selftests/sgx: Page removal stress test

mainline inclusion
from mainline-6.0-rc1
commit 6507cce5
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5USAM


CVE: NA

Intel-SIG: commit 6507cce5 selftests/sgx: Page removal stress test.
Backport for SGX EDMM support.

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

Create enclave with additional heap that consumes all physical SGX
memory and then remove it.

Depending on the available SGX memory this test could take a
significant time to run (several minutes) as it (1) creates the
enclave, (2) changes the type of every page to be trimmed,
(3) enters the enclave once per page to run EACCEPT, before
(4) the pages are finally removed.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/e7c6aa2ab30cb1c41e52b776958409c06970d168.1652137848.git.reinette.chatre@intel.com


Signed-off-by: Zhiquan Li <zhiquan1.li@intel.com>