Re: [RFC PATCH V2 4/5] vhost: introduce helpers to get the size of metadata area

[Jason Wang <jasowang@xxxxxxxxxx>]

On 2019/3/7 上午2:43, Souptick Joarder wrote:
> On Wed, Mar 6, 2019 at 12:48 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> Is the change log left with any particular reason ?


Nope, will add the log.

Thanks


> > ---
> >   drivers/vhost/vhost.c | 46 ++++++++++++++++++++++++++++------------------
> >   1 file changed, 28 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > index 2025543..1015464 100644
> > --- a/drivers/vhost/vhost.c
> > +++ b/drivers/vhost/vhost.c
> > @@ -413,6 +413,27 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev)
> >                  vhost_vq_free_iovecs(dev->vqs[i]);
> >   }
> >
> > +static size_t vhost_get_avail_size(struct vhost_virtqueue *vq, int num)
> > +{
> > +       size_t event = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> > +
> > +       return sizeof(*vq->avail) +
> > +              sizeof(*vq->avail->ring) * num + event;
> > +}
> > +
> > +static size_t vhost_get_used_size(struct vhost_virtqueue *vq, int num)
> > +{
> > +       size_t event = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> > +
> > +       return sizeof(*vq->used) +
> > +              sizeof(*vq->used->ring) * num + event;
> > +}
> > +
> > +static size_t vhost_get_desc_size(struct vhost_virtqueue *vq, int num)
> > +{
> > +       return sizeof(*vq->desc) * num;
> > +}
> > +
> >   void vhost_dev_init(struct vhost_dev *dev,
> >                      struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
> >   {
> > @@ -1253,13 +1274,9 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
> >                           struct vring_used __user *used)
> >
> >   {
> > -       size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> > -
> > -       return access_ok(desc, num * sizeof *desc) &&
> > -              access_ok(avail,
> > -                        sizeof *avail + num * sizeof *avail->ring + s) &&
> > -              access_ok(used,
> > -                       sizeof *used + num * sizeof *used->ring + s);
> > +       return access_ok(desc, vhost_get_desc_size(vq, num)) &&
> > +              access_ok(avail, vhost_get_avail_size(vq, num)) &&
> > +              access_ok(used, vhost_get_used_size(vq, num));
> >   }
> >
> >   static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
> > @@ -1311,22 +1328,18 @@ static bool iotlb_access_ok(struct vhost_virtqueue *vq,
> >
> >   int vq_meta_prefetch(struct vhost_virtqueue *vq)
> >   {
> > -       size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> >          unsigned int num = vq->num;
> >
> >          if (!vq->iotlb)
> >                  return 1;
> >
> >          return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
> > -                              num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
> > +                              vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
> >                 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
> > -                              sizeof *vq->avail +
> > -                              num * sizeof(*vq->avail->ring) + s,
> > +                              vhost_get_avail_size(vq, num),
> >                                 VHOST_ADDR_AVAIL) &&
> >                 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
> > -                              sizeof *vq->used +
> > -                              num * sizeof(*vq->used->ring) + s,
> > -                              VHOST_ADDR_USED);
> > +                              vhost_get_used_size(vq, num), VHOST_ADDR_USED);
> >   }
> >   EXPORT_SYMBOL_GPL(vq_meta_prefetch);
> >
> > @@ -1343,13 +1356,10 @@ bool vhost_log_access_ok(struct vhost_dev *dev)
> >   static bool vq_log_access_ok(struct vhost_virtqueue *vq,
> >                               void __user *log_base)
> >   {
> > -       size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> > -
> >          return vq_memory_access_ok(log_base, vq->umem,
> >                                     vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
> >                  (!vq->log_used || log_access_ok(log_base, vq->log_addr,
> > -                                       sizeof *vq->used +
> > -                                       vq->num * sizeof *vq->used->ring + s));
> > +                                 vhost_get_used_size(vq, vq->num)));
> >   }
> >
> >   /* Can we start vq? */
> > --
> > 1.8.3.1