麒麟安装增强功能失败（未解决）：Could not downgrade policy file /etc/selinux/targeted/policy/policy.29

详细错误：

VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel 
modules.  This may take a while.
VirtualBox Guest Additions: To build modules for other installed kernels, run
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup <version>
VirtualBox Guest Additions: or
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup all
VirtualBox Guest Additions: Building the modules for kernel 
4.4.131-20200710.kylin.x86-generic.
 
VirtualBox Guest Additions: Look at /var/log/vboxadd-setup.log to find out what 
went wrong
update-initramfs: Generating /boot/initrd.img-4.4.131-20200710.kylin.x86-generic
Adding IMA binaries
W: plymouth module (/usr/lib/x86_64-linux-gnu/plymouth//ubuntu-text.so) missing, skipping that theme.
SELinux:  Could not downgrade policy file /etc/selinux/targeted/policy/policy.29, searching for an older version.
SELinux:  Could not open policy file <= /etc/selinux/targeted/policy/policy.29:  No such file or directory
/sbin/load_policy:  Can't load policy:  No such file or directory
libsemanage.semanage_reload_policy: load_policy returned error code 2.
SELinux:  Could not downgrade policy file /etc/selinux/targeted/policy/policy.29, searching for an older version.
SELinux:  Could not open policy file <= /etc/selinux/targeted/policy/policy.29:  No such file or directory
/sbin/load_policy:  Can't load policy:  No such file or directory
libsemanage.semanage_reload_policy: load_policy returned error code 2.
OSError: Error
VirtualBox Guest Additions: Running kernel modules will not be replaced until 
the system is restarted      

解决办法：

$ sestatus
SELinux status:                 disabled
 
$ getenforce
Disabled
 
 
# 有的系统，文件是：/etc/sysconfig/selinux
sudo vi /etc/selinux/config
 
SELINUX=enforcing
# enforce      

重启后还是无法安装。