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[142.68.80.239]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-454fe0f54dasm62179621cf.52.2024.08.28.07.17.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Aug 2024 07:17:08 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1sjJTw-005592-5D; Wed, 28 Aug 2024 11:17:08 -0300 Date: Wed, 28 Aug 2024 11:17:08 -0300 From: Jason Gunthorpe To: Doug Miller Cc: Dennis Dalessandro , linux-remoteproc@vger.kernel.org, Bjorn Andersson , Mathieu Poirier , OFED mailing list Subject: Re: Using RPMSG to communicate between host and guest drivers Message-ID: <20240828141708.GQ3468552@ziepe.ca> References: <133c1301-dd19-4cce-82dc-3e8ee145c594@cornelisnetworks.com> <842aef7f-d6e1-490a-97b9-163287ddfe2d@cornelisnetworks.com> <20240826234530.GK3468552@ziepe.ca> <0f6e27d3-8942-492e-86e8-730c00a5aa37@cornelisnetworks.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0f6e27d3-8942-492e-86e8-730c00a5aa37@cornelisnetworks.com> On Wed, Aug 28, 2024 at 06:49:27AM -0500, Doug Miller wrote: > > Typically in cases like this you'd paravirtualize some of the VF > > before sticking it in the VM so that there is a tidy channel between > > the VF driver and the VMM to do whatever this coordination is. There > > are many examples, but it is hard to see if you don't know the device > > architectures in detail. > > Can you give more detail on how this paravirtualization is accomplished? > Or point to an example? Not sure I have easy examples, several devices I've seen proxy things through their FW/HW. I think some of the Intel NICs were working like this. Some have full vfio-mdevs or qemu modules to intercept registers and build it. > It seems to me that rpmsg would be a cleaner solution, at least > until I can see how paravirtualization is implemented for > comparison. I think you will find it very hard to connect such a thing up throughout all the peices of software. Having two related devices across everything is not easy. Jason