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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Haoqian He <haoqian.he@smartx.com>
Cc: qemu-devel@nongnu.org, sgarzare@redhat.com,
	raphael@enfabrica.net, fengli@smartx.com, yuhua@smartx.com,
	"Kevin Wolf" <kwolf@redhat.com>,
	"Hanna Reitz" <hreitz@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Laurent Vivier" <lvivier@redhat.com>,
	"Amit Shah" <amit@kernel.org>,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Gerd Hoffmann" <kraxel@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>, "Fam Zheng" <fam@euphon.net>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Cédric Le Goater" <clg@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"reviewer:vhost-user-scmi" <mzamazal@redhat.com>,
	"David Hildenbrand" <david@redhat.com>,
	"Gonglei (Arei)" <arei.gonglei@huawei.com>,
	"Eric Auger" <eric.auger@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"open list:Block layer core" <qemu-block@nongnu.org>,
	"open list:virtiofs" <virtio-fs@lists.linux.dev>
Subject: Re: [PATCH v4 3/3] vhost-user: return failure if backend crash when live migration
Date: Thu, 3 Apr 2025 17:15:05 -0400	[thread overview]
Message-ID: <20250403171046-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20250401151819.1526461-4-haoqian.he@smartx.com>

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.he@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


  reply	other threads:[~2025-04-03 21:15 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20250314101535.1059308-1-haoqian.he@smartx.com>
2025-03-27  6:43 ` [PATCH v3 0/3] vhost: fix the IO error after live migration Haoqian He
2025-03-27  6:43   ` [PATCH v3 1/3] system/runstate: add VM state change cb with return value Haoqian He
2025-03-27  6:43   ` [PATCH v3 2/3] vhost: return failure if stop virtqueue failed in vhost_dev_stop Haoqian He
2025-03-27  6:43   ` [PATCH v3 3/3] vhost-user: return failure if backend crash when live migration Haoqian He
2025-04-01 15:18   ` [PATCH v4 0/3] vhost: fix the IO error after " Haoqian He
2025-04-01 15:18     ` [PATCH v4 1/3] system/runstate: add VM state change cb with return value Haoqian He
2025-04-01 15:18     ` [PATCH v4 2/3] vhost: return failure if stop virtqueue failed in vhost_dev_stop Haoqian He
2025-04-01 15:18     ` [PATCH v4 3/3] vhost-user: return failure if backend crash when live migration Haoqian He
2025-04-03 21:15       ` Michael S. Tsirkin [this message]
2025-04-07 12:25         ` Haoqian He
2025-04-16  2:47     ` [PATCH v5 0/3] vhost: fix the IO error after " Haoqian He
2025-04-16  2:47       ` [PATCH v5 1/3] system/runstate: add VM state change cb with return value Haoqian He
2025-04-16  2:47       ` [PATCH v5 2/3] vhost: return failure if stop virtqueue failed in vhost_dev_stop Haoqian He
2025-04-16  2:47       ` [PATCH v5 3/3] vhost-user: return failure if backend crash when live migration Haoqian He
2025-04-23  6:45         ` Haoqian He
2025-04-23 10:03           ` Michael S. Tsirkin
2025-04-23 10:04             ` Michael S. Tsirkin
2025-04-17  1:48       ` [PATCH v5 0/3] vhost: fix the IO error after " Lei Yang
2025-05-11 18:00       ` Michael S. Tsirkin

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