Re: [Xen-devel] [PATCH 2 of 3] support of cpupools in xl: commands and library changes

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2010-10-08 at 09:41 +0100, Juergen Gross wrote:
> On 10/06/10 15:47, Gianni Tedesco wrote:
> > On Tue, 2010-10-05 at 14:45 +0100, Juergen Gross wrote:
> >> diff -r cfce8e755505 -r baee85a24411 tools/python/xen/lowlevel/xl/xl.c
> >> --- a/tools/python/xen/lowlevel/xl/xl.c Tue Oct 05 14:19:13 2010 +0200
> >> +++ b/tools/python/xen/lowlevel/xl/xl.c Tue Oct 05 15:26:24 2010 +0200
> >> @@ -208,6 +208,11 @@
> >>       return -1;
> >>   }
> >>
> >> +int attrib__uint64_t_ptr_set(PyObject *v, uint64_t * *pptr)
> >> +{
> >> +    return -1;
> >> +}
> >> +
> >>   int attrib__libxl_cpumap_set(PyObject *v, libxl_cpumap *pptr)
> >>   {
> >>       return -1;
> >> @@ -254,6 +259,11 @@
> >>   }
> >>
> >>   PyObject *attrib__libxl_cpuid_policy_list_get(libxl_cpuid_policy_list
> >> *pptr)
> >> +{
> >> +    return NULL;
> >> +}
> >> +
> >> +PyObject *attrib__uint64_t_ptr_get(uint64_t * *pptr)
> >>   {
> >>       return NULL;
> >>   }
> >
> > Because of using Reference(Uint64) directly in the idl - the python
> > bindings autogenerate these type-marshalling functions. It's not quite
> > clear how these are supposed to be implemented in a generic way! :)
> >
> > There ought to be a builtin type for this ala libxl_uuid and other types
> > to generate correct bindings.
> 
> Gianni, I suppose I need a builtin for the complete libxl_cpumap type, not
> only for the uint64_t array due to the size info which is needed to access
> the array correctly.

Yes, I think so.

There is no way in the IDL to have a pure bitmap type which refers to a
different field in the containing structure to get the length, and doing
this would likely be unnecessarily complicated.

> I'm not sure how to translate this into the correct bindings. I think the
> cpumap should be translated into a python list.

Yes, I think lists make sense.

> Which methods do I need to include in xc.c?

I think it will become clear when you try to build it, just follow the
build errors ;-)

> Or would it be okay to add just some minimal dummy
> functions and put in the functionality if needed?

Personally, given that you are planning to change the type from uint64_t
to bytes I'd be happy if you stubbed them out for uint64_t for now and
only implemented properly during the conversion.

Ian.



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