Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934713Ab3E1Q16 (ORCPT ); Tue, 28 May 2013 12:27:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41339 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934576Ab3E1Q15 (ORCPT ); Tue, 28 May 2013 12:27:57 -0400 Subject: [PATCH 3/2] vfio: Provide module option to disable vfio_iommu_type1 hugepage support To: alex.williamson@redhat.com From: Alex Williamson Cc: kvm@vger.kernel.org, konrad.wilk@oracle.com, qemu-devel@nongnu.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, chegu_vinod@hp.com Date: Tue, 28 May 2013 10:27:52 -0600 Message-ID: <20130528162637.28848.76733.stgit@bling.home> In-Reply-To: <20130524171613.14229.84050.stgit@bling.home> References: <20130524171613.14229.84050.stgit@bling.home> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1837 Lines: 50 Add a module option to vfio_iommu_type1 to disable IOMMU hugepage support. This causes iommu_map to only be called with single page mappings, disabling the IOMMU driver's ability to use hugepages. This option can be enabled by loading vfio_iommu_type1 with disable_hugepages=1 or dynamically through sysfs. If enabled dynamically, only new mappings are restricted. Signed-off-by: Alex Williamson --- As suggested by Konrad. This is cleaner to add as a follow-on drivers/vfio/vfio_iommu_type1.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 6654a7e..8a2be4e 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -48,6 +48,12 @@ module_param_named(allow_unsafe_interrupts, MODULE_PARM_DESC(allow_unsafe_interrupts, "Enable VFIO IOMMU support for on platforms without interrupt remapping support."); +static bool disable_hugepages; +module_param_named(disable_hugepages, + disable_hugepages, bool, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(disable_hugepages, + "Disable VFIO IOMMU support for IOMMU hugepages."); + struct vfio_iommu { struct iommu_domain *domain; struct mutex lock; @@ -270,6 +276,11 @@ static long vfio_pin_pages(unsigned long vaddr, long npage, return -ENOMEM; } + if (unlikely(disable_hugepages)) { + vfio_lock_acct(1); + return 1; + } + /* Lock all the consecutive pages from pfn_base */ for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) { unsigned long pfn = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/