KVM CPU flags ('ibpb', 'ssbd', 'virt-ssbd', 'amd-ssbd', 'amd-no-ssb', 'pdpe1gb')

TwiX

Renowned Member
Feb 3, 2015
310
23
83
Hi,

On a small cluster, I have 2 different CPU model for nodes, one is Broadwell, the others are Haswell.

I usually set the CPU VM as 'host'. Indeed, live migrations works as expected from Haswell to Haswell and Haswell to Broadwell. But it crashes from Broadwell to Haswell, some flags are not available on Haswell.

So I decided to switch from host to Haswell-noTSX, which seems to be the best choice in my case.
I checked pcid and spec-ctrl options and it's ok but some flags are missing in order to avoid CVE-2018-3639 for example.

The related flags are 'ibpb', 'ssbd', 'virt-ssbd', 'amd-ssbd', 'amd-no-ssb', 'pdpe1gb'

What is the proper way to add these flags to cpu vms ?

Thanks in advanced !

Antoine
 
qm set ID -cpu cputype=Haswell-noTSX,flags=+pcid;+spec-ctrl
etc.
 
Thanks,

Do you plan to add some kind of check boxes to add these flags (or maybe via datacenter cfg file) ?

Antoine
 
Do you plan to add some kind of check boxes to add these flags (or maybe via datacenter cfg file) ?
for pcid and spec-ctrl there are already checkboxes in the cpu advanced settings,
for the remaining ones we have to come up with a better input (we do no treally like to have dozens of checkboxes)
 

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