From patchwork Tue Sep 8 15:26:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 310045 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 3F955C433E2 for ; Tue, 8 Sep 2020 17:58:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 041182074B for ; Tue, 8 Sep 2020 17:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599587905; bh=woD0s/c+KQ9dldAxsGjx8OIeX9K9as3mRw1U7kI2VXo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nyqRYvrwsuLu+vAikZZyUPGf3rB8XdgTi+mOhmTsoXxKia1PGq3bTQohu5+U0qMxl iyvZ62EiobKcqXYbagqLd631s2UaLf/ke2tjXCr3wlycUT/iMUkVUdpaM8pr4cmf3w hyOach7snhfkIPdJNJrbwP+ToGCxmkOg44K3QlKo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732208AbgIHR6I (ORCPT ); Tue, 8 Sep 2020 13:58:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:56080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731565AbgIHQMr (ORCPT ); Tue, 8 Sep 2020 12:12:47 -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 7822A24890; Tue, 8 Sep 2020 15:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599580338; bh=woD0s/c+KQ9dldAxsGjx8OIeX9K9as3mRw1U7kI2VXo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YaXhWCk5J4dT+eWh8eFnmKdzz7vaA935Bh51aqu4Zr0BGdUcN2dfbfoBquDeY73j0 NL6Zo+n3KTaXyyNnUlVDCIis9xiAJq7SYZfganIZSY+m8FtpXJlrS21t21lv6pGQtV YsB3+pwVWwjB7rI56BYp+6ENrtug2pfu3NtNH6wI= 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 4.14 35/65] iommu/vt-d: Serialize IOMMU GCMD register modifications Date: Tue, 8 Sep 2020 17:26:20 +0200 Message-Id: <20200908152218.853442226@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152217.022816723@linuxfoundation.org> References: <20200908152217.022816723@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 7cc5b04e30b7a..09c6b17aaf80e 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -479,12 +479,18 @@ 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