Re: [PATCH RFC 2/4] vdpa/mlx5: implement .reset_map driver op

From: Dragos Tatulea
Date: Tue Aug 15 2023 - 04:27:04 EST


On Mon, 2023-08-14 at 18:43 -0700, Si-Wei Liu wrote:
> This patch is based on top of the "vdpa/mlx5: Fixes
> for ASID handling" series [1].
>
> [1] vdpa/mlx5: Fixes for ASID handling
> https://lore.kernel.org/virtualization/20230802171231.11001-1-dtatulea@xxxxxxxxxx/
>
> Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> ---
>  drivers/vdpa/mlx5/core/mlx5_vdpa.h |  1 +
>  drivers/vdpa/mlx5/core/mr.c        | 72 +++++++++++++++++++++----------------
> -
>  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 18 +++++++---
>  3 files changed, 54 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> index b53420e..5c9a25a 100644
> --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> @@ -123,6 +123,7 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> struct vhost_iotlb *iotlb,
>                         unsigned int asid);
>  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev);
>  void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev *mvdev, unsigned int
> asid);
> +int mlx5_vdpa_reset_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
>  
>  #define mlx5_vdpa_warn(__dev, format,
> ...)                                                         \
>         dev_warn((__dev)->mdev->device, "%s:%d:(pid %d) warning: " format,
> __func__, __LINE__,     \
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 5a1971fc..c8d64fc 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -489,21 +489,15 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev,
> struct mlx5_vdpa_mr *mr
>         }
>  }
>  
> -static void _mlx5_vdpa_destroy_cvq_mr(struct mlx5_vdpa_dev *mvdev, unsigned
> int asid)
> +static void _mlx5_vdpa_destroy_cvq_mr(struct mlx5_vdpa_dev *mvdev)
>  {
> -       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
> -               return;
> -
>         prune_iotlb(mvdev);
>  }
>  
> -static void _mlx5_vdpa_destroy_dvq_mr(struct mlx5_vdpa_dev *mvdev, unsigned
> int asid)
> +static void _mlx5_vdpa_destroy_dvq_mr(struct mlx5_vdpa_dev *mvdev)
>  {
>         struct mlx5_vdpa_mr *mr = &mvdev->mr;
>  
> -       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
> -               return;
> -
>         if (!mr->initialized)
>                 return;
>  
> @@ -521,8 +515,10 @@ void mlx5_vdpa_destroy_mr_asid(struct mlx5_vdpa_dev
> *mvdev, unsigned int asid)
>  
>         mutex_lock(&mr->mkey_mtx);
>  
> -       _mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
> -       _mlx5_vdpa_destroy_cvq_mr(mvdev, asid);
> +       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid)
> +               _mlx5_vdpa_destroy_dvq_mr(mvdev);
> +       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid)
> +               _mlx5_vdpa_destroy_cvq_mr(mvdev);
>  
>         mutex_unlock(&mr->mkey_mtx);
>  }
> @@ -534,25 +530,17 @@ void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev)
>  }
>  
>  static int _mlx5_vdpa_create_cvq_mr(struct mlx5_vdpa_dev *mvdev,
> -                                   struct vhost_iotlb *iotlb,
> -                                   unsigned int asid)
> +                                   struct vhost_iotlb *iotlb)
>  {
> -       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] != asid)
> -               return 0;
> -
>         return dup_iotlb(mvdev, iotlb);
>  }
>  
>  static int _mlx5_vdpa_create_dvq_mr(struct mlx5_vdpa_dev *mvdev,
> -                                   struct vhost_iotlb *iotlb,
> -                                   unsigned int asid)
> +                                   struct vhost_iotlb *iotlb)
>  {
>         struct mlx5_vdpa_mr *mr = &mvdev->mr;
>         int err;
>  
> -       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] != asid)
> -               return 0;
> -
>         if (mr->initialized)
>                 return 0;
>  
> @@ -574,20 +562,18 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev
> *mvdev,
>  {
>         int err;
>  
> -       err = _mlx5_vdpa_create_dvq_mr(mvdev, iotlb, asid);
> -       if (err)
> -               return err;
> -
> -       err = _mlx5_vdpa_create_cvq_mr(mvdev, iotlb, asid);
> -       if (err)
> -               goto out_err;
> +       if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) {
> +               err = _mlx5_vdpa_create_dvq_mr(mvdev, iotlb, asid);
> +               if (err)
> +                       return err;
> +       }
> +       if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid) {
> +               err = _mlx5_vdpa_create_cvq_mr(mvdev, iotlb);
> +               if (err)
> +                       return err;
I think you still need the goto here, when CVQ and DVQ fall in same asid and
there's a CVQ mr creation error, you are left stuck with the DVQ mr.

