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[87.10.72.39]) by smtp.gmail.com with ESMTPSA id ar2sm1973327ejc.20.2021.11.10.03.17.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Nov 2021 03:17:21 -0800 (PST) Date: Wed, 10 Nov 2021 12:17:18 +0100 From: Stefano Garzarella To: "Wang, Wei W" Cc: "davem@davemloft.net" , "kuba@kernel.org" , Stefan Hajnoczi , "mst@redhat.com" , Paolo Bonzini , "kys@microsoft.com" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "Yamahata, Isaku" , "Nakajima, Jun" , "Kleen, Andi" , Andra Paraschiv , Sergio Lopez Pascual Subject: Re: [RFC] hypercall-vsock: add a new vsock transport Message-ID: <20211110111718.5cvt6vgory3fzqld@steredhat> References: <71d7b0463629471e9d4887d7fcef1d8d@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <71d7b0463629471e9d4887d7fcef1d8d@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 10, 2021 at 07:12:36AM +0000, Wang, Wei W wrote: >Hi, > >We plan to add a new vsock transport based on hypercall (e.g. vmcall on Intel CPUs). >It transports AF_VSOCK packets between the guest and host, which is similar to >virtio-vsock, vmci-vsock and hyperv-vsock. > >Compared to the above listed vsock transports which are designed for high performance, >the main advantages of hypercall-vsock are: > >1) It is VMM agnostic. For example, one guest working on hypercall-vsock can run on > >either KVM, Hyperv, or VMware. > >2) It is simpler. It doesn't rely on any complex bus enumeration > >(e.g. virtio-pci based vsock device may need the whole implementation of PCI). > >An example usage is the communication between MigTD and host (Page 8 at >https://static.sched.com/hosted_files/kvmforum2021/ef/TDX%20Live%20Migration_Wei%20Wang.pdf). >MigTD communicates to host to assist the migration of the target (user) >TD. >MigTD is part of the TCB, so its implementation is expected to be as simple as possible >(e.g. bare mental implementation without OS, no PCI driver support). Adding Andra and Sergio, because IIRC Firecracker and libkrun emulates virtio-vsock with virtio-mmio so the implementation should be simple and also not directly tied to a specific VMM. Maybe this fit for your use case too, in this way we don't have to maintain another driver. Thanks, Stefano