From: Reinette Chatre <reinette.chatre@intel.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: <dave.hansen@linux.intel.com>, <tglx@linutronix.de>,
<bp@alien8.de>, <luto@kernel.org>, <mingo@redhat.com>,
<linux-sgx@vger.kernel.org>, <x86@kernel.org>,
<seanjc@google.com>, <kai.huang@intel.com>,
<cathy.zhang@intel.com>, <cedric.xing@intel.com>,
<haitao.huang@intel.com>, <mark.shanahan@intel.com>,
<hpa@zytor.com>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 16/25] x86/sgx: Support modifying SGX page type
Date: Mon, 6 Dec 2021 13:48:31 -0800 [thread overview]
Message-ID: <dc74a876-54fe-5caa-6602-8887cfe34315@intel.com> (raw)
In-Reply-To: <Yav9g4+L8zg48DRf@iki.fi>
Hi Jarkko,
On 12/4/2021 3:45 PM, Jarkko Sakkinen wrote:
> On Wed, Dec 01, 2021 at 11:23:14AM -0800, Reinette Chatre wrote:
>> Every enclave contains one or more Thread Control Structures (TCS). The
>> TCS contains meta-data used by the hardware to save and restore thread
>> specific information when entering/exiting the enclave. With SGX1 an
>> enclave needs to be created with enough TCSs to support the largest
>> number of threads expecting to use the enclave and enough enclave pages
>> to meet all its anticipated memory demands. In SGX1 all pages remain in
>> the enclave until the enclave is unloaded.
>>
>> Earlier changes added support for the SGX2 feature where pages can be
>> added dynamically to an initialized enclave.
>
> Please remove this paragraph, i.e. do not tie the commit order like
> this.
Will do.
>>
>> SGX2 introduces a new function, ENCLS[EMODT], that is used to change
>> the type of an enclave page from a regular (SGX_PAGE_TYPE_REG) enclave
>> page to a TCS (SGX_PAGE_TYPE_TCS) page or change the type from a
>> regular (SGX_PAGE_TYPE_REG) or TCS (SGX_PAGE_TYPE_TCS)
>> page to a trimmed (SGX_PAGE_TYPE_TRIM) page (setting it up for later
>> removal).
>>
>> With the existing support of dynamically adding regular enclave pages
>> to an initialized enclave and changing the page type to TCS it is
>> possible to dynamically increase the number of threads supported by an
>> enclave.
>>
>> Changing the enclave page type to SGX_PAGE_TYPE_TRIM is the first step
>> of dynamically removing pages from an initialized enclave. The complete
>> page removal flow is:
>> 1) Change the type of the pages to be removed to SGX_PAGE_TYPE_TRIM
>> using the ioctl introduced here.
>> 2) Approve the page removal by running ENCLU[EACCEPT] from within
>> the enclave.
>> 3) Initiate actual page removal using the new ioctl introduced in the
>> following patch.
>>
>> Support changing SGX enclave page types with a new ioctl. With this
>
> What is "a new ioctl"? Why not just write "Add <ioctl name>""?
I do so to reduce the changes required during the ioctl naming
discussion churn.
>> ioctl the user specifies a page range and the enclave page type to be
>> applied to all pages in the provided range. The ioctl itself can return
>> an error code based on failures encountered by the OS. It is also
>> possible for SGX specific failures to be encountered. Add a result
>> output parameter to communicate the SGX return code. It is
>> possible for the enclave page type change request to fail on any page
>> within the provided range. Support partial success by returning
>> the number of pages that were successfully changed.
>>
>> After the page type is changed to SGX_PAGE_TYPE_TRIM the page continues
>> to be accessible from the OS perspective with page table entries and
>> internal state. The page may be moved to swap. Any invalid access
>> (any access except ENCLU[EACCEPT]) will encounter a page fault with
>> SGX flag set in error code until the page is removed. Removal of
>> trimmed enclave pages on user request will be supported in following
>> patch. Trimmed enclave pages are also removed when enclave is unloaded.
