RE: [virtio-comment] Re: [PATCH v1 3/8] device-context: Define the device context fields for device migration

[Parav Pandit <parav@nvidia.com>]

> From: virtio-comment@lists.oasis-open.org <virtio-comment@lists.oasis-
> open.org> On Behalf Of Michael S. Tsirkin
> Sent: Monday, October 30, 2023 4:58 PM
> 
> On Thu, Oct 26, 2023 at 07:04:38AM +0000, Parav Pandit wrote:
> > 1. It breaks the future TDISP model
> 
> I really think brinding in TDISP muddies the waters a lot and should be avoided.
> We simply won't know until someone does the legwork and proposed the
> necessary spec extensions.
> In particular current legacy access commands are I thn
> 
> 
> > 2. Without hypervisor getting involved, all the member device MMIO
> > space is accessible which follows the efficiency and equivalency
> > principle of Jason listed paper
> >
> > I hope you are not implying to trap+emulate virtio interfaces (which is not
> listed in the pci-spec) in hypervisor for member passthrough devices.
> 
> I feel this discussion will keep meandering because the terminology is vague.
> There's no single thing that is called "passthrough" - vendors just build what is
> expedient with current hardware and software. Nvidia has a bunch of people
> working on vfio so they call that passthrough, Red Hat has people working on
> VDPA and they call that passthrough, etc.
> 
> 
> Before I mute this discussion for good, does anyone here have any feeling
> progress is made? What kind of progress?

I received valuable comments from you and some from Jason, and some were offline.
I will post v3 that fits the current OS use case for vfio and vdpa using the current admin command infrastructure.