Re: [PATCH for 8.0 v8 04/12] vhost: move iova_tree set to vhost_svq_start

[Jason Wang]

On Thu, Nov 24, 2022 at 11:52 PM Eugenio Pérez <eperezma@redhat.com> wrote:
>
> Since we don't know if we will use SVQ at qemu initialization, let's
> allocate iova_tree only if needed. To do so, accept it at SVQ start, not
> at initialization.
>
> This will avoid to create it if the device does not support SVQ.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  hw/virtio/vhost-shadow-virtqueue.h | 5 ++---
>  hw/virtio/vhost-shadow-virtqueue.c | 9 ++++-----
>  hw/virtio/vhost-vdpa.c             | 5 ++---
>  3 files changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.h 
> b/hw/virtio/vhost-shadow-virtqueue.h
> index d04c34a589..926a4897b1 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.h
> +++ b/hw/virtio/vhost-shadow-virtqueue.h
> @@ -126,11 +126,10 @@ size_t vhost_svq_driver_area_size(const 
> VhostShadowVirtqueue *svq);
>  size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
>
>  void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
> -                     VirtQueue *vq);
> +                     VirtQueue *vq, VhostIOVATree *iova_tree);
>  void vhost_svq_stop(VhostShadowVirtqueue *svq);
>
> -VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree,
> -                                    const VhostShadowVirtqueueOps *ops,
> +VhostShadowVirtqueue *vhost_svq_new(const VhostShadowVirtqueueOps *ops,
>                                      void *ops_opaque);
>
>  void vhost_svq_free(gpointer vq);
> diff --git a/hw/virtio/vhost-shadow-virtqueue.c 
> b/hw/virtio/vhost-shadow-virtqueue.c
> index 3b05bab44d..4307296358 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.c
> +++ b/hw/virtio/vhost-shadow-virtqueue.c
> @@ -642,9 +642,10 @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue 
> *svq, int svq_kick_fd)
>   * @svq: Shadow Virtqueue
>   * @vdev: VirtIO device
>   * @vq: Virtqueue to shadow
> + * @iova_tree: Tree to perform descriptors translations
>   */
>  void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
> -                     VirtQueue *vq)
> +                     VirtQueue *vq, VhostIOVATree *iova_tree)
>  {
>      size_t desc_size, driver_size, device_size;
>
> @@ -655,6 +656,7 @@ void vhost_svq_start(VhostShadowVirtqueue *svq, 
> VirtIODevice *vdev,
>      svq->last_used_idx = 0;
>      svq->vdev = vdev;
>      svq->vq = vq;
> +    svq->iova_tree = iova_tree;
>
>      svq->vring.num = virtio_queue_get_num(vdev, virtio_get_queue_index(vq));
>      driver_size = vhost_svq_driver_area_size(svq);
> @@ -712,18 +714,15 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
>   * Creates vhost shadow virtqueue, and instructs the vhost device to use the
>   * shadow methods and file descriptors.
>   *
> - * @iova_tree: Tree to perform descriptors translations
>   * @ops: SVQ owner callbacks
>   * @ops_opaque: ops opaque pointer
>   */
> -VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree,
> -                                    const VhostShadowVirtqueueOps *ops,
> +VhostShadowVirtqueue *vhost_svq_new(const VhostShadowVirtqueueOps *ops,
>                                      void *ops_opaque)
>  {
>      VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
>
>      event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
> -    svq->iova_tree = iova_tree;
>      svq->ops = ops;
>      svq->ops_opaque = ops_opaque;
>      return svq;
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 3df2775760..691bcc811a 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -430,8 +430,7 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, 
> struct vhost_vdpa *v,
>      for (unsigned n = 0; n < hdev->nvqs; ++n) {
>          VhostShadowVirtqueue *svq;
>
> -        svq = vhost_svq_new(v->iova_tree, v->shadow_vq_ops,
> -                            v->shadow_vq_ops_opaque);
> +        svq = vhost_svq_new(v->shadow_vq_ops, v->shadow_vq_ops_opaque);
>          g_ptr_array_add(shadow_vqs, svq);
>      }
>
> @@ -1063,7 +1062,7 @@ static bool vhost_vdpa_svqs_start(struct vhost_dev *dev)
>              goto err;
>          }
>
> -        vhost_svq_start(svq, dev->vdev, vq);
> +        vhost_svq_start(svq, dev->vdev, vq, v->iova_tree);
>          ok = vhost_vdpa_svq_map_rings(dev, svq, &addr, &err);
>          if (unlikely(!ok)) {
>              goto err_map;
> --
> 2.31.1
>