Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices

[Alex Williamson <alex.williamson@redhat.com>]

On Fri, 2012-05-25 at 18:28 +1000, Benjamin Herrenschmidt wrote:
> On Fri, 2012-05-25 at 17:35 +1000, Alexey Kardashevskiy wrote:
> > Some adapters (like NEC PCI USB controller) do not flush their config
> > on a sioftware reset and remember DMA config, etc.
> > 
> > If we use such an adapter with QEMU, then crash QEMU (stop it with
> > ctrl-A ctrl-X), and try to use it in QEMU again, it may start working
> > immediately with previous config when pci_enable_device() is called
> > on that PCI function.
> > 
> > To eliminate such effect, some quirk should be called. The proposed
> > pci_fixup_final does its job well for mentioned NEC PCI USB but not
> > sure if it is 100% correct.
> 
> I think we should create a new quirk category... call it pci_fixup_reset
> or something like that, which is responsible for blasting the thing into
> submission when ownership changes.
> 
> We'll need these for more than just USB I suspect.

We already have pci_dev_specific_reset() called from pci_dev_reset().
Does this device support any of the standard reset mechanisms?  It would
be nice to know what within the final fixups keeps this device working.
Thanks,

Alex