因为 Intel SGX 的驱动从 5.x 内核主线才开始支持，因此 5.x 以下的内核版本要使用SGX的功能，需要额外编译安装驱动。
以 Ubuntu 18.04为例，安装驱动也非常简单，从 Intel 的官网下载驱动 bin 包，直接执行即可：
$ sudo ./sgx_linux_x64_driver_1.41.bin
Unpacking Intel SGX Driver ... done.
Verifying the integrity of the install package ... done.
Installing Intel SGX Driver ...
/tmp/sgx-driver-F6eUsR ~/workspace/sgx
install -d /opt/intel/sgxdriver/package
install -d /opt/intel/sgxdriver/scripts
cp -r package/* /opt/intel/sgxdriver/package
install scripts/* /opt/intel/sgxdriver/scripts
~/workspace/sgx
Creating symlink /var/lib/DKMS/sgx/1.41/source ->
/usr/src/sgx-1.41
DKMS: add completed.
Kernel preparation unnecessary for this kernel. Skipping...
Building module:
cleaning build area...
'make' KDIR=/lib/modules/4.15.0-153-generic/build....
Signing module:
Generating a new Secure Boot signing key:
Can't load /var/lib/shim-signed/mok/.rnd into RNG
140349876240832:error:2406F079:random number generator:RAND_load_File:Cannot open file:../crypto/rand/randfile.c:88:Filename=/var/lib/shim-signed/mok/.rnd
Generating a RSA private key
...........................................................................................
......................
writing new private key to '/var/lib/shim-signed/mok/MOK.priv'
-----
- /var/lib/dkms/sgx/1.41/4.15.0-153-generic/x86_64/module/intel_sgx.ko
EFI variables are not supported on this system
/sys/firmware/efi/efivars not found, aborting.
cleaning build area...
DKMS: build completed.
intel_sgx:
Running module version sanity check.
- Original module
- No original module exists within this kernel
- Installation
- Installing to /lib/modules/4.15.0-153-generic/updates/dkms/
depmod.....
DKMS: install completed.
You may need to run "/sbin/modprobe intel_sgx (--allow-unsupported)" or reboot system manually!
uninstall.sh script generated in "/opt/intel/sgxdriver".
$
安装完成后，加载内核模块，应该能在 /dev 下看到 sgx 样的设备。如果没有，说明这款 CPU 硬件不支持 SGX。
从安装过程中可以看出 SGX 驱动安装采用了 DKMS 的方式，这是什么呢？DKMS 的全称是 Dynamic Kernel Module Support，它使一些设备商可以以源码的方式提供驱动版本，当内核升级时，会自动编译出与新内核兼容的驱动版本。
