Re: [PATCH vhost] vdpa/mlx5: Fix oversized null mkey longer than 32bit

[Eugenio Perez Martin]

On Mon, Feb 17, 2025 at 8:45 PM Dragos Tatulea <dtatulea@xxxxxxxxxx> wrote:
>
> From: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
>
> create_user_mr() has correct code to count the number of null keys
> used to fill in a hole for the memory map. However, fill_indir()
> does not follow the same to cap the range up to the 1GB limit
> correspondinly.

s/correspondinly/correspondingly/g

Sounds to me the logic can be merged in a helper?

Either way,

Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>

Thanks!

> Fill in more null keys for the gaps in between,
> so that null keys are correctly populated.
>
> Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> ---
>  drivers/vdpa/mlx5/core/mr.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 8455f08f5d40..61424342c096 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -190,9 +190,12 @@ static void fill_indir(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mkey, v
>                         klm->bcount = cpu_to_be32(klm_bcount(dmr->end - dmr->start));
>                         preve = dmr->end;
>                 } else {
> +                       u64 bcount = min_t(u64, dmr->start - preve, MAX_KLM_SIZE);
> +
>                         klm->key = cpu_to_be32(mvdev->res.null_mkey);
> -                       klm->bcount = cpu_to_be32(klm_bcount(dmr->start - preve));
> -                       preve = dmr->start;
> +                       klm->bcount = cpu_to_be32(klm_bcount(bcount));
> +                       preve += bcount;
> +
>                         goto again;
>                 }
>         }
> --
> 2.43.0
>