>>
>> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
>
> This is lacking discussion of EPCM interaction, most importanly
> .MODIFY field of an EPCM entry.
I will add that. I have the same question here as in EAUG patch - would
you like a duplicate description in this patch and a new patch that
introduces just the __emodt() wrapper or would you be ok with all new
wrappers introduced together and the detailed description of their
hardware supported flows only present in the patch that uses those wrappers?
>> ---
>> arch/x86/include/uapi/asm/sgx.h | 19 +++
>> arch/x86/kernel/cpu/sgx/ioctl.c | 235 ++++++++++++++++++++++++++++++++
>> 2 files changed, 254 insertions(+)
>>
>> diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
>> index 24bebc31e336..f70caccd166c 100644
>> --- a/arch/x86/include/uapi/asm/sgx.h
>> +++ b/arch/x86/include/uapi/asm/sgx.h
>> @@ -31,6 +31,8 @@ enum sgx_page_flags {
>> _IO(SGX_MAGIC, 0x04)
>> #define SGX_IOC_PAGE_MODP \
>> _IOWR(SGX_MAGIC, 0x05, struct sgx_page_modp)
>> +#define SGX_IOC_PAGE_MODT \
>> + _IOWR(SGX_MAGIC, 0x06, struct sgx_page_modt)
>
> I'd suggest to change this as SGX_IOC_ENCLAVE_MODIFY_TYPE.
How about SGX_IOC_ENCLAVE_MOD_TYPE to be consistent with your earlier
suggestion of SGX_IOC_ENCLAVE_MOD_PROTECTIONS ?
Reinette
next prev parent reply other threads:[~2021-12-06 21:48 UTC|newest]
Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-01 19:22 [PATCH 00/25] x86/sgx and selftests/sgx: Support SGX2 Reinette Chatre
2021-12-01 19:22 ` [PATCH 01/25] x86/sgx: Add shortlog descriptions to ENCLS wrappers Reinette Chatre
2021-12-04 18:30 ` Jarkko Sakkinen
2021-12-06 21:13 ` Reinette Chatre
2021-12-11 5:28 ` Jarkko Sakkinen
2021-12-13 22:06 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 02/25] x86/sgx: Add wrappers for SGX2 functions Reinette Chatre
2021-12-04 22:04 ` Jarkko Sakkinen
2021-12-06 21:15 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 03/25] x86/sgx: Support VMA permissions exceeding enclave permissions Reinette Chatre
2021-12-04 22:25 ` Jarkko Sakkinen
2021-12-04 22:27 ` Jarkko Sakkinen
2021-12-06 21:16 ` Reinette Chatre
2021-12-11 5:39 ` Jarkko Sakkinen
2021-12-13 22:08 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 04/25] x86/sgx: Add pfn_mkwrite() handler for present PTEs Reinette Chatre
2021-12-04 22:43 ` Jarkko Sakkinen
2021-12-06 21:18 ` Reinette Chatre
2021-12-11 7:37 ` Jarkko Sakkinen
2021-12-13 22:09 ` Reinette Chatre
2021-12-28 14:51 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 05/25] x86/sgx: Introduce runtime protection bits Reinette Chatre
2021-12-03 19:28 ` Andy Lutomirski
2021-12-03 22:12 ` Reinette Chatre
2021-12-04 0:38 ` Andy Lutomirski
2021-12-04 1:14 ` Reinette Chatre
2021-12-04 17:56 ` Andy Lutomirski
2021-12-04 23:55 ` Reinette Chatre
2021-12-13 22:34 ` Reinette Chatre
2021-12-04 23:57 ` Jarkko Sakkinen
2021-12-06 21:20 ` Reinette Chatre
