From patchwork Mon Oct 30 18:20:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haitao Huang X-Patchwork-Id: 13440797 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A63AFC4167B for ; Mon, 30 Oct 2023 18:20:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231709AbjJ3SUe (ORCPT ); Mon, 30 Oct 2023 14:20:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230422AbjJ3SUc (ORCPT ); Mon, 30 Oct 2023 14:20:32 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10B8EED; Mon, 30 Oct 2023 11:20:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698690029; x=1730226029; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=AEQMsn7V1pZDjP5p6/D9jve46YyOOCLObeovwu5yHLE=; b=Pg487iIpMgRZGvFFk3Ux7U0plokhVF0oMQEIb6a6rUQQJ0rWHeURIcmZ 4362ezoGVj31tmA5acj3nh4dlYPD1Z9OKoxZMq8D2gMke1P8O40a7wgCw zooXdR1I0nGeZ1ZpeYWytLrGcDxMJ7/IntkbSLaQWMpRqTyvC3O0wrrBQ C25ywTooxXMtokUbP6Ao3WzJaIu+cGFmfVbnQ9IBeVkfQ89fDHNpeyiTk E+plE4zbBKKIRN+lcXJlUKX76dO+bCketk9yyIKat7QmCEtTnKx/kTOIK QN79wPy+vFk6oZbWRPeR/gN+EebuQxhJizN7QPwrLx9EP9PkBqnSzH2q8 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10879"; a="367479513" X-IronPort-AV: E=Sophos;i="6.03,263,1694761200"; d="scan'208";a="367479513" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Oct 2023 11:20:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10879"; a="789529492" X-IronPort-AV: E=Sophos;i="6.03,263,1694761200"; d="scan'208";a="789529492" Received: from b4969161e530.jf.intel.com ([10.165.56.46]) by orsmga008.jf.intel.com with ESMTP; 30 Oct 2023 11:20:27 -0700 From: Haitao Huang To: jarkko@kernel.org, dave.hansen@linux.intel.com, tj@kernel.org, mkoutny@suse.com, linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, x86@kernel.org, cgroups@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, sohil.mehta@intel.com Cc: zhiquan1.li@intel.com, kristen@linux.intel.com, seanjc@google.com, zhanb@microsoft.com, anakrish@microsoft.com, mikko.ylinen@linux.intel.com, yangjie@microsoft.com, Haitao Huang Subject: [PATCH v6 00/12] Add Cgroup support for SGX EPC memory Date: Mon, 30 Oct 2023 11:20:01 -0700 Message-Id: <20231030182013.40086-1-haitao.huang@linux.intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org SGX Enclave Page Cache (EPC) memory allocations are separate from normal RAM allocations, and are managed solely by the SGX subsystem. The existing cgroup memory controller cannot be used to limit or account for SGX EPC memory, which is a desirable feature in some environments, e.g., support for pod level control in a Kubernates cluster on a VM or baremetal host [1,2]. This patchset implements the support for sgx_epc memory within the misc cgroup controller. The user can use the misc cgroup controller to set and enforce a max limit on total EPC usage per cgroup. The implementation reports current usage and events of reaching the limit per cgroup as well as the total system capacity. With the EPC misc controller enabled, every EPC page allocation is accounted for a cgroup's usage, reflected in the 'sgx_epc' entry in the 'misc.current' interface file of the cgroup. Much like normal system memory, EPC memory can be overcommitted via virtual memory techniques and pages can be swapped out of the EPC to their backing store (normal system memory allocated via shmem, accounted by the memory controller). When the EPC usage of a cgroup reaches its hard limit ('sgx_epc' entry in the 'misc.max' file), the cgroup starts a reclamation process to swap out some EPC pages within the same cgroup and its descendant to their backing store. Although the SGX architecture supports swapping for all pages, to avoid extra complexities, this implementation does not support swapping for certain page types, e.g. Version Array(VA) pages, and treat them as unreclaimable pages. When the limit is reached but nothing left in the cgroup for reclamation, i.e., only unreclaimable pages left, any new EPC allocation in the cgroup will result in an ENOMEM error. The EPC pages allocated for guest VMs by the virtual EPC driver are not reclaimable by the host kernel [5]. Therefore they are also treated as unreclaimable from cgroup's point of view. And the virtual EPC driver translates an ENOMEM error resulted from an EPC allocation request into a SIGBUS to the user process. This work was originally authored by Sean Christopherson a few years ago, and previously modified by Kristen C. Accardi to utilize the misc cgroup controller rather than a custom controller. I have been updating the patches based on review comments since V2 [3, 4, 10], simplified the implementation/design and fixed some stability issues found from testing. The patches are organized as following: - Patches 1-3 are prerequisite misc cgroup changes for adding new APIs, structs, resource types. - Patch 4 implements basic misc controller for EPC without reclamation. - Patches 5-9 prepare for