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Date:   Tue, 17 Jan 2023 16:34:17 +0200
From:   Leon Romanovsky <leon@kernel.org>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     Israel Rukshin <israelr@nvidia.com>,
        Bryan Tan <bryantan@vmware.com>,
        Christoph Hellwig <hch@lst.de>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>, Jens Axboe <axboe@fb.com>,
        Keith Busch <kbusch@kernel.org>, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Max Gurtovoy <mgurtovoy@nvidia.com>, netdev@vger.kernel.org,
        Paolo Abeni <pabeni@redhat.com>,
        Saeed Mahameed <saeedm@nvidia.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Selvin Xavier <selvin.xavier@broadcom.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vishnu Dasa <vdasa@vmware.com>,
        Yishai Hadas <yishaih@nvidia.com>
Subject: Re: [PATCH rdma-next 03/13] RDMA: Split kernel-only create QP flags
 from uverbs create QP flags
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On Tue, Jan 17, 2023 at 10:21:18AM -0400, Jason Gunthorpe wrote:
> On Tue, Jan 17, 2023 at 04:14:22PM +0200, Leon Romanovsky wrote:
> > On Tue, Jan 17, 2023 at 09:49:28AM -0400, Jason Gunthorpe wrote:
> > > On Tue, Jan 17, 2023 at 02:03:07PM +0200, Leon Romanovsky wrote:
> > > > On Mon, Jan 16, 2023 at 01:39:38PM -0400, Jason Gunthorpe wrote:
> > > > > On Mon, Jan 16, 2023 at 03:05:50PM +0200, Leon Romanovsky wrote:
> > > > > 
> > > > > > diff --git a/drivers/infiniband/hw/mlx4/mlx4_ib.h b/drivers/infiniband/hw/mlx4/mlx4_ib.h
> > > > > > index 17fee1e73a45..c553bf0eb257 100644
> > > > > > --- a/drivers/infiniband/hw/mlx4/mlx4_ib.h
> > > > > > +++ b/drivers/infiniband/hw/mlx4/mlx4_ib.h
> > > > > > @@ -184,7 +184,7 @@ enum mlx4_ib_qp_flags {
> > > > > >  	/* Mellanox specific flags start from IB_QP_CREATE_RESERVED_START */
> > > > > >  	MLX4_IB_ROCE_V2_GSI_QP = MLX4_IB_QP_CREATE_ROCE_V2_GSI,
> > > > > >  	MLX4_IB_SRIOV_TUNNEL_QP = 1 << 30,
> > > > > > -	MLX4_IB_SRIOV_SQP = 1 << 31,
> > > > > > +	MLX4_IB_SRIOV_SQP = 1ULL << 31,
> > > > > >  };
> > > > > 
> > > > > These should be moved to a uapi if we are saying they are userspace
> > > > > available
> > > > > 
> > > > > But I'm not sure they are?
> > > > 
> > > > I don't think so.
> > > 
> > > Then they should be > 32 bits right?
> > 
> > Right now, they are in reserved range:
> >         /* reserve bits 26-31 for low level drivers' internal use */
> >         IB_QP_CREATE_RESERVED_START             = 1 << 26,
> >         IB_QP_CREATE_RESERVED_END               = 1ULL << 31,
> > 
> > If we move them to kernel part, we will need to define reserved range
> > there too. So we just "burn" extra bits just for mlx4, also I don't see
> > any reason to promote mlx4 bits to be general ones.
> 
> Is the reserved range kernel only? It would be nice to clarify that
> detail
> 
> If yes we should move it so that userspace cannot set it. Do we have a
> bug here already?

No, we always checked that users can't provide these bits and fail create QP.

It means that we can safely move that range too.

Thanks

> 
> Jason