2021-12-11 7:42 ` Jarkko Sakkinen
2021-12-13 22:10 ` Reinette Chatre
2021-12-28 14:52 ` Jarkko Sakkinen
2022-01-06 17:46 ` Reinette Chatre
2022-01-07 12:16 ` Jarkko Sakkinen
2022-01-07 16:14 ` Haitao Huang
2022-01-08 15:45 ` Jarkko Sakkinen
2022-01-08 15:51 ` Jarkko Sakkinen
2022-01-08 16:22 ` Jarkko Sakkinen
2022-01-10 22:05 ` Haitao Huang
2022-01-11 1:53 ` Jarkko Sakkinen
2022-01-11 1:55 ` Jarkko Sakkinen
2022-01-11 2:03 ` Jarkko Sakkinen
2022-01-11 2:15 ` Jarkko Sakkinen
2022-01-11 3:48 ` Haitao Huang
2022-01-12 23:48 ` Jarkko Sakkinen
2022-01-13 2:41 ` Haitao Huang
2022-01-14 21:36 ` Jarkko Sakkinen
2022-01-11 17:13 ` Reinette Chatre
2022-01-12 23:50 ` Jarkko Sakkinen
2022-01-12 23:56 ` Jarkko Sakkinen
2022-01-13 20:09 ` Nathaniel McCallum
2022-01-13 21:42 ` Reinette Chatre
2022-01-14 21:53 ` Jarkko Sakkinen
2022-01-14 21:57 ` Jarkko Sakkinen
2022-01-14 22:00 ` Jarkko Sakkinen
2022-01-14 22:17 ` Jarkko Sakkinen
2022-01-14 22:23 ` Jarkko Sakkinen
2022-01-14 22:34 ` Jarkko Sakkinen
2022-01-14 23:05 ` Reinette Chatre
2022-01-14 23:15 ` Jarkko Sakkinen
2022-01-15 0:01 ` Reinette Chatre
2022-01-15 0:27 ` Jarkko Sakkinen
2022-01-15 0:41 ` Reinette Chatre
2022-01-15 1:18 ` Jarkko Sakkinen
2022-01-15 11:56 ` Jarkko Sakkinen
2022-01-15 11:59 ` Jarkko Sakkinen
2022-01-17 13:13 ` Nathaniel McCallum
2022-01-18 1:59 ` Jarkko Sakkinen
2022-01-18 2:22 ` Jarkko Sakkinen
2022-01-18 3:31 ` Jarkko Sakkinen
2022-01-18 20:59 ` Reinette Chatre
2022-01-20 12:53 ` Jarkko Sakkinen
2022-01-20 16:52 ` Reinette Chatre
2022-01-26 14:41 ` Jarkko Sakkinen
2022-01-15 16:49 ` Jarkko Sakkinen
2022-01-18 21:18 ` Reinette Chatre
2022-01-17 13:27 ` Nathaniel McCallum
2022-01-18 21:11 ` Reinette Chatre
2021-12-04 22:50 ` Jarkko Sakkinen
2021-12-06 21:28 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 06/25] x86/sgx: Use more generic name for enclave cpumask function Reinette Chatre
2021-12-04 22:56 ` Jarkko Sakkinen
2021-12-06 21:29 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 07/25] x86/sgx: Move PTE zap code to separate function Reinette Chatre
2021-12-04 22:59 ` Jarkko Sakkinen
2021-12-06 21:30 ` Reinette Chatre
2021-12-11 7:52 ` Jarkko Sakkinen
2021-12-13 22:11 ` Reinette Chatre
2021-12-28 14:55 ` Jarkko Sakkinen
2022-01-06 17:46 ` Reinette Chatre
2022-01-07 12:26 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 08/25] x86/sgx: Make SGX IPI callback available internally Reinette Chatre
2021-12-04 23:00 ` Jarkko Sakkinen
2021-12-06 21:36 ` Reinette Chatre
2021-12-11 7:53 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 09/25] x86/sgx: Keep record of SGX page type Reinette Chatre
2021-12-04 23:03 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 10/25] x86/sgx: Support enclave page permission changes Reinette Chatre
2021-12-02 23:48 ` Dave Hansen
2021-12-03 18:18 ` Reinette Chatre
2021-12-03 0:32 ` Dave Hansen
2021-12-03 18:18 ` Reinette Chatre
