Re: [virtio-dev] Backend libraries for VirtIO device emulation

[Srivatsa Vaddagiri <vatsa.ml@gmail.com>]

On Mon, Mar 9, 2020 at 9:16 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> That already exists today.  Pick a vhost-user device implementation from
> QEMU, DPDK/SPDK, or rust-vmm and run it with your VMM of choice.
>
> > backend be emulated purely with some shared memory and some sockets for
> > passing messages/kicks from/to the VMM which then deals with the hypervisor
> > specifics of the virtio-transport?
>
> Yes, that is what vhost-user does.

Are there vhost-user based backends that emulates block and console devices?

From my quick read, vhost-user seems to depend on having backend complete access
to front-end's memory. Is that true? We are looking for a backend solution that
does not assume access to whole of front-end memory. Only the memory regions
hosting IO buffers need to be ideally shared between the two VMs. Also the
mechanism of memory sharing and signalling between VMs could be very
hypervisor specific.
Does vhost-user allow for such hyp-specific memory sharing and
signalling interfaces?

- vatsa