Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934852Ab3E1Qm0 (ORCPT ); Tue, 28 May 2013 12:42:26 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:48931 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934805Ab3E1QmZ (ORCPT ); Tue, 28 May 2013 12:42:25 -0400 Date: Tue, 28 May 2013 12:42:14 -0400 From: Konrad Rzeszutek Wilk To: Alex Williamson Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, chegu_vinod@hp.com Subject: Re: [PATCH 3/2] vfio: Provide module option to disable vfio_iommu_type1 hugepage support Message-ID: <20130528164214.GC6073@phenom.dumpdata.com> References: <20130524171613.14229.84050.stgit@bling.home> <20130528162637.28848.76733.stgit@bling.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130528162637.28848.76733.stgit@bling.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2054 Lines: 54 On Tue, May 28, 2013 at 10:27:52AM -0600, Alex Williamson wrote: > 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 Reviewed-by: Konrad Rzeszutek Wilk > --- > > 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/