RE: [RFC 1/3] vdpa/mlx5: reset iotlb at dup_iotlb

[Eli Cohen]

> From: Eugenio Pérez <eperezma@xxxxxxxxxx>
> Sent: Thursday, 12 January 2023 16:22
> To: mst@xxxxxxxxxx; Eli Cohen <elic@xxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; Parav Pandit <parav@xxxxxxxxxx>;
> lulu@xxxxxxxxxx; jasowang@xxxxxxxxxx; virtualization@lists.linux-
> foundation.org; sgarzare@xxxxxxxxxx; si-wei.liu@xxxxxxxxxx
> Subject: [RFC 1/3] vdpa/mlx5: reset iotlb at dup_iotlb
> 
> Regular memory region changes already reset cvq iotlb at set_map.
> However this is not true if CVQ and data VQs are in different ASID.
> 
> Clean the CVQ iotlb every time we hit dup_iotlb.
> 
> Fixes: 8fcd20c30704 ("vdpa/mlx5: Support different address spaces for
> control and data")
> Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> ---
>  drivers/vdpa/mlx5/core/mr.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 0a1e0b0dc37e..ae34dcac9a3f 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -456,6 +456,8 @@ static int dup_iotlb(struct mlx5_vdpa_dev *mvdev,
> struct vhost_iotlb *src)
>  	u64 start = 0, last = ULLONG_MAX;
>  	int err;
> 
> +	vhost_iotlb_reset(mvdev->cvq.iotlb);
> +

As far as I can see, mlx5_vdpa_destroy_mr() is called independently of the asid
and it will calls prune_iotlb() which resets the cvq iotlb. Am I missing something?

>  	if (!src) {
>  		err = vhost_iotlb_add_range(mvdev->cvq.iotlb, start, last,
> start, VHOST_ACCESS_RW);
>  		return err;
> --
> 2.31.1