On Monday 25 May 2009 17:22:34 Avi Kivity wrote: > Sheng Yang wrote: > > I think that means the PV interface for lapic. And yes, we can support it > > follow MS's interface, but x2apic still seems another story as you > > noted... I still don't think support x2apic here would bring us more > > benefits. > > x2apic has the following benefit: > > - msr exits are faster than mmio (no page table walk, emulation) Need PV(at least part of). I don't think Hyper-V considered this, and not sure the community's aptitude. > - no need to read back ICR to look at the busy bit > - one ICR write instead of two Maybe the key issue. > - potential to support large guests once we add interrupt remapping Then it can be added before we have it. Compared to the workload, x2apic is not the problem, interrupt remapping/VT-d is. > - shared code with the Hyper-V paravirt interface So I think the key thing are ICR related(and seems no data available currently). Compare the benefit of ICR improve(can it improved in another way? Does Hyper-V interface has related things?), and the workload of x2apic virtualization as well as guest OS support, well, I don't know, but not optimistic. -- regards Yang, Sheng -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
