x86/sgx: Add an SGX misc driver interface

mainline inclusion
from mainline-v5.11-rc1
commit 3fe0778e
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SIGI


CVE: NA

--------------------------------

Intel(R) SGX is a new hardware functionality that can be used by
applications to set aside private regions of code and data called
enclaves. New hardware protects enclave code and data from outside
access and modification.

Add a driver that presents a device file and ioctl API to build and
manage enclaves.

 [ bp: Small touchups, remove unused encl variable in sgx_encl_find() as
   Reported-by: kernel test robot <lkp@intel.com> ]

Intel-SIG: commit 3fe0778e x86/sgx: Add an SGX misc driver interface
Backport for SGX Foundations support

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Jethro Beekman <jethro@fortanix.com>
Link: https://lkml.kernel.org/r/20201112220135.165028-12-jarkko@kernel.org


Signed-off-by: Fan Du <fan.du@intel.com> #openEuler_contributor
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Reviewed-by: Bamvor Zhang <bamvor.zhang@suse.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>