> +       }
>  
>         return 0;
> -
> -out_err:
> -       _mlx5_vdpa_destroy_dvq_mr(mvdev, asid);
> -
> -       return err;
>  }
>  
>  int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> *iotlb,
> @@ -601,6 +587,28 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> struct vhost_iotlb *iotlb,
>         return err;
>  }
>  
> +int mlx5_vdpa_reset_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid)
> +{
> +       struct mlx5_vdpa_mr *mr = &mvdev->mr;
> +       int err = 0;
> +
> +       if (asid != 0)
> +               return 0;
> +
> +       mutex_lock(&mr->mkey_mtx);
> +       if (!mr->user_mr)
> +               goto out;
> +       _mlx5_vdpa_destroy_dvq_mr(mvdev);
> +       if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
> +               err = _mlx5_vdpa_create_dvq_mr(mvdev, NULL, 0);
> +               if (err)
> +                       mlx5_vdpa_warn(mvdev, "create DMA MR failed\n");
> +       }
> +out:
> +       mutex_unlock(&mr->mkey_mtx);
> +       return err;
> +}
> +
>  int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb
> *iotlb,
>                              bool *change_map, unsigned int asid)
>  {
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 61c10ba..399a690 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2816,7 +2816,6 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
>         unregister_link_notifier(ndev);
>         teardown_driver(ndev);
>         clear_vqs_ready(ndev);
> -       mlx5_vdpa_destroy_mr(&ndev->mvdev);
>         ndev->mvdev.status = 0;
>         ndev->mvdev.suspended = false;
>         ndev->cur_num_vqs = 0;
> @@ -2827,10 +2826,6 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
>         init_group_to_asid_map(mvdev);
>         ++mvdev->generation;
>  
> -       if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
> -               if (mlx5_vdpa_create_mr(mvdev, NULL, 0))
> -                       mlx5_vdpa_warn(mvdev, "create MR failed\n");
> -       }
>         up_write(&ndev->reslock);
>  
>         return 0;
> @@ -2895,6 +2890,18 @@ static int mlx5_vdpa_set_map(struct vdpa_device *vdev,
> unsigned int asid,
>         return err;
>  }
>  
> +static int mlx5_vdpa_reset_map(struct vdpa_device *vdev, unsigned int asid)
> +{
> +       struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> +       struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> +       int err;
> +
> +       down_write(&ndev->reslock);
> +       err = mlx5_vdpa_reset_mr(mvdev, asid);
> +       up_write(&ndev->reslock);
> +       return err;
> +}
> +
>  static struct device *mlx5_get_vq_dma_dev(struct vdpa_device *vdev, u16 idx)
>  {
>         struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> @@ -3154,6 +3161,7 @@ static int mlx5_set_group_asid(struct vdpa_device *vdev,
> u32 group,
>         .set_config = mlx5_vdpa_set_config,
>         .get_generation = mlx5_vdpa_get_generation,
>         .set_map = mlx5_vdpa_set_map,
> +       .reset_map = mlx5_vdpa_reset_map,
>         .set_group_asid = mlx5_set_group_asid,
>         .get_vq_dma_dev = mlx5_get_vq_dma_dev,
>         .free = mlx5_vdpa_free,