Re: [Qemu-devel] SR-IOV PF reset and QEMU VFs VFIO passthrough

[Benoît Canet]

> >I was asking this because the PF driver should reset the PF while the VF are
> >used by VFIO/QEMU when the PF doesn't respond anymore.
> >
> What your VF does while your PF is being reset is PF (& VF) dependent.
> A 'good design' would not impact the VF operation, other than to stall it 
> until
> the PF completed reset.  My experience, though, is that the PF has to be 
> brought
> up to some level of functionality to share the physical resources with the 
> VFs.

When the PF does an FLR the hardware go back to its default state, the SR-IOV
configuration is gone and the VFs disappears from the bus.
Then the restore state function of the kernel reset code would bring the SR-IOV
PF configuration back.

The hardware also have a privately owned SR-IOV related configuration in the PF
configuration space. This configuration is used to configure the VFs resources.
(memory)

Best regards

Benoît Canet