Re: [PATCH 0/2] rust: pci: expose is_virtfn() and reject VFs in nova-core

[John Hubbard <jhubbard@nvidia.com>]

On 10/1/25 6:43 PM, Alexandre Courbot wrote:
> On Thu Oct 2, 2025 at 6:13 AM JST, Zhi Wang wrote:
>> On 1.10.2025 17.48, Jason Gunthorpe wrote:
>>> On Wed, Oct 01, 2025 at 08:09:37AM +0000, Zhi Wang wrote:
...
>> Right, I also mentioned the same use cases of NIC/GPU in another reply
>> to Danilo. But what I get is NVIDIA doesn't use bare metal VF to support
>> linux container, it seems there have been other solutions. IMHO, it is
>> not mandatory that we have to support VF driver on bare metal so far
>> yet.
> 
> For my education, what gets in the way of supporting a VF on the bare
> metal if we already support it from inside a VM?

Synthesizing a response from what I've learned here:

First of all, the PF and VFs will probe() nova-core with the same 
device ID, so nova-core will get multiple probe() calls for the
same device. That has to be handled. (Thanks to Joel for pointing
that out.)

Next, for actual true VF support, nova-core will need to "provision"
the VFs, which I have learned involves the following:

    * allocate vidmem (or "VRAM" in DRM terminology)
    * set up compute quotas
    * configure which GPU features are exposed


thanks,
-- 
John Hubbard