Re: [Qemu-devel] [PATCH v6] s390x/pci: add common function measurement block

[Pierre Morel]

On 07/01/2019 12:30, David Hildenbrand wrote:
> On 03.01.19 11:17, Pierre Morel wrote:
> > From: Yi Min Zhao <address@hidden>
> >
> > Common function measurement block is used to report zPCI internal
> > counters of successful pcilg/stg/stb and rpcit instructions to
> > a memory location provided by the program.
> >
> > This patch introduces a new ZpciFmb structure and schedules a timer
> > callback to copy the zPCI measures to the FMB in the guest memory
> > at an interval time set to 4s.
> >
> > An error while attemping to update the FMB, would generate an error
> > event to the guest.
> >
> > The pcilg/stg/stb and rpcit interception handlers increase the
> > related counter on a successful call.
> > The guest shall pass a null FMBA (FMB address) in the FIB (Function
> > Information Block) when it issues a Modify PCI Function Control
> > instruction to switch off FMB and stop the corresponding timer.
> >
> > Signed-off-by: Yi Min Zhao <address@hidden>
> > Signed-off-by: Pierre Morel <address@hidden>
> > ---
> >   hw/s390x/s390-pci-bus.c  |   4 +-
> >   hw/s390x/s390-pci-bus.h  |  29 +++++++++++
> >   hw/s390x/s390-pci-inst.c | 133 +++++++++++++++++++++++++++++++++++++++++++++--
> >   hw/s390x/s390-pci-inst.h |   1 +
> >   4 files changed, 163 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
> > index 060ff06..f0d34dd 100644
> > --- a/hw/s390x/s390-pci-bus.c
> > +++ b/hw/s390x/s390-pci-bus.c
> > @@ -989,6 +989,7 @@ static void s390_pcihost_hot_unplug(HotplugHandler 
> > *hotplug_dev,
> >       bus = pci_get_bus(pci_dev);
> >       devfn = pci_dev->devfn;
> >       object_unparent(OBJECT(pci_dev));
> > +    fmb_timer_free(pbdev);
>
> I wonder if this should go into the unrealize function instead.

What make you think it should?
All zPCI specific resources are free inside the hot_unplug callback.
Why should the timer be handled differently?

The timer is not setup during realize, but later on a guest request.

AFAIK unrealize would be called after the unplug handler or is there a 
case for which unrealize would be called and not the hotplug handler?

Regards,
Pierre


--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany