virtio-dev message

Subject: Re: RFC: virtio-peer shared memory based peer communication device

From: Paolo Bonzini <pbonzini@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>, Claudio Fontana <claudio.fontana@huawei.com>, "Zhang, Yang Z" <yang.z.zhang@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, "virtio-dev@lists.oasis-open.org" <virtio-dev@lists.oasis-open.org>, "opnfv-tech-discuss@lists.opnfv.org" <opnfv-tech-discuss@lists.opnfv.org>
Date: Mon, 21 Sep 2015 14:15:41 +0200

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