2021-12-03 18:14 ` Dave Hansen
2021-12-03 18:49 ` Reinette Chatre
2021-12-03 19:38 ` Andy Lutomirski
2021-12-03 22:34 ` Reinette Chatre
2021-12-04 0:42 ` Andy Lutomirski
2021-12-04 1:35 ` Reinette Chatre
2021-12-04 23:08 ` Jarkko Sakkinen
2021-12-06 20:19 ` Dave Hansen
2021-12-11 5:17 ` Jarkko Sakkinen
2021-12-06 21:42 ` Reinette Chatre
2021-12-11 7:57 ` Jarkko Sakkinen
2021-12-13 22:12 ` Reinette Chatre
2021-12-28 14:56 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 11/25] selftests/sgx: Add test for EPCM " Reinette Chatre
2021-12-01 19:23 ` [PATCH 12/25] selftests/sgx: Add test for TCS page " Reinette Chatre
2021-12-01 19:23 ` [PATCH 13/25] x86/sgx: Support adding of pages to initialized enclave Reinette Chatre
2021-12-03 0:38 ` Dave Hansen
2021-12-03 18:47 ` Reinette Chatre
2021-12-04 23:13 ` Jarkko Sakkinen
2021-12-06 21:44 ` Reinette Chatre
2021-12-11 8:00 ` Jarkko Sakkinen
2021-12-13 22:12 ` Reinette Chatre
2021-12-28 14:57 ` Jarkko Sakkinen
2022-03-01 15:13 ` Jarkko Sakkinen
2022-03-01 17:08 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 14/25] x86/sgx: Tighten accessible memory range after enclave initialization Reinette Chatre
2021-12-04 23:14 ` Jarkko Sakkinen
2021-12-06 21:45 ` Reinette Chatre
2021-12-11 8:01 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 15/25] selftests/sgx: Test two different SGX2 EAUG flows Reinette Chatre
2021-12-01 19:23 ` [PATCH 16/25] x86/sgx: Support modifying SGX page type Reinette Chatre
2021-12-04 23:45 ` Jarkko Sakkinen
2021-12-06 21:48 ` Reinette Chatre [this message]
2021-12-11 8:02 ` Jarkko Sakkinen
2021-12-13 17:43 ` Dave Hansen
2021-12-21 8:52 ` Jarkko Sakkinen
2021-12-01 19:23 ` [PATCH 17/25] x86/sgx: Support complete page removal Reinette Chatre
2021-12-04 23:45 ` Jarkko Sakkinen
2021-12-06 21:49 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 18/25] selftests/sgx: Introduce dynamic entry point Reinette Chatre
2021-12-01 19:23 ` [PATCH 19/25] selftests/sgx: Introduce TCS initialization enclave operation Reinette Chatre
2021-12-01 19:23 ` [PATCH 20/25] selftests/sgx: Test complete changing of page type flow Reinette Chatre
2021-12-01 19:23 ` [PATCH 21/25] selftests/sgx: Test faulty enclave behavior Reinette Chatre
2021-12-01 19:23 ` [PATCH 22/25] selftests/sgx: Test invalid access to removed enclave page Reinette Chatre
2021-12-01 19:23 ` [PATCH 23/25] selftests/sgx: Test reclaiming of untouched page Reinette Chatre
2021-12-01 19:23 ` [PATCH 24/25] x86/sgx: Free up EPC pages directly to support large page ranges Reinette Chatre
2021-12-04 23:47 ` Jarkko Sakkinen
2021-12-06 22:07 ` Reinette Chatre
2021-12-01 19:23 ` [PATCH 25/25] selftests/sgx: Page removal stress test Reinette Chatre
2021-12-02 18:30 ` [PATCH 00/25] x86/sgx and selftests/sgx: Support SGX2 Dave Hansen
2021-12-02 20:38 ` Nathaniel McCallum
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