Re: [RFC 18/29] nvkm/vgpu: introduce pci_driver.sriov_configure() in nvkm

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Oct 14, 2024 at 08:32:03AM +0000, Zhi Wang wrote:

> Turning on the SRIOV feature is just a part of the process enabling a 
> vGPU. The VF is not instantly usable before a vGPU type is chosen via 
> another userspace interface (e.g. fwctl).

That's OK, that has become pretty normal now that VFs are just empty
handles when they are created until they are properly profiled.

> Besides, admin has to enable the vGPU support by some means (e.g. a 
> kernel parameter is just one candidate) and GSP firmware needs to be 
> configured accordingly when being loaded.

Definitely not a kernel parameter..

> As this is related to user space interface, I am leaning towards putting 
> some restriction/checks for the pre-condition in the 
> driver.sriov_configure(), so admin would know there is something wrong 
> in his configuration as early as possible, instead of he failed to 
> creating vGPUs again and again, then he found he forgot to enable the 
> vGPU support.

Well, as I've said, this is poor, you shouldn't have a FW SRIOV enable
bit at all, or at least it shouldn't be user configurable.

If the PCI function supports SRIOV then it should work to turn it on.

Jason