On Thu, Oct 18, 2018 at 1:44 PM, Christian Ehrhardt <lk@xxxxxxx> wrote: > > Change efdab992: "KVM: x86: fix escape of guest dr6 to the host" > has negative effects if Linux runs as the L1 guest in a nested > VM setup: > > Each call to kvm_arch_vcpu_put causes an additional L1->L0 exit due > to the %dr6 write even if neither L1 nor L2 uses debug registers. > As the current hardware value of %dr6 is already in vcpu->arch.dr6 > we can avoid the debug register write if all non-reserved bits have > their default value. > > Update the comment and reformat it while there. > > Signed-off-by: Christian Ehrhardt <lk@xxxxxxx> Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
