On Mon, Jan 09, 2017 at 03:58:11PM +0100, Paolo Bonzini wrote: > > > On 08/01/2017 21:28, Eduardo Habkost wrote: > >> Well just export KVM_GET_TSC_KHZ in a QMP command right? Its pretty > >> easy. > >> > >> Let me know if you need any help coding or testing. > > I just found out that KVM doesn't provide something that QEMU and > > libvirt need: the value of kvm_max_guest_tsc_khz. Without it, we > > have no way to know if a given VM is really migratable to a host. > > > > Could we add a KVM_CAP_MAX_TSC_KHZ capability for that? > > The ratio is really quite high, 256x the host frequency for AMD and > 65536x for Intel. Anything below 2^32 Hz (above that, there would > probably be other failures) is safe. 2^32 Hz (~4.3 GHz) sounds like a limit likely to be hit by future CPUs. Which kind of failures do you think we could see? -- 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
