Re: [PATCH V3] vdpa/mlx5: preserve CVQ vringh index

Steven Sistare
2023-12-04T13:33:50Z

What's the decision here, pull it, or do not fix it?

- Steve

On 11/3/2023 8:26 AM, Steve Sistare wrote:
> mlx5_vdpa does not preserve userland's view of vring base for the control
> queue in the following sequence:
>
> ioctl VHOST_SET_VRING_BASE
> ioctl VHOST_VDPA_SET_STATUS VIRTIO_CONFIG_S_DRIVER_OK
> mlx5_vdpa_set_status()
> setup_cvq_vring()
> vringh_init_iotlb()
> vringh_init_kern()
> vrh->last_avail_idx = 0;
> ioctl VHOST_GET_VRING_BASE
>
> To fix, restore the value of cvq->vring.last_avail_idx after calling
> vringh_init_iotlb.
>
> Fixes: 5262912ef3cf ("vdpa/mlx5: Add support for control VQ and MAC setting")
>
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> Acked-by: Eugenio Pérez <eperezma@redhat.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> ---
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 946488b8989f..ca972af3c89a 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2795,13 +2795,18 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
> struct mlx5_control_vq *cvq = &mvdev->cvq;
> int err = 0;
>
> - if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
> + if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)) {
> + u16 idx = cvq->vring.last_avail_idx;
> +
> err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
> MLX5_CVQ_MAX_ENT, false,
> (struct vring_desc *)(uintptr_t)cvq->desc_addr,
> (struct vring_avail *)(uintptr_t)cvq->driver_addr,
> (struct vring_used *)(uintptr_t)cvq->device_addr);
>
> + if (!err)
> + cvq->vring.last_avail_idx = cvq->vring.last_used_idx = idx;
> + }
> return err;
> }
>