[Intel-gfx] [PATCH v3 09/14] vfio/pci: Change vfio_pci_try_bus_reset() to use the dev_set

[Alex Williamson]

On Tue, 3 Aug 2021 13:41:52 -0300
Jason Gunthorpe <jgg at nvidia.com> wrote:
> On Tue, Aug 03, 2021 at 10:34:06AM -0600, Alex Williamson wrote:
> > I think the vfio_pci_find_reset_target() function needs to be re-worked
> > to just tell us true/false that it's ok to reset the provided device,
> > not to anoint an arbitrary target device.  Thanks,  
> 
> Yes, though this logic is confusing, why do we need to check if any
> device needs a reset at this point? If we are being asked to reset
> vdev shouldn't vdev needs_reset?
> 
> Or is the function more of a 'synchronize pending reset' kind of
> thing?

Yes, the latter.  For instance think about a multi-function PCI device
such as a GPU.  The functions have dramatically different capabilities,
some might have function level reset abilities and others not.  We want
to be able to trigger a bus reset as the last device of the set is
released, no matter the order they're released and no matter the
capabilities of the device we're currently processing.  Thanks,

Alex