[libvirt] [Solved]FYI//Re: [Qemu-devel] [Question] why x2apic's set by default without host support(on Nehalem CPU).

FYI, just for information sharing. KVM emulated x2apic feature no matter host supports it or not. You can get the code from arch/x86/kvm/cpuid.c. kvm_dev_ioctl_get_supported_cpuid ()->do_cpuid_ent() /* we support x2apic emulation even if host does not support * it since we emulate x2apic in software */ entry->ecx |= F(*X2APIC*); QEMU will get this feature through kvm_ioctl(). On 2013-07-24 8:48, Peter Huang(Peng) wrote:

Hi,Jiri

Thanks for replying.

So why VM identified different features from host is due to the hypervisor filtering. I will dig into the hypervisor of how it filter features, and update status later.

Thanks again.