Re: [Qemu-devel] [PATCH 4/4] ppc: spapr: Make VCPU ID handling private to SPAPR

[Sam Bobroff]

On Fri, Aug 04, 2017 at 01:10:19PM +1000, David Gibson wrote:
> On Thu, Aug 03, 2017 at 04:28:52PM +1000, Sam Bobroff wrote:
> > The concept of a VCPU ID that differs from the CPU's index
> > (cpu->cpu_index) exists only within SPAPR machines so, move the
> > functions ppc_get_vcpu_id() and ppc_get_cpu_by_vcpu_id() into spapr.c
> > and rename them appropriately.
> > 
> > Signed-off-by: Sam Bobroff <address@hidden>
> 
> Mostly good, but...
> 
> [snip]
> > +int spapr_vcpu_id(PowerPCCPU *cpu)
> > +{
> > +    return cpu->vcpu_id;
> > +}
> > +
> > +PowerPCCPU *spapr_find_cpu(int vcpu_id)
> > +{
> > +    CPUState *cs;
> > +
> > +    CPU_FOREACH(cs) {
> > +        PowerPCCPU *cpu = POWERPC_CPU(cs);
> > +
> > +        if (cpu->vcpu_id == vcpu_id) {
> > +            return cpu;
> > +        }
> > +    }
> > +
> > +    return NULL;
> > +}
> 
> [...]
> > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> > index 7ccb350c5f..2bf2727860 100644
> > --- a/target/ppc/kvm.c
> > +++ b/target/ppc/kvm.c
> > @@ -512,7 +512,7 @@ bool kvmppc_is_mem_backend_page_size_ok(const char 
> > *obj_path)
> >  
> >  unsigned long kvm_arch_vcpu_id(CPUState *cpu)
> >  {
> > -    return ppc_get_vcpu_id(POWERPC_CPU(cpu));
> > +    return spapr_vcpu_id(POWERPC_CPU(cpu));
> >  }
> 
> Here you've replaced an implicit dependency on spapr details in the
> generic code with an explicit dependency on spapr details.  That's the
> wrong direction.

Ah right, I'll flip it around.

> Instead _this_ one should directly reference vcpu_id, the spapr one
> should be something like:
> 
>       if (kvm)
>               return kvm_arch_vcpu_id(...)
>       else
>               return cpu_index;

OK.

> -- 
> David Gibson                  | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au        | minimalist, thank you.  NOT _the_ 
> _other_
>                               | _way_ _around_!
> http://www.ozlabs.org/~dgibson