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

Reinette Chatre
2021-07-06T18:34:59Z

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