On 2017-01-17 10:59, Stefan Hajnoczi wrote: > On Mon, Jan 16, 2017 at 02:10:17PM +0100, Jan Kiszka wrote: >> On 2017-01-16 13:41, Marc-André Lureau wrote: >>> On Mon, Jan 16, 2017 at 12:37 PM Jan Kiszka <jan.kis...@siemens.com >>> <mailto:jan.kis...@siemens.com>> wrote: >>> So, this is our proposal. Would be great to hear some opinions if you >>> see value in adding support for such an "ivshmem 2.0" device to QEMU as >>> well and expand its ecosystem towards Linux upstream, maybe also DPDK >>> again. If you see problems in the new design /wrt what QEMU provides so >>> far with its ivshmem device, let's discuss how to resolve them. Looking >>> forward to any feedback! >>> >>> >>> My feeling is that ivshmem is not being actively developped in qemu, but >>> rather virtio-based solutions (vhost-pci for vm2vm). >> >> As pointed out, for us it's most important to keep the design simple - >> even at the price of "reinventing" some drivers for upstream (at least, >> we do not need two sets of drivers because our interface is fully >> symmetric). I don't see yet how vhost-pci could achieve the same, but >> I'm open to learn more! > > The concept of symmetry is nice but only applies for communications > channels like networking and serial. > > It doesn't apply for I/O that is fundamentally asymmetric like disk I/O. > > I just wanted to point this out because lack symmetry has also bothered > me about virtio but it's actually impossible to achieve it for all > device types.
That's true. Not sure what all is planned for vhost-pci. Our scope is limited (though mass storage proxying could be interesting at some point), plus there is the option to do X-over-network. Jan -- Siemens AG, Corporate Technology, CT RDA ITP SES-DE Corporate Competence Center Embedded Linux
