From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E57FDC433DB for ; Sun, 21 Feb 2021 19:06:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA1C364EBE for ; Sun, 21 Feb 2021 19:06:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230477AbhBUTGd (ORCPT ); Sun, 21 Feb 2021 14:06:33 -0500 Received: from mga09.intel.com ([134.134.136.24]:2043 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230449AbhBUTCl (ORCPT ); Sun, 21 Feb 2021 14:02:41 -0500 IronPort-SDR: UIGFRNHHWs1J4zFPcAhizN39V26477eGLvSSc2TJvKECVdk40hIswCEbe7l1vtIp6LywiE8ol8 pIQem1ZmYyXg== X-IronPort-AV: E=McAfee;i="6000,8403,9902"; a="184382826" X-IronPort-AV: E=Sophos;i="5.81,195,1610438400"; d="scan'208";a="184382826" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2021 11:01:27 -0800 IronPort-SDR: A5Qb7TxBXr9iHRAmBoWgBbZrUmKrA+yUzTusT7uoZd2yqHGtgDK9kuT8VDGVpB6pSu6VlJBsgc UeWRQiyJXx/Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,195,1610438400"; d="scan'208";a="429792099" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by FMSMGA003.fm.intel.com with ESMTP; 21 Feb 2021 11:01:27 -0800 From: "Chang S. Bae" To: bp@suse.de, luto@kernel.org, tglx@linutronix.de, mingo@kernel.org, x86@kernel.org Cc: len.brown@intel.com, dave.hansen@intel.com, jing2.liu@intel.com, ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org, chang.seok.bae@intel.com Subject: [PATCH v4 07/22] x86/fpu/xstate: Calculate and remember dynamic xstate buffer sizes Date: Sun, 21 Feb 2021 10:56:22 -0800 Message-Id: <20210221185637.19281-8-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210221185637.19281-1-chang.seok.bae@intel.com> References: <20210221185637.19281-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The xstate buffer is currently embedded into struct fpu with static size. To accommodate dynamic user xstates, record the maximum and minimum buffer sizes. Rename the size calculation function. It calculates the maximum xstate size and sanity checks it with CPUID. It also calculates the static embedded buffer size by excluding the dynamic user states from the maximum size. Signed-off-by: Chang S. Bae Reviewed-by: Len Brown Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from v3: * Updated the changelog. (Borislav Petkov) * Updated the code comment. (Borislav Petkov) * Adjusted the calculation function naming. * Moved out the new variable addition into a new patch. Changes from v2: * Updated the changelog with task->fpu removed. (Borislav Petkov) * Renamed the in-line size variable. * Updated some code comments. --- arch/x86/kernel/fpu/xstate.c | 52 +++++++++++++++++++++++------------- 1 file changed, 33 insertions(+), 19 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 16379c368714..b7686f107f3a 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -655,23 +655,31 @@ static void check_xstate_against_struct(int nr) } /* - * This essentially double-checks what the cpu told us about - * how large the XSAVE buffer needs to be. We are recalculating - * it to be safe. + * Calculate the xstate per-task buffer sizes -- maximum and minimum. + * + * And record the minimum. Also double-check the maximum against what + * the cpu told. + * + * Dynamic user states are stored in this buffer. They account for the + * delta between the maximum and the minimum. * * Dynamic supervisor XSAVE features allocate their own buffers and are - * not covered by these checks. Only the size of the buffer for task->fpu - * is checked here. + * not covered by these checks. */ -static void do_extra_xstate_size_checks(void) +static void calculate_xstate_sizes(void) { - int paranoid_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + int paranoid_min_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + int paranoid_max_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; int i; for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { + bool user_dynamic; + if (!xfeature_enabled(i)) continue; + user_dynamic = (xfeatures_mask_user_dynamic & BIT_ULL(i)) ? true : false; + check_xstate_against_struct(i); /* * Supervisor state components can be managed only by @@ -681,23 +689,32 @@ static void do_extra_xstate_size_checks(void) XSTATE_WARN_ON(xfeature_is_supervisor(i)); /* Align from the end of the previous feature */ - if (xfeature_is_aligned(i)) - paranoid_xstate_size = ALIGN(paranoid_xstate_size, 64); + if (xfeature_is_aligned(i)) { + paranoid_max_size = ALIGN(paranoid_max_size, 64); + if (!user_dynamic) + paranoid_min_size = ALIGN(paranoid_min_size, 64); + } /* * The offset of a given state in the non-compacted * format is given to us in a CPUID leaf. We check * them for being ordered (increasing offsets) in * setup_xstate_features(). */ - if (!using_compacted_format()) - paranoid_xstate_size = xfeature_uncompacted_offset(i); + if (!using_compacted_format()) { + paranoid_max_size = xfeature_uncompacted_offset(i); + if (!user_dynamic) + paranoid_min_size = xfeature_uncompacted_offset(i); + } /* * The compacted-format offset always depends on where * the previous state ended. */ - paranoid_xstate_size += xfeature_size(i); + paranoid_max_size += xfeature_size(i); + if (!user_dynamic) + paranoid_min_size += xfeature_size(i); } - XSTATE_WARN_ON(paranoid_xstate_size != get_xstate_config(XSTATE_MAX_SIZE)); + XSTATE_WARN_ON(paranoid_max_size != get_xstate_config(XSTATE_MAX_SIZE)); + set_xstate_config(XSTATE_MIN_SIZE, paranoid_min_size); } @@ -798,14 +815,11 @@ static int __init init_xstate_size(void) */ set_xstate_config(XSTATE_MAX_SIZE, possible_xstate_size); - /* Perform an extra check for the maximum size. */ - do_extra_xstate_size_checks(); - /* - * Set the minimum to be the same as the maximum. The dynamic - * user states are not supported yet. + * Calculate and double-check the maximum size. Calculate and record + * the minimum size. */ - set_xstate_config(XSTATE_MIN_SIZE, possible_xstate_size); + calculate_xstate_sizes(); /* Ensure the minimum size fits in the statically-alocated buffer: */ if (!is_supported_xstate_size(get_xstate_config(XSTATE_MIN_SIZE))) -- 2.17.1