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

[Jason Gunthorpe]

On Wed, Oct 01, 2025 at 08:09:37AM +0000, Zhi Wang wrote:
> >> But if the guest sees the passed-through VF as a PF, won't it try to
> >> do things it is not supposed to do like loading the GSP firmware (which
> >> is managed by the host)?
> >
> 
> The guest driver will read PMC_BOOT_1 and check PMC_BOOT_1_VGPU_VF flag 
> to tell if it is running on a VF or a PF.

Yes exactly, and then novacore should modify its behavior and operate
the device in the different mode.

It doesn't matter if a VM is involved or not, a VF driver running side
by side wit the PF driver should still work.

There are use cases where people do this, eg they can stick the VF
into a linux container and use the SRIOV mechanism as a QOS control.
'This container only gets 1/4 of a GPU'

Jason