Re: [PATCH 7/7] vdpa: Use ring hwaddr at vhost_vdpa_svq_unmap_ring

[Eugenio Perez Martin]

On Tue, Aug 23, 2022 at 8:40 AM Jason Wang <jasowang@redhat.com> wrote:
>
>
> 在 2022/8/20 00:53, Eugenio Pérez 写道:
> > Reduce code duplication.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
>
>
> Acked-by: Jason Wang <jasowang@redhat.com>
>
> (In the future, we need to look for other cases where a function may use
> only a partial of DMAMap.)
>

Do you have a use case in mind? The IOVA tree also trusts the memory
listener will unmap and map chunks symmetrically.

Thanks!

> Thanks
>
>
> > ---
> >   hw/virtio/vhost-vdpa.c | 17 ++++++++---------
> >   1 file changed, 8 insertions(+), 9 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > index 07d00f5284..45d6e86b45 100644
> > --- a/hw/virtio/vhost-vdpa.c
> > +++ b/hw/virtio/vhost-vdpa.c
> > @@ -884,10 +884,12 @@ static int vhost_vdpa_svq_set_fds(struct vhost_dev 
> > *dev,
> >   /**
> >    * Unmap a SVQ area in the device
> >    */
> > -static void vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v,
> > -                                      const DMAMap *needle)
> > +static void vhost_vdpa_svq_unmap_ring(struct vhost_vdpa *v, hwaddr addr)
> >   {
> > -    const DMAMap *result = vhost_iova_tree_find_iova(v->iova_tree, needle);
> > +    const DMAMap needle = {
> > +        .translated_addr = addr,
> > +    };
> > +    const DMAMap *result = vhost_iova_tree_find_iova(v->iova_tree, 
> > &needle);
> >       hwaddr size;
> >       int r;
> >
> > @@ -908,17 +910,14 @@ static void vhost_vdpa_svq_unmap_ring(struct 
> > vhost_vdpa *v,
> >   static void vhost_vdpa_svq_unmap_rings(struct vhost_dev *dev,
> >                                          const VhostShadowVirtqueue *svq)
> >   {
> > -    DMAMap needle = {};
> >       struct vhost_vdpa *v = dev->opaque;
> >       struct vhost_vring_addr svq_addr;
> >
> >       vhost_svq_get_vring_addr(svq, &svq_addr);
> >
> > -    needle.translated_addr = svq_addr.desc_user_addr;
> > -    vhost_vdpa_svq_unmap_ring(v, &needle);
> > +    vhost_vdpa_svq_unmap_ring(v, svq_addr.desc_user_addr);
> >
> > -    needle.translated_addr = svq_addr.used_user_addr;
> > -    vhost_vdpa_svq_unmap_ring(v, &needle);
> > +    vhost_vdpa_svq_unmap_ring(v, svq_addr.used_user_addr);
> >   }
> >
> >   /**
> > @@ -996,7 +995,7 @@ static bool vhost_vdpa_svq_map_rings(struct vhost_dev 
> > *dev,
> >       ok = vhost_vdpa_svq_map_ring(v, &device_region, errp);
> >       if (unlikely(!ok)) {
> >           error_prepend(errp, "Cannot create vq device region: ");
> > -        vhost_vdpa_svq_unmap_ring(v, &driver_region);
> > +        vhost_vdpa_svq_unmap_ring(v, driver_region.translated_addr);
> >       }
> >       addr->used_user_addr = device_region.iova;
> >
>