Paolo Bonzini
2015-Sep-18 21:11 UTC
RFC: virtio-peer shared memory based peer communication device
On 18/09/2015 18:29, Claudio Fontana wrote:> > this is a first RFC for virtio-peer 0.1, which is still very much a work in progress: > > https://github.com/hw-claudio/virtio-peer/wiki > > It is also available as PDF there, but the text is reproduced here for commenting: > > Peer shared memory communication device (virtio-peer)Apart from the windows idea, how does virtio-peer compare to virtio-rpmsg? Paolo
Jan Kiszka
2015-Sep-21 10:47 UTC
RFC: virtio-peer shared memory based peer communication device
On 2015-09-18 23:11, Paolo Bonzini wrote:> On 18/09/2015 18:29, Claudio Fontana wrote: >> >> this is a first RFC for virtio-peer 0.1, which is still very much a work in progress: >> >> https://github.com/hw-claudio/virtio-peer/wiki >> >> It is also available as PDF there, but the text is reproduced here for commenting: >> >> Peer shared memory communication device (virtio-peer) > > Apart from the windows idea, how does virtio-peer compare to virtio-rpmsg?rpmsg is a very specialized thing. It targets single AMP cores, assuming that those have full access to the main memory. And it is also a centralized approach where all message go through the main Linux instance. I suspect we could cover that use case as well with generic inter-vm shared memory device, but I didn't think about all details yet. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux
Paolo Bonzini
2015-Sep-21 12:15 UTC
RFC: virtio-peer shared memory based peer communication device
On 21/09/2015 12:47, Jan Kiszka wrote:>> > Apart from the windows idea, how does virtio-peer compare to virtio-rpmsg? > rpmsg is a very specialized thing. It targets single AMP cores, assuming > that those have full access to the main memory.Yes, this is why I did say "apart from the windows idea".> And it is also a > centralized approach where all message go through the main Linux > instance. I suspect we could cover that use case as well with generic > inter-vm shared memory device, but I didn't think about all details yet.The virtqueue handling seems very similar between the two. However, the messages for rpmsg however have a small header (struct rpmsg_hdr in include/linux/rpmsg.h) and there is a weird feature bit VIRTIO_RPMSG_F_NS. So I guess virtio-rpmsg and virtio-peer are about as similar as virtio-serial and virtio-peer. Paolo
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- RFC: virtio-peer shared memory based peer communication device
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