Re: [PATCH 1/2] vdpa/mlx5: Fix umem sizes assignments on VQ create

[Michael S. Tsirkin]

On Sun, May 30, 2021 at 11:15:36AM +0300, Eli Cohen wrote:
> On Sun, May 30, 2021 at 04:05:16AM -0400, Michael S. Tsirkin wrote:
> > On Sun, May 30, 2021 at 09:31:28AM +0300, Eli Cohen wrote:
> > > Fix copy paste bug assigning umem1 size to umem2 and umem3.
> > > 
> > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> > > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> > 
> > could you clarify the impact of the bug please?
> > 
> 
> I leads to firmware failure to create the virtqueue resource when you
> try to use a 1:1 mapping MR. This kind of usage is presented in the
> virtio_vdpa support I sent earlier.

OK pls include this info in the commit log. And is 1:1 the only case where
sizes differ? Is it true that in other cases sizes are all the same?

> > > ---
> > >  drivers/vdpa/mlx5/net/mlx5_vnet.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > index 189e4385df40..53312f0460ad 100644
> > > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > > @@ -828,9 +828,9 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
> > >  	MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
> > >  	MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
> > >  	MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
> > > -	MLX5_SET(virtio_q, vq_ctx, umem_2_size, mvq->umem1.size);
> > > +	MLX5_SET(virtio_q, vq_ctx, umem_2_size, mvq->umem2.size);
> > >  	MLX5_SET(virtio_q, vq_ctx, umem_3_id, mvq->umem3.id);
> > > -	MLX5_SET(virtio_q, vq_ctx, umem_3_size, mvq->umem1.size);
> > > +	MLX5_SET(virtio_q, vq_ctx, umem_3_size, mvq->umem3.size);
> > >  	MLX5_SET(virtio_q, vq_ctx, pd, ndev->mvdev.res.pdn);
> > >  	if (MLX5_CAP_DEV_VDPA_EMULATION(ndev->mvdev.mdev, eth_frame_offload_type))
> > >  		MLX5_SET(virtio_q, vq_ctx, virtio_version_1_0, 1);
> > > -- 
> > > 2.31.1
> >