per-cgroup reclamation. * Separate out the existing infrastructure of tracking reclaimable pages from the global reclaimer(ksgxd) to a newly created LRU list struct. * Separate out reusable top-level functions for reclamation. - Patch 10 adds support for per-cgroup reclamation. - Patch 11 adds documentation for the EPC cgroup. - Patch 12 adds test scripts. I appreciate your review and providing tags if appropriate. --- V6: - Dropped OOM killing path, only implement non-preemptive enforcement of max limit (Dave, Michal) - Simplified reclamation flow by taking out sgx_epc_reclaim_control, forced reclamation by ignoring 'age". - Restructured patches: split misc API + resource types patch and the big EPC cgroup patch (Kai, Michal) - Dropped some Tested-by/Reviewed-by tags due to significant changes - Added more selftests v5: - Replace the manual test script with a selftest script. - Restore the "From" tag for some patches to Sean (Kai) - Style fixes (Jarkko) v4: - Collected "Tested-by" from Mikko. I kept it for now as no functional changes in v4. - Rebased on to v6.6_rc1 and reordered patches as described above. - Separated out the bug fixes [7,8,9]. This series depend on those patches. (Dave, Jarkko) - Added comments in commit message to give more preview what's to come next. (Jarkko) - Fixed some documentation error, gap, style (Mikko, Randy) - Fixed some comments, typo, style in code (Mikko, Kai) - Patch format and background for reclaimable vs unreclaimable (Kai, Jarkko) - Fixed typo (Pavel) - Exclude the previous fixes/enhancements for self-tests. Patch 18 now depends on series [6] - Use the same to list for cover and all patches. (Solo) v3: - Added EPC states to replace flags in sgx_epc_page struct. (Jarkko) - Unrolled wrappers for cond_resched, list (Dave) - Separate patches for adding reclaimable and unreclaimable lists. (Dave) - Other improvements on patch flow, commit messages, styles. (Dave, Jarkko) - Simplified the cgroup tree walking with plain css_for_each_descendant_pre. - Fixed race conditions and crashes. - OOM killer to wait for the victim enclave pages being reclaimed. - Unblock the user by handling misc_max_write callback asynchronously. - Rebased onto 6.4 and no longer base this series on the MCA patchset. - Fix an overflow in misc_try_charge. - Fix a NULL pointer in SGX PF handler. - Updated and included the SGX selftest patches previously reviewed. Those patches fix issues triggered in high EPC pressure required for cgroup testing. - Added test scripts to help setup and test SGX EPC cgroups. [1]https://lore.kernel.org/all/DM6PR21MB11772A6ED915825854B419D6C4989@DM6PR21MB1177.namprd21.prod.outlook.com/ [2]https://lore.kernel.org/all/ZD7Iutppjj+muH4p@himmelriiki/ [3]https://lore.kernel.org/all/20221202183655.3767674-1-kristen@linux.intel.com/ [4]https://lore.kernel.org/linux-sgx/20230712230202.47929-1-haitao.huang@linux.intel.com/ [5]Documentation/arch/x86/sgx.rst, Section "Virtual EPC" [6]https://lore.kernel.org/linux-sgx/20220905020411.17290-1-jarkko@kernel.org/ [7]https://lore.kernel.org/linux-sgx/ZLcXmvDKheCRYOjG@slm.duckdns.org/ [8]https://lore.kernel.org/linux-sgx/20230721120231.13916-1-haitao.huang@linux.intel.com/ [9]https://lore.kernel.org/linux-sgx/20230728051024.33063-1-haitao.huang@linux.intel.com/ [10]https://lore.kernel.org/all/20230923030657.16148-1-haitao.huang@linux.intel.com/ Haitao Huang (2): x86/sgx: Introduce EPC page states selftests/sgx: Add scripts for EPC cgroup testing Kristen Carlson Accardi (5): cgroup/misc: Add per resource callbacks for CSS events cgroup/misc: Export APIs for SGX driver cgroup/misc: Add SGX EPC resource type x86/sgx: Implement basic EPC misc cgroup functionality x86/sgx: Implement EPC reclamation for cgroup Sean Christopherson (5): x86/sgx: Add sgx_epc_lru_list to encapsulate LRU list x86/sgx: Use sgx_epc_lru_list for existing active page list x86/sgx: Use a list to track to-be-reclaimed pages x86/sgx: Restructure top-level EPC reclaim function Docs/x86/sgx: Add description for cgroup support Documentation/arch/x86/sgx.rst | 74 ++++ arch/x86/Kconfig | 13 + arch/x86/kernel/cpu/sgx/Makefile | 1 + arch/x86/kernel/cpu/sgx/encl.c | 2 +- arch/x86/kernel/cpu/sgx/epc_cgroup.c | 319 ++++++++++++++++++ arch/x86/kernel/cpu/sgx/epc_cgroup.h | 49 +++ arch/x86/kernel/cpu/sgx/main.c | 245 +++++++++----- arch/x86/kernel/cpu/sgx/sgx.h | 88 ++++- include/linux/misc_cgroup.h | 42 +++ kernel/cgroup/misc.c | 52 ++- .../selftests/sgx/run_epc_cg_selftests.sh | 196 +++++++++++ .../selftests/sgx/watch_misc_for_tests.sh | 13 + 12 files changed, 996 insertions(+), 98 deletions(-) create mode 100644 arch/x86/kernel/cpu/sgx/epc_cgroup.c create mode 100644 arch/x86/kernel/cpu/sgx/epc_cgroup.h create mode 100755 tools/testing/selftests/sgx/run_epc_cg_selftests.sh create mode 100755 tools/testing/selftests/sgx/watch_misc_for_tests.sh