[PATCH v2 3/3] vfio/pci: Don't probe devices that can't be reset

Alex Williamson
2017-08-18T14:12:51Z

On Fri, 18 Aug 2017 15:42:31 +0200
Jan Glauber <jan.glauber@caviumnetworks.com> wrote:

> On Thu, Aug 17, 2017 at 07:00:17AM -0600, Alex Williamson wrote:
> > On Thu, 17 Aug 2017 10:14:23 +0200
> > Jan Glauber <jglauber@cavium.com> wrote:
> >
> > > If a PCI device supports neither function-level reset, nor slot
> > > or bus reset then refuse to probe it. A line is printed to inform
> > > the user.
> >
> > But that's not what this does, this requires that the device is on a
> > reset-able bus. This is a massive regression. With this we could no
> > longer assign devices on the root complex or any device which doesn't
> > return from bus reset and currently makes use of the NO_BUS_RESET flag
> > and works happily otherwise. Full NAK. Thanks,
>
> Looks like I missed the slot reset check. So how about this:
>
> if (pci_probe_reset_slot(pdev->slot) && pci_probe_reset_bus(pdev->bus)) {
> dev_warn(...);
> return -ENODEV;
> }
>
> Or am I still missing something here?

We don't require that a device is on a reset-able bus/slot, so any
attempt to impose that requirement means that there are devices that
might work perfectly fine that are now excluded from assignment. The
entire premise is unacceptable. Thanks,

Alex