Re: [Xen-devel] [PATCH 04 of 18] x86/mm: Update mem sharing interface to (re)allow sharing of grants

["Andres Lagar-Cavilla" <andres@xxxxxxxxxxxxxxxx>]

> Hi,
>
> At 02:47 -0500 on 08 Dec (1323312439), Andres Lagar-Cavilla wrote:
>> +            if (
>> XEN_DOMCTL_MEM_SHARING_FIELD_IS_GREF(mec->u.share.client_gfn) )
>> +            {
>> +                grant_ref_t gref = (grant_ref_t)
>> +
>> (XEN_DOMCTL_MEM_SHARING_FIELD_GET_GREF(
>> +                                        mec->u.share.client_gfn));
>> +                if ( (!source_is_gref) ||
>> +                     (mem_sharing_gref_to_gfn(cd, gref, &cgfn) < 0) )
>> +                {
>> +                    put_domain(cd);
>> +                    return -EINVAL;
>> +                }
>> +            } else {
>> +                if ( source_is_gref )
>> +                {
>> +                    put_domain(cd);
>> +                    return -EINVAL;
>> +                }
>
> Why can't one input be a grant and the other not?  If there's a problem
> with that it should probably be documented in the hypercall interface.
>
No particular problem. The gref use case is the current target of
tools/memshr, which always does gref-to-gref sharing. I imagine
gref-to-gfn sharing to be extremely unlikely.

But there is no need to disallow it.

Andres
> Cheers,
>
> Tim.
>



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel