Re: [libvirt] [RFC] cpu_map: Remove pconfig from Icelake-Server CPU model
On 30/09/19 16:31, Hu, Robert wrote:
> This might be a problem if there are plans to eventually make KVM
support
> pconfig, though. Paolo, Robert, are there plans to support pconfig in KVM in the
> future?
[Robert Hoo]
Thanks Eduardo for efforts in resolving this issue, introduced from my Icelake CPU
model patch.
I've no idea about PCONFIG's detail and plan. Let me sync with Huang, Kai and
answer
you soon.
It's really, really unlikely. It's possible that some future processor
overloads PCONFIG in such a way that it will become virtualizable, but
not IceLake.
Would it make sense for libvirt to treat absent CPU flags as "default
off" during migration, so that it can leave out the flag in the command
line if it's off? If it's on, libvirt would pass pconfig=on as usual.
This is a variant of [2], but more generally applicable:
[2] However starting a domain with Icelake-Server so that it can be
migrated or saved/restored on QEMU in 3.1.1 and 4.0.0 would be
impossible. This can be solved by a different hack, which would drop
pconfig=off from QEMU command line.
Paolo