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[142.162.113.180]) by smtp.gmail.com with ESMTPSA id t65sm617238qkh.99.2019.11.20.17.38.17 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 20 Nov 2019 17:38:17 -0800 (PST) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iXbQH-0000cf-5H; Wed, 20 Nov 2019 21:38:17 -0400 Date: Wed, 20 Nov 2019 21:38:17 -0400 From: Jason Gunthorpe To: "Michael S. Tsirkin" Cc: Jason Wang , Parav Pandit , Jeff Kirsher , "davem@davemloft.net" , "gregkh@linuxfoundation.org" , Dave Ertman , "netdev@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "nhorman@redhat.com" , "sassmann@redhat.com" , Kiran Patil , Alex Williamson , "Bie, Tiwei" Subject: Re: [net-next v2 1/1] virtual-bus: Implementation of Virtual Bus Message-ID: <20191121013817.GA16914@ziepe.ca> References: <20191119231023.GN4991@ziepe.ca> <20191119191053-mutt-send-email-mst@kernel.org> <20191120014653.GR4991@ziepe.ca> <20191120022141-mutt-send-email-mst@kernel.org> <20191120130319.GA22515@ziepe.ca> <20191120083908-mutt-send-email-mst@kernel.org> <20191120143054.GF22515@ziepe.ca> <20191120093607-mutt-send-email-mst@kernel.org> <20191120164525.GH22515@ziepe.ca> <20191120165748-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191120165748-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Nov 20, 2019 at 05:05:00PM -0500, Michael S. Tsirkin wrote: > On Wed, Nov 20, 2019 at 12:45:25PM -0400, Jason Gunthorpe wrote: > > > > For instance, this VFIO based approach might be very suitable to the > > > > intel VF based ICF driver, but we don't yet have an example of non-VF > > > > HW that might not be well suited to VFIO. > > > > > > I don't think we should keep moving the goalposts like this. > > > > It is ABI, it should be done as best we can as we have to live with it > > for a long time. Right now HW is just starting to come to market with > > VDPA and it feels rushed to design a whole subsystem style ABI around > > one, quite simplistic, driver example. > > Well one has to enable hardware in some way. It's not really reasonable > to ask for multiple devices to be available just so there's a driver and > people can use them. Er, this has actually been a fairly standard ask for new subsystems. I think virtio is well grounded here compared to other things I've seen, but it should still be done with a lot more NIC community involvement. > At this rate no one will want to be the first to ship new devices ;) Why? > > > If people write drivers and find some infrastruture useful, > > > and it looks more or less generic on the outset, then I don't > > > see why it's a bad idea to merge it. > > > > Because it is userspace ABI, caution is always justified when defining > > new ABI. > > Reasonable caution, sure. Asking Alex to block Intel's driver until > someone else catches up and ships competing hardware isn't reasonable > though. If that's your proposal I guess we'll have to agree to disagree. Vendors may be willing to participate, as Mellanox is doing, pre-product. Jason