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 Jason Wang
> Sent: Tuesday, October 31, 2023 7:07 AM
> 
> On Mon, Oct 30, 2023 at 12:28âPM Parav Pandit <parav@nvidia.com> wrote:
> >
> >
> > > From: Jason Wang <jasowang@redhat.com>
> > > Sent: Monday, October 30, 2023 9:35 AM
> > >
> > > å 2023/10/26 11:50, Parav Pandit åé:
> > > >> From: virtio-comment@lists.oasis-open.org
> > > >> <virtio-comment@lists.oasis- open.org> On Behalf Of Jason Wang
> > > >> For example, you still haven't succeeded in defining passthrough.
> > > > It was defined on 19th Oct in [1].
> > > > What part is not clear to you in definition of passthrough device?
> > > >
> > > > [1]
> > > > https://lore.kernel.org/virtio-
> > > comment/PH0PR12MB5481EA6A4D0C64C5AF6D3A
> > > > 57DCD4A@PH0PR12MB5481.namprd12.prod.outlook.com/
> > >
> > >
> > > Let me copy-paste it again:
> > >
> > > For example, assuming you are correct, you still fail to explain
> > >
> > > 1) what is trapped and what's not, or what's the boundary
> > Passthrough definition was replied few times.
> > One of them is here,
> > https://lore.kernel.org/virtio-
> comment/PH0PR12MB5481EA6A4D0C64C5AF6D3A
> > 57DCD4A@PH0PR12MB5481.namprd12.prod.outlook.com/
> > I donât know what you mean by 'explain'. What do you want to be explained?
> > What is trapped is listed in
> > https://lore.kernel.org/virtio-
> comment/PH0PR12MB5481EA6A4D0C64C5AF6D3A
> > 57DCD4A@PH0PR12MB5481.namprd12.prod.outlook.com/
> > What is not trapped is also listed in
> > https://lore.kernel.org/virtio-
> comment/PH0PR12MB5481EA6A4D0C64C5AF6D3A
> > 57DCD4A@PH0PR12MB5481.namprd12.prod.outlook.com/
> > So what more do you want to explain in there?
> 
> You explained that MSI-X is trapped but not the others. People may know why.
> or what's the boundary to choose to trap or not.
> 
If a platform can support without trapping, it can be avoided as well and can be added in the future.

> >
> > > 2) if the hypervisor is not developed with those assumptions, things
> > > can work
> > What to explain in #2. :)
> > Things can expand when such hypervisor is born.
> 
> So the point is still, to make your proposal to be useful in more use cases.
>
When a use case arise, device context can be expanded.
No point in making things no one implements or not present in hypervisor.
The infrastructure is extendible so spec is covered for it.