On Wed, Aug 01, 2012 at 06:07:07PM +0300, Nadav Har'El wrote: > On Wed, Aug 01, 2012, Avi Kivity wrote about "Re: Nested kvm_intel broken on pre 3.3 hosts": > > Right - it's not just kvm-as-a-guest that will trip on this. But > > there's no point in everyone backporting it on their own. If you're > > doing the backport, please post it here and we'll forward it to the > > stable branch. > > If I understand correctly, the failure occurs because new versions of > KVM refuse to work if the processor doesn't support CPU_BASED_RDPMC_EXITING - > which older versions of nested VMX didn't say that they did. > > But must the KVM guest refuse to work if this feature isn't supported? > I.e., why not move in setup_vmcs_config() the CPU_BASED_RDPMC_EXITING > from "min" to "opt"? Isn't losing the PMU feature a lesser evil than > not working at all? In any case, perhaps the original reporter can use > this as a workaround, at least, because it requires modifying the (L1) > guest, not the host. > > Since L2 or L1 have to be fixed anyway for setup to work it is better to fix L1 to work according to a spec than fixing L2 to workaround L1 bug. -- 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
