Re: [PATCH rdma-core 1/2] mlx5: Use non-cached mapping when Blueflame is not used

Jason Gunthorpe
2017-10-30T16:38:13Z

On Mon, Oct 30, 2017 at 06:31:12PM +0200, Yishai Hadas wrote:
> On 10/30/2017 4:57 PM, Jason Gunthorpe wrote:
> >On Sun, Oct 29, 2017 at 11:26:04PM +0200, Yishai Hadas wrote:
> >>>>@@ -632,6 +632,11 @@ enum mlx5dv_set_ctx_attr_type {
> >>>> MLX5DV_CTX_ATTR_BUF_ALLOCATORS = 1,
> >>>> };
> >>>>+enum {
> >>>>+ MLX5_MMAP_GET_REGULAR_PAGES_CMD = 0,
> >>>>+ MLX5_MMAP_GET_NC_PAGES_CMD = 3,
> >>>>+};
> >>>>+
> >>>
> >>>These are added to a public header, but I couldn't see where they
> >>>would get used by a DV user??
> >>
> >>A DV user already had access to the mlx5 mmap command before this series by
> >>using the mlx5dv_get_qp() API:
> >>qp_out->uar_mmap_offset = mqp->bf->uar_mmap_offset;
> >
> >Okay.
> >
> >As long as existing users can reasonably be expected to handle this
> >new value in the uar_mmap_offset output field...
> >
>
> Yes, we expect existing users to work properly.
>
> This output field was exposed by the DV API to enable re-mmap of the UAR
> address by a secondary process by using the same 'uar_mmap_offset'
> regardless its internal command value.

Ah, I see.. Seems OK then.

The values kernel side in drivers/infiniband/hw/mlx5/mlx5_ib.h related
to this need to be moved to a uapi header :|

Jason