Re: [PATCH v4 3/5] vfio/pci: Disable INTx in vfio_realize error path

[Cédric Le Goater]

On 6/29/23 13:24, Joao Martins wrote:
> On 29/06/2023 09:40, Zhenzhong Duan wrote:
> > When vfio realize fails, INTx isn't disabled if it has been enabled.
> > This may confuse host side with unhandled interrupt report.
> >
> > Add a new label to be used for vfio_intx_enable() failed case.
> >
> > Fixes: a9994687cb9b ("vfio/display: core & wireup")
> > Fixes: b290659fc3dd ("hw/vfio/display: add ramfb support")
> > Fixes: c62a0c7ce34e ("vfio/display: add xres + yres properties")
>
> Sounds to me the correct Fixes tag is the same as first patch i.e.:
>
> Fixes: c5478fea27ac ("vfio/pci: Respond to KVM irqchip change notifier")
>
> > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>
> Looks good, but see some clarifications below.
>
> > ---
> >   hw/vfio/pci.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > index ab6645ba60af..54a8179d1c64 100644
> > --- a/hw/vfio/pci.c
> > +++ b/hw/vfio/pci.c
> > @@ -3167,7 +3167,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
> >           kvm_irqchip_add_change_notifier(&vdev->irqchip_change_notifier);
> >           ret = vfio_intx_enable(vdev, errp);
> >           if (ret) {
> > -            goto out_deregister;
> > +            goto out_intx_disable;
> >           }
> >       }
> >   
> > @@ -3220,6 +3220,8 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
> >       return;
> >   
> >   out_deregister:
> > +    vfio_disable_interrupts(vdev);
>
> You are calling vfio_disable_interrupts() when what you want is
> vfio_intx_disable() ? But I guess your thinking was to call
> vfio_disable_interrupt() which eventually calls vfio_intx_disable() in case INTx
> was really setup, thus saving the duplicated check. The MSIx/MSI in realize() I
> don't think they will be enabled at this point. Let me know if I misunderstood.
>
> > +out_intx_disable:
>
> Maybe 'out_intx_teardown' or 'out_intx_deregister' because you are not really
> disabling INTx.

or simply extract from vfio_disable_interrupts() :
 
    if (vdev->interrupt == VFIO_INT_INTx) {
        vfio_intx_disable(vdev);
    }

and add the above code before cleaning up the intx routing
notifier without any new goto labels.

Thanks,

C.


> >       pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
> >       if (vdev->irqchip_change_notifier.notify) {
> >           kvm_irqchip_remove_change_notifier(&vdev->irqchip_change_notifier);