From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752552AbaHKLNk (ORCPT ); Mon, 11 Aug 2014 07:13:40 -0400 Received: from david.siemens.de ([192.35.17.14]:42002 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbaHKLNi (ORCPT ); Mon, 11 Aug 2014 07:13:38 -0400 Message-ID: <53E8A555.5010905@siemens.com> Date: Mon, 11 Aug 2014 13:13:25 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Joerg Roedel , iommu , Linux Kernel Mailing List CC: Jiang Liu Subject: [PATCH] iommu/vt-d: Don't store SIRTP request Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Don't store the SIRTP request bit in the register state. It will otherwise become sticky and could request an Interrupt Remap Table Pointer update on each command register write. Found while starting to emulate IR in QEMU, not by observing problems on real hardware. Signed-off-by: Jan Kiszka --- drivers/iommu/intel_irq_remapping.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index 0df41f6..a872874 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -438,8 +438,7 @@ static void iommu_set_irq_remapping(struct intel_iommu *iommu, int mode) (addr) | IR_X2APIC_MODE(mode) | INTR_REMAP_TABLE_REG_SIZE); /* Set interrupt-remapping table pointer */ - iommu->gcmd |= DMA_GCMD_SIRTP; - writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG); + writel(iommu->gcmd | DMA_GCMD_SIRTP, iommu->reg + DMAR_GCMD_REG); IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl, (sts & DMA_GSTS_IRTPS), sts); -- 1.8.1.1.298.ge7eed54