Re: [Qemu-devel] [PATCH v2] target/i386: kvm: add VMX migration blocker

[Cole Robinson]

On 11/20/18 6:44 AM, Dr. David Alan Gilbert wrote:
> * Paolo Bonzini (address@hidden) wrote:
>> Nested VMX does not support live migration yet.  Add a blocker
>> until that is worked out.
>>
>> Nested SVM only does not support it, but unfortunately it is
>> enabled by default for -cpu host so we cannot really disable it.
>>
>> Signed-off-by: Paolo Bonzini <address@hidden>
> 
> So I'm OK with this, but it does need a release note warning whenever it
> goes in, because it'll surprise those who've already enabled nesting
> but don't use it on all their VMs.
> 

We are hitting this in Fedora 30. Now that nested VMX is enabled by
default at the kernel level, and virt-manager/boxes will use the
equivalent of -cpu host by default, libvirt managedsave (migrate to
file) and virt-manager snapshots (savevm) are rejected for default
created VMs on intel. That's quite unfortunate.

Any ideas on how to resolve this?

FYI it's the root of this bug though there's libvirt issues mixed in:
https://bugzilla.redhat.com/show_bug.cgi?id=1697997

Thanks,
Cole