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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 3F707C43461 for ; Fri, 11 Sep 2020 17:22:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1A25221E5 for ; Fri, 11 Sep 2020 17:22:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599844970; bh=nCJ/LEhl7wKjpj2NUqkEt2s1w9T0+lXZhzCNOn9f6bo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mlIRuvQ+ie2Ff9OfPhevvc7h+leGohEa2wWCnSMYyMMPe260xn/HIeAdg5AVkKdAe YWEGONJR3MODHS6ot3eXim84fwVJPJx1D9o2hBm7Wx/81Un3CL/JaAQLJttChkCrrb VDJDYH7tVFyJDULoZrnK1ORbKRZ6R2uWDLSTP9P4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726424AbgIKRWm (ORCPT ); Fri, 11 Sep 2020 13:22:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:52820 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726139AbgIKNAL (ORCPT ); Fri, 11 Sep 2020 09:00:11 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6F43322274; Fri, 11 Sep 2020 12:56:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599829000; bh=nCJ/LEhl7wKjpj2NUqkEt2s1w9T0+lXZhzCNOn9f6bo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NDlaiks1+CAG+F0p8o5AZIuGGK5UoFPvcLE3QNz7JdJmlesny/lbaEY27SPU7dR6j fcrnfZPIwKTUCCNxlM8Ij8qJPRW8+VSluKkdGsBovlnLLJO5ZikskP5KL1N1HFdxdA 7xkCK/KyRLtq2+dMhXXAvCUPjZdCU2DEABtT6jPA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lu Baolu , Kevin Tian , Andy Lutomirski , Jacob Pan , Ashok Raj , Joerg Roedel , Sasha Levin Subject: [PATCH 4.9 26/71] iommu/vt-d: Serialize IOMMU GCMD register modifications Date: Fri, 11 Sep 2020 14:46:10 +0200 Message-Id: <20200911122506.238456130@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200911122504.928931589@linuxfoundation.org> References: <20200911122504.928931589@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lu Baolu [ Upstream commit 6e4e9ec65078093165463c13d4eb92b3e8d7b2e8 ] The VT-d spec requires (10.4.4 Global Command Register, GCMD_REG General Description) that: If multiple control fields in this register need to be modified, software must serialize the modifications through multiple writes to this register. However, in irq_remapping.c, modifications of IRE and CFI are done in one write. We need to do two separate writes with STS checking after each. It also checks the status register before writing command register to avoid unnecessary register write. Fixes: af8d102f999a4 ("x86/intel/irq_remapping: Clean up x2apic opt-out security warning mess") Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian Cc: Andy Lutomirski Cc: Jacob Pan Cc: Kevin Tian Cc: Ashok Raj Link: https://lore.kernel.org/r/20200828000615.8281-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/intel_irq_remapping.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index ac596928f6b40..ce125ec23d2a5 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -486,12 +486,18 @@ static void iommu_enable_irq_remapping(struct intel_iommu *iommu) /* Enable interrupt-remapping */ iommu->gcmd |= DMA_GCMD_IRE; - iommu->gcmd &= ~DMA_GCMD_CFI; /* Block compatibility-format MSIs */ writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG); - IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl, (sts & DMA_GSTS_IRES), sts); + /* Block compatibility-format MSIs */ + if (sts & DMA_GSTS_CFIS) { + iommu->gcmd &= ~DMA_GCMD_CFI; + writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG); + IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, + readl, !(sts & DMA_GSTS_CFIS), sts); + } + /* * With CFI clear in the Global Command register, we should be * protected from dangerous (i.e. compatibility) interrupts -- 2.25.1