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

[Wang, Wei W]

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.