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From: Reinette Chatre <reinette.chatre@intel.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>,
	linux-kselftest@vger.kernel.org, linux-sgx@vger.kernel.org,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] selftests/sgx: Trigger the reclaimer and #PF handler
Date: Tue, 6 Jul 2021 17:10:38 -0700	[thread overview]
Message-ID: <16505466-e001-c4b0-ec41-5384ddcf194b@intel.com> (raw)
In-Reply-To: <20210706235016.uucukyrr3ckk57pi@kernel.org>

Hi Jarkko,

On 7/6/2021 4:50 PM, Jarkko Sakkinen wrote:
> On Tue, Jul 06, 2021 at 11:34:54AM -0700, Reinette Chatre wrote:
>> 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
> 
> Re-initializing the test enclave is mandatory thing to do for all tests
> because it has an internals state.
> 

Right, but not all tests require the same enclave. In kselftest 
terminology I think you are attempting to force all tests to depend on 
the same test fixture. Is it not possible to have a separate "reclaimer" 
test fixture that would build an enclave with a large heap and then have 
reclaimer tests that exercise it by being tests that are specific to 
this "reclaimer fixture"?

Reinette

  reply	other threads:[~2021-07-07  0:10 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05 14:36 [PATCH 0/4] selftests/sgx: Trigger the page reclaimer and #PF handler Jarkko Sakkinen
2021-07-05 14:36 ` [PATCH 1/4] x86/sgx: Add sgx_nr_all_pages to the debugfs Jarkko Sakkinen
2021-07-06 14:56   ` Dave Hansen
2021-07-06 15:39     ` Greg KH
2021-07-06 22:08     ` Jarkko Sakkinen
2021-07-05 14:36 ` [PATCH 2/4] selftests/sgx: Fix Q1 and Q2 calculation in sigstruct.c Jarkko Sakkinen
2021-07-06 20:53   ` Dave Hansen
2021-07-06 23:52     ` Jarkko Sakkinen
2021-07-05 14:36 ` [PATCH 3/4] selftests/sgx: Assign source for each segment Jarkko Sakkinen
2021-07-05 14:36 ` [PATCH 4/4] selftests/sgx: Trigger the reclaimer and #PF handler Jarkko Sakkinen
2021-07-06 18:34   ` Reinette Chatre
2021-07-06 23:50     ` Jarkko Sakkinen
2021-07-07  0:10       ` Reinette Chatre [this message]
2021-07-07  9:17         ` Jarkko Sakkinen
2021-07-07 15:02           ` Reinette Chatre
2021-07-07 20:50             ` Jarkko Sakkinen
2021-07-07 21:20               ` Reinette Chatre
2021-07-09 16:22                 ` Jarkko Sakkinen
2021-07-07 21:20               ` Dave Hansen
2021-07-09 16:25                 ` Jarkko Sakkinen

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