Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index

[Paolo Bonzini]

On 14/06/2017 15:22, Eduardo Habkost wrote:
>> Yes, definitely.  At this point let's add a new "KVM_CAP_HYPERV_SYNIC2"
>> capability and declare the old one broken, that will make things easier.
> What do we need a capability for?  Can't we just call
> KVM_SET_MSRS using arch_id (== apic_id) and warn the user if it
> doesn't work?

As mentioned in the review of patch 16/23, we may want to break
backwards compatibility (meaning we drop the old capability and
introduce a new one) for other reasons.

Paolo