a99..01bf6062af 100644
> --- a/include/hw/virtio/vhost-vsock-common.h
> +++ b/include/hw/virtio/vhost-vsock-common.h
> @@ -42,7 +42,7 @@ struct VHostVSockCommon {
> };
>
> int vhost_vsock_common_start(VirtIODevice *vdev);
> -void vhost_vsock_common_stop(VirtIODevice *vdev);
> +int vhost_vsock_common_stop(VirtIODevice *vdev);
> int vhost_vsock_common_pre_save(void *opaque);
> int vhost_vsock_common_post_load(void *opaque, int version_id);
> void vhost_vsock_common_realize(VirtIODevice *vdev);
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 6386910280..a7ee9bec75 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -186,7 +186,7 @@ struct VirtioDeviceClass {
> void (*get_config)(VirtIODevice *vdev, uint8_t *config);
> void (*set_config)(VirtIODevice *vdev, const uint8_t *config);
> void (*reset)(VirtIODevice *vdev);
> - void (*set_status)(VirtIODevice *vdev, uint8_t val);
> + int (*set_status)(VirtIODevice *vdev, uint8_t val);
> /* Device must validate queue_index. */
> void (*queue_reset)(VirtIODevice *vdev, uint32_t queue_index);
> /* Device must validate queue_index. */
> diff --git a/include/system/vhost-user-backend.h
> b/include/system/vhost-user-backend.h
> index 327b0b84f1..87765a1218 100644
> --- a/include/system/vhost-user-backend.h
> +++ b/include/system/vhost-user-backend.h
> @@ -43,6 +43,6 @@ struct VhostUserBackend {
> int vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
> unsigned nvqs, Error **errp);
> void vhost_user_backend_start(VhostUserBackend *b);
> -void vhost_user_backend_stop(VhostUserBackend *b);
> +int vhost_user_backend_stop(VhostUserBackend *b);
>
> #endif
> --
> 2.44.0
