[pve-devel] qemu-server : cpu hotplug rework

[Alexandre Derumier]

Cpu hotplug "maxcpus" was wrong,
we need to compute maxcpus from sockets && cores topology.

This patch add a new option "vcpus".
It's the same than old option "smp", not sure we can't reuse it without breaking old config.


by default, I generate

socket:2
cores:1

-smp 2,sockets=2,cores=1,maxcpus=2

(smp = maxcpus = sockets * cores)

This don't break live migration from old command line

-smp sockets=2,cores=1

and this enable cpu hotplug feature




we can define:

socket:4
cores:2
vcpus:1

-smp 1,sockets=4,cores=1,maxcpus=2

This will start a vm with 1 vcpu (core), but with topology a 4sockets and 2cores.
We can hotplug up to 8 vcpus (cores) with this config.