Re: [libvirt] cpu_map data access for libxl driver

On Thu, Jul 07, 2016 at 13:47:28 +0100, Daniel P. Berrange wrote: > On Thu, Jul 07, 2016 at 02:37:39PM +0200, Cedric Bosdonnat wrote: > > Hi Jiri, all, > > > > As I mentioned earlier today on IRC, I have started implementing CPU configuration > > support for libxl driver. > > > > libxl expects a string definition the state of all the feature (easy to create), but also > > the numeric values for the CPU family and model. virCPUDef holds the name as a string, but > > not the numeric values though there are stored in the cpu_map.xml. Yeah, the family/model values are currently only used for better host CPU detection so they are not exposed outside the cpu driver. > > For what libxl expects, search for 'cpuid=' in this man page: > > http://xenbits.xen.org/docs/unstable/man/xl.cfg.5.html Oh, I was about to suggest the cpuEncode API to translate virCPUDef into CPUID data, but now I see libxl added a new syntax which does not require messing with raw CPUID data, which is nice. > > Any idea how to get those values from the libxl driver? > > I'd suggest just extending the virCPUDef to hold them, and populating it from > the cpu_map.xml This is an option, but if model/family is stored in virCPUDef, which is just an internal representation of the <cpu> XML element, we should probably format and parse the values. But doing so would mean users can set them in domain XML, which I believe is not something we want to allow. So either we will not add any formatting/parsing code for family and model breaking the relation between *Def and XML elements, or we need to come up with a different solution...