Nouveau - Sep 2024 - [RFC 00/29] Introduce NVIDIA GPU Virtualization (vGPU) Support

On Mon, Sep 23, 2024 at 10:49:07AM +0200, Danilo Krummrich
wrote:
> > 2. Proposal for upstream
> > =======================> 
> What is the strategy in the mid / long term with this?
> 
> As you know, we're trying to move to Nova and the blockers with the
device /
> driver infrastructure have been resolved and we're able to move
forward. Besides
> that, Dave made great progress on the firmware abstraction side of things.
> 
> Is this more of a proof of concept? Do you plan to work on Nova in general
and
> vGPU support for Nova?
This is intended to be a real product that customers would use, it is
not a proof of concept. There is alot of demand for this kind of
simplified virtualization infrastructure in the host side. The series
here is the first attempt at making thin host infrastructure and
Zhi/etc are doing it with an upstream-first approach.
>From the VFIO side I would like to see something like this merged in
nearish future as it would bring a previously out of tree approach to
be fully intree using our modern infrastructure. This is a big win for
the VFIO world.

As a commercial product this will be backported extensively to many
old kernels and that is harder/impossible if it isn't exclusively in
C. So, I think nova needs to co-exist in some way.

Jason

On Mon, Sep 23, 2024 at 12:01:40PM -0300, Jason Gunthorpe
wrote:
> On Mon, Sep 23, 2024 at 10:49:07AM +0200, Danilo Krummrich wrote:
> > > 2. Proposal for upstream
> > > =======================> > 
> > What is the strategy in the mid / long term with this?
> > 
> > As you know, we're trying to move to Nova and the blockers with
the device /
> > driver infrastructure have been resolved and we're able to move
forward. Besides
> > that, Dave made great progress on the firmware abstraction side of
things.
> > 
> > Is this more of a proof of concept? Do you plan to work on Nova in
general and
> > vGPU support for Nova?
> 
> This is intended to be a real product that customers would use, it is
> not a proof of concept. There is alot of demand for this kind of
> simplified virtualization infrastructure in the host side.
I see...
> The series
> here is the first attempt at making thin host infrastructure and
> Zhi/etc are doing it with an upstream-first approach.
This is great!
> 
> From the VFIO side I would like to see something like this merged in
> nearish future as it would bring a previously out of tree approach to
> be fully intree using our modern infrastructure. This is a big win for
> the VFIO world.
> 
> As a commercial product this will be backported extensively to many
> old kernels and that is harder/impossible if it isn't exclusively in
> C. So, I think nova needs to co-exist in some way.
We'll surely not support two drivers for the same thing in the long term,
neither does it make sense, nor is it sustainable.

We have a lot of good reasons why we decided to move forward with Nova as a
successor of Nouveau for GSP-based GPUs in the long term -- I also just held a
talk about this at LPC.

For the short/mid term I think it may be reasonable to start with Nouveau, but
this must be based on some agreements, for instance:

- take responsibility, e.g. commitment to help with maintainance with some of
  NVKM / NVIDIA GPU core (or whatever we want to call it) within Nouveau
- commitment to help with Nova in general and, once applicable, move the vGPU
  parts over to Nova

But I think the very last one naturally happens if we stop further support for
new HW in Nouveau at some point.
> 
> Jason
>

On Mon, Sep 23, 2024 at 12:01:40PM -0300, Jason Gunthorpe
wrote:
> On Mon, Sep 23, 2024 at 10:49:07AM +0200, Danilo Krummrich wrote:
> > > 2. Proposal for upstream
> > > =======================> > 
> > What is the strategy in the mid / long term with this?
> > 
> > As you know, we're trying to move to Nova and the blockers with
the device /
> > driver infrastructure have been resolved and we're able to move
forward. Besides
> > that, Dave made great progress on the firmware abstraction side of
things.
> > 
> > Is this more of a proof of concept? Do you plan to work on Nova in
general and
> > vGPU support for Nova?
> 
> This is intended to be a real product that customers would use, it is
> not a proof of concept. There is alot of demand for this kind of
> simplified virtualization infrastructure in the host side. The series
> here is the first attempt at making thin host infrastructure and
> Zhi/etc are doing it with an upstream-first approach.
> 
> >From the VFIO side I would like to see something like this merged in
> nearish future as it would bring a previously out of tree approach to
> be fully intree using our modern infrastructure. This is a big win for
> the VFIO world.
> 
> As a commercial product this will be backported extensively to many
> old kernels and that is harder/impossible if it isn't exclusively in
> C. So, I think nova needs to co-exist in some way.
Please never make design decisions based on old ancient commercial
kernels that have any relevance to upstream kernel development today.
If you care about those kernels, work with the companies that get paid
to support such things.  Otherwise development upstream would just
completely stall and never go forward, as you well know.

As it seems that future support for this hardware is going to be in
rust, just use those apis going forward and backport the small number of
missing infrastructure patches to the relevant ancient kernels as well,
it's not like that would even be noticed in the overall number of
patches they take for normal subsystem improvements :)

thanks,

greg k-h