Re: [libvirt] [Xen-devel] [PATCH] libxl: use LIBXL_API_VERSION 0x040200

On Thu, 2016-04-14 at 09:33 +0100, George Dunlap wrote: Err... I'm not good at this things, but I don't think it will break. So, libxl_set_vcpuaffinity(ctx,d,v,map,map) was defined in Xen 4.5. Xen 4.4 only has libxl_set_vcpuaffinity(ctx,d,v,map). Libvirt only uses libxl_set_vcpuaffinity(ctx,d,v,map) (i.e., the latter == the older one). On anything below Xen 4.5 --which also means LIBXL_HAVE_VCPU_SOFT_AFFINITY is not defined-- the variant with only one map parameter is available, and therefore things should build and work. For anything above Xen 4.5 _and_ with LIBXL_API_VERSION<4.5 (which would be the case, with this patch), libxl.h provides the stub for the variant with only one map argument, so everything should again be fine. Or am I missing something? Perhaps, the point is that the hunk being removed above should really have been using LIBXL_API_VERSION already, rather than LIBXL_HAVE_VCPUINFO_SOFT_AFFINITY. But, at the time, as far as I can recall, libvirt was not setting LIBXL_API_VERSION to anything, and doing that was not considered necessary. Therefore I did use LIBXL_HAVE_VCPUINFO_SOFT_AFFINITY for the check, which is always present, starting from Xen 4.5 (or never present, before that). Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)