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 7FB7CC433E2 for ; Tue, 8 Sep 2020 19:28:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 45A9A2087D for ; Tue, 8 Sep 2020 19:28:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599593324; bh=rfQrTDsy7LmPQLr7yjcnM0Glk1dzh2rcpHJLjnpn68A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TPkfmK4UjQWlC5j8rkEywC+nTEQO9NFbTeivB6PxNNtaDiWBoEjGeKpsp0L5AQZ0F 3OwTldQxH3Ui8S5SSndZB4UXELOPjwpVC+5p9Qtk6L3Ws9A9LJusP3fCw/awPFM5uC 2kow3KJMNwhT9iX/+ATOoYTHkXNoasy+CEJ+AGvc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732209AbgIHT2l (ORCPT ); Tue, 8 Sep 2020 15:28:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:47748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731061AbgIHQAE (ORCPT ); Tue, 8 Sep 2020 12:00:04 -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 5154124692; Tue, 8 Sep 2020 15:39:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599579581; bh=rfQrTDsy7LmPQLr7yjcnM0Glk1dzh2rcpHJLjnpn68A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rg2jF/u4Pixi3JW9ygKeW5V7eb2RpRTQgeXj3o48Rgmpge3Dyy3RlYrHJPkiBFpuc KVTzmSemxKXIHfrQ3mvBdRMN/+90bih1VaNQS09Q3xEzwPxlpQiJPeYhayO6haDC5C 5NVzjnDXKu+iKwzJnjBmImlAzirtlO+ppQajA4gw= 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 5.8 110/186] iommu/vt-d: Serialize IOMMU GCMD register modifications Date: Tue, 8 Sep 2020 17:24:12 +0200 Message-Id: <20200908152246.966312595@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152241.646390211@linuxfoundation.org> References: <20200908152241.646390211@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 aa096b333a991..4828f4fe09ab5 100644 --- a/drivers/iommu/intel/irq_remapping.c +++ b/drivers/iommu/intel/irq_remapping.c @@ -507,12 +507,18 @@ 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