Re: [virtio-comment] RFC: virtio-hostmem (+ Continuation of discussion from [virtio-dev] Memory sharing device)

On Wed, Mar 06, 2019 at 12:28:30PM -0500, Michael S. Tsirkin wrote:
> On Wed, Mar 06, 2019 at 04:36:16PM +0000, Stefan Hajnoczi wrote:
> > > \section{Host Memory Device}\label{sec:Device Types / Host Memory Device}
> > 
> > The Host Memory Device defines an entirely new device model that bypasses
> > VIRTIO.  Why make this a VIRTIO device if the VIRTIO device model is not a good
> > fit for what you're trying to achieve?  This device seems out of scope to me.
> 
> It's different from virtio pci.
> But this looks a bit like a special transport to me.
> I'll look at it more next week sometime.

It resembles ivshmem.

Frank: ivshmem is an existing (non-VIRTIO) PCI device that offers
similar functionality to what you're proposing.  It was not actively
maintained over the years and is not widely used, but you can look at
QEMU's docs/specs/ivshmem-spec.txt and hw/misc/ivshmem.c.

Stefan