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

[Dragos Tatulea]

On 02/18, Eugenio Perez Martin wrote:
> 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
>
Will fix in v2.

> Sounds to me the logic can be merged in a helper?
>
Not sure if possible in a useful way: the logic in create_user_mr() is
different.

Also: this patch is kept small for stable tre.

> 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
> >
>