On Wed, Apr 10, 2013 at 11:29:42AM +0200, Andre Przywara wrote: > In a real world VendorSpecific should be replaced with something more > meaningful. Depends on KVMs intention to emulate instructions, actually > out of scope for a pure virtualizer. > Something like EmulateOnUD. > What is the opinion from the KVM folks on this? Shall we start to > emulate instructions the host does not provide? In this particular case > a relatively simple patch fixes a problem (starting Atom optimized > kernels on non-Atom machines). We can add the emulation, but we should not start announcing the instruction availability to a guest if host cpu does not have it by default. This may trick a guest into thinking that movbe is the fastest way to do something when it is not. > > (And if one can believe the AMD Fam16h SWOG [1], PS4^Wfuture AMD > processors have MOVBE, so it's not even actually one CPU anymore). If a host CPU has the instruction emulation is not needed unless the instruction is used for MMIO access. -- Gleb. -- 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
