Re: [Qemu-devel] [Qemu-trivial] [PATCH 2/2] KVM: PPC: Add dummy kvm_arch_init_irq_routing()

[Scott Wood <scottwood@freescale.com>]

On 06/08/2013 02:24:21 AM, Michael Tokarev wrote:
> 06.06.2013 07:59, Alexey Kardashevskiy wrote:
> > From: Scott Wood <scottwood@freescale.com>
> >
> > The common KVM code insists on calling kvm_arch_init_irq_routing()
> > as soon as it sees kernel header support for it (regardless of  
> whether
> > QEMU supports it).  Provide a dummy function to satisfy this.
> >
> > Unlike x86, PPC does not have one default irqchip, so there's no  
> common
> > code that we'd stick here.  Even if you ignore the routes  
> themselves,
> > which even on x86 are not set up in this function, the initial XICS
> > kernel implementation will not support IRQ routing, so it's best to
> > leave even the general feature flags up to the specific irqchip  
> code.
> 
> As Scott Wood already pointed out, this should come in before the
> actual header update, which is no problem.  We'll have to deal
> with a new warning (-Wmissing-prototypes) which can be dealt with
> by wrapping this function into #ifdef KVM_CAP_IRQ_ROUTING .. #endif
> (I can add this).

Why?  I don't see where the prototype is guarded by that, and I don't  
see a warning when applying this patch to master...

> But how about other architectures?  Before, this function were only
> defined for x86, now it is defined for two arches - x86 and ppc.
> Aren't other arches need this as well?

Yes, it looks like KVM_CAP_IRQ_ROUTING is no longer conditionally  
defined, so all KVM architectures will need this (unless they provide a  
non-dummy version).  Are weak functions acceptable in QEMU?  I don't  
see any current examples.

-Scott