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

[David Gibson <david@gibson.dropbear.id.au>]

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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 <sam.bobroff@au1.ibm.com>

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.

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;

-- 
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

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