Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933843AbdGTEdH (ORCPT ); Thu, 20 Jul 2017 00:33:07 -0400 Received: from mail-qk0-f174.google.com ([209.85.220.174]:33805 "EHLO mail-qk0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933782AbdGTEdE (ORCPT ); Thu, 20 Jul 2017 00:33:04 -0400 From: Anup Patel To: Will Deacon , Robin Murphy , Joerg Roedel , Baptiste Reynal , Alex Williamson Cc: Scott Branden , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, Anup Patel Subject: [PATCH v2 1/2] vfio: Allow No-IOMMU mode without checking iommu_present() Date: Thu, 20 Jul 2017 10:02:33 +0530 Message-Id: <1500525154-5200-2-git-send-email-anup.patel@broadcom.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1500525154-5200-1-git-send-email-anup.patel@broadcom.com> References: <1500525154-5200-1-git-send-email-anup.patel@broadcom.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1351 Lines: 37 Not allowing No-IOMMU mode for devices already having iommu_ops on their bus is very conservative. We now have IOMMU (such as ARM SMMU) which can bypass transcations when IOMMU is not configured for a given device. In addition, it is not necessary to have all devices on bus to be upstream to an IOMMU on that bus. Due above reasons, having iommu_present() check for VFIO No-IOMMU mode is not appropriate. Signed-off-by: Anup Patel --- drivers/vfio/vfio.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 330d505..9d90de7 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -124,11 +124,10 @@ struct iommu_group *vfio_iommu_group_get(struct device *dev) #ifdef CONFIG_VFIO_NOIOMMU /* * With noiommu enabled, an IOMMU group will be created for a device - * that doesn't already have one and doesn't have an iommu_ops on their - * bus. We set iommudata simply to be able to identify these groups - * as special use and for reclamation later. + * that doesn't already have one. We set iommudata simply to be able + * to identify these groups as special use and for reclamation later. */ - if (group || !noiommu || iommu_present(dev->bus)) + if (group || !noiommu) return group; group = iommu_group_alloc(); -- 2.7.4