VM_REG_GUEST_R13
if ((error = vm_set_register(vcpu, VM_REG_GUEST_R13, zero)) != 0)
case VM_REG_GUEST_R13:
case VM_REG_GUEST_R13:
VM_REG_GUEST_R13,
{ .id = VM_REG_GUEST_R13, .size = 8 },
error = vm_get_register(vcpu, VM_REG_GUEST_R13, &r13);