Re: [PATCH] vfio/pci: Separate SR-IOV VF dev_set

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Jun 26, 2025 at 04:56:18PM -0600, Alex Williamson wrote:
> @@ -2149,7 +2149,7 @@ int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
>  		return -EBUSY;
>  	}
>  
> -	if (pci_is_root_bus(pdev->bus)) {
> +	if (pci_is_root_bus(pdev->bus) || pdev->is_virtfn) {
>  		ret = vfio_assign_device_set(&vdev->vdev, vdev);
>  	} else if (!pci_probe_reset_slot(pdev->slot)) {
>  		ret = vfio_assign_device_set(&vdev->vdev, pdev->slot);

What about the logic in vfio_pci_dev_set_resettable()?

I guess in most cases vfio_pci_dev_set_resettable() == NULL already
for VFs since it would be rare that the PFs and VFs are all under
VFIO.

But it could happen and this would permanently block hot reset? Maybe
just mention it in the commit?

I guess the commit message is also trying to say that we don't use
VFIO_DEVICE_PCI_HOT_RESET if VFs are present on either the VF or
PF - and this change will block that.

All VF resets should go through VFIO_DEVICE_RESETF. If you want to
slot/bus reset the PF then you have to disable SRIOV first.

?

Jason