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 Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A89A4C43219 for ; Fri, 28 Jan 2022 20:29:35 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 5F5CC41D56; Fri, 28 Jan 2022 20:29:35 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7dcHrWhJm2DQ; Fri, 28 Jan 2022 20:29:34 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp4.osuosl.org (Postfix) with ESMTPS id 4010841D5B; Fri, 28 Jan 2022 20:29:34 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 29F86C001A; Fri, 28 Jan 2022 20:29:34 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 15F2DC000B for ; Fri, 28 Jan 2022 20:29:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 5657E827A5 for ; Fri, 28 Jan 2022 20:29:25 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp1.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=intel.com Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rkAlUw26yYTB for ; Fri, 28 Jan 2022 20:29:24 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by smtp1.osuosl.org (Postfix) with ESMTPS id A231083449 for ; Fri, 28 Jan 2022 20:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643401764; x=1674937764; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Zs6a0hud3tcEUziiNk3cD8a/Ewh7oEDNlHJ8E4IWhEw=; b=lKqIXX0p02GpFVC7oUDjK1/a/hEMRl4Dl3FvqZJ5TferIzjdirxUb3nI SwXF+uGP15HlyEcKtuAlo5u1ZbnWQx4MM2Y3uJWqf4JUwcifgamBSJHo+ CgK0a3SpAInKzxDxRGK/SAVRsiGF0XwGkCfZKj+Qw2x2AsdU71dql0DvB SxhBOuC3lPPwbcAKtxpiwK5UhXZkJD/BO4QyjrhdfFoLnLwCzQ75fsvhj csyLnT72WqSAAp9TK2/dkcZbYpvSz1UNJa3OOFHlIJrEaQZ8vwErUgGzO /ld2LVSGUSi24ursW/G4uw8Q2tL03TU38ckFK2su+4uP/TN88aKDCiykR w==; X-IronPort-AV: E=McAfee;i="6200,9189,10241"; a="227862451" X-IronPort-AV: E=Sophos;i="5.88,324,1635231600"; d="scan'208";a="227862451" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2022 12:29:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,324,1635231600"; d="scan'208";a="618827715" Received: from otcwcpicx3.sc.intel.com ([172.25.55.73]) by FMSMGA003.fm.intel.com with ESMTP; 28 Jan 2022 12:29:23 -0800 From: Fenghua Yu To: "Thomas Gleixner" , "Dave Hansen" , "Ingo Molnar" , "Borislav Petkov" , "Peter Zijlstra" , "Andy Lutomirski" , "Tony Luck" , "Lu Baolu" , "Joerg Roedel" , Josh Poimboeuf , "Jacob Pan" , "Ashok Raj" , "Ravi V Shankar" Subject: [PATCH v3 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel Date: Fri, 28 Jan 2022 12:29:04 -0800 Message-Id: <20220128202905.2274672-11-fenghua.yu@intel.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20220128202905.2274672-1-fenghua.yu@intel.com> References: <20220128202905.2274672-1-fenghua.yu@intel.com> MIME-Version: 1.0 Cc: Fenghua Yu , iommu@lists.linux-foundation.org, x86 , linux-kernel X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" The ENQCMD implicitly accesses the PASID_MSR to fill in the pasid field of the descriptor being submitted to an accelerator. But there is no precise (and stable across kernel changes) point at which the PASID_MSR is updated from the value for one task to the next. Kernel code that uses accelerators must always use the ENQCMDS instruction which does not access the PASID_MSR. Check for use of the ENQCMD instruction in the kernel and warn on its usage. Signed-off-by: Fenghua Yu Reviewed-by: Tony Luck Acked-by: Josh Poimboeuf --- v3: - Add Acked-by: Josh Poimboeuf v2: - Simplify handling ENQCMD (PeterZ and Josh) tools/objtool/arch/x86/decode.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index c10ef78df050..479e769ca324 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -112,7 +112,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec const struct elf *elf = file->elf; struct insn insn; int x86_64, ret; - unsigned char op1, op2, + unsigned char op1, op2, op3, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0, sib = 0, /* sib_scale = 0, */ sib_index = 0, sib_base = 0; @@ -139,6 +139,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec op1 = insn.opcode.bytes[0]; op2 = insn.opcode.bytes[1]; + op3 = insn.opcode.bytes[2]; if (insn.rex_prefix.nbytes) { rex = insn.rex_prefix.bytes[0]; @@ -491,6 +492,14 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec /* nopl/nopw */ *type = INSN_NOP; + } else if (op2 == 0x38 && op3 == 0xf8) { + if (insn.prefixes.nbytes == 1 && + insn.prefixes.bytes[0] == 0xf2) { + /* ENQCMD cannot be used in the kernel. */ + WARN("ENQCMD instruction at %s:%lx", sec->name, + offset); + } + } else if (op2 == 0xa0 || op2 == 0xa8) { /* push fs/gs */ -- 2.35.0 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu