On Fri, Nov 22, 2024 at 10:32:47PM +0100, Jiri Denemark wrote:
Each CPU model with -v* suffix is defined as a standalone model copying all attributes of the previous version. CPU model versions with an alias are handled differently. The full definition is used for the alias and the versioned model is created as an identical copy of the alias.
To avoid breaking migration compatibility of host-model CPUs all versioned models are marked with <decode guest='off'/> so that they are ignored when selecting candidates for host-model. It's not ideal but not doing so would break almost all host-model CPUs as the new versioned CPU models have all vmx-* features included since their introduction while existing CPU models were updated later. This meas existing models would be accompanied with a long list of vmx-* features to properly describe a host CPU while the newly added CPU models would have those features enabled implicitly and their list of features would be significantly shorter. Thus the new models would always be better candidates for host-model than the existing models.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com> ---
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|