Re: [Qemu-devel] [PATCH] virtio-scsi: define dummy handle_output for vhost-scsi vqs

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/06/2014 10:12, Ming Lei ha scritto:
> vhost userspace needn't to handle vq's notification from guest,
> so define dummy handle_output callback for all vqs of vhost-scsi.
>
> In some corner cases(such as when handling vq's reset from VM), virtio-pci
> still trys to handle pending virtio-scsi events, then object check failure
> inside virtio_scsi_handle_event() for vhost-scsi can be triggered.
>
> The issue can be reproduced by 'rmmod virtio-scsi', 'system sleep' or reboot
> inside VM.
>
> Cc: qemu-stable@nongnu.org
> Cc: Anthony Liguori <aliguori@amazon.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> ---
>  hw/scsi/vhost-scsi.c            |    8 +++++++-
>  hw/scsi/virtio-scsi.c           |   14 +++++++++-----
>  include/hw/virtio/virtio-scsi.h |    7 ++++++-
>  3 files changed, 22 insertions(+), 7 deletions(-)
>
> diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
> index 3983a5b..9099192 100644
> --- a/hw/scsi/vhost-scsi.c
> +++ b/hw/scsi/vhost-scsi.c
> @@ -196,6 +196,10 @@ static void vhost_scsi_set_status(VirtIODevice *vdev, uint8_t val)
>      }
>  }
>
> +static void vhost_dummy_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +}
> +
>  static void vhost_scsi_realize(DeviceState *dev, Error **errp)
>  {
>      VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
> @@ -217,7 +221,9 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
>          }
>      }
>
> -    virtio_scsi_common_realize(dev, &err);
> +    virtio_scsi_common_realize(dev, &err, vhost_dummy_handle_output,
> +                               vhost_dummy_handle_output,
> +                               vhost_dummy_handle_output);
>      if (err != NULL) {
>          error_propagate(errp, err);
>          return;
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index b0d7517..c57cefb 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -595,7 +595,9 @@ static struct SCSIBusInfo virtio_scsi_scsi_info = {
>      .load_request = virtio_scsi_load_request,
>  };
>
> -void virtio_scsi_common_realize(DeviceState *dev, Error **errp)
> +void virtio_scsi_common_realize(DeviceState *dev, Error **errp,
> +                                HandleOutput ctrl, HandleOutput evt,
> +                                HandleOutput cmd)
>  {
>      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>      VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev);
> @@ -609,12 +611,12 @@ void virtio_scsi_common_realize(DeviceState *dev, Error **errp)
>      s->cdb_size = VIRTIO_SCSI_CDB_SIZE;
>
>      s->ctrl_vq = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE,
> -                                  virtio_scsi_handle_ctrl);
> +                                  ctrl);
>      s->event_vq = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE,
> -                                   virtio_scsi_handle_event);
> +                                   evt);
>      for (i = 0; i < s->conf.num_queues; i++) {
>          s->cmd_vqs[i] = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE,
> -                                         virtio_scsi_handle_cmd);
> +                                         cmd);
>      }
>  }
>
> @@ -625,7 +627,9 @@ static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
>      static int virtio_scsi_id;
>      Error *err = NULL;
>
> -    virtio_scsi_common_realize(dev, &err);
> +    virtio_scsi_common_realize(dev, &err, virtio_scsi_handle_ctrl,
> +                               virtio_scsi_handle_event,
> +                               virtio_scsi_handle_cmd);
>      if (err != NULL) {
>          error_propagate(errp, err);
>          return;
> diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
> index 367afc6..a54b973 100644
> --- a/include/hw/virtio/virtio-scsi.h
> +++ b/include/hw/virtio/virtio-scsi.h
> @@ -185,7 +185,12 @@ typedef struct {
>      DEFINE_PROP_BIT("param_change", _state, _feature_field,                    \
>                                              VIRTIO_SCSI_F_CHANGE, true)
>
> -void virtio_scsi_common_realize(DeviceState *dev, Error **errp);
> +typedef void (*HandleOutput)(VirtIODevice *, VirtQueue *);
> +
> +void virtio_scsi_common_realize(DeviceState *dev, Error **errp,
> +                                HandleOutput ctrl, HandleOutput evt,
> +                                HandleOutput cmd);
> +
>  void virtio_scsi_common_unrealize(DeviceState *dev, Error **errp);
>
>  #endif /* _QEMU_VIRTIO_SCSI_H */
>

Thanks, applied to scsi-next branch.

Paolo