Re: [libvirt] What is the strategy to update the CPU Models in src/cpu/cpu_map.xml based on?

Hi Jiri, At 05/30/2018 06:14 PM, Jiri Denemark wrote: > [Dropping random people from Cc] > > On Wed, May 30, 2018 at 18:00:56 +0800, Dou Liyang wrote: >> Hi All, >> >> I am not sure about the update strategy of CPU models in libvirt. >> >> IMO, It's depend on the CPU model in qemu-kvm, if some CPU models >> were updated in qemu-kvm. Then, we should modify the src/cpu/cpu_map.xml >> of libvirt to synchronize? > > No, we never change existing CPU models in cpu_map.xml to make sure the > same CPU model is the same across libvirt versions. Not to mention that > QEMU only changes existing CPU models for new machine type (for the same > compatibility reason) so we can't just change our CPU models since we > don't know what machine type their going to be used with. Libvirt will > handle the differences in runtime by remembering any additionally > enabled or disabled features once domain starts to make sure the exact > same CPU is recreated after, e.g., migration. > I see. Btw, If we found there is a wrong feature in the existing CPU models, what should we do?

If we add a new CPU model, what we refer to? CPU models spec or hypervisors' code(eg, qemu-kvm)