On Fri, Apr 12, 2019 at 08:37:49PM +0800, Pu Wen wrote: > Add two new base CPU models called 'Dhyana' and 'Dhyana-IBPB' to model > processors from Hygon Dhyana (family 18h), which derived from AMD EPYC > (family 17h). 'Dhyana-IBPB' is a copy of the 'Dhyana' CPU model with > just CPUID_8000_0008_EBX_IBPB added.
Do we really need to support both CPU variants ? The IBPB feature is the Spectre fix which dates from January 2018. Having both made (limited) sense for EPYC as EPYC CPUs existed already, so there would be a mix of EPYC CPUs with and without the microcode that adds IBPB. The Google results I see suggest that Dhyana CPUs started to become available in July 2018, so surely they would come with microcode that has the IBPB right from day 1 ? Am I missing anything that means there will be a compelling need to support Dhyana /without/ IBPB ? If not, then we only need 1 CPU model and that would include IBPB. 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 :|
