Re: [PATCH RFC 0/9] A rendezvous module

From: Christoph Hellwig <hch@infradead.org>
To: "Rimmer, Todd" <todd.rimmer@intel.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
	"Wan, Kaike" <kaike.wan@intel.com>,
	Jason Gunthorpe <jgg@nvidia.com>,
	"dledford@redhat.com" <dledford@redhat.com>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH RFC 0/9] A rendezvous module
Date: Tue, 23 Mar 2021 15:30:41 +0000	[thread overview]
Message-ID: <20210323153041.GA2434215@infradead.org> (raw)
In-Reply-To: <BL0PR11MB329976F1C41951957E2DBE79F6689@BL0PR11MB3299.namprd11.prod.outlook.com>

On Fri, Mar 19, 2021 at 10:57:20PM +0000, Rimmer, Todd wrote:
> We'd like advise on a challenging situation.  Some customers desire NICs to support nVidia GPUs in some environments.
> Unfortunately the nVidia GPU drivers are not upstream, and have not been for years.  So we are forced to have both out of tree
> and upstream versions of the code.  We need the same applications to be able to work over both, so we would like the
> GPU enabled versions of the code to have the same ABI as the upstream code as this greatly simplifies things.
> We have removed all GPU specific code from the upstream submission, but used both the "alignment holes" and the "reserved"
> mechanisms to hold places for GPU specific fields which can't be upstreamed.

NVIDIA GPUs are supported by drivers/gpu/drm/nouveau/, and your are
encourage to support them just like all the other in-tree GPU drivers.
Not sure what support a network protocol would need for a specific GPU.
You're probably trying to do something amazingly stupid here instead of
relying on proper kernel subsystem use.