selftests/sgx: Test reclaiming of untouched page

mainline inclusion
from mainline-6.0-rc1
commit 08ceab2c
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5USAM


CVE: NA

Intel-SIG: commit 08ceab2c selftests/sgx: Test reclaiming of
untouched page.
Backport for SGX EDMM support.

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

Removing a page from an initialized enclave involves three steps:
(1) the user requests changing the page type to PT_TRIM via the
    SGX_IOC_ENCLAVE_MODIFY_TYPES ioctl()
(2) on success the ENCLU[EACCEPT] instruction is run from within
    the enclave to accept the page removal
(3) the user initiates the actual removal of the page via the
    SGX_IOC_ENCLAVE_REMOVE_PAGES ioctl().

Remove a page that has never been accessed. This means that when the
first ioctl() requesting page removal arrives, there will be no page
table entry, yet a valid page table entry needs to exist for the
ENCLU[EACCEPT] function to succeed. In this test it is verified that
a page table entry can still be installed for a page that is in the
process of being removed.

Suggested-by: Haitao Huang <haitao.huang@intel.com>
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/45e1b2a2fcd8c14597d04e40af5d8a9c1c5b017e.1652137848.git.reinette.chatre@intel.com


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