From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: [PATCH 3/2] vfio: Provide module option to disable vfio_iommu_type1 hugepage support Date: Tue, 28 May 2013 10:27:52 -0600 Message-ID: <20130528162637.28848.76733.stgit@bling.home> References: <20130524171613.14229.84050.stgit@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, chegu_vinod-VXdhtT5mjnY@public.gmane.org To: alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org Return-path: In-Reply-To: <20130524171613.14229.84050.stgit-xdHQ/5r00wBBDLzU/O5InQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: kvm.vger.kernel.org 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;