[CentOS-virt] How does KVM handle multiple cores?

[compdoc]

I can't say if KVM will see 6 or 12 cores as I don't run the same hardware.
It's easy enough to install centos and find out.

When you create a virtual machine in KVM, you assign virtual cpus to the
guest - from 1, to as many as you think the guest will need.

For performance reasons, I personally think it's better to keep the total
number of virtual cpus in all of your guests close to the number of real
cpus. But since most computers are idle 99% of the time, you have a lot of
room for experiment...