On Wed, Jan 12, 2022 at 6:15 AM Si-Wei Liu <si-wei.liu@xxxxxxxxxx> wrote:
>
>
>
> On 1/11/2022 10:34 AM, Eli Cohen wrote:
> > Modify the code such that ndev->cur_num_vqs better reflects the actual
> > number of data virtqueues. The value can be accurately realized after
> > features have been negotiated.
> >
> > This is to prevent possible failures when modifying the RQT object if
> > the cur_num_vqs bears invalid value.
> >
> > No issue was actually encountered but this also makes the code more
> > readable.
> >
> > Fixes: c5a5cd3d3217 ("vdpa/mlx5: Support configuring max data virtqueue")
> > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> > ---
> > drivers/vdpa/mlx5/net/mlx5_vnet.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > index 9eacfdb48434..b53603d94082 100644
> > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > @@ -1246,8 +1246,7 @@ static int create_rqt(struct mlx5_vdpa_net *ndev)
> > if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_MQ)))
> > num = 1;
> > else
> > - num = mlx5vdpa16_to_cpu(&ndev->mvdev,
> > - ndev->config.max_virtqueue_pairs);
> > + num = ndev->cur_num_vqs / 2;
> Nit: the if branch can be consolidated
>
> >
> > max_rqt = min_t(int, roundup_pow_of_two(num),
> > 1 << MLX5_CAP_GEN(ndev->mvdev.mdev, log_max_rqt_size));
> > @@ -1983,6 +1982,11 @@ static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
> > return err;
> >
> > ndev->mvdev.actual_features = features & ndev->mvdev.mlx_features;
> > + if (ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_MQ))
> > + ndev->cur_num_vqs = 2 * mlx5vdpa16_to_cpu(mvdev, ndev->config.max_virtqueue_pairs);
> Hmmm, not this patch, but there should've been validation done in the
> upper layer to guarantee set_featuers() for VIRTIO_NET_F_MQ always comes
> with VIRTIO_NET_F_CTRL_VQ. Maybe checking both: BIT_ULL(VIRTIO_NET_F_MQ)
> | BIT_ULL(VIRTIO_NET_F_CTRL_VQ)?
So the upper layer is unaware of the device type. It's better to do
that in mlx5's set_features() according to the spec:
The device MUST NOT offer a feature which requires another feature
which was not offered.
Thanks
>
> otherwise it looks good to me.
>
> Reviewed-by: Si-Wei Liu<si-wei.liu@xxxxxxxxxx>
> > + else
> > + ndev->cur_num_vqs = 2;
> > +
> > update_cvq_info(mvdev);
> > return err;
> > }
> > @@ -2233,6 +2237,7 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
> > clear_vqs_ready(ndev);
> > mlx5_vdpa_destroy_mr(&ndev->mvdev);
> > ndev->mvdev.status = 0;
> > + ndev->cur_num_vqs = 0;
> > memset(ndev->event_cbs, 0, sizeof(*ndev->event_cbs) * (mvdev->max_vqs + 1));
> > ndev->mvdev.actual_features = 0;
> > ++mvdev->generation;
> > @@ -2641,9 +2646,8 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
> >
> > ndev->nb.notifier_call = event_handler;
> > mlx5_notifier_register(mdev, &ndev->nb);
> > - ndev->cur_num_vqs = 2 * mlx5_vdpa_max_qps(max_vqs);
> > mvdev->vdev.mdev = &mgtdev->mgtdev;
> > - err = _vdpa_register_device(&mvdev->vdev, ndev->cur_num_vqs + 1);
> > + err = _vdpa_register_device(&mvdev->vdev, 2 * mlx5_vdpa_max_qps(max_vqs) + 1);
> > if (err)
> > goto err_reg;
> >
>
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