Re: [PATCH 4/4] selftests/sgx: Trigger the reclaimer and #PF handler

From: Reinette Chatre
Date: Tue Jul 06 2021 - 14:35:00 EST


Hi Jarkko,

On 7/5/2021 7:36 AM, Jarkko Sakkinen wrote:
Create a heap for the test enclave, which has the same size as all
available Enclave Page Cache (EPC) pages in the system. This will guarantee
that all test_encl.elf pages *and* SGX Enclave Control Structure (SECS)
have been swapped out by the page reclaimer during the load time. Actually,
this adds a bit more stress than that since part of the EPC gets reserved
for the Version Array (VA) pages.

For each test, the page fault handler gets triggered in two occasions:

- When SGX_IOC_ENCLAVE_INIT is performed, SECS gets swapped in by the
page fault handler.
- During the execution, each page that is referenced gets swapped in
by the page fault handler.


If I understand this correctly, all EPC pages are now being consumed during fixture setup and thus every SGX test, no matter how big or small, now becomes a stress test of the reclaimer instead of there being a unique reclaimer test. Since an enclave is set up and torn down for every test this seems like a significant addition. It also seems like this would impact future tests of dynamic page addition where not all scenarios could be tested with all EPC pages already consumed.

Reinette