Re: [PATCH v9 06/12] vdpa: request iova_range only once

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Dec 21, 2022 at 04:21:52PM +0800, Jason Wang wrote:
> On Fri, Dec 16, 2022 at 5:53 PM Eugenio Perez Martin
> <eperezma@redhat.com> wrote:
> >
> > On Fri, Dec 16, 2022 at 8:29 AM Jason Wang <jasowang@redhat.com> wrote:
> > >
> > > On Thu, Dec 15, 2022 at 7:32 PM Eugenio Pérez <eperezma@redhat.com> wrote:
> > > >
> > > > Currently iova range is requested once per queue pair in the case of
> > > > net. Reduce the number of ioctls asking it once at initialization and
> > > > reusing that value for each vhost_vdpa.
> > > >
> > > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > > > ---
> > > >  hw/virtio/vhost-vdpa.c | 15 ---------------
> > > >  net/vhost-vdpa.c       | 27 ++++++++++++++-------------
> > > >  2 files changed, 14 insertions(+), 28 deletions(-)
> > > >
> > > > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > > > index 691bcc811a..9b7f4ef083 100644
> > > > --- a/hw/virtio/vhost-vdpa.c
> > > > +++ b/hw/virtio/vhost-vdpa.c
> > > > @@ -365,19 +365,6 @@ static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
> > > >      return 0;
> > > >  }
> > > >
> > > > -static void vhost_vdpa_get_iova_range(struct vhost_vdpa *v)
> > > > -{
> > > > -    int ret = vhost_vdpa_call(v->dev, VHOST_VDPA_GET_IOVA_RANGE,
> > > > -                              &v->iova_range);
> > > > -    if (ret != 0) {
> > > > -        v->iova_range.first = 0;
> > > > -        v->iova_range.last = UINT64_MAX;
> > > > -    }
> > > > -
> > > > -    trace_vhost_vdpa_get_iova_range(v->dev, v->iova_range.first,
> > > > -                                    v->iova_range.last);
> > > > -}
> > > > -
> > > >  /*
> > > >   * The use of this function is for requests that only need to be
> > > >   * applied once. Typically such request occurs at the beginning
> > > > @@ -465,8 +452,6 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
> > > >          goto err;
> > > >      }
> > > >
> > > > -    vhost_vdpa_get_iova_range(v);
> > > > -
> > > >      if (!vhost_vdpa_first_dev(dev)) {
> > > >          return 0;
> > > >      }
> > > > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> > > > index 2c0ff6d7b0..b6462f0192 100644
> > > > --- a/net/vhost-vdpa.c
> > > > +++ b/net/vhost-vdpa.c
> > > > @@ -541,14 +541,15 @@ static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
> > > >  };
> > > >
> > > >  static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
> > > > -                                           const char *device,
> > > > -                                           const char *name,
> > > > -                                           int vdpa_device_fd,
> > > > -                                           int queue_pair_index,
> > > > -                                           int nvqs,
> > > > -                                           bool is_datapath,
> > > > -                                           bool svq,
> > > > -                                           VhostIOVATree *iova_tree)
> > > > +                                       const char *device,
> > > > +                                       const char *name,
> > > > +                                       int vdpa_device_fd,
> > > > +                                       int queue_pair_index,
> > > > +                                       int nvqs,
> > > > +                                       bool is_datapath,
> > > > +                                       bool svq,
> > > > +                                       struct vhost_vdpa_iova_range iova_range,
> > > > +                                       VhostIOVATree *iova_tree)
> > >
> > > Nit: it's better not mix style changes.
> > >
> >
> > The style changes are because the new parameter is longer than 80
> > characters, do you prefer me to send a previous patch reducing
> > indentation?
> >
> 
> Michale, what's your preference? I'm fine with both.
> 
> Thanks

I think it doesn't matter much, but generally 80 char limit is
not a hard limit. We can just let it be.

> > Thanks!
> >
> > > Other than this:
> > >
> > > Acked-by: Jason Wang <jasonwang@redhat.com>
> > >
> > > Thanks
> > >
> > > >  {
> > > >      NetClientState *nc = NULL;
> > > >      VhostVDPAState *s;
> > > > @@ -567,6 +568,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
> > > >      s->vhost_vdpa.device_fd = vdpa_device_fd;
> > > >      s->vhost_vdpa.index = queue_pair_index;
> > > >      s->vhost_vdpa.shadow_vqs_enabled = svq;
> > > > +    s->vhost_vdpa.iova_range = iova_range;
> > > >      s->vhost_vdpa.iova_tree = iova_tree;
> > > >      if (!is_datapath) {
> > > >          s->cvq_cmd_out_buffer = qemu_memalign(qemu_real_host_page_size(),
> > > > @@ -646,6 +648,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
> > > >      int vdpa_device_fd;
> > > >      g_autofree NetClientState **ncs = NULL;
> > > >      g_autoptr(VhostIOVATree) iova_tree = NULL;
> > > > +    struct vhost_vdpa_iova_range iova_range;
> > > >      NetClientState *nc;
> > > >      int queue_pairs, r, i = 0, has_cvq = 0;
> > > >
> > > > @@ -689,14 +692,12 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
> > > >          return queue_pairs;
> > > >      }
> > > >
> > > > +    vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
> > > >      if (opts->x_svq) {
> > > > -        struct vhost_vdpa_iova_range iova_range;
> > > > -
> > > >          if (!vhost_vdpa_net_valid_svq_features(features, errp)) {
> > > >              goto err_svq;
> > > >          }
> > > >
> > > > -        vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
> > > >          iova_tree = vhost_iova_tree_new(iova_range.first, iova_range.last);
> > > >      }
> > > >
> > > > @@ -705,7 +706,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
> > > >      for (i = 0; i < queue_pairs; i++) {
> > > >          ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
> > > >                                       vdpa_device_fd, i, 2, true, opts->x_svq,
> > > > -                                     iova_tree);
> > > > +                                     iova_range, iova_tree);
> > > >          if (!ncs[i])
> > > >              goto err;
> > > >      }
> > > > @@ -713,7 +714,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
> > > >      if (has_cvq) {
> > > >          nc = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
> > > >                                   vdpa_device_fd, i, 1, false,
> > > > -                                 opts->x_svq, iova_tree);
> > > > +                                 opts->x_svq, iova_range, iova_tree);
> > > >          if (!nc)
> > > >              goto err;
> > > >      }
> > > > --
> > > > 2.31.1
> > > >
> > >
> >