Comment 17 for bug 1978064

Hello all,

I've been working with libvirt upstream for a while now, but it seems they do not want to add a new CPU model for 10nm Icelake. Their reasoning is that the list of capabilities for a given processor is not used within libvirt, so they don't believe maintaining a noMPX version of Icelake-Server is worth it.

Moving forward there are a few options:

The first is to deploy OpenStack with custom libvirt flags. Information on how to do that can be found here: https://docs.openstack.org/nova/latest/admin/cpu-models.html#cpu-feature-flags
In this case, something like the following can be added to the conf file:

[libvirt]
cpu_mode = custom
cpu_models = Icelake-Server,Icelake-Server-noTSX
cpu_model_extra_flags = -mpx

Secondarily, <feature name='mpx' removed='yes'/> can be added manually in x86_Icelake-Server-noTSX.xml or x86_Icelake-Server.xml, but that doesn't seem very efficient or sustainable for deployment.

If neither of these work, I can try and push harder for upstream to specify noMPX as a model or find a way to make this work in Ubuntu specifically.

Let me know what you prefer. Thanks!