On Thu, Apr 24, 2014 at 04:42:33PM -0400, Paolo Bonzini wrote: > Il 22/04/2014 21:14, Eduardo Habkost ha scritto: > >Not for "-cpu host". If somebody needs migration to work, they shouldn't > >be using "-cpu host" anyway (I don't know if you have seen the other > >comments in my message?). > > I'm not entirely sure. If you have hosts with exactly identical > chipsets, "-cpu host" migration will in all likelihood work. > Marcelo's approach is safer. If that didn't break other use cases, I would agree. But "-cpu host" today covers two use cases: 1) enabling everything that can be enabled, even if it breaks migration; 2) enabling all stuff that can be safely enabled without breaking migration. Now we can't do both at the same time[1]. (1) is important for management software; (2) works only if you are lucky. Why would it make sense to break (1) to try make (2) work? [1] I would even argue that we never did both at the same time."-cpu host" depends on host hardware capabilities, host kernel capabilities, and host QEMU version (we never took care of keeping guest ABI with "-cpu host"). If migration did work, it was never supposed to. -- Eduardo -- 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