Re: [PATCH v1] target/i386: kvm: Block migration when enfore_cpuid is set to false

[Daniel P . Berrangé]

On Thu, Jul 11, 2024 at 02:13:31PM +0000, Wang, Wei W wrote:
> On Thursday, July 11, 2024 8:25 PM, Daniel P. Berrangé wrote:
> > On Thu, Jul 11, 2024 at 12:10:34PM +0000, Wang, Wei W wrote:
> > > On Thursday, July 11, 2024 7:48 PM, Daniel P. Berrangé wrote:
> > > > On Wed, Jul 03, 2024 at 10:49:12PM +0800, Wei Wang wrote:
> > > AFAIK, many users are not aware of this, and also we couldn't assume
> > > everybody knows it. That's why we want to add the enforcement.
> > 
> > Users who directly launch QEMU are expected to know about QEMU config
> > details for migration. If they don't, then they ought to be using a higher 
> > level
> > tool like libvirt, which ensures the configuration is migration compatible.
> 
> Agree that libvirt has this advantage and is more user friendly. But it 
> doesn't seem to
> solve the issue mentioned by this patch - if users don't explicitly set 
> "enforce=true"
> in libvirt configs for the guest, then migrating the guest across hosts with 
> different
> features could still be risky. Unless there is similar enforcement in libvirt 
> to require
> users to set "enforce=true" for the guest to be migratable.

Yes, libvirt takes steps to ensure CPU compatibility before migrating.

With regards,
Daniel
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