[pve-devel] cpuflag: pcid needed in guest for good performance after meltdown

[Stefan Priebe - Profihost AG]

Hello,

for meltdown mitigation and performance it's important to have the pcid
flag passed down to the guest (f.e.
https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU).

My host shows the flag:
# grep ' pcid ' /proc/cpuinfo  | wc -l
56

But the guest does not:
# grep pcid /proc/cpuinfo
#

Guest was started with:
-cpu IvyBridge,+kvm_pv_unhalt,+kvm_pv_eoi,enforce,vendor=GenuineIntel

Is this something missing in host kernel or in PVE?

Greets,
Stefan