Re: [PATCH v1 06/11] KVM: x86: use hardware-compatible format for APIC ID register

Paolo Bonzini
2016-07-01T16:37:55Z

On 01/07/2016 17:53, Radim Krčmář wrote:
>> >> enable_xapic()
>> >> id = apic_id()
>> >> set_apic_id(id+1) // ?
>> >> enable_x2apic()
>> >> id == apic_id() & 0xff
>> >> disable_apic()
>> >> enable_xapic()
>> >> id == apic_id()
>> >>
> >
> > Yes, plus checking that it "moves" appropriately between low and high bits.
>
> x2APIC cannot use MMIO interface, so apic_id() already does the best we
> can ... if KVM is shifting wrong somwhere, then the id should differ.

Yeah, fair enough.

Paolo