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=unavailable 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 EC874C43461 for ; Fri, 11 Sep 2020 17:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B01D7221E7 for ; Fri, 11 Sep 2020 17:34:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599845660; bh=nCJ/LEhl7wKjpj2NUqkEt2s1w9T0+lXZhzCNOn9f6bo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mbQCq9cgsol97/qXugA52jx8DYVjGyrP6v9I3P3g3pWArlZtX42A5dVu0jx8/PqPV CtWhAX3reABrl5As99rTE93acYQwwHEwAUQdsYSp4bazhcDWaP1F6/pnaBG1ky7YJM a9pT/LP7iJed4Z67XJvHjDXdfe3EzM+YD9vClYEo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726442AbgIKReS (ORCPT ); Fri, 11 Sep 2020 13:34:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:49244 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726045AbgIKMye (ORCPT ); Fri, 11 Sep 2020 08:54:34 -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 39DC32220F; Fri, 11 Sep 2020 12:53:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599828818; bh=nCJ/LEhl7wKjpj2NUqkEt2s1w9T0+lXZhzCNOn9f6bo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q9r0F86c7pxSfxeOpPlGbG+d4YYkFf97Z4O2E8FgrCNHQVTmPN9lcGSvNLZVZ/bCT jPF4hrxMhb2CChRm4pHZJIU9aXfr4Z8xOZ+775j6LOQTw27zD72rn9twiZww/geCqP 9yj+LcETPcE4z4PjoDk7isB3azZLmvGbFFM8du1g= 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 4.4 19/62] iommu/vt-d: Serialize IOMMU GCMD register modifications Date: Fri, 11 Sep 2020 14:46:02 +0200 Message-Id: <20200911122503.354193819@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200911122502.395450276@linuxfoundation.org> References: <20200911122502.395450276@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