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

On Wed, May 30, 2018 at 12:55:19 -0300, Eduardo Habkost wrote: Yes, it is still used. Mainly for reporting host CPU capabilities (even those retrieved from QEMU), because we only get a list of features (both from QEMU and CPUID) and need to somehow choose a corresponding CPU model. And its also partially used to check whether a particular CPU can be provided on the host when we start a domain. But this checking is done mostly for backward compatibility and it is not very strict, the final decision of what can or cannot be used is on QEMU. In other words, we accept any feature which is either supported by the host CPU (using CPUID) or reported by QEMU as enabled for the "host" CPU model. Any requested features which cannot be provided by QEMU would just be disabled in the virtual CPU. This is of course all about the default check='partial'. Libvirt doesn't do any checks with check='full' and just asks QEMU whether it disabled any requested features. The file format is not considered an API and it can change, but the CPU models, features and any other names defined there which can be used to describe a CPU are an API similarly to domain XML, for example. That is, each name has the same meaning across all versions of libvirt which support it. Jirka