Re: [Qemu-devel] [RFC PATCH v2 13/15] cpu-model/s390: Add processor property routines

[Michael Mueller <mimu@linux.vnet.ibm.com>]

On Fri, 20 Feb 2015 15:03:30 +0100
Alexander Graf <agraf@suse.de> wrote:

> > 
> > - s390_get_proceccor_props()
> > - s390_set_proceccor_props()
> > 
> > They can be used to request or retrieve processor related information from an accelerator.
> > That information comprises the cpu identifier, the ICB value and the facility lists.
> > 
> > Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>  
> 
> Hrm, I still seem to miss the point of this interface. What do you need
> it for?

These functions make the internal s390 cpu model API independent from a specific accelerator:  

int s390_set_processor_props(S390ProcessorProps *prop)
{
    if (kvm_enabled()) {
        return kvm_s390_set_processor_props(prop);
    }
    return -ENOSYS;
}

It's called by:

s390_select_cpu_model(const char *model)

which is itself called by:

S390CPU *cpu_s390x_init(const char *cpu_model)
{
    S390CPU *cpu;

    cpu = S390_CPU(object_new(s390_select_cpu_model(cpu_model)));

    object_property_set_bool(OBJECT(cpu), true, "realized", NULL);

    return cpu;
}

So above s390_set/get_processor_props() the code is accelerator independent.

Michael