Re: [PATCH 09/12] s390x/pci: enable adapter event notification for interpreted devices

[Matthew Rosato]

On 12/8/21 6:29 AM, Thomas Huth wrote:
> On 07/12/2021 22.04, Matthew Rosato wrote:
> > Use the associated vfio feature ioctl to enable adapter event 
> > notification
> > and forwarding for devices when requested.  This feature will be set up
> > with or without firmware assist based upon the 'intassist' setting.
> >
> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > ---
> >   hw/s390x/s390-pci-bus.c          | 24 +++++++--
> >   hw/s390x/s390-pci-inst.c         | 54 +++++++++++++++++++-
> >   hw/s390x/s390-pci-vfio.c         | 88 ++++++++++++++++++++++++++++++++
> >   include/hw/s390x/s390-pci-bus.h  |  1 +
> >   include/hw/s390x/s390-pci-vfio.h | 20 ++++++++
> >   5 files changed, 182 insertions(+), 5 deletions(-)
> [...]
> > diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
> > index 78093aaac7..6f9271df87 100644
> > --- a/hw/s390x/s390-pci-vfio.c
> > +++ b/hw/s390x/s390-pci-vfio.c
> > @@ -152,6 +152,94 @@ int 
> > s390_pci_update_passthrough_fh(S390PCIBusDevice *pbdev)
> >       return 0;
> >   }
> > +int s390_pci_probe_aif(S390PCIBusDevice *pbdev)
> > +{
> > +    VFIOPCIDevice *vdev = container_of(pbdev->pdev, VFIOPCIDevice, 
> > pdev);
>
> Should this use VFIO_PCI() instead of container_of ?

Yes, VFIO_PCI(pbdev->pdev) should work.

> > +    struct vfio_device_feature feat = {
> > +        .argsz = sizeof(struct vfio_device_feature),
> > +        .flags = VFIO_DEVICE_FEATURE_PROBE + 
> > VFIO_DEVICE_FEATURE_ZPCI_AIF
> > +    };
> > +
> > +    assert(vdev);
>
> ... then you could likely also drop the assert(), I think?

If I've understood qom.h correctly then yes you're right, if we use the 
instance checker VFIO_PCI() we should trigger an assert through 
object_dynamic_cast_assert() already if the pdev isn't a vfio-pci device 
-- I just verified that by trying to call VFIO_PCI() with something else 
and we indeed get an assert e.g. 'VFIO_PCI: Object 0x... is not an 
instance of type vfio-pci'

So I'll change these and get rid of the extra asserts, thanks.