On Wed, Nov 13, 2019 at 04:42:25PM +0800, Tao Xu wrote:
Hi Eduardo，
After kvm use "-overcommit cpu-pm=on" to expose MONITOR/MWAIT
(commit id 6f131f13e68d648a8e4f083c667ab1acd88ce4cd), the MONITOR/MWAIT
feature in CPU model (phenom core2duo coreduo n270 Opteron_G3 EPYC Snowridge
Denverton) may be unused. For example, when we boot a guest with Denverton
cpu model, guest cannot detect MONITOR and boot with no warning. Should we
remove this feature from some CPU model?
Good catch, thanks!
Yes, we should remove them from Opteron_G3, EPYC, Snowridge, and
Denverton, at least. The other older CPU models can be left
alone: they are more useful for use with TCG than with KVM, and
TCG supports MONITOR/MWAIT.
I would like to understand why this wasn't detected during
testing by Intel. I suggest always testing CPU models using the
"enforce" flag to make sure warnings don't go unnoticed.