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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no 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 0781EC2BA13 for ; Thu, 2 Apr 2020 06:26:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D307F2078B for ; Thu, 2 Apr 2020 06:26:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="Df6tQLD5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733174AbgDBG0h (ORCPT ); Thu, 2 Apr 2020 02:26:37 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:59802 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729282AbgDBG0g (ORCPT ); Thu, 2 Apr 2020 02:26:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1585808797; x=1617344797; h=from:to:cc:subject:date:message-id:mime-version; bh=INjASc5VYRvoGeBiJ1p7WuJDA8sR20pLeuBfaTLPg1Y=; b=Df6tQLD5wtjpoTvoInpwaM4LExd0UoPwGRuflXeC5e5OMgdJ4NElrpWH 5d7g9FVWOGwbmna1YZHvUD250czcEMqrupIIy/UgwApHBbS5ZekTw1itC IsUMYlUf4L1gLKzrV5n9viSwMUaxPMVzfiVJTEYjf7MFwg1QoyeUC0DHr A=; IronPort-SDR: 4RJ3gBK15+qT9PoWc0XeqAuscasQ/jGHssJbdfdRewIbYl2tkpcgkrtkUPDjzYoaqGrZ/0CcI0 ygl+iMIIUIgg== X-IronPort-AV: E=Sophos;i="5.72,334,1580774400"; d="scan'208";a="25215332" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-38ae4ad2.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 02 Apr 2020 06:26:24 +0000 Received: from EX13MTAUWA001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-38ae4ad2.us-east-1.amazon.com (Postfix) with ESMTPS id 4394EA30D0; Thu, 2 Apr 2020 06:26:20 +0000 (UTC) Received: from EX13D01UWA003.ant.amazon.com (10.43.160.107) by EX13MTAUWA001.ant.amazon.com (10.43.160.58) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 2 Apr 2020 06:26:20 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13d01UWA003.ant.amazon.com (10.43.160.107) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 2 Apr 2020 06:26:20 +0000 Received: from localhost (10.85.6.202) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Thu, 2 Apr 2020 06:26:19 +0000 From: Balbir Singh To: , CC: , , , , , Balbir Singh Subject: [PATCH 0/3] arch/x86: Optionally flush L1D on context switch Date: Thu, 2 Apr 2020 17:23:58 +1100 Message-ID: <20200402062401.29856-1-sblbir@amazon.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Provide a mechanisn to flush the L1D cache on context switch. The goal is to allow tasks that are paranoid due to the recent snoop assisted data sampling vulnerabilites, to flush their L1D on being switched out. This protects their data from being snooped or leaked via side channels after the task has context switched out. The core of the patches is patch 3, the first two refactor the code so that common bits can be reused. Changelog: - Refactor the code and reuse cond_ibpb() - code bits provided by tglx - Merge mm state tracking for ibpb and l1d flush - Rename TIF_L1D_FLUSH to TIF_SPEC_FLUSH_L1D Changelog RFC: - Reuse existing code for allocation and flush - Simplify the goto logic in the actual l1d_flush function - Optimize the code path with jump labels/static functions The RFC patch was previously posted at https://lore.kernel.org/lkml/20200325071101.29556-1-sblbir@amazon.com/ Balbir Singh (3): arch/x86/kvm: Refactor l1d flush lifecycle management arch/x86: Refactor tlbflush and l1d flush arch/x86: Optionally flush L1D on context switch arch/x86/include/asm/cacheflush.h | 6 ++ arch/x86/include/asm/thread_info.h | 6 +- arch/x86/include/asm/tlbflush.h | 2 +- arch/x86/include/uapi/asm/prctl.h | 3 + arch/x86/kernel/Makefile | 1 + arch/x86/kernel/l1d_flush.c | 85 +++++++++++++++++++++++++++ arch/x86/kernel/process_64.c | 10 +++- arch/x86/kvm/vmx/vmx.c | 56 +++--------------- arch/x86/mm/tlb.c | 92 +++++++++++++++++++++++------- 9 files changed, 189 insertions(+), 72 deletions(-) create mode 100644 arch/x86/kernel/l1d_flush.c -- 2.17.1