Re: [Qemu-devel] [PATCH 0/2] RFC: powerpc-vfio: adding support

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

On Wed, 2012-07-11 at 12:25 +1000, Alexey Kardashevskiy wrote:
> On 11/07/12 02:57, Alex Williamson wrote:
> > On Tue, 2012-07-10 at 15:51 +1000, Alexey Kardashevskiy wrote:
> >> The two patches in this set are supposed to add VFIO support for POWER.
> >>
> >> The first one adds one more step in the initalizaion sequence which I am not
> >> sure is correct.
> >>
> >> The second patch adds actual VFIO support. It is not ready to submit but
> >> ready to discuss. I would like to get rid of all #ifdef TARGET_PPC64 in patch #2
> >> and I wonder if there is any plan to implement some generic EOI support code, etc.
> > 
> > A generic EOI notifier is on my todo list, but I have no idea what it's
> > going to look like.  As you know, I've got an ioapic specific notifier
> > in my tree, you add a spapr specific one.  I welcome ideas on how to
> > create something generic that has a chance of being accepted.  Thanks,
> 
> 
> So far the only platform specific call is xxxx_add_gsi_eoi_notifier. The
> xxxx_remove_gsi_eoi_notifier only calls notifier_remove, you've got to fix yours
> ioapic_remove_gsi_eoi_notifier() as it does too much :)
> 
> 
> The only place for placing "add_eoi" callback I can see right now is QEMUMachine as there is no
> unified machine interrupt controller - IOAPIC has its own type TYPE_IOAPIC_COMMON and XICS is not
> even a SysBusDevice. And the callback is not specific for any kind of bus so it cannot go to PCIBus.
> 
> Does it sound reasonable?

I suspect we'd need to somehow tie it into qemu_irq where both handlers
and notifiers are allocated so we don't really care the underlying
implementation.  Something like qemu_add_irq_eoi_notifier(qemu_irq
irq, ...).  It's another mess like adding the PCIBus interrupt line to
gsi effort though.  Thanks,

Alex