On 05/28/2018 09:18 AM, Thomas Huth wrote: > On 28.05.2018 09:06, Cédric Le Goater wrote: >> On 05/28/2018 08:17 AM, Thomas Huth wrote: >>> On 25.05.2018 16:02, Greg Kurz wrote: >>>> On Fri, 18 May 2018 18:44:02 +0200 >>>> Cédric Le Goater <c...@kaod.org> wrote: >>>> >>>>> This IRQ number hint can possibly be used by the VIO devices if the >>>>> "irq" property is defined on the command line but it seems it is never >>>>> the case. It is not used in libvirt for instance. So, let's remove it >>>>> to simplify future changes. >>>>> >>>> >>>> Setting an irq manually looks a bit anachronistic. I doubt anyone would >>>> do that nowadays, and the patch does a nice cleanup. So this looks like >>>> a good idea. >>> [...] >>>>> diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c >>>>> index 472dd6f33a96..cc064f64fccf 100644 >>>>> --- a/hw/ppc/spapr_vio.c >>>>> +++ b/hw/ppc/spapr_vio.c >>>>> @@ -455,7 +455,7 @@ static void spapr_vio_busdev_realize(DeviceState >>>>> *qdev, Error **errp) >>>>> dev->qdev.id = id; >>>>> } >>>>> >>>>> - dev->irq = spapr_irq_alloc(spapr, dev->irq, false, &local_err); >>>>> + dev->irq = spapr_irq_alloc(spapr, false, &local_err); >>>> >>>> Silently breaking "irq" like this looks wrong. I'd rather officially remove >>>> it first (ie, kill spapr_vio_props, -5 lines in spapr_vio.c). >>>> >>>> Of course, this raises the question of interface deprecation, and it should >>>> theoretically follow the process described at: >>>> >>>> https://wiki.qemu.org/Features/LegacyRemoval#Rules_for_removing_an_interface >>>> >>>> Cc'ing Thomas, our Chief Deprecation Officer, for insights :) >>> >>> The property is a public interface. Just because it's not used by >>> libvirt does not mean that nobody is using it. So yes, please follow the >>> rules and mark it as deprecated first for two release, before you really >>> remove it. >> >> This "irq" property is a problem to introduce a new static layout of IRQ >> numbers. It is in complete opposition. >> >> Can we keep it as it is for old pseries machine (settable) and ignore it >> for newer ? Would that be fine ? > > I think that would be fine, too. You likely need to keep the settable > IRQs around for the old machines anyway, to make sure that migration of > the old machine types still works, right?
Yes, that is the goal of patch 3. It introduces a common sPAPR IRQ frontend, the first backend being the current one. C.
